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Bus JS, Su S, Li W, Goodman JE. Styrene lung cancer risk assessment: an alternative evaluation of human lung cancer risk assuming mouse lung tumors are potentially human relevant and operating by a threshold-based non-genotoxic mode of action. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2024; 27:264-286. [PMID: 39056307 DOI: 10.1080/10937404.2024.2380449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Rodent inhalation studies indicate styrene is a mouse lung-specific carcinogen. Mode-of-action (MOA) analyses indicate that the lung tumors cannot be excluded as weakly quantitatively relevant to humans due to shared oxidative metabolites detected in rodents and humans. However, styrene also is not genotoxic following in vivo dosing. The objective of this review was to characterize occupational and general population cancer risks by conservatively assuming mouse lung tumors were relevant to humans but operating by a non-genotoxic MOA. Inhalation cancer values reference concentrations for respective occupational and general population exposures (RfCcar-occup and RfCcar-genpop) were derived from initial benchmark dose (BMD) modeling of mouse inhalation tumor dose-response data. An overall lowest BMDL10 of 4.7 ppm was modeled for lung tumors, which was further duration- and dose-adjusted by physiologically based pharmacokinetic (PBPK) modeling to derive RfCcar-occup/genpop values of 6.2 ppm and 0.8 ppm, respectively. With the exception of open-mold fiber reinforced composite workers not using personal protective equipment (PPE), the RfCcar-occup/genpop values are greater than typical occupational and general population human exposures, thus indicating styrene exposures represent a low potential for human lung cancer risk. Consistent with this conclusion, a review of styrene occupational epidemiology did not support a conclusion of an association between styrene exposure and lung cancer occurrence, and further supports a conclusion that the conservatively derived RfCcar-occup is lung cancer protective.
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Affiliation(s)
- J S Bus
- Exponent, Inc, Palo Alto, CA, USA
| | - S Su
- Exponent, Inc, Palo Alto, CA, USA
| | - W Li
- Gradient, Boston, MA, USA
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Winiarska E, Jutel M, Zemelka-Wiacek M. The potential impact of nano- and microplastics on human health: Understanding human health risks. ENVIRONMENTAL RESEARCH 2024; 251:118535. [PMID: 38460665 DOI: 10.1016/j.envres.2024.118535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/29/2024] [Accepted: 02/20/2024] [Indexed: 03/11/2024]
Abstract
Plastics are used all over the world. Unfortunately, due to limited biodegradation, plastics cause a significant level of environmental pollution. The smallest recognized to date are termed nanoplastics (1 nm [nm] up to 1 μm [μm]) and microplastics (1 μm-5 mm). These nano- and microplastics can enter the human body through the respiratory system via inhalation, the digestive tract via consumption of contaminated food and water, or penetration through the skin via cosmetics and clothes contact. Bioaccumulation of plastics in the human body can potentially lead to a range of health issues, including respiratory disorders like lung cancer, asthma and hypersensitivity pneumonitis, neurological symptoms such as fatigue and dizziness, inflammatory bowel disease and even disturbances in gut microbiota. Most studies to date have confirmed that nano- and microplastics can induce apoptosis in cells and have genotoxic and cytotoxic effects. Understanding the cellular and molecular mechanisms of plastics' actions may help extrapolate the risks to humans. The article provides a comprehensive review of articles in databases regarding the impact of nano- and microplastics on human health. The review included retrospective studies and case reports of people exposed to nanoplastics and microplastics. This research highlights the need for further research to fully understand the extent of the impact of plastics on human health.
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Affiliation(s)
- Ewa Winiarska
- Department of Clinical Immunology, Wroclaw Medical University, Wroclaw, Poland
| | - Marek Jutel
- Department of Clinical Immunology, Wroclaw Medical University, Wroclaw, Poland; ALL-MED Medical Research Institute, Wroclaw, Poland
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Frank EA, Meek MEB. Procedural application of mode-of-action and human relevance analysis: styrene-induced lung tumors in mice. Crit Rev Toxicol 2024; 54:134-151. [PMID: 38440945 DOI: 10.1080/10408444.2024.2310600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 01/18/2024] [Indexed: 03/06/2024]
Abstract
Risk assessment of human health hazards has traditionally relied on experiments that use animal models. Although exposure studies in rats and mice are a major basis for determining risk in many cases, observations made in animals do not always reflect health hazards in humans due to differences in biology. In this critical review, we use the mode-of-action (MOA) human relevance framework to assess the likelihood that bronchiolar lung tumors observed in mice chronically exposed to styrene represent a plausible tumor risk in humans. Using available datasets, we analyze the weight-of-evidence 1) that styrene-induced tumors in mice occur through a MOA based on metabolism of styrene by Cyp2F2; and 2) whether the hypothesized key event relationships are likely to occur in humans. This assessment describes how the five modified Hill causality considerations support that a Cyp2F2-dependent MOA causing lung tumors is active in mice, but only results in tumorigenicity in susceptible strains. Comparison of the key event relationships assessed in the mouse was compared to an analogous MOA hypothesis staged in the human lung. While some biological concordance was recognized between key events in mice and humans, the MOA as hypothesized in the mouse appears unlikely in humans due to quantitative differences in the metabolic capacity of the airways and qualitative uncertainties in the toxicological and prognostic concordance of pre-neoplastic and neoplastic lesions arising in either species. This analysis serves as a rigorous demonstration of the framework's utility in increasing transparency and consistency in evidence-based assessment of MOA hypotheses in toxicological models and determining relevance to human health.
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Affiliation(s)
- Evan A Frank
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - M E Bette Meek
- School of Epidemiology and Public Health in the Faculty of Medicine, University of Ottawa, Ottawa, Canada
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Turner MC, Cogliano V, Guyton K, Madia F, Straif K, Ward EM, Schubauer-Berigan MK. Research Recommendations for Selected IARC-Classified Agents: Impact and Lessons Learned. ENVIRONMENTAL HEALTH PERSPECTIVES 2023; 131:105001. [PMID: 37902675 PMCID: PMC10615125 DOI: 10.1289/ehp12547] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 10/31/2023]
Abstract
BACKGROUND The International Agency for Research on Cancer (IARC) Monographs program assembles expert working groups who publish a critical review and evaluation of data on agents of interest. These comprehensive reviews provide a unique opportunity to identify research needs to address classification uncertainties. A multidisciplinary expert review and workshop held in 2009 identified research gaps and needs for 20 priority occupational chemicals, metals, dusts, and physical agents, with the goal of stimulating advances in epidemiological studies of cancer and carcinogen mechanisms. Overarching issues were also described. OBJECTIVES In this commentary we review the current status of the evidence for the 20 priority agents identified in 2009. We examine whether identified Research Recommendations for each agent were addressed and their potential impact on resolving classification uncertainties. METHODS We reviewed the IARC classifications of each of the 20 priority agents and identified major new epidemiological and human mechanistic studies published since the last evaluation. Information sources were either the published Monograph for agents that have been reevaluated or, for agents not yet reevaluated, Advisory Group reports and literature searches. Findings are described in view of recent methodological developments in Monographs evidence evaluation processes. DISCUSSION The majority of the 20 priority agents were reevaluated by IARC since 2009. The overall carcinogen classifications of 9 agents advanced, and new cancer sites with either "sufficient" or "limited" evidence of carcinogenicity were also identified for 9 agents. Examination of published findings revealed whether evidence gaps and Research Recommendations have been addressed and highlighted remaining uncertainties. During the past decade, new research addressed a range of the 2009 recommendations and supported updated classifications for priority agents. This supports future efforts to systematically apply findings of Monograph reviews to identify research gaps and priorities relevant to evaluation criteria established in the updated IARC Monograph Preamble. https://doi.org/10.1289/EHP12547.
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Affiliation(s)
- Michelle C. Turner
- Barcelona Institute for Global Health, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
- CIBER Epidemiología y Salud Pública, Madrid, Spain
| | - Vincent Cogliano
- California Environmental Protection Agency Office of Environmental Health Hazard Assessment, Oakland, California, USA
| | - Kathryn Guyton
- National Academies of Sciences, Engineering, and Medicine, Washington, District of Columbia, USA
| | - Federica Madia
- International Agency for Research on Cancer, Lyon, France
| | - Kurt Straif
- Barcelona Institute for Global Health, Barcelona, Spain
- Boston College, Massachusetts, USA
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Sathiakumar N, Bolaji BE, Brill I, Chen L, Tipre M, Leader M, Arora T, Delzell E. 1,3-Butadiene, styrene and lymphohaematopoietic cancers among North American synthetic rubber polymer workers: exposure-response analyses. Occup Environ Med 2021; 78:859-868. [PMID: 34108254 PMCID: PMC8606437 DOI: 10.1136/oemed-2020-107197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/01/2021] [Accepted: 04/29/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To evaluate exposure-response between 1,3-butadiene, styrene and lymphohaematopoietic cancers in an updated cohort of workers at six North American plants that made synthetic rubber polymers. METHODS Employees were followed from 1943 through 2009 to determine mortality outcomes. Cox regression analyses estimated rate ratios (RRs) and 95% CIs by quartile of cumulative exposure to butadiene or styrene, measured in parts per million-years (ppm-years), and exposure-response trends for all leukaemia, lymphoid leukaemia, myeloid leukaemia, acute myeloid leukaemia, non-Hodgkin's lymphoma (NHL), multiple myeloma and all B-cell malignancies. RESULTS Among 21 087 workers, adjusted RRs for butadiene and all leukaemia (132 deaths) rose with increasing exposure, with an RR of 2.53 (95% CI 1.37 to 4.67) in the highest exposure quartile (≥363.64 ppm-years), and the exposure-response trend was statistically significant for all leukaemia (p=0.014) and for lymphoid leukaemia (52 deaths, p=0.007). Styrene exposure-response trends for all leukaemia and lymphoid leukaemia were less consistent than those for butadiene. Cumulative exposures to butadiene and styrene were not associated consistently with myeloid leukaemias or the B-cell malignancies, NHL and multiple myeloma. CONCLUSIONS We confirmed a positive exposure-response relationship between butadiene and all leukaemia among workers, most of whom had coexposure to styrene. Results supported an association between butadiene and lymphoid leukaemia, but not myeloid leukaemia, and provided little evidence of any association of butadiene or styrene exposures with major subtypes of B-cell malignancies other than lymphoid leukaemia, including NHL and multiple myeloma.
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Affiliation(s)
- Nalini Sathiakumar
- Epidemiology, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
| | - Bolanle E Bolaji
- Epidemiology, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
| | - Ilene Brill
- Epidemiology, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
| | - Ligong Chen
- Biostatistician, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
| | - Meghan Tipre
- Medicine, The University of Alabama at Birmingham Department of Medicine, Birmingham, Alabama, USA
| | - Mark Leader
- Epidemiology, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
| | - Tarun Arora
- Epidemiology, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
| | - Elizabeth Delzell
- Epidemiology, The University of Alabama at Birmingham School of Public Health, Birmingham, Alabama, USA
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Cong Z, Liu W, Song Z, Zhu M, Zhang Y, Yao W, Wu S, Gao E. A Zn‐based metal–organic framework for the irreversible determination of trace biomarkers of styrene and ethylbenzene in urine. Appl Organomet Chem 2021. [DOI: 10.1002/aoc.6468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zhenzhong Cong
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
| | - Wei Liu
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
| | - Zhenfeng Song
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
| | - Mingchang Zhu
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
| | - Ying Zhang
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
| | - Wei Yao
- School of Chemical Engineering University of Science and Technology Liaoning Anshan China
| | - Shuangyan Wu
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
| | - Enjun Gao
- The Key Laboratory of the Inorganic Molecule‐Based Chemistry of Liaoning Province and Laboratory of Coordination Chemistry Shenyang University of Chemical Technology Shenyang China
- School of Chemical Engineering University of Science and Technology Liaoning Anshan China
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Bertke SJ, Keil AP, Daniels RD. Lung Cancer Mortality and Styrene Exposure in the Reinforced-Plastics Boatbuilding Industry: Evaluation of Healthy Worker Survivor Bias. Am J Epidemiol 2021; 190:1784-1792. [PMID: 33847736 DOI: 10.1093/aje/kwab108] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 11/15/2022] Open
Abstract
The evidence for styrene's being a human lung carcinogen has been inconclusive. Occupational cohorts within the reinforced-plastics industry are an ideal population in which to study this association because of their relatively high levels of exposure to styrene and lack of concomitant exposures to other known carcinogens. However, healthy worker survivor bias (HWSB), where healthier workers stay employed longer and thus have higher exposure potential, is a likely source of confounding bias for exposure-response associations, in part due to styrene's acute effects. Through December 31, 2016, we studied a cohort of 5,163 boatbuilders exposed to styrene in Washington State who were employed between 1959 and 1978; prior regression analyses had demonstrated little evidence for an exposure-response relationship between styrene exposure and lung cancer mortality. Based on estimates of necessary components of HWSB, we found evidence for a potentially large HWSB. Using g-estimation of a structural nested model to account for HWSB, we estimated that 1 year of styrene exposure at more than 30 parts per million accelerated time to lung cancer death by 2.29 years (95% confidence interval: 1.53, 2.94). Our results suggest possibly strong HWSB in our small cohort and indicate that large, influential studies of styrene-exposed workers may suffer from similar biases, warranting a reassessment of the evidence of long-term health effects of styrene exposure.
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1,3-Butadiene, styrene and selected outcomes among synthetic rubber polymer workers: Updated exposure-response analyses. Chem Biol Interact 2021; 347:109600. [PMID: 34324853 DOI: 10.1016/j.cbi.2021.109600] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/14/2021] [Accepted: 07/22/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE - To evaluate exposure-response relationships between 1,3-butadiene and styrene and selected diseases among synthetic rubber polymer workers. METHODS - 21,087 workers (16,579 men; 4508 women) were followed from 1943 through 2009 to determine mortality outcomes. Cox regression models estimated rate ratios (RRs) and 95% confidence intervals (CIs) by quartile of cumulative exposure to butadiene or styrene and exposure-response trends for cancers of the bladder, lung, kidney, esophagus and pancreas, and for all nonmalignant respiratory disease (NMRD), chronic obstructive pulmonary disease (COPD) and pneumonia. RESULTS - Bladder cancer RRs were 2.13 (95% CI = 1.03 to 4.41) and 1.64 (95% CI = 0.76 to 3.54) in the highest quartiles of cumulative exposure to butadiene and styrene, respectively, and exposure-response trends were positive for both monomers (butadiene, trend p = 0.001; styrene, trend p = 0.004). Further analyses indicated that the exposure-response effect of each monomer on bladder cancer was demonstrated clearly only in the subgroup with high cumulative exposure (at or above the median) to the other monomer. Lung cancer was not associated with either monomer among men. Among women, lung cancer RRs were above 1.0 in each quartile of cumulative exposure to each monomer, but exposure-response was not seen for either monomer. Male workers had COPD RRs slightly above 1.0 in each quartile of cumulative exposure to each monomer, but there was no evidence of exposure-response among the exposed. Monomer exposure was not consistently associated with COPD in women or with the other cancer outcomes. CONCLUSIONS - This study found a positive exposure-response relationship between monomer exposures and bladder cancer. The independent effects of butadiene and styrene on this cancer could not be delineated. In some analyses, monomer exposure was associated with lung cancer in women and with COPD in men, but inconsistent exposure-response trends and divergent results by sex do not support a causal interpretation of the isolated positive associations.
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DeBono NL, Logar-Henderson C, Warden H, Shakik S, Dakouo M, MacLeod J, Demers PA. Cancer surveillance among workers in plastics and rubber manufacturing in Ontario, Canada. Occup Environ Med 2020; 77:847-856. [PMID: 32847990 DOI: 10.1136/oemed-2020-106581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/08/2020] [Accepted: 07/24/2020] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Occupational exposure to agents in plastics and rubber manufacturing has been associated with elevated risk of certain cancers. We sought to evaluate cancer risk among workers employed in occupations and industries with these exposures as part of an ongoing surveillance programme in Ontario, Canada. METHODS The Occupational Disease Surveillance System (ODSS) cohort was established using workers' compensation claims data and includes 2.18 million workers employed from 1983 to 2014. Workers were followed for site-specific cancer diagnoses in the Ontario Cancer Registry through 2016. Cox proportional hazard models were used to estimate adjusted HR and 95% CI. RESULTS We identified 81 127 workers employed in plastics and rubber manufacturing industries or materials processing and product fabricating occupations. Compared with all other women in the ODSS, those in materials processing occupations had an elevated rate of lung cancer (HR 1.38, 95% CI 1.20 to 1.58) that was not observed among men. An elevated rate of breast cancer was observed among female labourers (HR 1.36, 95% CI 1.01 to 1.82) and moulders (HR 1.47, 95% CI 0.91 to 2.37) in plastics and rubber product fabricating occupations. Overall, elevated rates were observed for oesophageal, liver, stomach, prostate and kidney cancer in job-specific subgroups, including mixing and blending, bonding and cementing, and labouring. There was little evidence of association for lymphatic or haematopoietic cancers. CONCLUSIONS Findings for lung and breast cancer in women are consistent with other studies and warrant further attention in Ontario. Given the relatively young age at end of follow-up, surveillance in these workers should continue as the cohort ages.
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Affiliation(s)
- Nathan L DeBono
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada .,Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada
| | | | - Hunter Warden
- Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada.,Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Sharara Shakik
- Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada
| | - Mamadou Dakouo
- Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada
| | - Jill MacLeod
- Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada
| | - Paul A Demers
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.,Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada
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Daniels RD, Bertke SJ. Exposure-response assessment of cancer mortality in styrene-exposed boatbuilders. Occup Environ Med 2020; 77:706-712. [PMID: 32471836 DOI: 10.1136/oemed-2020-106445] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/29/2020] [Accepted: 05/11/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To improve exposure estimates and reexamine exposure-response relationships between cumulative styrene exposure and cancer mortality in a previously studied cohort of US boatbuilders exposed between 1959 and 1978 and followed through 2016. METHODS Cumulative styrene exposure was estimated from work assignments and air-sampling data. Exposure-response relationships between styrene and select cancers were examined in Cox proportional hazards models matched on attained age, sex, race, birth cohort and employment duration. Models adjusted for socioeconomic status (SES). Exposures were lagged 10 years or by a period maximising the likelihood. HRs included 95% profile-likelihood CIs. Actuarial methods were used to estimate the styrene exposure corresponding to 10-4 extra lifetime risk. RESULTS The cohort (n= 5163) contributed 201 951 person-years. Exposures were right-skewed, with mean and median of 31 and 5.7 ppm-years, respectively. Positive, monotonic exposure-response associations were evident for leukaemia (HR at 50 ppm-years styrene = 1.46; 95% CI 1.04 to 1.97) and bladder cancer (HR at 50 ppm-years styrene =1.64; 95% CI 1.14 to 2.33). There was no evidence of confounding by SES. A working lifetime exposure to 0.05 ppm styrene corresponded to one extra leukaemia death per 10 000 workers. CONCLUSIONS The study contributes evidence of exposure-response associations between cumulative styrene exposure and cancer. Simple risk projections at current exposure levels indicate a need for formal risk assessment. Future recommendations on worker protection would benefit from additional research clarifying cancer risks from styrene exposure.
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Affiliation(s)
- Robert Douglas Daniels
- Division of Science Integration, National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA
| | - Stephen J Bertke
- Division of Field Studies and Engineering, National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA
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11
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Mortality Among Men and Women in the North American Synthetic Rubber Industry, 1943 to 2009. J Occup Environ Med 2019; 61:887-897. [DOI: 10.1097/jom.0000000000001688] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Banton MI, Bus JS, Collins JJ, Delzell E, Gelbke HP, Kester JE, Moore MM, Waites R, Sarang SS. Evaluation of potential health effects associated with occupational and environmental exposure to styrene - an update. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2019; 22:1-130. [PMID: 31284836 DOI: 10.1080/10937404.2019.1633718] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The potential chronic health risks of occupational and environmental exposure to styrene were evaluated to update health hazard and exposure information developed since the Harvard Center for Risk Analysis risk assessment for styrene was performed in 2002. The updated hazard assessment of styrene's health effects indicates human cancers and ototoxicity remain potential concerns. However, mechanistic research on mouse lung tumors demonstrates these tumors are mouse-specific and of low relevance to human cancer risk. The updated toxicity database supports toxicity reference levels of 20 ppm (equates to 400 mg urinary metabolites mandelic acid + phenylglyoxylic acid/g creatinine) for worker inhalation exposure and 3.7 ppm and 2.5 mg/kg bw/day, respectively, for general population inhalation and oral exposure. No cancer risk value estimates are proposed given the established lack of relevance of mouse lung tumors and inconsistent epidemiology evidence. The updated exposure assessment supports inhalation and ingestion routes as important. The updated risk assessment found estimated risks within acceptable ranges for all age groups of the general population and workers with occupational exposures in non-fiber-reinforced polymer composites industries and fiber-reinforced polymer composites (FRP) workers using closed-mold operations or open-mold operations with respiratory protection. Only FRP workers using open-mold operations not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures. In addition, given the reported interaction of styrene exposure with noise, noise reduction to sustain levels below 85 dB(A) needs be in place.
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Affiliation(s)
- M I Banton
- a Gorge View Consulting LLC , Hood River , OR , USA
| | - J S Bus
- b Health Sciences , Exponent , Midland , MI , USA
| | - J J Collins
- c Health Sciences , Saginaw Valley State University , Saginaw , MI , USA
| | - E Delzell
- d Private consultant , Birmingham , AL , USA
| | | | - J E Kester
- f Kester Consulting LLC , Wentzville , MO , USA
| | | | - R Waites
- h Sabic , Innovative Plastics US LLC , Mount Vernon , IN , USA
| | - S S Sarang
- i Shell Health , Shell International , Houston , TX , USA
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Kobos L, Teimouri Sendesi SM, Whelton AJ, Boor BE, Howarter JA, Shannahan J. In vitro toxicity assessment of emitted materials collected during the manufacture of water pipe plastic linings. Inhal Toxicol 2019; 31:131-146. [PMID: 31187656 DOI: 10.1080/08958378.2019.1621966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Objectives: US water infrastructure is in need of widespread repair due to age-related deterioration. Currently, the cured-in-place (CIPP) procedure is the most common method for water pipe repair. This method involves the on-site manufacture of a new polymer composite plastic liner within the damaged pipe. The CIPP process can release materials resulting in occupational and public health concerns. To understand hazards associated with CIPP-related emission exposures, an in vitro toxicity assessment was performed. Materials and Methods: Mouse alveolar epithelial and alveolar macrophage cell lines and condensates collected at 3 worksites utilizing styrene-based resins were utilized for evaluations. All condensate samples were normalized based on the major emission component, styrene. Further, a styrene-only exposure group was used as a control to determine mixture related toxicity. Results: Cytotoxicity differences were observed between worksite samples, with the CIPP worksite 4 sample inducing the most cell death. A proteomic evaluation was performed, which demonstrated styrene-, worksite-, and cell-specific alterations. This examination of protein expression changes determined potential biomarkers of exposure including transglutaminase 2, advillin, collagen type 1, perilipin-2, and others. Pathway analysis of exposure-induced proteomic alterations identified MYC and p53 to be regulators of cellular responses. Protein changes were also related to pathways involved in cell damage, immune response, and cancer. Conclusions: Together these findings demonstrate potential risks associated with the CIPP procedure as well as variations between worksites regarding emissions and toxicity. Our evaluation identified biological pathways that require a future evaluation and also demonstrates that exposure assessment of CIPP worksites should examine multiple chemical components beyond styrene, as many cellular responses were styrene-independent.
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Affiliation(s)
- Lisa Kobos
- a School of Health Sciences, College of Human and Health Sciences , Purdue University , West Lafayette , IN , USA
| | - Seyedeh Mahboobeh Teimouri Sendesi
- b Lyles School of Civil Engineering and Division of Environmental and Ecological Engineering , College of Engineering, Purdue University , West Lafayette , IN , USA
| | - Andrew J Whelton
- b Lyles School of Civil Engineering and Division of Environmental and Ecological Engineering , College of Engineering, Purdue University , West Lafayette , IN , USA
| | - Brandon E Boor
- b Lyles School of Civil Engineering and Division of Environmental and Ecological Engineering , College of Engineering, Purdue University , West Lafayette , IN , USA
| | - John A Howarter
- c Division of Environmental and Ecological Engineering, and School of Materials Engineering, College of Engineering , Purdue University , West Lafayette , IN , USA
| | - Jonathan Shannahan
- a School of Health Sciences, College of Human and Health Sciences , Purdue University , West Lafayette , IN , USA
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