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Luben TJ, Shaffer RM, Kenyon E, Nembhard WN, Weber KA, Nuckols J, Wright JM. Comparison of Trihalomethane exposure assessment metrics in epidemiologic analyses of reproductive and developmental outcomes. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2024; 34:115-125. [PMID: 37316533 DOI: 10.1038/s41370-023-00559-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/12/2023] [Accepted: 05/31/2023] [Indexed: 06/16/2023]
Abstract
BACKGROUND Researchers have developed exposure assessment metrics for disinfection by-products (DBPs) utilizing drinking water monitoring data and accounting for spatial and temporal variability, water consumption, and showering and bathing time with an expectation of decreasing exposure misclassification compared to the use of measured concentrations at public water supply (PWS) monitoring locations alone. OBJECTIVE We used exposure data collected for a previous study of DBPs to evaluate how different sources of information impact trihalomethane (THM) exposure estimates. METHODS We compared gestational exposure estimates to THMs based on water utility monitoring data alone, statistical imputation of daily concentrations to incorporate temporal variability, and personal water consumption and use (bathing and showering). We used Spearman correlation coefficients and ranked kappa statistics to compare exposure classifications. RESULTS Exposure estimates based on measured or imputed daily THM concentrations, self-reported consumption, or bathing and showering differed substantially from estimates based solely on concentrations from PWS quarterly monitoring reports. Ranked exposure classifications, high to low quartiles or deciles, were generally consistent across each exposure metric (i.e., a subject with "high" exposure based on measured or imputed THM concentrations generally remained in the "high" category across exposure metrics.) The measured concentrations and imputed daily (i.e., spline regression) concentrations were highly correlated (r = 0.98). The weighted kappa statistics comparing exposure estimates using different exposure metrics ranged from 0.27 to 0.89, with the highest values for the ingestion + bathing/showering metrics compared to metrics for bathing/showering only (0.76 and 0.89). Bathing and showering contributed the most to "total" THM exposure estimates. IMPACT STATEMENT We compare exposure metrics capturing temporal variability and multiple estimates of personal THM exposure with THM concentrations from PWS monitoring data. Our results show exposure estimates based on imputed daily concentrations accounting for temporal variability were very similar to the measured THM concentrations. We observed low agreement between imputed daily concentrations and ingestion-based estimates. Considering additional routes of exposure (e.g., inhalation and dermal) slightly increased agreement with the measured PWS exposure estimate in this population. Overall, the comparison of exposure assessment metrics allows researchers to understand the added value of additional data collection for future epidemiologic analyses of DBPs.
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Affiliation(s)
- Thomas J Luben
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency. RTP, NC, Washington, DC, Cincinnati, OH, USA.
| | - Rachel M Shaffer
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency. RTP, NC, Washington, DC, Cincinnati, OH, USA
| | - Elaina Kenyon
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, RTP, RTP, NC, USA
| | - Wendy N Nembhard
- Arkansas Center for Birth Defects Research and Prevention and the Department of Epidemiology, Fay. W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Kari A Weber
- Arkansas Center for Birth Defects Research and Prevention and the Department of Epidemiology, Fay. W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - John Nuckols
- Colorado State University, Fort Collins, CO, USA; JRN Environmental Health Sciences, LTD, North Bethesda, MD, USA
| | - J Michael Wright
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency. RTP, NC, Washington, DC, Cincinnati, OH, USA
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Xiao C, Wang C, Zhang Q, Yang X, Huang S, Luo Y, Feng Y, Zheng Q. Transcriptomic analysis of adult zebrafish heart and brain in response to 2, 6-dichloro-1, 4-benzoquinone exposure. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 226:112835. [PMID: 34600292 DOI: 10.1016/j.ecoenv.2021.112835] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/14/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Halobenzoquinones (HBQs) are emerging and widespread disinfection byproducts (DBPs), but their toxicological mechanisms to aquatic organisms remain elusive. Herein, we evaluated oxidative stress, cardiac toxicity, and cerebral toxicity after 2, 6-dichloro-1, 4-benzoquinone (2,6-DCBQ) exposure in zebrafish. Adult zebrafish were respectively exposed to 0.25, 0.5, and 1 μM 2,6-DCBQ for 96 h. The mortality rate of 2,6-DCBQ (1 μM) was 10%, while the LC50 value was 1.532 μM. Besides, 2,6-DCBQ exposure caused irregularity and elimination of myocardial fiber in the heart, and the pyknosis of nuclears and the agglutination of chromatin in the brain. We measured the 2,6-DCBQ-induced oxidative stresses in the heart and brain. Additionally, the glutathione (GSH) content, superoxide dismutase (SOD) activity, catalase (CAT) activity, and total antioxidant capacity (T-AOC) were significantly inhibited. To better understand the potential toxicity of 2,6-DCBQ, transcriptomic analysis was performed in the control and 1 μM group after 96 h exposure. As a result, 545 and 1228 differentially expressed genes (DEGs) were detected in the heart and brain, respectively. GO analysis revealed that these DEGs were primarily enriched in blood vessel development, vasculature development, and oxidoreductase activity in the heart; response to stimulus, nervous system development, and oxidoreductase activity in the brain. KEGG enrichment analysis indicated that the DEGs were mainly enriched in VEGF signaling pathway and vascular smooth muscle contraction pathway in the heart; neuroactive ligand-receptor interaction, and NOD-like receptor signaling pathway in the brain. These findings exposed the underlying toxicity mechanism of 2,6-DCBQ exposure on zebrafish cardiovascular and brain systems.
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Affiliation(s)
- Chen Xiao
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Chang Wang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China.
| | - Qiwei Zhang
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China
| | - Xiaoqiu Yang
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China
| | - Shiqi Huang
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China
| | - Yinjian Luo
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China
| | - Yunfeng Feng
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China
| | - Qi Zheng
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environment Engineering, Jianghan University, Wuhan 430056, China.
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Säve-Söderbergh M, Toljander J, Donat-Vargas C, Åkesson A. Drinking Water Disinfection by-Products and Congenital Malformations: A Nationwide Register-Based Prospective Study. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:97012. [PMID: 34585603 PMCID: PMC8480150 DOI: 10.1289/ehp9122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/19/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Drinking water chlorination by-products have been associated with adverse reproductive outcomes, although the findings for congenital malformations are still inconclusive. OBJECTIVE We conducted a nationwide register-based prospective study to assess whether first trimester maternal exposure to the four most common trihalomethanes [total trihalomethanes (TTHM)] via municipal drinking water was associated with risk of congenital malformation among newborns. METHODS We included all births during 2005-2015 (live and stillbirths) of mothers residing in Swedish localities having >10,000 inhabitants, two or fewer operating water works, and sufficient municipal TTHM monitoring data. Individual maternal first trimester exposure was obtained by linking TTHM measurements to residential information, categorized into no chlorination and <5, 5-15, and >15μg TTHM/L. We also made chlorination treatment-specific analyses (exclusive use of chloramine or hypochlorite). Outcomes and covariates were obtained via linkage to health care and administrative registers. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. RESULTS Based on 623,468 births and a prevalence of congenital malformation of ∼2 cases/100 births, we observed associations between TTHM exposure in areas using chloramine and malformations of the nervous system (OR=1.82; 95% CI: 1.07, 3.12), urinary system (OR=2.06; 95% CI: 1.53, 2.78), genitals (OR=1.77; 95% CI: 1.38, 2.26), and limbs (OR=1.34; 95% CI: 1.10, 1.64), comparing the highest exposed category with the unexposed. No associations were observed in areas using exclusively hypochlorite as the primary water treatment method. By contrast, for malformations of the heart, a significant inverse association was observed only in areas using hypochlorite. DISCUSSION TTHM exposure was associated with the increased risk of malformations of the nervous system, urinary system, genitals, and limbs in areas exclusively using chloramine. An association between chloramine-related chlorination by-products and congenital malformations has not previously been highlighted and needs further attention. https://doi.org/10.1289/EHP9122.
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Affiliation(s)
- Melle Säve-Söderbergh
- Science Division, Swedish Food Agency, Uppsala, Sweden
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Carolina Donat-Vargas
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
- Instituto Madrileño de Estudios Avanzados (IMDEA)-Alimentación, Campus of International Excellence, Universidad Autónoma de Madrid + Consejo Superior de Investigaciones Científicas (CEI UAM+CSIC), Madrid, Spain
| | - Agneta Åkesson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Summerhayes RJ, Rahman B, Morgan GG, Beresin G, Moreno C, Wright JM. Meta-analysis of small for gestational age births and disinfection byproduct exposures. ENVIRONMENTAL RESEARCH 2021; 196:110280. [PMID: 33035558 DOI: 10.1016/j.envres.2020.110280] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Some epidemiological studies show associations between disinfection byproducts (DBPs) and adverse developmental outcomes. OBJECTIVES We undertook a meta-analysis of epidemiological studies on maternal exposure to trihalomethanes (THMs) and haloacetic acids (HAAs) and risk of small for gestational age (SGA) birth. METHODS We identified forty-five publications including two reports and five theses via a 2020 literature search. Nineteen study populations from 16 publications met the inclusion criteria and were systematically evaluated. Effect measures were pooled using random effects meta-analytic methods along with cumulative, sub-group and meta-regression analyses to examine between-study heterogeneity and variation in risk across different DBP measures. RESULTS We detected a small increased risk for SGA with exposure to the sum of four (i.e., THM4) THM4 (odds ratio (OR) = 1.07; 95%CI: 1.03, 1.11), chloroform (OR = 1.05; 95%CI: 1.01, 1.08), bromodichloromethane (OR = 1.08; 95%CI: 1.05, 1.11) and the sum of the brominated THM4 (OR = 1.05; 95%CI: 1.02, 1.09). Larger ORs were detected for the sum of five haloacetic acids (i.e., HAA5) (OR = 1.12; 95%CI: 1.01, 1.25), dichloroacetic acid (OR = 1.25; 95%CI: 1.01, 1.41) and trichloroacetic acid (OR = 1.21; 95%CI: 1.07, 1.37). We detected larger SGA risks for several THM4 among the prospective cohort and case-control studies compared to retrospective cohorts and for the SGA3/5% (vs. SGA10%) studies. The THM4 meta-regression showed associations between SGA and the total quality score based on categorical or continuous measures. For example, an OR of 1.03 (95%CI: 1.01, 1.06) was detected for each 10-point increase in the study quality score based on our systematic review. CONCLUSIONS We detected a small increased risk of SGA based on 18 THM4 study populations that was comparable to a previous meta-analysis of eight THM4 study populations. We also found increased risks for other THM4 and HAA measures not previously examined; these results were robust after accounting for outliers, publication bias, type of SGA classification, different exposure windows, and other factors.
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Affiliation(s)
| | - B Rahman
- University of Sydney, School of Public Health and University Centre for Rural Health, Australia
| | - G G Morgan
- University of Sydney, School of Public Health and University Centre for Rural Health, Australia
| | - G Beresin
- Massachusetts Department of Public Health, USA
| | - C Moreno
- Oak Ridge Associated Universities, USA
| | - J M Wright
- US EPA, Center for Public Health and Environmental Assessment, USA.
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Kim DH, Park CG, Kim YJ. Characterizing the potential estrogenic and androgenic activities of two disinfection byproducts, mono-haloacetic acids and haloacetamides, using in vitro bioassays. CHEMOSPHERE 2020; 242:125198. [PMID: 31689635 DOI: 10.1016/j.chemosphere.2019.125198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
Exposure to disinfection byproducts (DBPs) is potentially related to cytotoxic, genotoxic, mutagenic, and tumorigenic effects in humans, in addition to their adverse effects on the environment. However, their impacts on endocrine disruption, especially reproductive toxicity, remain largely unknown. In this study, the estrogenic and androgenic activities of DBPs and corresponding antagonistic activities were investigated using a yeast-based reporter assay, focusing on haloacetic acids and haloacetamides. We also examined the cytotoxicity of DBPs and mechanisms of antagonistic activities. Of the DBPs assayed, iodoacetamide (IAM) and bromoacetamide (BAM) were the most cytotoxic, with LC50 values of 0.0462 and 0.0537 mM, respectively, followed by chloroacetic acid (CAA; LC50 = 4.87 mM) and chloroacetamide (CAM; LC50 = 5.28 mM). Iodoacetic acid (IAA) and bromoacetic acid (BAA) were the least cytotoxic, with LC50 values of 5.52 and 6.35 mM, respectively. IAA (EC10 = 0.00573 mM; EC50 = 0.0215 mM) exhibited most potent estrogenic activity, and CAA (EC10 = 0.0434 mM) and BAM (EC10 = 0.0150 mM) showed weak estrogenic and androgenic activities, respectively. By contrast, IAM exhibited anti-estrogenic effects. These results suggest that DBPs interact with hormone receptors.
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Affiliation(s)
- Da-Hye Kim
- Environmental Safety Group, Korea Institute of Science and Technology (KIST)Europe, Saarbrucken, 66123, Germany
| | - Chang Gyun Park
- Environmental Safety Group, Korea Institute of Science and Technology (KIST)Europe, Saarbrucken, 66123, Germany
| | - Young Jun Kim
- Environmental Safety Group, Korea Institute of Science and Technology (KIST)Europe, Saarbrucken, 66123, Germany.
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6
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Weyer P, Rhoads A, Suhl J, Luben TJ, Conway KM, Langlois PH, Shen D, Liang D, Puzhankara S, Anderka M, Bell E, Feldkamp ML, Hoyt AT, Mosley B, Reefhuis J, Romitti PA. Drinking water disinfection byproducts and risk of orofacial clefts in the National Birth Defects Prevention Study. Birth Defects Res 2019; 110:1027-1042. [PMID: 30133956 DOI: 10.1002/bdr2.1348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/13/2018] [Accepted: 04/20/2018] [Indexed: 01/05/2023]
Abstract
BACKGROUND Maternal exposure to drinking water disinfection byproducts (DBP)s may contribute to orofacial cleft (OFC) development, but studies are sparse and beset with limitations. METHODS Population-based, maternal interview reports of drinking water filtration and consumption for 680 OFC cases (535 isolated) and 1826 controls were linked with DBP concentration data using maternal residential addresses and public water system monitoring data. Maternal individual-level exposures to trihalomethanes (THM)s and haloacetic acids (HAA)s (µg/L of water consumed) were estimated from reported consumption at home, work, and school. Compared to no exposure, associations with multisource maternal exposure <1/2 or ≥1/2 the Maximum Contaminant Levels (MCL)s for total THMs (TTHM)s and HAAs (HAA5) or Maximum Contaminant Level Goals (MCLG)s for individual THMs and HAAs (if non-zero) were estimated for all OFCs and isolated OFCs, cleft palate (CP), and cleft lip ± cleft palate (CL/P) using logistic regression analyses. RESULTS Compared to controls, associations were near or below unity for maternal TTHM, HAA5, and individual THM exposures with all OFCs and isolated OFCs, CP, and CL/P. Associations also were near or below unity for individual HAAs with statistically significant, inverse associations observed with each OFC outcome group except CL/P. CONCLUSIONS This study examined associations for maternal reports of drinking water filtration and consumption and maternal DBP exposure from drinking water with OFCs in offspring. Associations observed were near or below unity and mostly nonsignificant. Continued, improved research using maternal individual-level exposure data will be useful in better characterizing these associations.
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Affiliation(s)
- Peter Weyer
- Center for Health Effects of Environmental Contamination, Office of the Vice President for Research and Economic Development, University of Iowa, Iowa City, Iowa
| | - Anthony Rhoads
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Jonathan Suhl
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Thomas J Luben
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Kristin M Conway
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Peter H Langlois
- Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Austin, Texas
| | - Dereck Shen
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Dong Liang
- Environmental Statistics Collaborative, Chesapeake Biological Laboratories, University of Maryland Center for Environmental Science, Solomons, Maryland
| | - Soman Puzhankara
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Marlene Anderka
- Center for Birth Defects Research and Prevention at the Massachusetts Department of Public Health, Boston, Massachusetts
| | - Erin Bell
- Department of Epidemiology and Biostatistics, School of Public Health, State University of New York at Albany, Rensselaer, New York
| | - Marcia L Feldkamp
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Adrienne T Hoyt
- Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Austin, Texas
| | - Bridget Mosley
- Department of Pediatrics, Arkansas Children's Hospital, Little Rock, Arkansas
| | - Jennita Reefhuis
- Division of Congenital and Developmental Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Paul A Romitti
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
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Ackerson NOB, Killinger AH, Liberatore HK, Ternes TA, Plewa MJ, Richardson SD, Duirk SE. Impact of chlorine exposure time on disinfection byproduct formation in the presence of iopamidol and natural organic matter during chloramination. J Environ Sci (China) 2019; 78:204-214. [PMID: 30665639 DOI: 10.1016/j.jes.2018.09.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 06/09/2023]
Abstract
Chloramines, in practice, are formed onsite by adding ammonia to chlorinated drinking water to achieve the required disinfection. While regulated disinfection byproducts (DBPs) are reduced during chloramine disinfection, other DBPs such as iodinated (iodo-) DBPs, that elicit greater toxicity are formed. The objective of this study was to investigate the impact of prechlorination time on the formation of both halogen-specific total organic halogen (TOX) and iodo/chlorinated (chloro-) DBPs during prechlorination/chloramination in source waters (SWs) containing iopamidol, an X-ray contrast medium. Barberton SW (BSW) and Cleveland SW (CSW) containing iopamidol were prechlorinated for 5-60 min and afterwards chloraminated for 72 hr with ammonium chloride. Chlorine contact time (CCT) did not significantly impact total organic iodine (TOI) concentrations after prechlorination or chloramination. Concentrations of total organic chlorine (TOCl) formed during prechlorination did not significantly change regardless of pH and prechlorination time, while TOCl appeared to decrease after 72 hr chloramination period. Dichloroiodomethane (CHCl2I) formation during prechlorination did not exhibit any significant trends as a function of pH or CCT, but after chloramination, significant increases were observed at pHs 6.5 and 7.5 with respect to CCT. Iodo-HAAs were not formed during prechlorination but were detected after chloramination. Significant quantities of chloroform (CHCl3) and trichloroacetic acid (TCAA) were formed during prechlorination but formation ceased upon ammonia addition. Therefore, prechlorination studies should measure TOX and DBP concentrations prior to ammonia addition to obtain data regarding the initial conditions.
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Affiliation(s)
| | - Alexis H Killinger
- Department of Civil Engineering, University of Akron, Akron, OH 44325, USA
| | - Hannah K Liberatore
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, SC 29208, USA
| | - Thomas A Ternes
- Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, D-56068 Koblenz, Germany
| | - Michael J Plewa
- Department of Crop Sciences and Safe Global Water Institute and NSF Science and Technology Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana-Champaign, 1101 West Peabody Drive, Urbana, IL 61801, USA
| | - Susan D Richardson
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, SC 29208, USA
| | - Stephen E Duirk
- Department of Civil Engineering, University of Akron, Akron, OH 44325, USA.
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Williams AL, Bates CA, Pace ND, Leonhard MJ, Chang ET, DeSesso JM. Impact of chloroform exposures on reproductive and developmental outcomes: A systematic review of the scientific literature. Birth Defects Res 2018; 110:1267-1313. [PMID: 30350414 DOI: 10.1002/bdr2.1382] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 06/26/2018] [Accepted: 07/27/2018] [Indexed: 12/26/2022]
Abstract
AIMS We assessed the animal and epidemiological data to determine if chloroform exposure causes developmental and/or reproductive toxicity. RESULTS AND DISCUSSION Initial scoping identified developmental toxicity as the primary area of concern. At levels producing maternal toxicity in rats and mice, chloroform caused decrements in fetal weights and associated delays in ossification. In a single mouse inhalation study, exposure to a high concentration of chloroform was associated with small fetuses and increased cleft palate. However, oral exposure of mice to chloroform at a dose 4 times higher was negative for cleft palate; multiple inhalation studies in rats were also negative. Epidemiologic data on low birth weight and small for gestational age were generally equivocal, preventing conclusions from being drawn for humans. The animal data also show evidence of very early (peri-implantation) total litter losses at very high exposure levels. This effect is likely maternally mediated rather than a direct effect on the offspring. Finally, the epidemiologic data indicate a possible association of higher chloroform exposure with lower risk of preterm birth (<37 weeks gestation). CONCLUSIONS The available animal data suggest that exposures lower than those causing maternal toxicity should be without developmental effects in the offspring. Also, most studies in humans rely on group-level geographic exposure data, providing only weak epidemiologic evidence for an association with development outcomes and fail to establish a causal role for chloroform in the induction of adverse developmental outcomes at environmentally relevant concentrations.
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Affiliation(s)
| | | | | | | | | | - John M DeSesso
- Exponent, Inc., Alexandria, Virginia.,Georgetown University School of Medicine, Washington, District of Columbia
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9
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Dong S, Page MA, Wagner ED, Plewa MJ. Thiol Reactivity Analyses To Predict Mammalian Cell Cytotoxicity of Water Samples. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:8822-8829. [PMID: 29965743 DOI: 10.1021/acs.est.8b01675] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An in chemico high throughput assay based on N-acetylcysteine was developed and used in conjunction with previous and new mammalian cell cytotoxicity data. Our objective was to derive an empirical equation with confidence levels for mammalian cell cytotoxicity prediction. Modeling data included 16 unique sources of waters and wastewaters of distinct water qualities to encompass a wide range of real environmental samples. This approach provides a quick screen to identify those water and wastewaters that could be prioritized for in depth analytical biological analyses and toxicity. The resulting model can serve as a preliminary convenient tool to screen for potential mammalian cell cytotoxicity in organic extracts of a wide variety of water samples.
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Affiliation(s)
| | - Martin A Page
- US Army Engineer Research and Development Center , 2902 Newmark Drive , Champaign , Illinois 61822 , United States
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10
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Parvez S, Rice GE, Teuschler LK, Simmons JE, Speth TF, Richardson SD, Miltner RJ, Hunter ES, Pressman JG, Strader LF, Klinefelter GR, Goldman JM, Narotsky MG. Method to assess component contribution to toxicity of complex mixtures: Assessment of puberty acquisition in rats exposed to disinfection byproducts. J Environ Sci (China) 2017; 58:311-321. [PMID: 28774622 PMCID: PMC8343928 DOI: 10.1016/j.jes.2017.05.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/19/2017] [Accepted: 05/31/2017] [Indexed: 05/04/2023]
Abstract
A method based on regression modeling was developed to discern the contribution of component chemicals to the toxicity of highly complex, environmentally realistic mixtures of disinfection byproducts (DBPs). Chemical disinfection of drinking water forms DBP mixtures. Because of concerns about possible reproductive and developmental toxicity, a whole mixture (WM) of DBPs produced by chlorination of a water concentrate was administered as drinking water to Sprague-Dawley (S-D) rats in a multigenerational study. Age of puberty acquisition, i.e., preputial separation (PPS) and vaginal opening (VO), was examined in male and female offspring, respectively. When compared to controls, a slight, but statistically significant delay in puberty acquisition was observed in females but not in males. WM-induced differences in the age at puberty acquisition were compared to those reported in S-D rats administered either a defined mixture (DM) of nine regulated DBPs or individual DBPs. Regression models were developed using individual animal data on age at PPS or VO from the DM study. Puberty acquisition data reported in the WM and individual DBP studies were then compared with the DM models. The delay in puberty acquisition observed in the WM-treated female rats could not be distinguished from delays predicted by the DM regression model, suggesting that the nine regulated DBPs in the DM might account for much of the delay observed in the WM. This method is applicable to mixtures of other types of chemicals and other endpoints.
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Affiliation(s)
- Shahid Parvez
- Indiana University Richard M. Fairbanks School of Public Health, Department of Environmental Health Sciences, IUPUI Campus, Indianapolis, IN 46202, USA
| | - Glenn E Rice
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
| | | | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Thomas F Speth
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Susan D Richardson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Richard J Miltner
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - E Sidney Hunter
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jonathan G Pressman
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Lillian F Strader
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Gary R Klinefelter
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jerome M Goldman
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Michael G Narotsky
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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11
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Plewa MJ, Wagner ED, Richardson SD. TIC-Tox: A preliminary discussion on identifying the forcing agents of DBP-mediated toxicity of disinfected water. J Environ Sci (China) 2017; 58:208-216. [PMID: 28774611 DOI: 10.1016/j.jes.2017.04.014] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/17/2017] [Accepted: 04/17/2017] [Indexed: 05/21/2023]
Abstract
The disinfection of drinking water is a major public health achievement; however, an unintended consequence of disinfection is the generation of disinfection by-products (DBPs). Many of the identified DBPs exhibit in vitro and in vivo toxicity, generate a diversity of adverse biological effects, and may be hazards to the public health and the environment. Only a few DBPs are regulated by several national and international agencies and it is not clear if these regulated DBPs are the forcing agents that drive the observed toxicity and their associated health effects. In this study, we combine analytical chemical and biological data to resolve the forcing agents associated with mammalian cell cytotoxicity of drinking water samples from three cities. These data suggest that the trihalomethanes (THMs) and haloacetic acids may be a small component of the overall cytotoxicity of the organic material isolated from disinfected drinking water. Chemical classes of nitrogen-containing DBPs, such as the haloacetonitriles and haloacetamides, appear to be the major forcing agents of toxicity in these samples. These findings may have important implications for the design of epidemiological studies that primarily rely on the levels of THMs to define DBP exposure among populations. The TIC-Tox approach constitutes a beginning step in the process of identifying the forcing agents of toxicity in disinfected water.
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Affiliation(s)
- Michael J Plewa
- Safe Global Water Institute, and the Department of Crop Sciences, University of Illinois at Urbana-Champaign, IL 61801, United States.
| | - Elizabeth D Wagner
- Safe Global Water Institute, and the Department of Crop Sciences, University of Illinois at Urbana-Champaign, IL 61801, United States
| | - Susan D Richardson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, United States
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Parvez S, Frost K, Sundararajan M. Evaluation of Drinking Water Disinfectant Byproducts Compliance Data as an Indirect Measure for Short-Term Exposure in Humans. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14050548. [PMID: 28531123 PMCID: PMC5451998 DOI: 10.3390/ijerph14050548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 11/16/2022]
Abstract
In the absence of shorter term disinfectant byproducts (DBPs) data on regulated Trihalomethanes (THMs) and Haloacetic acids (HAAs), epidemiologists and risk assessors have used long-term annual compliance (LRAA) or quarterly (QA) data to evaluate the association between DBP exposure and adverse birth outcomes, which resulted in inconclusive findings. Therefore, we evaluated the reliability of using long-term LRAA and QA data as an indirect measure for short-term exposure. Short-term residential tap water samples were collected in peak DBP months (May–August) in a community water system with five separate treatment stations and were sourced from surface or groundwater. Samples were analyzed for THMs and HAAs per the EPA (U.S. Environmental Protection Agency) standard methods (524.2 and 552.2). The measured levels of total THMs and HAAs were compared temporally and spatially with LRAA and QA data, which showed significant differences (p < 0.05). Most samples from surface water stations showed higher levels than LRAA or QA. Significant numbers of samples in surface water stations exceeded regulatory permissible limits: 27% had excessive THMs and 35% had excessive HAAs. Trichloromethane, trichloroacetic acid, and dichloroacetic acid were the major drivers of variability. This study suggests that LRAA and QA data are not good proxies of short-term exposure. Further investigation is needed to determine if other drinking water systems show consistent findings for improved regulation.
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Affiliation(s)
- Shahid Parvez
- Department of Environmental Health Science, Indiana University Fairbanks School of Public Health, 1050 Wishard Boulevard, Indianapolis, IN 46202, USA.
| | - Kali Frost
- Department of Environmental Health Science, Indiana University Fairbanks School of Public Health, 1050 Wishard Boulevard, Indianapolis, IN 46202, USA.
| | - Madhura Sundararajan
- Department of Epidemiology, Indiana University Fairbanks School of Public Health, 1050 Wishard Boulevard, Indianapolis, IN 46202, USA.
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13
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Dong S, Lu J, Plewa MJ, Nguyen TH. Comparative Mammalian Cell Cytotoxicity of Wastewaters for Agricultural Reuse after Ozonation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:11752-11759. [PMID: 27689387 DOI: 10.1021/acs.est.6b04796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Reusing wastewater in agriculture is becoming increasingly common, which necessitates disinfection to ensure reuse safety. However, disinfectants can react with wastewater constituents to form disinfection byproducts (DBPs), many of which are toxic and restrict the goal of safe reuse. Our objective was to benchmark the induction of mammalian cell cytotoxicity after ozonation against chlorination for three types of real wastewaters: municipal secondary effluent and two sources of minimally treated swine farm wastewaters. A new method to evaluate samples of suspected high cytotoxicity was devised. For the secondary effluent, ozonation reduced the cytotoxicity by as much as 10 times; chlorination lowered the cytotoxicity only when followed by dechlorination. The swine farm wastewaters were up to 2000 times more cytotoxic than the secondary effluent, and the highest reduction in cytotoxicity was 17 times as achieved by ozonation. These results indicate that secondary effluent is preferred over swine wastewaters for agricultural reuse regardless of the tested disinfectants. Ozonation consistently reduced the cytotoxicity of both the full strength and the organic extracts of all tested wastewaters more than chlorination. The only significant correlation was observed in the secondary wastewater between total haloacetonitriles and cytotoxicity. While the association of reduced toxicity with the modification or reduction of specific compound(s) is unclear, regulated DBPs may not be the primary forcing agents.
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Affiliation(s)
- Shengkun Dong
- Department of Civil and Environmental Engineering, §Department of Crop Sciences, ‡Safe Global Water Institute, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
- College of Environmental Science and Engineering, ⊥Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University , Tianjin 300350, P. R. China
| | - Jinfeng Lu
- Department of Civil and Environmental Engineering, §Department of Crop Sciences, ‡Safe Global Water Institute, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
- College of Environmental Science and Engineering, ⊥Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University , Tianjin 300350, P. R. China
| | - Michael J Plewa
- Department of Civil and Environmental Engineering, §Department of Crop Sciences, ‡Safe Global Water Institute, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
- College of Environmental Science and Engineering, ⊥Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University , Tianjin 300350, P. R. China
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, §Department of Crop Sciences, ‡Safe Global Water Institute, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
- College of Environmental Science and Engineering, ⊥Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University , Tianjin 300350, P. R. China
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14
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Iszatt N, Nieuwenhuijsen MJ, Bennett JE, Toledano MB. Trihalomethanes in public drinking water and stillbirth and low birth weight rates: an intervention study. ENVIRONMENT INTERNATIONAL 2014; 73:434-439. [PMID: 25244706 DOI: 10.1016/j.envint.2014.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 08/06/2014] [Accepted: 08/07/2014] [Indexed: 06/03/2023]
Abstract
During 2003-2004, United Utilities water company in North West England introduced enhanced coagulation (EC) to four treatment works to mitigate disinfection by-product (DBP) formation. This enabled examination of the relation between DBPs and birth outcomes whilst reducing socioeconomic confounding. We compared stillbirth, and low and very low birth weight rates three years before (2000-2002) with three years after (2005-2007) the intervention, and in relation to categories of THM change. We created exposure metrics for EC and trihalomethane (THM) concentration change (n=258 water zones). We linked 429,599 live births and 2279 stillbirths from national birth registers to the water zone at birth. We used Poisson regression to model the differences in birth outcome rates with an interaction between before/after the intervention and EC or THM change. EC treatment reduced chloroform concentrations more than non-treatment (mean -29.7 µg/l vs. -14.5 µg/l), but not brominated THM concentrations. Only 6% of EC water zones received 100% EC water, creating exposure misclassification concerns. EC intervention was not associated with a statistically significant reduction in birth outcome rates. Areas with the highest chloroform decrease (30 - 65 μg/l) had the greatest percentage decrease in low -9 % (-12, -5) and very low birth weight -16% (-24, -8) rates. The interaction between before/after intervention and chloroform change was statistically significant only for very low birth weight, p=0.02. There were no significant decreases in stillbirth rates. In a novel approach for studying DBPs and adverse reproductive outcomes, the EC intervention to reduce DBPs did not affect birth outcome rates. However, a measured large decrease in chloroform concentrations was associated with statistically significant reductions in very low birth weight rates.
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Affiliation(s)
- Nina Iszatt
- Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK; Department of Genes and the Environment, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Mark J Nieuwenhuijsen
- Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK; Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; Municipal Institute of Medical Research Foundation (IMIM), Barcelona, Spain; Centre for Biomedical Investigation Network of Epidemiology and Public Health (CIBERESP), Barcelona, Spain
| | - James E Bennett
- Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
| | - Mireille B Toledano
- Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK.
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15
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Gonsior M, Schmitt-Kopplin P, Stavklint H, Richardson SD, Hertkorn N, Bastviken D. Changes in dissolved organic matter during the treatment processes of a drinking water plant in Sweden and formation of previously unknown disinfection byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:12714-22. [PMID: 25322143 DOI: 10.1021/es504349p] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The changes in dissolved organic matter (DOM) throughout the treatment processes in a drinking water treatment plant in Sweden and the formation of disinfection byproducts (DBPs) were evaluated by using ultra-high-resolution mass spectrometry (resolution of ∼500,000 at m/z 400) and nuclear magnetic resonance (NMR). Mass spectrometric results revealed that flocculation induced substantial changes in the DOM and caused quantitative removal of DOM constituents that usually are associated with DBP formation. While half of the chromophoric DOM (CDOM) was removed by flocculation, ∼4-5 mg L(-1) total organic carbon remained in the finished water. A conservative approach revealed the formation of ∼800 mass spectrometry ions with unambiguous molecular formula assignments that contained at least one halogen atom. These molecules likely represented new DBPs, which could not be prevented by the flocculation process. The most abundant m/z peaks, associated with formed DBPs, could be assigned to C5HO3Cl3, C5HO3Cl2Br, and C5HO3ClBr2 using isotope simulation patterns. Other halogen-containing formulas suggested the presence of halogenated polyphenolic and aromatic acid-type structures, which was supported by possible structures that matched the lower molecular mass range (maximum of 10 carbon atoms) of these DBPs. 1H NMR before and after disinfection revealed an ∼2% change in the overall 1H NMR signals supporting a significant change in the DOM caused by disinfection. This study underlines the fact that a large and increasing number of people are exposed to a very diverse pool of organohalogens through water, by both drinking and uptake through the skin upon contact. Nontarget analytical approaches are indispensable for revealing the magnitude of this exposure and to test alternative ways to reduce it.
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Affiliation(s)
- Michael Gonsior
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science , Solomons, Maryland 20688, United States
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16
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Yang Y, Komaki Y, Kimura SY, Hu HY, Wagner ED, Mariñas BJ, Plewa MJ. Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:12362-9. [PMID: 25222908 DOI: 10.1021/es503621e] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.
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Affiliation(s)
- Yang Yang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University , Beijing, P.R. China
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17
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Development of an Analytical Procedure for the Determination of Trihalomethanes in Leafy Vegetable by Headspace-SPME Followed by GC-ECD Determination. FOOD ANAL METHOD 2014. [DOI: 10.1007/s12161-014-9965-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Vinikoor-Imler LC, Davis JA, Meyer RE, Messer LC, Luben TJ. Associations between prenatal exposure to air pollution, small for gestational age, and term low birthweight in a state-wide birth cohort. ENVIRONMENTAL RESEARCH 2014; 132:132-9. [PMID: 24769562 DOI: 10.1016/j.envres.2014.03.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 05/12/2023]
Abstract
A range of health effects, including adverse pregnancy outcomes, have been associated with exposure to ambient concentrations of particulate matter (PM) and ozone (O3). The objective of this study was to determine whether maternal exposure to fine particulate matter (PM2.5) and O3 during pregnancy is associated with the risk of term low birthweight and small for gestational age infants in both single and co-pollutant models. Term low birthweight and small for gestational age were determined using all birth certificates from North Carolina from 2003 to 2005. Ambient air concentrations of PM2.5 and O3 were predicted using a hierarchical Bayesian model of air pollution that combined modeled air pollution estimates from the EPA׳s Community Multi-Scale Air Quality (CMAQ) model with air monitor data measured by the EPA׳s Air Quality System. Binomial regression, adjusted for multiple potential confounders, was performed. In adjusted single-pollutant models for the third trimester, O3 concentration was positively associated with small for gestational age and term low birthweight births [risk ratios for an interquartile range increase in O3: 1.16 (95% CI 1.11, 1.22) for small for gestational age and 2.03 (95% CI 1.80, 2.30) for term low birthweight]; however, inverse or null associations were observed for PM2.5 [risk ratios for an interquartile range increase in PM2.5: 0.97 (95% CI 0.95, 0.99) for small for gestational age and 1.01 (95% CI 0.97, 1.06) for term low birthweight]. Findings were similar in co-pollutant models and linear models of birthweight. These results suggest that O3 concentrations in both urban and rural areas may be associated with an increased risk of term low birthweight and small for gestational age births.
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Affiliation(s)
- Lisa C Vinikoor-Imler
- National Center for Environmental Assessment (NCEA), U.S. Environmental Protection Agency (EPA), 109 T.W. Alexander Drive, Attn: MD B243-01, Research Triangle Park, NC 27711, USA.
| | - J Allen Davis
- National Center for Environmental Assessment (NCEA), U.S. Environmental Protection Agency (EPA), 109 T.W. Alexander Drive, Attn: MD B243-01, Research Triangle Park, NC 27711, USA
| | - Robert E Meyer
- North Carolina Birth Defects Monitoring Program, State Center for Health Statistics, Raleigh, NC 27699, USA
| | - Lynne C Messer
- School of Community Health, College of Urban and Public Affairs, Portland State University, Portland, OR 97207, USA
| | - Thomas J Luben
- National Center for Environmental Assessment (NCEA), U.S. Environmental Protection Agency (EPA), 109 T.W. Alexander Drive, Attn: MD B243-01, Research Triangle Park, NC 27711, USA
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Villanueva CM, Kogevinas M, Cordier S, Templeton MR, Vermeulen R, Nuckols JR, Nieuwenhuijsen MJ, Levallois P. Assessing exposure and health consequences of chemicals in drinking water: current state of knowledge and research needs. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:213-21. [PMID: 24380896 PMCID: PMC3948022 DOI: 10.1289/ehp.1206229] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/24/2013] [Indexed: 05/20/2023]
Abstract
BACKGROUND Safe drinking water is essential for well-being. Although microbiological contamination remains the largest cause of water-related morbidity and mortality globally, chemicals in water supplies may also cause disease, and evidence of the human health consequences is limited or lacking for many of them. OBJECTIVES We aimed to summarize the state of knowledge, identify gaps in understanding, and provide recommendations for epidemiological research relating to chemicals occurring in drinking water. DISCUSSION Assessing exposure and the health consequences of chemicals in drinking water is challenging. Exposures are typically at low concentrations, measurements in water are frequently insufficient, chemicals are present in mixtures, exposure periods are usually long, multiple exposure routes may be involved, and valid biomarkers reflecting the relevant exposure period are scarce. In addition, the magnitude of the relative risks tends to be small. CONCLUSIONS Research should include well-designed epidemiological studies covering regions with contrasting contaminant levels and sufficient sample size; comprehensive evaluation of contaminant occurrence in combination with bioassays integrating the effect of complex mixtures; sufficient numbers of measurements in water to evaluate geographical and temporal variability; detailed information on personal habits resulting in exposure (e.g., ingestion, showering, swimming, diet); collection of biological samples to measure relevant biomarkers; and advanced statistical models to estimate exposure and relative risks, considering methods to address measurement error. Last, the incorporation of molecular markers of early biological effects and genetic susceptibility is essential to understand the mechanisms of action. There is a particular knowledge gap and need to evaluate human exposure and the risks of a wide range of emerging contaminants. CITATION Villanueva CM, Kogevinas M, Cordier S, Templeton MR, Vermeulen R, Nuckols JR, Nieuwenhuijsen MJ, Levallois P. 2014. Assessing exposure and health consequences of chemicals in drinking water: current state of knowledge and research needs. Environ Health Perspect 122:213–221; http://dx.doi.org/10.1289/ehp.1206229
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20
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Evans AM, Wright JM, Meyer A, Rivera-Núñez Z. Spatial variation of disinfection by-product concentrations: exposure assessment implications. WATER RESEARCH 2013; 47:6130-6140. [PMID: 23993731 DOI: 10.1016/j.watres.2013.07.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/27/2013] [Accepted: 07/21/2013] [Indexed: 06/02/2023]
Abstract
The use of public water system (PWS) average trihalomethane (THM) and haloacetic acid (HAA) concentrations as surrogates of "personal" exposures in epidemiological studies of disinfection by-products (DBPs) may result in exposure misclassification bias from various sources of measurement error including intra-system variation of DBPs. Using 2000-2004 data from 107 PWSs in Massachusetts, we assessed two approaches for characterizing DBP spatial variability by identifying PWSs with low spatial variability (LSV) and examining differences in LSV across DBP groups and by type of source water and primary disinfectant. We also used spatial differences to examine the association between THM concentrations and indices of social disadvantage; however, we found no correlations or statistically significant differences based on the available data. We observed similar patterns for the percentage of quarterly sampling dates with LSV across different types of source water for all DBPs but not across disinfectants. We found there was little overlap between sites classified as having LSV across different DBP groups. In the main analysis, we found moderate correlations between both approaches (φ(THM4) = 0.55; φ(BrTHM) = 0.64; φ(HAA5) = 0.67); although Method 1 (based on concentration differences between samples) may be better suited for identifying PWSs for inclusion in epidemiological studies because it is more easily adapted to study-specific exposure gradients than Method 2 (based on categorical exposure percentiles). These data reinforce the need to consider different exposure assessment approaches when examining the spatial variation of multiple DBP surrogates as they can represent different DBP mixtures.
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Affiliation(s)
- Amanda M Evans
- Oak Ridge Institute for Science and Education, 26 West Martin Luther King Blvd (MS-A110), Cincinnati, OH 45268, USA.
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21
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Association of Brominated Trihalomethane and Haloacetic Acid Exposure With Fetal Growth and Preterm Delivery in Massachusetts. J Occup Environ Med 2013; 55:1125-34. [DOI: 10.1097/jom.0b013e3182a4ffe4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zhang XL, Yang HW, Wang XM, Fu J, Xie YF. Formation of disinfection by-products: effect of temperature and kinetic modeling. CHEMOSPHERE 2013; 90:634-639. [PMID: 23026162 DOI: 10.1016/j.chemosphere.2012.08.060] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 08/24/2012] [Accepted: 08/27/2012] [Indexed: 06/01/2023]
Abstract
The temperature of drinking water fluctuates naturally in water distribution systems as well as often deliberately heated for household or public uses. In this study, the temperature effect on the formation of disinfection by-products (DBPs) was investigated by monitoring the temporal variations of twenty-one DBPs during the chlorination of a humic precursors-containing water at different temperatures. It was found that chloroform, DCAA, TCAA, DCAN and CH were detected at the considerable level of tens of μg L(-1). The three regulated DBPs (chloroform, DCAA and TCAA) were found increasing with both contact time and water temperature, while the five typical emerging DBPs (DCAN, CH, TCNM 1,1-DCPN and 1,1,1-TCPN) revealed the significant auto-decomposition in addition to the initial growth in the first few hours. Increasing water temperature could enhance the formation rates of all the eight detected DBPs and the decomposition rates of the five emerging DBPs. Further, a kinetic model was developed for the simulation of DBP formation. The validity and universality of the model were verified by its excellent correlation with the detected values of each DBP species at various temperatures. The formation rates of 1,1-DCPN and 1,1,1-TCPN, and the decomposition rate of 1,1,1-TCPN were faster as compared to the other DBPs. And the formation reaction activation energies of CH, DCAN and 1,1-DCPN were relatively large, indicating that their occurrence levels in the finished water were more susceptible to temperature variations.
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Affiliation(s)
- Xiao-lu Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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23
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Rivera-Núñez Z, Wright JM, Blount BC, Silva LK, Jones E, Chan RL, Pegram RA, Singer PC, Savitz DA. Comparison of trihalomethanes in tap water and blood: a case study in the United States. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:661-7. [PMID: 22281753 PMCID: PMC3346785 DOI: 10.1289/ehp.1104347] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/26/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND Epidemiological studies have used various measures to characterize trihalomethane (THM) exposures, but the relationship of these indicators to exposure biomarkers remains unclear. OBJECTIVES We examined temporal and spatial variability in baseline blood THM concentrations and assessed the relationship between these concentrations and several exposure indicators (tap water concentration, water-use activities, multiroute exposure metrics). METHODS We measured water-use activity and THM concentrations in blood and residential tap water from 150 postpartum women from three U.S. locations. RESULTS Blood ΣTHM [sum of chloroform (TCM), bromodichloromethane (BDCM), dibromo-chloromethane (DBCM), and bromoform (TBM)] concentrations varied by site and season. As expected based on variable tap water concentrations and toxicokinetic properties, the proportion of brominated species (BDCM, DBCM, and TBM) in blood varied by site (site 1, 24%; site 2, 29%; site 3, 57%) but varied less markedly than in tap water (site 1, 35%; site 2, 75%; site 3, 68%). The blood-water ΣTHM Spearman rank correlation coefficient was 0.36, with correlations higher for individual brominated species (BDCM, 0.62; DBCM, 0.53; TBM, 0.54) than for TCM (0.37). Noningestion water activities contributed more to the total exposure metric than did ingestion, but tap water THM concentrations were more predictive of blood THM levels than were metrics that incorporated water use. CONCLUSIONS Spatial and temporal variability in THM concentrations was greater in water than in blood. We found consistent blood-water correlations across season and site for BDCM and DBCM, and multivariate regression results suggest that water THM concentrations may be an adequate surro-gate for baseline blood levels.
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The effect of water disinfection by-products on pregnancy outcomes in two southeastern US communities. J Occup Environ Med 2012; 53:1172-8. [PMID: 21915074 DOI: 10.1097/jom.0b013e31822b8334] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To determine if exposure to disinfection by-products (DBPs) during gestation increases the risk of adverse birth outcomes, specifically term small for gestational age (SGA) birth, preterm birth (PTB), and very PTB (<32 weeks' gestation). METHODS We used weekly measurements total trihalomethanes (TTHMs), five haloacetic acids (HAA5), and total organic halides (TOX) collected from two distribution systems to evaluate the associations between DBP concentrations and term SGA, PTB, and very PTB using logistic regression. RESULTS We found no associations between DBPs and term-SGA. In the site with higher concentrations of bromine-containing DBPs, we found an association between TOX and PTB; this association was larger, though less precise, for very PTB. CONCLUSIONS Our results do not support an association between TTHMs or HAA5 and the birth outcomes investigated, but an association was found between increased TOX and PTB.
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Villanueva CM, Gracia-Lavedán E, Ibarluzea J, Santa Marina L, Ballester F, Llop S, Tardón A, Fernández MF, Freire C, Goñi F, Basagaña X, Kogevinas M, Grimalt JO, Sunyer J. Exposure to trihalomethanes through different water uses and birth weight, small for gestational age, and preterm delivery in Spain. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:1824-30. [PMID: 21810554 PMCID: PMC3261969 DOI: 10.1289/ehp.1002425] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 08/02/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Evidence associating exposure to water disinfection by-products with reduced birth weight and altered duration of gestation remains inconclusive. OBJECTIVE We assessed exposure to trihalomethanes (THMs) during pregnancy through different water uses and evaluated the association with birth weight, small for gestational age (SGA), low birth weight (LBW), and preterm delivery. METHODS Mother-child cohorts set up in five Spanish areas during the years 2000-2008 contributed data on water ingestion, showering, bathing, and swimming in pools. We ascertained residential THM levels during pregnancy periods through ad hoc sampling campaigns (828 measurements) and regulatory data (264 measurements), which were modeled and combined with personal water use and uptake factors to estimate personal uptake. We defined outcomes following standard definitions and included 2,158 newborns in the analysis. RESULTS Median residential THM ranged from 5.9 μg/L (Valencia) to 114.7 μg/L (Sabadell), and speciation differed across areas. We estimated that 89% of residential chloroform and 96% of brominated THM uptakes were from showering/bathing. The estimated change of birth weight for a 10% increase in residential uptake was -0.45 g (95% confidence interval: -1.36, 0.45 g) for chloroform and 0.16 g (-1.38, 1.70 g) for brominated THMs. Overall, THMs were not associated with SGA, LBW, or preterm delivery. CONCLUSIONS Despite the high THM levels in some areas and the extensive exposure assessment, results suggest that residential THM exposure during pregnancy driven by inhalation and dermal contact routes is not associated with birth weight, SGA, LBW, or preterm delivery in Spain.
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Colman J, Rice GE, Wright JM, Hunter ES, Teuschler LK, Lipscomb JC, Hertzberg RC, Simmons JE, Fransen M, Osier M, Narotsky MG. Identification of developmentally toxic drinking water disinfection byproducts and evaluation of data relevant to mode of action. Toxicol Appl Pharmacol 2011; 254:100-26. [DOI: 10.1016/j.taap.2011.02.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 04/22/2010] [Accepted: 04/22/2010] [Indexed: 12/26/2022]
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Bateson TF, Wright JM. Regression calibration for classical exposure measurement error in environmental epidemiology studies using multiple local surrogate exposures. Am J Epidemiol 2010; 172:344-52. [PMID: 20573838 DOI: 10.1093/aje/kwq123] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Environmental epidemiologic studies are often hierarchical in nature if they estimate individuals' personal exposures using ambient metrics. Local samples are indirect surrogate measures of true local pollutant concentrations which estimate true personal exposures. These ambient metrics include classical-type nondifferential measurement error. The authors simulated subjects' true exposures and their corresponding surrogate exposures as the mean of local samples and assessed the amount of bias attributable to classical and Berkson measurement error on odds ratios, assuming that the logit of risk depends on true individual-level exposure. The authors calibrated surrogate exposures using scalar transformation functions based on observed within- and between-locality variances and compared regression-calibrated results with naive results using surrogate exposures. The authors further assessed the performance of regression calibration in the presence of Berkson-type error. Following calibration, bias due to classical-type measurement error, resulting in as much as 50% attenuation in naive regression estimates, was eliminated. Berkson-type error appeared to attenuate logistic regression results less than 1%. This regression calibration method reduces effects of classical measurement error that are typical of epidemiologic studies using multiple local surrogate exposures as indirect surrogate exposures for unobserved individual exposures. Berkson-type error did not alter the performance of regression calibration. This regression calibration method does not require a supplemental validation study to compute an attenuation factor.
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Affiliation(s)
- Thomas F Bateson
- National Center for Environmental Assessment, Environmental Protection Agency, 1200 Pennsylvania Avenue NW, Mail Code 8623P, Washington, DC 20460, USA.
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Green RS, Malig B, Windham GC, Fenster L, Ostro B, Swan S. Residential exposure to traffic and spontaneous abortion. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:1939-44. [PMID: 20049215 PMCID: PMC2799470 DOI: 10.1289/ehp.0900943] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 08/31/2009] [Indexed: 05/03/2023]
Abstract
BACKGROUND Studies have shown associations between air pollution or traffic exposure and adverse birth outcomes, such as low birth weight. However, very few studies have examined the effect of traffic emissions on spontaneous abortion (SAB). OBJECTIVE The goal of this study was to determine whether residential exposure to vehicular traffic was associated with SAB. METHODS Pregnant women from a prepaid health plan in California were recruited into a prospective cohort study in 1990-1991. Three measures of traffic exposure were constructed for the 4,979 participants using annual average daily traffic (AADT) counts near each residence and distance from residence to major roads. SAB was examined in relation to the traffic exposure measures using logistic regression adjusting for a number of demographic and lifestyle variables. RESULTS Of the traffic measures, maximum annual average traffic within 50 m showed the strongest association with SAB, although it was not statistically significant. The adjusted odds ratio (AOR) for the top 90th percentile (AADT greater than 15,199) versus the bottom 75th percentile (AADT = 0-1,089) was 1.18 [95% confidence interval (CI), 0.87-1.60]. However, subgroup analyses showed statistically significant associations for traffic with SAB among African Americans (AOR = 3.11; 95% CI, 1.26-7.66) and nonsmokers (AOR = 1.47; 95% CI, 1.07-2.04). CONCLUSION In this cohort, living within 50 m of a road with AADT of 15,200 or more was significantly associated with SAB among African Americans and nonsmokers. Further research is needed to confirm these results and possibly elucidate the mechanisms responsible for the findings.
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Affiliation(s)
- Rochelle S Green
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, California 94612, USA.
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Nieuwenhuijsen MJ, Grellier J, Smith R, Iszatt N, Bennett J, Best N, Toledano M. The epidemiology and possible mechanisms of disinfection by-products in drinking water. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:4043-4076. [PMID: 19736233 DOI: 10.1098/rsta.2009.0116] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This paper summarizes the epidemiological evidence for adverse health effects associated with disinfection by-products (DBPs) in drinking water and describes the potential mechanism of action. There appears to be good epidemiological evidence for a relationship between exposure to DBPs, as measured by trihalomethanes (THMs), in drinking water and bladder cancer, but the evidence for other cancers including colorectal cancer is inconclusive and inconsistent. There appears to be some evidence for an association between exposure to DBPs, specifically THMs, and little for gestational age/intrauterine growth retardation and, to a lesser extent, pre-term delivery, but evidence for relationships with other outcomes such as low birth weight, stillbirth, congenital anomalies and semen quality is inconclusive and inconsistent. Major limitations in exposure assessment, small sample sizes and potential biases may account for the inconclusive and inconsistent results in epidemiological studies. Moreover, most studies have focused on total THMs as the exposure metric, whereas other DBPs appear to be more toxic than the THMs, albeit generally occurring at lower levels in the water. The mechanisms through which DBPs may cause adverse health effects including cancer and adverse reproductive effects have not been well investigated. Several mechanisms have been suggested, including genotoxicity, oxidative stress, disruption of folate metabolism, disruption of the synthesis and/or secretion of placental syncytiotrophoblast-derived chorionic gonadotropin and lowering of testosterone levels, but further work is required in this area.
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Affiliation(s)
- Mark J Nieuwenhuijsen
- Centre for Research in Environmental Epidemiology (CREAL), Parc de Recerca Biomèdica de Barcelona-PRBB (Office 183.05), , C. Doctor Aiguader, 88, 08003 Barcelona, Spain.
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Forssén UM, Wright JM, Herring AH, Savitz DA, Nieuwenhuijsen MJ, Murphy PA. Variability and predictors of changes in water use during pregnancy. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2009; 19:593-602. [PMID: 18830235 DOI: 10.1038/jes.2008.59] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 08/28/2008] [Indexed: 05/24/2023]
Abstract
Disinfection by-products in tap water have been found in some studies to be associated with adverse pregnancy outcomes, but little is known about how water use and consumption might change during early pregnancy. Estimating water-related activities only at one time during pregnancy could easily lead to exposure misclassification. To evaluate changes in water use among pregnant women, we used data from a large epidemiologic study in which 1990 women were interviewed around 9 and 20 weeks' gestation. The water variables that were examined included ingestion of cold and hot tap water as well as of bottled water, showering and bathing. Changes were detected between early and mid-pregnancy for ingested cold tap water and showering. Thirty-three percent of the subjects changed cold-water ingestion by > or =1.0 liters/day and 44% changed their time showering by > or =35 min per week during this period. Increases in cold tap water intake were associated with age >35 years, income < $40,000, and non-Hispanic white ethnicity. We also found that the proportion of the total variation due to within-subject variability was 62% for hot tap water ingestion but only 35% for showering and approximately 50% for cold tap water, bottled water and bathing. Limited resources in epidemiologic studies often require a decision between collecting data for a large number of people or collecting multiple measurements for a smaller number of people. The results in this study will be useful to researchers who need to determine where to invest their effort when assessing water-related exposures and should help in evaluation of previously performed studies.
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Affiliation(s)
- Ulla M Forssén
- Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.
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Affiliation(s)
- Elizabeth D. Wagner
- Department of Crop Sciences College of Agricultural Consumer and Environmental Sciences University of Illinois at Urbana-Champaign 366 NSRC MC-635, 1101 West Peabody Drive Urbana IL 61801 USA
| | - Michael J. Plewa
- Department of Crop Sciences College of Agricultural Consumer and Environmental Sciences University of Illinois at Urbana-Champaign 366 NSRC MC-635, 1101 West Peabody Drive Urbana IL 61801 USA
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Richter W, Hart TF, Luben T, Freud S, Nuckols JR. Evaluation of two methods of interpolating quarterly trihalomethane levels between sampling dates. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2009; 19:405-413. [PMID: 18506206 DOI: 10.1038/jes.2008.30] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 03/20/2008] [Indexed: 05/26/2023]
Abstract
Epidemiological studies of the relationship between disinfection byproducts (DBPs) and adverse birth outcomes often use a single quarterly sample result to characterize an exposure period during a pregnancy. Concentrations of trihalomethanes (THMs), a frequently studied class of DBPs, can fluctuate considerably between sampling periods so that a single point measurement in time may not adequately characterize levels over an exposure period. In addition to obtaining compliance samples that are required quarterly at a limited number of sampling sites, the New York City water supply system takes monthly THM samples at a large number of sites. We used these monthly data to investigate two methods for interpolating between quarterly measurements: cubic splines and linear interpolation. We based interpolations on 1 month in each calendar quarter and checked the interpolated values against the actual data values from the other 2 months of the quarter. Both methods produced generally acceptable fits: 90% of the observed discrepancies between fitted and actual values were less than 14 microg/l and over half were less than 5 microg/l for total trihalomethanes (THM4). These numbers are about half the change in THM4 level from one quarter to the next and compare favorably with the range of 0-80 microg/l or more used in many studies. Comparable results were obtained for chloroform and bromodichloromethane, the two THMs with levels high enough to analyze. Linear interpolation generally performed better than the spline fit, producing lower average discrepancies and fewer large discrepancies. Linear interpolation can be a useful and easily applied method for developing improved exposure estimates using quarterly sampling data.
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Affiliation(s)
- Wayne Richter
- New York State Department of Health, Troy, New York 12180, USA.
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Elliott P, Savitz DA. Design issues in small-area studies of environment and health. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:1098-104. [PMID: 18709174 PMCID: PMC2516594 DOI: 10.1289/ehp.10817] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 08/28/2007] [Accepted: 04/25/2008] [Indexed: 05/04/2023]
Abstract
BACKGROUND Small-area studies are part of the tradition of spatial epidemiology, which is concerned with the analysis of geographic patterns of disease with respect to environmental, demographic, socioeconomic, and other factors. We focus on etiologic research, where the aim is to make inferences about spatially varying environmental factors influencing the risk of disease. METHODS AND RESULTS We illustrate the approach through three exemplars: a) magnetic fields from overhead electric power lines and the occurrence of childhood leukemia, which illustrates the use of geographic information systems to focus on areas with high exposure prevalence; b) drinking-water disinfection by-products and reproductive outcomes, taking advantage of large between- to within-area variability in exposures from the water supply; and c) chronic exposure to air pollutants and cardiorespiratory health, where issues of socioeconomic confounding are particularly important. DISCUSSION The small-area epidemiologic approach assigns exposure estimates to individuals based on location of residence or other geographic variables such as workplace or school. In this way, large populations can be studied, increasing the ability to investigate rare exposures or rare diseases. The approach is most effective when there is well-defined exposure variation across geographic units, limited within-area variation, and good control for potential confounding across areas. CONCLUSIONS In conjunction with traditional individual-based approaches, small-area studies offer a valuable addition to the armamentarium of the environmental epidemiologist. Modeling of exposure patterns coupled with collection of individual-level data on subsamples of the population should lead to improved risk estimates (i.e., less potential for bias) and help strengthen etiologic inference.
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Affiliation(s)
- Paul Elliott
- Small Area Health Statistics Unit, Department of Epidemiology and Public Health, Imperial College London, London, UK.
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Plewa MJ, Muellner MG, Richardson SD, Fasano F, Buettner KM, Woo YT, McKague AB, Wagner ED. Occurrence, synthesis, and mammalian cell cytotoxicity and genotoxicity of haloacetamides: an emerging class of nitrogenous drinking water disinfection byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:955-961. [PMID: 18323128 DOI: 10.1021/es071754h] [Citation(s) in RCA: 369] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The haloacetamides, a class of emerging nitrogenous drinking water disinfection byproduct (DBPs), were analyzed for their chronic cytotoxicity and for the induction of genomic DNA damage in Chinese hamster ovary cells. The rank order for cytotoxicity of 13 haloacetamides was DIAcAm > IAcAm > BAcAm > TBAcAm > BIAcAm > DBCAcAm > CIAcAm > BDCAcAm > DBAcAm > BCAcAm > CAcAm > DCAcAm > TCAcAm. The rank order of their genotoxicity was TBAcAm > DIAcAm approximately equal to IAcAm > BAcAm > DBCAcAm > BIAcAm > BDCAcAm > CIAcAm > BCAcAm > DBAcAm > CAcAm > TCAcAm. DCAcAm was not genotoxic. Cytotoxicity and genotoxicity were primarily determined by the leaving tendency of the halogens and followed the order I > Br > > Cl. With the exception of brominated trihaloacetamides, most of the toxicity rank order was consistent with structure-activity relationship expectations. For di- and trihaloacetamides, the presence of at least one good leaving halogen group (I or Br but not Cl) appears to be critical for significant toxic activity. Log P was not a factor for monohaloacetamides but may play a role in the genotoxicity of trihaloacetamides and possible activation of dihaloacetamides by intracellular GSH and -SH compounds.
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Affiliation(s)
- Michael J Plewa
- College of Agricultural, Consumer and Environmental Sciences, Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1101 West Peabody Drive, Urbana, Illinois 61801, USA.
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Richardson SD, Thruston AD, Krasner SW, Weinberg HS, Miltner RJ, Schenck KM, Narotsky MG, McKague AB, Simmons JE. Integrated disinfection by-products mixtures research: comprehensive characterization of water concentrates prepared from chlorinated and ozonated/postchlorinated drinking water. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:1165-1186. [PMID: 18636390 DOI: 10.1080/15287390802182417] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This article describes the disinfection by-product (DBP) characterization portion of a series of experiments designed for comprehensive chemical and toxicological evaluation of two drinking-water concentrates containing highly complex mixtures of DBPs. This project, called the Four Lab Study, involved the participation of scientists from four laboratories and centers of the U.S. Environmental Protection Agency (EPA) Office of Research and Development, along with collaborators from the water industry and academia, and addressed toxicologic effects of complex DBP mixtures, with an emphasis on reproductive and developmental effects that are associated with DBP exposures in epidemiologic studies. Complex mixtures of DBPs from two different disinfection schemes (chlorination and ozonation/postchlorination) were concentrated successfully, while maintaining a water matrix suitable for animal studies. An array of chlorinated/brominated/iodinated DBPs was created. The DBPs were relatively stable over the course of the animal experiments, and a significant portion of the halogenated DBPs formed in the drinking water was accounted for through a comprehensive qualitative and quantitative identification approach. DBPs quantified included priority DBPs that are not regulated but have been predicted to produce adverse health effects, as well as those currently regulated in the United States and those targeted during implementation of the Information Collection Rule. New by-products were also reported for the first time. These included previously undetected and unreported bromo- and chloroacids, iodinated compounds, bromo- and iodophenols, and bromoalkyltins.
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Affiliation(s)
- Susan D Richardson
- Office of Research and Development, U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605, USA.
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Simmons JE, Richardson SD, Teuschler LK, Miltner RJ, Speth TF, Schenck KM, Hunter ES, Rice G. Research issues underlying the four-lab study: integrated disinfection by-products mixtures research. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:1125-1132. [PMID: 18636387 DOI: 10.1080/15287390802181906] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Chemical disinfection of drinking water is a major public health triumph of the 20th century, resulting in significant decreases in morbidity and mortality from waterborne diseases. Disinfection by-products (DBP) are chemicals formed by the reaction of oxidizing disinfectants with inorganic and organic materials in the source water. To address potential health concerns that cannot be answered directly by toxicological research on individual DBPs or defined DBP mixtures, scientists residing within the various organizations of the U.S. Environmental Protection Agency's Office of Research and Development (the National Health and Environmental Effects Research Laboratory, the National Risk Management Research Laboratory, the National Exposure Research Laboratory, and the National Center for Environmental Assessment) engaged in joint investigation of environmentally realistic complex mixtures of DBP. Research on complex mixtures of DBP is motivated by three factors: (a) DBP exposure is ubiquitous to all segments of the population; (b) some positive epidemiologic studies are suggestive of potential developmental, reproductive, or carcinogenic health effects in humans exposed to DBP; and (c) significant amounts of the material that makes up the total organic halide portion of the DBP have not been identified. The goal of the Integrated Disinfection Byproducts Mixtures Research Project (the 4Lab Study) is provision of sound, defensible, experimental data on environmentally relevant mixtures of DBP and an improved estimation of the potential health risks associated with exposure to the mixtures of DBP formed during disinfection of drinking water. A phased research plan was developed and implemented. The present series of articles provides the results from the first series of experiments.
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Affiliation(s)
- Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA.
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Rice G, Teuschler LK, Speth TF, Richardson SD, Miltner RJ, Schenck KM, Gennings C, Hunter ES, Narotsky MG, Simmons JE. Integrated disinfection by-products research: assessing reproductive and developmental risks posed by complex disinfection by-product mixtures. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:1222-1234. [PMID: 18636394 DOI: 10.1080/15287390802182649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This article presents a toxicologically-based risk assessment strategy for identifying the individual components or fractions of a complex mixture that are associated with its toxicity. The strategy relies on conventional component-based mixtures risk approaches such as dose addition, response addition, and analyses of interactions. Developmental toxicity data from two drinking-water concentrates containing disinfection by-products (DBP) mixtures were used to illustrate the strategy. The results of this study showed that future studies of DBP concentrates using the Chernoff-Kavlock bioassay need to consider evaluating DBP that are concentrated more than 130-fold and using a rat strain that is more sensitive to chemically-induced pregnancy loss than Sprague-Dawley rats. The results support the planned experimental design of a multigeneration reproductive and developmental study of DBP concentrates. Finally, this article discusses the need for a systematic evaluation of DBP concentrates obtained from multiple source waters and treatment types. The development of such a database could be useful in evaluating whether a specific DBP concentrate is sufficiently similar to tested combinations of source waters and treatment alternatives so that health risks for the former may be estimated using data on the latter.
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Affiliation(s)
- Glenn Rice
- U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA.
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Marabini L, Frigerio S, Chiesara E, Maffei F, Cantelli Forti G, Hrelia P, Buschini A, Martino A, Poli P, Rossi C, Radice S. In vitro cytotoxicity and genotoxicity of chlorinated drinking waters sampled along the distribution system of two municipal networks. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2007; 634:1-13. [PMID: 17884717 DOI: 10.1016/j.mrgentox.2007.05.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 03/27/2007] [Accepted: 05/20/2007] [Indexed: 11/19/2022]
Abstract
When chlorine is used as a disinfectant for drinking water it may react with organic materials present in or released by the water pipes and thus form by-products that may represent a genotoxic hazard. The aim of this study was to assess the potential genotoxicity and cytotoxicity of extracts of chlorinated drinking water supplied by local aquifers of two Italian towns, Plants 1 and 2, located in the sub-Alpine area and on the Po plain, respectively. The raw water fell within the legal limits with regards to its chemical and physical properties. Water from Plant 2 contained higher levels of total organics (TOC) and nitrate than water from Plant 1. Water was sampled at different points along the distribution networks to evaluate the influence of the system on the amount and quality of the by-products. Cytotoxic and genotoxic damage was assessed in freshly isolated human white blood cells (WBC) and Hep-G2 cells by use of the micronucleus (MN) test and the Comet assay to measure primary DNA damage. While they did not show significant cytotoxicity, all Plant 1 water concentrates induced short-time genotoxic effects on leukocytes at concentrations > or =1 Lequiv./mL. Plant 2 samples were able to induce cytotoxic effects in both Hep-G2 cells and leukocytes. Furthermore, although there was no significant increase in MN frequency, DNA migration was strongly increased both in human leukocytes (> or =0.5 Lequiv./mL, 1h treatment, water samples collected from all points) and in Hep-G2 cells (> or =0.75 Lequiv./mL, 24 h treatment, tap water sampled at the nearest distribution point). The current use of these in vitro cytotoxicity/genotoxicity tests together with the normal chemical analyses could provide information to help water-works managers and health authorities evaluate drinking water quality and adopt strategies to reduce genotoxic compounds in tap water and prevent human exposure to these compounds.
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Affiliation(s)
- Laura Marabini
- Department of Pharmacology, Chemotherapy and Medical Toxicology E Trabucchi, University of Milan, Via Vanvitelli 32, 20129, Milan, Italy.
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Wright JM, Murphy PA, Nieuwenhuijsen MJ, Savitz DA. The impact of water consumption, point-of-use filtration and exposure categorization on exposure misclassification of ingested drinking water contaminants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2006; 366:65-73. [PMID: 16126253 DOI: 10.1016/j.scitotenv.2005.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 07/22/2005] [Accepted: 08/04/2005] [Indexed: 04/14/2023]
Abstract
The use of population-level indices to estimate individual exposures is an important limitation of previous epidemiologic studies of disinfection by-products (DBPs). We examined exposure misclassification resulting from the use of system average DBP concentrations to estimate individual-level exposures. Data were simulated (n=1000 iterations) for 100 subjects across 10 water systems based on the following assumptions: DBP concentrations ranged from 0-99 microg/L with limited intra-system variability; water intake ranged from 0.5-2.5 L/day; 20% of subjects used bottled water exclusively; 20% of subjects used filtered tap water exclusively; DBP concentrations were reduced by 50% or 90% following filtration. DBP exposure percentiles were used to classify subjects into different exposure levels (e.g., low, intermediate, high and very high) for four classification approaches. Compared to estimates of DBP ingestion that considered daily consumption, source type (i.e., unfiltered tap, filtered tap, and bottled water), and filter efficiency (with 90% DBP removal), 48-62% of subjects were misclassified across one category based on system average concentrations. Average misclassification across at least two exposure categories (e.g., from high to low) ranged from 4-14%. The median classification strategy resulted in the least misclassification, and volume of water intake was the most influential modifier of ingestion exposures. These data illustrate the importance of individual water use information in minimizing exposure misclassification in epidemiologic studies of drinking water contaminants.
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Affiliation(s)
- J Michael Wright
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive (MS-A130), Cincinnati, OH 45268, USA.
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Meunier L, Canonica S, von Gunten U. Implications of sequential use of UV and ozone for drinking water quality. WATER RESEARCH 2006; 40:1864-76. [PMID: 16635504 DOI: 10.1016/j.watres.2006.02.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 02/20/2006] [Accepted: 02/26/2006] [Indexed: 05/08/2023]
Abstract
The formation of bromate levels exceeding the drinking water standard of 10 microg L-1 may impose the reduction of ozone doses used in the treatment of drinking water. This paper illustrates the procedure of evaluating the use of reduced ozone doses while implementing an additional UV disinfection step for an actual drinking water treatment plant. Ozonation was performed at low ozone doses in bench-scale experiments with a pretreated river water from the Paris area (France). At the low ozone dose of 0.5 mg L-1, bromate formation could be kept below 0.4 microg L-1, while inactivation of vegetative bacteria and UV-resistant viruses was calculated to exceed 5 log units, and a substantial decoloration (31% of the absorption at lambda=254 nm) was achieved. Based on the measured transient ozone and OH radical concentrations, the oxidation of micropollutants was calculated. Fast reacting micropollutants containing phenol, amine or double bond moieties, such as sulfamethoxazole, diclofenac and 17-alpha-ethinylestradiol, were completely oxidized. Slow-reacting synthetic micropollutants, e.g., atrazine, iopromide and methyl tertiary butyl ether (MTBE), were oxidized by only 20%, 20% and 10%, respectively, and the taste and odor compounds 2-methylisoborneol (MIB) and geosmin by 40% and 50%, respectively. The addition of an UV treatment step to the existing treatment train, which should guarantee disinfection of ozone-resistant pathogenic microorganisms, including Cryptosporidium parvum oocysts, has negligible effects on water matrix components but may induce significant transformation of micropollutants. Overall, the combination of ozonation at reduced doses and UV treatment leads to an improved water quality with regard to disinfection, oxidation of micropollutants and minimization of bromate.
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Affiliation(s)
- Laurence Meunier
- Swiss Federal Institute of Aquatic Science and Technology, Eawag, 8600 Dübendorf, Switzerland
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Tardiff RG, Carson ML, Ginevan ME. Updated weight of evidence for an association between adverse reproductive and developmental effects and exposure to disinfection by-products. Regul Toxicol Pharmacol 2006; 45:185-205. [PMID: 16624462 DOI: 10.1016/j.yrtph.2006.03.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Indexed: 11/16/2022]
Abstract
Disinfection by-products (DBP) are produced when water is treated with chemical disinfectants. Some toxicological and epidemiological studies suggest an association between DBP exposure and adverse reproductive and developmental effects. In a previous critical review, [Graves, C.G., Matanoski, G.M., Tardiff, R.G., 2001. Weight of evidence for an association between adverse reproductive and developmental effects and exposure to disinfection by-products: a critical review. Regul. Toxicol. Pharmacol. 34, (2) 103-124] evaluated the weight of evidence for this exposure and these effects. This investigation updates the previous evaluation and considers all toxicological and epidemiological evidence since the earlier review and reassesses the weight-of-evidence for all of the data on the various effects, outcome by outcome. The updated toxicity weight of evidence found little indication of previously unreported reproductive or developmental toxicity. In particular, the recently published findings of an exceptionally well conducted cohort study of broad scope found no impact of chlorination by-products on the highly controversial outcome of spontaneous abortion, unlike predecessor studies of more limited methodology, leading the authors to recommend no further epidemiologic pursuit for this hypothesis since the cohort was scrutinized very closely and dispelled any concern of such an association. The updated epidemiologic weight of evidence demonstrated that no association with DBP exposure exists for over a dozen outcomes including low and very low birth weight, preterm delivery, some specific congenital anomalies, and neonatal death. The analysis found inconsistent or very weak results for all congenital anomalies/birth defects, all central nervous system anomalies, neural tube defects, and spontaneous abortion. As in the previous article, the updated weight of evidence suggested a positive association with DBP exposure and some measure of growth retardation such as intrauterine growth retardation, small for gestational age, term low birth weight, and small body length or head circumference. Exposure assessment in most epidemiological studies remains inadequate to definitively demonstrate any association of small magnitude.
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Hunter ES, Rogers E, Blanton M, Richard A, Chernoff N. Bromochloro-haloacetic acids: Effects on mouse embryos in vitro and QSAR considerations. Reprod Toxicol 2006; 21:260-6. [PMID: 16293395 DOI: 10.1016/j.reprotox.2005.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 08/30/2005] [Accepted: 09/13/2005] [Indexed: 11/26/2022]
Abstract
The haloacetic acids (HAA) are a family of chemicals that are drinking water disinfection by-products. We previously reported that haloacetic acids, including several bromo- and chloro-HAAs, alter embryonic development when mouse conceptuses are directly exposed to these xenobiotics in whole embryo culture. Craniofacial dysmorphogenesis was observed in exposed embryos and a quantitative structure activity relationship (QSAR) for induction of cranial neural tube dysmorphogenesis was established for a series of 10 HAAs, which also included fluoro- and iodo-HAA representatives. In the current study, we evaluate the effects of exposing neurulation staged (3-6 somite pairs) CD-1 mouse conceptuses to bromochloro- (BCA), dibromochloro- (DBCA) and bromodichloro-acetic (BDCA) acids in whole embryo culture at concentrations ranging from 50 to 2500 microM. Morphological development was assessed after a 26 h exposure period. Exposure of conceptuses to these HAAs produced dysmorphogenesis, including prosencephalic and pharyngeal arch hypoplasia as well as eye and heart tube abnormalities. Benchmark concentrations for induction of neural tube dysmorphogenesis were 63, 500 and 536 microM for BCA, DBCA and BDCA, respectively. Our previously developed HAA QSAR accurately predicted placement of these three chemicals in the larger context of the previously tested di- and tri-HAAs, also correctly predicting that BCA would be more potent than DBCA and BDCA, and that the latter two HAAs would be near equi-potent. This study describes the concentration-dependent induction of dysmorphogenesis in whole embryo culture by three mixed chloro/bromo-HAAs and demonstrates the ability of the HAA QSAR to predict relative potencies within this family of xenobiotics.
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Affiliation(s)
- E Sidney Hunter
- Reproductive Toxicology Division, National Health and Environmental Effects Research Lab, US EPA, RTP, NC 27711, USA.
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Hinckley AF, Bachand AM, Nuckols JR, Reif JS. Identifying public water facilities with low spatial variability of disinfection by-products for epidemiological investigations. Occup Environ Med 2005; 62:494-9. [PMID: 15961627 PMCID: PMC1741051 DOI: 10.1136/oem.2004.017798] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND AND AIMS Epidemiological studies of disinfection by-products (DBPs) and reproductive outcomes have been hampered by misclassification of exposure. In most epidemiological studies conducted to date, all persons living within the boundaries of a water distribution system have been assigned a common exposure value based on facility-wide averages of trihalomethane (THM) concentrations. Since THMs do not develop uniformly throughout a distribution system, assignment of facility-wide averages may be inappropriate. One approach to mitigate this potential for misclassification is to select communities for epidemiological investigations that are served by distribution systems with consistently low spatial variability of THMs. METHODS AND RESULTS A feasibility study was conducted to develop methods for community selection using the Information Collection Rule (ICR) database, assembled by the US Environmental Protection Agency. The ICR database contains quarterly DBP concentrations collected between 1997 and 1998 from the distribution systems of 198 public water facilities with minimum service populations of 100,000 persons. Facilities with low spatial variation of THMs were identified using two methods; 33 facilities were found with low spatial variability based on one or both methods. Because brominated THMs may be important predictors of risk for adverse reproductive outcomes, sites were categorised into three exposure profiles according to proportion of brominated THM species and average TTHM concentration. The correlation between THMs and haloacetic acids (HAAs) in these facilities was evaluated to see whether selection by total trihalomethanes (TTHMs) corresponds to low spatial variability for HAAs. TTHMs were only moderately correlated with HAAs (r = 0.623). CONCLUSIONS Results provide a simple method for a priori selection of sites with low spatial variability from state or national public water facility datasets as a means to reduce exposure misclassification in epidemiological studies of DBPs.
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Affiliation(s)
- A F Hinckley
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1681, USA.
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45
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Wright JM, Bateson TF. A sensitivity analysis of bias in relative risk estimates due to disinfection by-product exposure misclassification. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 2005; 15:212-6. [PMID: 15226753 DOI: 10.1038/sj.jea.7500389] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
We conducted a sensitivity analysis of relative risk estimates using local area mean disinfection by-product exposures. We used Monte Carlo simulations to generate data representing 100 towns, each with 100 births (n=10,000). Each town was assigned a mean total trihalomethane (TTHM) exposure value (mean=45, SD=28) based on a variable number of sampling locations (range 2-10). True maternal TTHM exposure was randomly assigned from a lognormal distribution using that town's true mean value. We compared the effect of a 20 microg/l increase in TTHM exposure on the risk of small-for-gestational age infancy using the true maternal exposure compared to various weighting measures of the town mean exposures. The exposure metrics included: (1) unweighted town mean, (2) town mean weighted by the inverse variance of the town mean, (3) town mean weighted by the inverse standard deviation of the town mean, (4) town mean weighted by 1-(standard deviation of sites per town/mean across all towns), and (5) a randomly selected value from one of the sites within the town of residence. To estimate the magnitude of misclassification bias from using the town mean concentrations, we compared the true exposure odds ratios (1.00, 1.20, 1.50, and 2.00) to the mean exposure odds ratios from the five exposure scenarios. Misclassification bias from the use of unweighted town mean exposures ranged from 19 to 39%, increasing in proportion to the size of the true effect estimates. Weighted town mean TTHM exposures were less biased than the unweighted estimates of maternal exposure, with bias ranging from 0 to 23%. The weighted town mean analyses showed that attenuation of the true effect of DBP exposure was diminished when town mean concentrations with large variability were downweighted. We observed a trade-off between bias and precision in the weighted exposure analyses, with the least biased effects estimates having the widest confidence intervals. Effect attenuation due to intrasystem variability was most evident in absolute and relative terms for larger odds ratios.
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Affiliation(s)
- J Michael Wright
- Office of Research and Development, US EPA, National Center for Environmental Assessment, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, USA.
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Krasner SW, Wright JM. The effect of boiling water on disinfection by-product exposure. WATER RESEARCH 2005; 39:855-864. [PMID: 15743631 DOI: 10.1016/j.watres.2004.12.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2004] [Revised: 12/20/2004] [Accepted: 12/21/2004] [Indexed: 05/24/2023]
Abstract
Chloraminated and chlorinated waters containing bromide were used to determine the impact of boiling on disinfection by-product (DBP) concentrations. No significant changes were detected in the concentrations of the dihalogenated haloacetic acids (DXAAs) (i.e., dichloro-, bromochloro-, dibromoacetic acid) upon boiling of chloraminated water, whereas the levels of the trihalogenated haloacetic acids (TXAAs) (i.e., trichloro- (TCAA), bromodichloro- (BDCAA), dibromochloroacetic acid (DBCAA)) decreased over time (e.g., 9-37% for TCAA). Increased DXAA concentrations (58-68%) were detected in the boiled chlorinated sample, which likely resulted from residual chlorine reacting with DXAA precursors. TCAA concentration was unchanged after boiling chlorinated water for 1 min, but a 30% reduction was observed after 5 min of boiling. BDCAA concentrations decreased 57% upon boiling for 1 min and were completely removed after 2 min of boiling, whereas DBCAA was removed after boiling chlorinated water for 1 min. Trihalomethane concentrations were reduced in both chloraminated (74-98%) and chlorinated (64-98%) water upon boiling. Boiling chloraminated water for 1 min reduced chloroform concentration by 75%. Chloroform was reduced by only 34% in chlorinated water after a 1 min boil, which indicates that simultaneous formation and volatilization of chloroform was occurring. Most of the remaining DBPs (e.g. haloketones, chloral hydrate, haloacetonitriles) were removed by at least 90% after 1 min of boiling in both samples. These data suggest that other mechanisms (e.g., hydrolysis) may have been responsible for removal of the non-volatile DBPs and further highlight the importance of examining individual species when estimating thermal effects on DBP concentrations.
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Affiliation(s)
- Stuart W Krasner
- Metropolitan Water District of Southern California, 700 Moreno Avenue, LaVerne, CA 91750-3399, USA
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47
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Toledano MB, Nieuwenhuijsen MJ, Best N, Whitaker H, Hambly P, de Hoogh C, Fawell J, Jarup L, Elliott P. Relation of trihalomethane concentrations in public water supplies to stillbirth and birth weight in three water regions in England. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:225-32. [PMID: 15687062 PMCID: PMC1277869 DOI: 10.1289/ehp.7111] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Accepted: 10/21/2004] [Indexed: 05/05/2023]
Abstract
We investigated the association between total trihalomethanes (TTHMs) and risk of stillbirth and low and very low birth weight in three water regions in England, 1992-1998; associations with individual trihalomethanes (THMs) were also examined. Modeled estimates of quarterly TTHM concentrations in water zones, categorized as low (< 30 microg/L), medium (30-59 microg/L), or high (> or = 60 microg/L), were linked to approximately 1 million routine birth and stillbirth records using maternal residence at time of birth. In one region, where there was a positive socioeconomic deprivation gradient across exposure categories, there was also a positive, significant association of TTHM with risk of stillbirth and low and very low birth weight. Overall summary estimates across the three regions using a random-effects model to allow for between-region heterogeneity in exposure effects showed small excess risks in areas with high TTHM concentrations for stillbirths [odds ratio (OR) = 1.11; 95% confidence interval (CI), 1.00-1.23), low birth weight (OR = 1.09; 95% CI, 0.93-1.27), and very low birth weight (OR = 1.05; 95% CI, 0.82-1.34). Among the individual THMs, chloroform showed a similar pattern of risk as TTHM, but no association was found with concentrations of bromodichloromethane or total brominated THMs. Our findings overall suggest a significant association of stillbirths with maternal residence in areas with high TTHM exposure. Further work is needed looking at cause-specific stillbirths and effects of other disinfection by-products and to help differentiate between alternative (noncausal) explanations and those that may derive from the water supply.
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Affiliation(s)
- Mireille B Toledano
- Department of Epidemiology and Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
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48
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Younglai EV, Holloway AC, Foster WG. Environmental and occupational factors affecting fertility and IVF success. Hum Reprod Update 2005; 11:43-57. [PMID: 15601728 DOI: 10.1093/humupd/dmh055] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Reproductive function has been shown to be sensitive to changes in the physical, psychosocial and chemical environments. Although reproductive effects of occupational exposure to hazardous chemicals have been well documented in the literature, the potential effects of chemical contaminants at levels representative of contemporary exposures in the general population are much less certain. Evidence for adverse effects of exposure to environmental contaminants is more conclusive among the lower animals than for humans where considerable controversy remains. In addition to potential reproductive hazards of exposure to environmental contaminants, there is also evidence for adverse reproductive effects of the physical and psychosocial environments. In this review we focus on the difficulties involved in linking exposure to putative hazardous substances in environmental and occupational settings to adverse reproductive outcomes, especially success of IVF procedures. We highlight the plausibility of adverse events through animal and cell studies and the application of these results to the interpretation of human data. We consider both the male and female partners since it is essentially their combined contributions of gametes which may be affected by chemicals, which lead to successful outcomes.
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Affiliation(s)
- Edward V Younglai
- Department of Obstetrics & Gynaecology, Reproductive Biology Division, McMaster University, Health Sciences Centre, Hamilton, Ontario, Canada.
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Plewa MJ, Wagner ED, Richardson SD, Thruston AD, Woo YT, McKague AB. Chemical and biological characterization of newly discovered iodoacid drinking water disinfection byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:4713-22. [PMID: 15487777 DOI: 10.1021/es049971v] [Citation(s) in RCA: 306] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Iodoacid drinking water disinfection byproducts (DBPs) were recently uncovered in drinking water samples from source water with a high bromide/iodide concentration that was disinfected with chloramines. The purpose of this paper is to report the analytical chemical identification of iodoacetic acid (IA) and other iodoacids in drinking water samples, to address the cytotoxicity and genotoxicity of IA in Salmonella typhimurium and mammalian cells, and to report a structure-function analysis of IA with its chlorinated and brominated monohalogenated analogues. The iodoacid DBPs were identified as iodoacetic acid, bromoiodoacetic acid, (Z)- and (E)-3-bromo-3-iodopropenoic acid, and (E)-2-iodo-3-methylbutenedioic acid. IA represents a new class (iodoacid DBPs) of highly toxic drinking water contaminants. The cytotoxicity of IA in S. typhimurium was 2.9x and 53.5x higher than bromoacetic acid (BA) and chloroacetic acid (CA), respectively. A similar trend was found with cytotoxicity in Chinese hamster ovary (CHO) cells; IA was 3.2x and 287.5x more potent than BA and CA, respectively. This rank order was also expressed in its genotoxicity with IA being 2.6x and 523.3x more mutagenic in S. typhimurium strain TA100 than BA and CA, respectively. IA was 2.0x more genotoxic than BA and 47.2x more genotoxic than CA in CHO cells. The rank order of the toxicity of these monohalogenated acetic acids is correlated with the electrophilic reactivity of the DBPs. IA is the most toxic and genotoxic DBP in mammalian cells reported in the literature. These data suggest that chloraminated drinking waters that have high bromide and iodide source waters may contain these iodoacids and most likely other iodo-DBPs. Ultimately, it will be important to know the levels at which these iodoacids occur in drinking water in order to assess the potential for adverse environmental and human health risks.
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Affiliation(s)
- Michael J Plewa
- College of Agricultural, Consumer and Environmental Sciences, Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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Simmons JE, Teuschler LK, Gennings C, Speth TF, Richardson SD, Miltner RJ, Narotsky MG, Schenck KD, Hunter ES, Hertzberg RC, Rice G. Component-based and whole-mixture techniques for addressing the toxicity of drinking-water disinfection by-product mixtures. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2004; 67:741-754. [PMID: 15192866 DOI: 10.1080/15287390490428215] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Chemical disinfection of water is of direct public health benefit as it results in decreased water-borne illness. The chemicals used to disinfect water react with naturally occurring organic matter, bromide, and iodide in the source water, resulting in the formation of disinfection by-products (DBPs). Despite the identification of several hundred DBPs, more than 50% of the mass of total organic halide formed during chlorination remains unidentified. The toxic contribution of the DBPs that are formed and present but not yet chemically identified, the unidentified fraction, has been largely unexplored. A better understanding of the potential for adverse human health consequences associated with exposure to the DBPs present in drinking water will be gained by integration of knowledge on the toxicity of individual DBPs; simple, defined DBP mixtures; complex, environmentally realistic DBP mixtures with partial chemical characterization; and the unidentified fraction.
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Affiliation(s)
- Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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