Population-based dietary intakes and tap water concentrations for selected elements in the EPA region V National Human Exposure Assessment Survey (NHEXAS)

Water, Water Everywhere, but Every Drop Unique: Challenges in the Science to Understand the Role of Contaminants of Emerging Concern in the Management of Drinking Water Supplies

The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.

Biomonitoring of Urinary Nickel Successfully Protects Employees and Introduces Effective Interventions

Nickel is a heavy metal used in many industries. Nickel exposure can induce respiratory diseases and allergic reactions, and increase cancer risk. This study evaluated the introduction of a grinding and polishing system to prevent injuries from nickel toxicity in workers. We performed a controlled, interventional, before-and-after study from January 2018 to December 2019 at a faucet component industrial manufacturing site. Results from workplace environmental monitoring, questionnaire responses, and biomonitoring were collected before and after the intervention. Thirty-seven workers (100% men) aged 25.0 (interquartile range (IQR): 22.0–33.5) years were categorized into two groups, those with and without nickel exposure. In the exposed group, the median exposure time was 18.0 months (IQR 14.0–20.0 months). Urinary nickel concentration was lower in the exposed group than in the non-exposed group (13.8 (IQR 1.7–20.7); 23.1 (IQR 11.3–32.8) μg/g creatinine, respectively; p = 0.047). The median urinary nickel concentration was lower in the second year than in the first year (17.4 (IQR 2.2–27.4), 7.7 (IQR 4.3–18.5) μg/g creatinine, respectively; p = 0.022). Significant reductions in urinary nickel concentration were observed following the intervention and educational program. Thus, biomonitoring of urinary nickel concentration can successfully reflect the effectiveness of interventions and their relationship to nickel exposure.

Toxic element levels in ingredients and commercial pet foods

Nowadays, there is a growing concern about contamination of toxic metals (TM) in pet food due to the great potential for health risks of these elements. TM concentrations in commercial pet foods (n = 100) as well as in ingredients used in their composition (n = 100) were analyzed and compared to the Food and Drug Administration (FDA) maximum tolerable level (MTL), and the TM concentrations found in the different sources of carbohydrate, protein, and fat were compared. The TM concentrations were determined by inductively coupled plasma with optical emission spectrometry (ICP-OES). Concentrations above the MTL for aluminum, mercury, lead, uranium, and vanadium were observed in both dog and cat foods, and the percentage of dog foods that exceeded the MTL of these TM were: 31.9%; 100%; 80.55%; 95.83%; and 75%, respectively, and in cat foods: 10.71%; 100%; 32.14%; 85.71%; 28.57%, respectively. The MTL values of these TMs and the mean values in dog foods (mg/kg dry matter basis) (MTL [mean ± standard deviation]) were: aluminum: 200 (269.17 ± 393.74); mercury: 0.27 (2.51 ± 1.31); lead: 10 (12.55 ± 4.30); uranium: 10 (76.82 ± 28.09); vanadium: 1 (1.35 ± 0.69), while in cat foods were: aluminum: 200 (135.51 ± 143.95); mercury: 0.27 (3.47 ± 4.31); lead: 10 (9.13 ± 5.42); uranium: 10 (49.83 ± 29.18); vanadium: 1 (0.81 ± 0.77). Dry foods presented higher concentrations of most TM (P < 0.05) than wet foods (P < 0.05). Among the carbohydrate sources, there were the highest levels of all TM except cobalt, mercury, and nickel in wheat bran (P < 0.05), while among the protein sources, in general, animal by-products had higher TM concentrations than plant-based ingredients. Pork fat had higher concentrations of arsenic, mercury, and antimony than fish oil and poultry fat. It was concluded that the pet foods evaluated in this study presented high concentrations of the following TM: aluminum, mercury, lead, uranium, and vanadium.

Damage to the Testicular Structure of Rats by Acute Oral Exposure of Cadmium

Cadmium (Cd) is one of the most important heavy metal toxicants, used throughout the world at the industrial level. It affects humans through environmental and occupational exposure and animals through the environment. The most severe effects of oral exposure to Cd on the male reproductive system, particularly spermatogenesis, have not been discussed. In this study, we observed the damage to the testes and heritable DNA caused by oral exposure to Cd. Adult male Sprague–Dawley rats were divided into four groups: a control group and three groups treated with 5, 10, and 15 mg Cd/kg/day for 17 days by oral gavage. Our results revealed that Cd significantly decreases weight gain in 10 and 15 mg/kg groups, whereas the 5 mg/kg groups showed no difference in weight gain. The histopathology showed adverse structural effects on the rat testis by significantly reducing the thickness of the tunica albuginea, the diameter of the tubular lumen, and the interstitial space among seminiferous tubules and increasing the height of the epithelium and the diameter of the seminiferous tubules in Cd treated groups. Comet assay in epididymal sperms demonstrated a significant difference in the lengths of the head and comet in all the 3 Cd treated groups, indicating damage in heritable DNA, although variations in daily sperm production were not significant. Only a slight decrease in sperm count was reported in Cd-treated groups as compared to the control group, whereas the tail length, percentage of DNA in head, and tail showed no significant difference in control and all the experimental groups. Overall, our findings indicate that Cd toxicity must be controlled using natural sources, such as herbal medicine or bioremediation, with non-edible plants, because it could considerably affect heritable DNA and induce damage to the reproductive system.

Individual species and cumulative mixture relationships of 24-hour urine metal concentrations with DNA methylation age variables in older men

BACKGROUND

Globally, toxic metal exposures are a well-recognized risk factor for many adverse health outcomes. DNA methylation-based measures of biological aging are predictive of disease, but have poorly understood relationships with metal exposures.

OBJECTIVE

We performed a pilot study examining the relationships of 24-h urine metal concentrations with three novel DNA methylation-based measures of biological aging: DNAmAge, GrimAge, and PhenoAge.

METHODS

We utilized a previously established urine panel of five common metals [arsenic (As), cadmium (Cd), lead (Pb), manganese (Mn), and mercury (Hg)] found in a subset of the elderly US Veterans Affairs Normative Aging Study cohort (N = 48). The measures of DNA methylation-based biological age were calculated using CpG sites on the Illumina HumanMethylation450 BeadChip. Bayesian Kernel Machine Regression (BKMR) was used to determine metals most important to the aging outcomes and the relationship of the cumulative metal mixture with the outcomes. Individual relationships of important metals with the biological aging outcomes were modeled using fully-adjusted linear models controlling for chronological age, renal function, and lifestyle/environmental factors.

RESULTS

Mn was selected as important to PhenoAge. A 1 ng/mL increase in urine Mn was associated with a 9.93-year increase in PhenoAge (95%CI: 1.24, 18.61, p = 0.03). The cumulative urine metal mixture was associated with increases in PhenoAge. Compared to a model where each metal in the mixture is set to its 50th percentile value, every one-unit increase of the cumulative mixture with each metal at its 70th percentile was associated with a 2.53-year increase in PhenoAge (95%CI: 0.10, 4.96, P<0.05).

CONCLUSION

Our results add novel evidence that metals detected in urine are associated with increases in biological aging and suggest that these DNA methylation-based measures may be useful for identifying individuals at-risk for diseases related to toxic metal exposures. Further research is necessary to confirm these findings more broadly.

Effects of Cadmium on ZO-1 Tight Junction Integrity of the Blood Brain Barrier

Cadmium (Cd) is a highly toxic environmental pollutant released from the smelting and refining of metals and cigarette smoking. Oral exposure to cadmium may result in adverse effects on a number of tissues, including the central nervous system (CNS). In fact, its toxicity has been related to neurological disorders, as well as neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Under normal conditions, Cd barely reaches the brain in adults because of the presence of the blood-brain barrier (BBB); however, it has been demonstrated that Cd-dependent BBB alteration contributes to pathogenesis of neurodegeneration. However, the mechanism underlying Cd-dependent BBB alteration remain obscure. Here, we investigated the signaling pathway of Cd-induced tight junction (TJ), F-actin, and vimentin protein disassembly in a rat brain endothelial cell line (RBE4). RBE4 cells treated with 10 μM cadmium chloride (CdCl2) showed a dose- and time-dependent significant increase in reactive oxygen species (ROS) production. This phenomenon was coincident with the alteration of the TJ zonula occludens-1 (ZO-1), F-actin, and vimentin proteins. The Cd-dependent ROS increase elicited the upregulation of GRP78 expression levels, a chaperone involved in endoplasmic reticulum (ER) stress that induces caspase-3 activation. Further signal profiling by the pannexin-1 (PANX1) specific inhibitor 10Panx revealed a PANX1-independent increase in ATP spillage in Cd-treated endothelial cells. Our results point out that a ROS-dependent ER stress-mediated signaling pathway involving caspase-3 activation and ATP release is behind the BBB morphological alterations induced by Cd.

Evaluation of Arsenic, Cadmium, Lead and Mercury Contamination in Over-the-Counter Available Dry Dog Foods With Different Animal Ingredients (Red Meat, Poultry, and Fish)

Objectives: To examine the relative levels of heavy metals and arsenic content in commercial dog foods (arsenic, cadmium, lead and mercury) of 51 over-the-counter maintenance or all-life-stage dry dog foods. All products were chosen and segregated based on meat sources (fish, poultry, red-meat—17 products from each category) as animal protein sources being the primary contaminated ingredient due to bioaccumulation.

Methods: Inductively coupled plasma mass spectrometry (ICP-MS) was performed on products that were classified as fish, red meat (beef, pork, venison, bison) or poultry (chicken, turkey, duck) based. A non-Gaussian data distribution for each heavy metal within category distribution led to non-parametric statistical testing and median (range) descriptive statistics. Comparison to average human consumption based on mg/megacalorie (Mcal)was also examined.

Results: Based on caloric consumption, total arsenic and heavy metal consumption is higher in dogs than in humans; however chronic toxic exposure levels are highly unlikely. Fish-based diets had significantly higher arsenic, cadmium and mercury content than the poultry or red meat-based diets (p < 0.01). Red meat-based diets (beef, venison and bison) had higher lead concentrations than poultry and fish-based diets (p < 0.03).

Clinical Significance: Based on the findings, commercial dog foods appear to be safe for chronic consumption and concentrations of the heavy metals were dependent on primary protein sources. Overall, poultry-based diets had relatively lower heavy metal and arsenic content than red meat and fish-based diets. Despite the safety of most pet foods occasional outliers for lead render some concern for chronic exposure based on other species toxicity data and a lack of data in dogs.

Selenium and zinc: Two key players against cadmium-induced neuronal toxicity

Cadmium (Cd), a worldwide occupational pollutant, is an extremely toxic heavy metal, capable of damaging several organs, including the brain. Its toxicity has been related to neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. The neurotoxic potential of Cd has been attributed to the changes induced in the brain enzyme network involved in counteracting oxidative stress. On the other hand, it is also known that trace elements, such as zinc (Zn) and selenium (Se), required for optimal brain functions, appears to have beneficial effects on the prevention of Cd intoxication. Based on this protective effect of Zn and Se, we aimed to investigate whether these elements could protect neuronal cells from Cd-induced excitotoxicity. The experiments, firstly carried out on SH-SY5Y catecholaminergic neuroblastoma cell line, demonstrated that the treatment with 10 μM cadmium chloride (CdCl₂) for 24 h caused significant modifications both in terms of oxidative stress and neuronal sprouting, triggered by endoplasmic reticulum (ER) stress. The evaluation of the effectiveness of 50 μM of zinc chloride (ZnCl₂) and 100 nM sodium selenite (Na₂SeO₃) treatments showed that both elements were able to attenuate the Cd-dependent neurotoxicity. However, considering that following induction with retinoic acid (RA), the neuroblastoma cell line undergoes differentiation into a cholinergic neurons, our second aim was to verify the zinc and selenium efficacy also in this neuronal phenotype. Our data clearly demonstrated that, while zinc played a crucial role on neuroprotection against Cd-induced neurotoxicity independently from the cellular phenotype, selenium is ineffective in differentiated cholinergic cells, supporting the notion that the molecular events occurring in differentiated SH-SY5Y cells are critical for the response to specific stimuli.

Association of Dietary Intake and Biomarker Levels of Arsenic, Cadmium, Lead, and Mercury among Asian Populations in the United States: NHANES 2011-2012

BACKGROUND

We have recently shown that biomarker levels of selected metals are higher in Asians than in other U.S. ethnic groups, with important differences within selected Asian subgroups. Much of this difference may be dietary in origin; however, this is not well established.

OBJECTIVE

We evaluated dietary intake of toxic metals as a source of increased biomarker levels of metals among U.S. Asians.

METHODS

We estimated daily food consumption and dietary intake of arsenic, cadmium, lead, and mercury by combining 24-hr dietary intake recall data from the 2011-2012 National Health and Nutrition Examination Survey (NHANES) with data from the USDA Food Composition Intake Database and FDA Total Dietary Study. We analyzed associations between dietary metal intake and biomarker levels of the metals using linear regression. Further, estimated food consumption and metal intake levels were compared between Asians and other racial/ethnic groups (white, black, Mexican American, and other Hispanic) and within three Asian subgroups (Chinese, Indian Asian, and other Asians).

RESULTS

Significant associations (p < 0.05) were found between biomarker levels and estimated dietary metal intake for total and inorganic arsenic and mercury among Asians. Asians had the highest daily fish and rice consumption across the racial/ethnic groups. Fish was the major contributor to dietary mercury and total arsenic intake, whereas rice was the major contributor to inorganic arsenic dietary intake. Fish consumption across the Asian subgroups varied, with Asian Indians having lower fish consumption than the other Asian subgroups. Rice consumption was similar across the Asian subgroups.

CONCLUSIONS

We confirmed that estimated dietary intake of arsenic (total and inorganic) and mercury is significantly associated with their corresponding biomarkers in U.S. Asians, using nationally representative data. In contrast, estimated dietary intake of cadmium and lead were not significantly associated with their corresponding biomarker levels in U.S. Asians. Citation: Awata H, Linder S, Mitchell LE, Delclos GL. 2017. Association of dietary intake and biomarker levels of arsenic, cadmium, lead, and mercury among Asian populations in the United States: NHANES 2011-2012. Environ Health Perspect 125:314-323; http://dx.doi.org/10.1289/EHP28.

Systematic review of differential inorganic arsenic exposure in minority, low-income, and indigenous populations in the United States

Inorganic arsenic (iAs) is a human carcinogen and associated with cardiovascular, respiratory, and skin diseases. Natural and anthropogenic sources contribute to low concentrations of iAs in water, food, soil, and air. Differential exposure to environmental hazards in minority, indigenous, and low income populations is considered an environmental justice (EJ) concern, yet it is unclear if higher iAs exposure occurs in these populations. A systematic review was conducted to evaluate evidence for differential iAs exposure in the United States (US). The peer-reviewed literature was searched for studies that (1) estimated iAs exposure based on environmental concentrations of iAs in water, food, soil, or iAs biomarkers and (2) examined iAs exposure in minority, indigenous, and low income US populations. Five studies were identified that estimated exposures and provided demographic information about EJ populations. These studies reported arsenic concentrations in water, soil, or food to estimate exposure, with varied evidence of differential exposure. Additionally, six studies were identified that suggested potential arsenic exposure from environmental sources including soil, rice, private well-water, and fish, but did not report data stratified by demographic information. Evidence across these 11 studies was qualitatively integrated to draw conclusions about differential iAs exposure. The total body of evidence is limited by lack of individual exposure measures, lack of iAs concentration data, and insufficient comparative demographic data. Based upon these data gaps, there is inadequate evidence to conclude whether differential exposure to iAs is an EJ concern in the US.

Simultaneous Exposure to Heavy Metals among Residents in the Industrial Complex: Korean National Cohort Study

A survey was conducted to evaluate the multi-exposure level and correlation among toxic metal biomarkers (Cd, Pb, and Hg). A total of 592 individuals who participated in the survey were residents near an industrial complex in Gwangyang and Yeosu (exposed group) and of Hadong and Namhae (control group) in southern Korea from May 2007 to November 2010. The Gwangyang and Yeosu area exposed groups had slightly higher blood Pb (2.21 and 1.90 µg/dL), urinary Cd observed values (2.20 and 1.46 µg/L), urinary Cd with a urinary creatinine correction (1.43 and 1.25 µg/g Cr), and urinary Hg observed values (2.26 and 0.98 µg/L) in women participants than those in the Hadong and Namhae area (control group). Blood Pb (3.18 and 2.55 µg/dL), urinary Hg observed values (1.14 and 0.92 µg/L), and urinary Hg with a urinary creatinine correction (1.06 and 0.96 µg/L) for male participants were also slightly higher than those in the Hadong and Namhae area (control group). The correlation among urinary Cd, Hg and Pb concentrations in the blood was significant. We suggest that the exposed group of residents were simultaneously exposed to Pb, Cd, and Hg from contaminated ambient air originating from the iron manufacturing industrial complex.

Daily dietary intakes of zinc, copper, lead, and cadmium as determined by duplicate portion sampling combined with either instrumental analysis or the use of food composition tables, Shiraz, Iran

Estimation of essential and toxic element intakes is crucial to evaluate the risks of deficiency or toxicity. The purpose of this study was to investigate and also to compare the dietary intakes of zinc (Zn) and copper (Cu) by adults living in Shiraz, Iran, determined by two procedures: duplicate portion sampling of 21 hospital meals combined with either instrumental analysis (voltammetric measurement) or the use of food composition tables (FCTs). The level of exposure to lead (Pb) and cadmium (Cd) was evaluated as well. The daily Zn intakes of both methods were not significantly different and were higher than the RDA values except the value measured by the instrumental analysis which was lower than the RDA established for a male adult. Daily intake of Cu determined by instrumental analysis was significantly lower and closer to RDA for adults compared with the value estimated by FCTs. The dietary intakes of Pb and Cd were 313 and 61% of the respective provisional tolerable weekly intakes (PTWIs), respectively. The accuracy of two methods used for estimation of Zn intake was similar. In the case of Cu, the use of FCTs, in which the influence of environmental conditions and dietary habits of meal preparation is not taken into account, overestimated dietary intake. The risk of zinc deficiency was found in adult males. Moreover, the estimated intake of Pb, but not Cd, could be a cause of concern for Shiraz population. Thus, conducting regular periodic studies to assess the dietary intake of mentioned elements are recommended.

Metals in commonly eaten groceries in Western Australia: a market basket survey and dietary assessment

Children's dietary exposure to metals has received limited attention in Australia. This study undertook a market basket survey and analysed 253 food and beverages for metals. These data were used in conjunction with recent average diet data for children in Western Australia to model dietary metals exposure, with mean metals intakes calculated for boys and girls aged 8, 12, 13 and 16 years. Results show that for some metals, including cadmium, nickel and manganese, dietary intake guidelines have been exceeded in younger children. The mean modelled cadmium intake in children aged 8 years was almost 60% of the World Health Organisation (WHO) guideline and exceeded the European Food Safety Authority (EFSA) guideline. Nickel and manganese intake was higher in younger children than reported in international studies. Modelling based on the 95% percentile of dietary consumption exceeded the respective guidelines or upper level of intake for several of the metals studied. The findings from this study support the need for further investigation into the exposure of children to metals from diet and the health implications of exposure.

Dietary cadmium exposure and kidney stone incidence: a population-based prospective cohort study of men & women

Cadmium exposure is associated with increased urinary calcium excretion. Hypercalciuria is recognised as a major risk factor for kidney stone formation. Increased prevalence of kidney stones among those occupationally exposed to cadmium has previously been suggested. Food is the main source of cadmium exposure in the general population with tobacco representing an important additional source among smokers. We aimed to assess the association between dietary cadmium exposure and kidney stone incidence in two large population-based, prospective cohorts of men (Cohort of Swedish Men; COSM) and women (The Swedish Mammography Cohort; SMC). Those with a history of kidney stones were excluded. At baseline 1997, men (45-79yrs) and women (48 to 83yrs), completed a self-administered questionnaire on diet and lifestyle. During 12years of follow-up, we ascertained 707 cases of kidney stones in men and 290 in women through linkage of the cohorts to the national inpatient and outpatient registers. Individual dietary cadmium exposure was estimated using dietary data and concentrations of cadmium in food. Hazard ratios (HR) were calculated using the Cox proportional hazards regression models with adjustment for other risk factors. Estimated dietary cadmium exposure was not associated with increased kidney stone incidence among men HR 0.97 (95% confidence interval (CI): 0.77-1.23) or women HR 0.99 (95% CI: 0.89-1.43), comparing the highest tertile with the lowest. In conclusion, our results do not support a strong association between dietary cadmium and kidney stone risk at the exposure levels seen in the general population.

Dietary cadmium exposure and prostate cancer incidence: a population-based prospective cohort study

BACKGROUND

Experimental data convincingly propose the toxic metal cadmium as a prostate carcinogen. Cadmium is widely dispersed into the environment and, consequently, food is contaminated.

METHODS

A population-based cohort of 41 089 Swedish men aged 45-79 years was followed prospectively from 1998 through 2009 to assess the association between food frequency questionnaire-based estimates of dietary cadmium exposure (at baseline, 1998) and incidence of prostate cancer (3085 cases, of which 894 were localised and 794 advanced) and through 2008 for prostate cancer mortality (326 fatal cases).

RESULTS

Mean dietary cadmium exposure was 19 μg per day±s.d. 3.7. Multivariable-adjusted dietary cadmium exposure was positively associated with overall prostate cancer, comparing extreme tertiles; rate ratio (RR) 1.13 (95% confidence interval (CI): 1.03-1.24). For subtypes of prostate cancer, the RR was 1.29 (95% CI: 1.08-1.53) for localised, 1.05 (95% CI: 0.87-1.25) for advanced, and 1.14 (95% CI: 0.86-1.51) for fatal cases. No statistically significant difference was observed in the multivariable-adjusted risk estimates between tumour subtypes (P(heterogeneity)=0.27). For localised prostate cancer, RR was 1.55 (1.16-2.08) among men with a small waist circumference and RR 1.45 (1.15, 1.83) among ever smokers.

CONCLUSION

Our findings provide support that dietary cadmium exposure may have a role in prostate cancer development.

Associations between dietary cadmium exposure and bone mineral density and risk of osteoporosis and fractures among women

Osteoporosis and its main health outcome, fragility fractures, are large and escalating public health problems. Cadmium, a widespread food contaminant, is a proposed risk factor; still the association between estimated dietary cadmium exposure and bone mineral density (BMD) has never been assessed. Within a sub-cohort of the Swedish Mammography Cohort, we assessed dietary cadmium exposure based on a food frequency questionnaire (1997) and urinary cadmium (2004-2008) in relation to total-body BMD and risk of osteoporosis and fractures (1997-2009) among 2676 women (aged 56-69 years). In multivariable-adjusted linear regression, dietary cadmium was inversely associated with BMD at the total body and lumbar spine. After further adjustment for dietary factors important for bone health and cadmium bioavailability--calcium, magnesium, iron and fiber, the associations became more pronounced. A 32% increased risk of osteoporosis (95% CI: 2-71%) and 31% increased risk for any first incident fracture (95% CI: 2-69%) were observed comparing high dietary cadmium exposure (≥13 μg/day, median) with lower exposures (<13 μg/day). By combining high dietary with high urinary cadmium (≥0.50 μg/g creatinine), odds ratios among never-smokers were 2.65 (95% CI: 1.43-4.91) for osteoporosis and 3.05 (95% CI: 1.66-5.59) for fractures. In conclusion, even low-level cadmium exposure from food is associated with low BMD and an increased risk of osteoporosis and fractures. The partial masking of the associations by essential nutrients indicates important interplay between dietary factors and contaminants present in food. In separate analyses, dietary and urinary cadmium underestimated the association with bone effects.

Community duplicate diet methodology: a new tool for estimating dietary exposures to pesticides

An observational field study was conducted to assess the feasibility of a community duplicate diet collection method; a dietary monitoring tool that is population-based. The purpose was to establish an alternative procedure to duplicate diet sampling that would be more efficient for a large, defined population, e.g., in the National Children's Study (NCS). Questionnaire data and food samples were collected in a residence so as not to lose the important component of storage, preparation, and handling in a contaminated microenvironment. The participants included nine Hispanic women of child bearing age living in Apopka, FL, USA. Foods highly consumed by Hispanic women were identified based on national food frequency questionnaires and prioritized by permethrin residue concentrations as measured for the Pesticide Data Program. Participants filled out questionnaires to determine if highly consumed foods were commonly eaten by them and to assess the collection protocol for the food samples. Measureable levels of permethrin were found in 54% of the samples. Questionnaire responses indicated that the collection of the community duplicate diet was feasible for a defined population.

Dietary cadmium exposure and fracture incidence among men: a population-based prospective cohort study

Cadmium is an osteotoxic metal present in food. It causes multiple fractures in those highly exposed and is associated with reduced bone mineral density at considerably lower exposures. Little is known about fracture rates following low-level cadmium exposure. We assessed the associations between dietary cadmium exposure and fracture incidence. Within a population-based prospective cohort of 22,173 Swedish men, we estimated individual dietary cadmium exposure using food frequency questionnaire data and levels of cadmium in food. The average intake was 19 µg/day. Hazard ratios (HRs) for any fracture and hip fracture were estimated using Cox's regression. During 10 years of follow-up, we ascertained 2183 cases of any fracture and 374 hip fractures by computerized linkage of the cohort to registry data. Multivariable-adjusted dietary cadmium intake was associated with a statistically significant 19% [HR = 1.19, 95% confidence interval (CI) 1.06-1.34] higher rate of any fracture comparing highest tertile with lowest (p ≤ .01 for trend). Moreover, men in the highest tertile of dietary cadmium and lowest tertile of fruit and vegetable consumption had a 41% higher rate of any fracture compared with contrasting tertiles. Hip fracture rates also were higher in the highest tertile of cadmium intake but only statistically significant among never smokers (HR = 1.70, 95% CI 1.04-2.77). Our results indicate that dietary cadmium exposure at general population levels is associated with an increased rate of fractures among men. This association was independent of smoking and was most pronounced among men with low fruit and vegetable consumption.

Dietary intake of lead and cadmium by children and adults - Result calculated from dietary recall and available lead/cadmium level in food in comparison to result from food duplicate diet method

The dietary intakes of lead and cadmium by 30 children and 30 adults living in Jinhu area in China were determined by the duplicate method with a 3-day sampling period. Dietary recall and available lead/cadmium level in food were also used to calculate dietary intakes. Lead intakes based on duplicate method were 15.66μg(kg(bw))(-1)week(-1) for children and 8.83μg(kg(bw))(-1)week(-1) for adults. Cadmium intakes were 2.07μg(kg(bw))(-1)week(-1) for children and 1.49μg(kg(bw))(-1)week(-1) for adult. The results from the dietary record method were as follows: lead intakes were 11.84μg(kg(bw))(-1)week(-1) for children and 7.70μg(kg(bw))(-1)week(-1) for adult. Cadmium intakes were 2.20μg(kg(bw))(-1)week(-1) for children and 1.44μg(kg(bw))(-1)week(-1) for adults. Children's dietary intakes were higher than those of adults'. The results of the dietary intakes calculated from two methods did not have significant difference. Compared to the FAO/WHO PTWIs for lead and cadmium, the average lead and cadmium dietary intakes are all below PTWIs. It was concluded that dietary record method can give comparatively accurate result for lead and cadmium dietary intakes compared with duplicate method. The average lead and cadmium dietary intakes for children and adults in Jinhu area are considered safe. However, the high level of dietary lead and cadmium intakes of children in this area deserves our attention.

Population toxicokinetic modeling of cadmium for health risk assessment

BACKGROUND

Cadmium is a widespread environmental pollutant that has been shown to exert toxic effects on kidney and bones in humans after long-term exposure. Urinary cadmium concentration is considered a good biomarker of accumulated cadmium in kidney, and diet is the main source of cadmium among nonsmokers.

OBJECTIVE

Modeling the link between urinary cadmium and dietary cadmium intake is a key step in the risk assessment of long-term cadmium exposure. There is, however, little knowledge on how this link may vary, especially for susceptible population strata.

METHODS

We used a large population-based study (the Swedish Mammography Cohort), with repeated dietary intake data covering a period of 20 years, to compare estimated dietary cadmium intake with urinary cadmium concentrations on an individual basis. A modified version of the Nordberg-Kjellström model and a one-compartment model were evaluated in terms of their predictions of urinary cadmium. We integrated the models and quantified the between-person variability of cadmium half-life in the population. Finally, sensitivity analyses and Monte Carlo simulations were performed to illustrate how the latter model could serve as a robust tool supporting the risk assessment of cadmium in humans.

RESULTS

The one-compartment population model appeared to be an adequate modeling option to link cadmium intake to urinary cadmium and to describe the population variability. We estimated the cadmium half-life to be about 11.6 years, with about 25% population variability.

CONCLUSIONS

Population toxicokinetic models can be robust and useful tools for risk assessment of chemicals, because they allow quantification and integration of population variability in toxicokinetics.

Long-term dietary cadmium intake and postmenopausal endometrial cancer incidence: a population-based prospective cohort study

Environmental pollutants mimicking the effects of estrogen are suggested to contribute to the high incidence of hormone-related cancers, but supporting data are sparse. A potent estrogen-like activity of the pollutant cadmium, mediated via the estrogen receptor-alpha, has been shown in vivo. We prospectively examined the association between cadmium exposure and incidence of postmenopausal endometrial cancer. The Swedish Mammography Cohort is a population-based prospective cohort of 30,210 postmenopausal women free of cancer diagnose at baseline (1987) and who completed a food frequency questionnaire at baseline and in 1997. We estimated the dietary cadmium intake based on the questionnaire data and the cadmium content in all foods. During 16.0 years (484,274 person-years) of follow-up between the baseline and mid-2006, we ascertained 378 incident cases of endometrioid adenocarcinoma. The average estimated dietary cadmium intake was 15 mug/day (80% from cereals and vegetables). Cadmium intake was statistically significantly associated with increased risk of endometrial cancer in all women; the multivariate relative risk (RR) was 1.39 [95% confidence interval (CI), 1.04-1.86; P(trend) = 0.019], comparing highest tertile versus lowest. Among never-smoking women with body mass index (BMI) of <27 kg/m(2), the RR was 1.86 (95% CI, 1.13-3.08; P(trend) = 0.009). We observed a 2.9-fold increased risk (95% CI, 1.05-7.79) associated with long-term cadmium intake consistently above the median at both baseline 1987 and in 1997 in never-smoking women with low bioavailable estrogen (BMI of <27 kg/m(2) and nonusers of postmenopausal hormones). Our results support the hypothesis that cadmium may exert estrogenic effects and thereby increase the risk of hormone-related cancers.

Biologically based modeling of multimedia, multipathway, multiroute population exposures to arsenic

This article presents an integrated, biologically based, source-to-dose assessment framework for modeling multimedia/multipathway/multiroute exposures to arsenic. Case studies demonstrating this framework are presented for three US counties (Hunderton County, NJ; Pima County, AZ; and Franklin County, OH), representing substantially different conditions of exposure. The approach taken utilizes the Modeling ENvironment for TOtal Risk studies (MENTOR) in an implementation that incorporates and extends the approach pioneered by Stochastic Human Exposure and Dose Simulation (SHEDS), in conjunction with a number of available databases, including NATA, NHEXAS, CSFII, and CHAD, and extends modeling techniques that have been developed in recent years. Model results indicate that, in most cases, the food intake pathway is the dominant contributor to total exposure and dose to arsenic. Model predictions are evaluated qualitatively by comparing distributions of predicted total arsenic amounts in urine with those derived using biomarker measurements from the NHEXAS--Region V study: the population distributions of urinary total arsenic levels calculated through MENTOR and from the NHEXAS measurements are in general qualitative agreement. Observed differences are due to various factors, such as interindividual variation in arsenic metabolism in humans, that are not fully accounted for in the current model implementation but can be incorporated in the future, in the open framework of MENTOR. The present study demonstrates that integrated source-to-dose modeling for arsenic can not only provide estimates of the relative contributions of multipathway exposure routes to the total exposure estimates, but can also estimate internal target tissue doses for speciated organic and inorganic arsenic, which can eventually be used to improve evaluation of health risks associated with exposures to arsenic from multiple sources, routes, and pathways.

A health risk assessment for exposure to trace metals via drinking water ingestion pathway

A health risk assessment was conducted for exposure to trace metals via drinking water ingestion pathway for Province of Izmir, Turkey. Concentrations of 11 trace metals were measured in drinking waters collected from 100 population weighted random sampling units (houses). The samples were analyzed in atomic absorption spectrometry for arsenic, and inductively coupled plasma-optical emission spectrometry for Be, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn. Questionnaires were administered to a participant from each sampling unit to determine drinking water consumption related information and demographics. Exposure and risks were estimated for each individual by direct calculation, and for Izmir population by Monte Carlo simulation. Six trace metals (As, Cr, Cu, Mn, Ni, and Zn) were detected in >50% of the samples. Concentrations of As and Ni exceeded the corresponding standards in 20% and 58% of the samples, respectively. As a result, arsenic noncarcinogenic risks were higher than the level of concern for 19% of the population, whereas carcinogenic risks were >10(-4) for 46%, and >10(-6) for 90% of the population.

Framework for metals risk assessment

EPA recognized that metals present unique risk assessment issues, and saw the need to develop a framework document that puts forth key scientific principles for metals risk assessments to help ensure consistency in metals assessments across EPA programs and regional offices. This framework, called the "Framework for Metals Risk Assessment," is a science-based document that describes basic principles that address the special attributes and behaviors of metals and metal compounds to be considered when assessing their human health and ecological risks. The Risk Assessment Forum oversaw the development of this document, including input from stakeholders and experts throughout the Agency, and obtained through several expert workshops, followed by peer review by the EPA Science Advisory Board (SAB). The Framework for Metals Risk Assessment document is intended to serve as a guide for all EPA programs and regional offices to supplement or update the policies, practices and guidance they currently use in their respective metals assessments. This framework document is not a prescriptive guide on how any particular type of assessment should be conducted within an EPA program office. Rather, it outlines key metal principles and describes how they should be considered in conducting human health and ecological risk assessments to advance our understanding of metals impact and foster consistency across EPA programs and regions. Although the audience for the framework is primarily intended to be Agency risk assessors, it also will communicate principles and recommendations for metals risk assessment to stakeholders and the public. This framework will be used in conjunction with guidance developed by the programs and regions for site-specific risk assessment, criteria derivation, ranking or categorization and other similar Agency activities related to metals. The Framework for Metals Risk Assessment document is intended to serve as a guide for all EPA programs and regional offices to supplement or update the policies, practices and guidance they currently use in their respective metals assessments. EPA assessments can vary in level of detail from simple, screening analyses to complex, definitive assessments. More complex scientific tools and metal specific methods should be applied as the complexity of the hazard assessment or risk assessment increases.

Dietary intake of toxic and essential trace elements by the children and parents living in Tokyo Metropolitan Area, Japan

This study estimated the dietary intakes of 25 pairs of Japanese children and their parents to 12 toxic and essential trace elements using 7-day duplicate diet composites. The estimated intakes of lead (children = 5.34 microg day-1, adults = 6.74 microg day-1) and tin (162 and 152 microg day-1) were below tolerable limits, but large difference in aluminium intakes (7.32 and 12.1 mg day-1) among the subjects warranted further investigations. Intakes of cadmium in both children and adults (13.2 and 15.9 microg day-1) were high, but a low uranium (U) intake was observed (0.593 and 0.587 microg day-1). Intakes of copper (567 and 784 microg day-1), manganese (1.56 and 2.72 mg day-1), zinc (4.93 and 6.75 mg day-1), and molybdenum (103 and 131 microg day-1) were close to the recommended values. Concentrations of chromium, nickel and selenium were lower than the detection limits in most cases.

Assessing the measurement precision of various arsenic forms and arsenic exposure in the National Human Exposure Assessment Survey (NHEXAS)

Archived samples collected from 1995 to 1997 in the National Human Exposure Assessment Survey (NHEXAS) in U.S. Environmental Protection Agency Region 5 (R5) and the Children's Study (CS) in Minnesota were analyzed for total arsenic, arsenate [As(V)], arsenite, dimethyl arsenic acid (DMA), monomethyl arsenic acid (MMA), arsenobetaine (AsB), and arsenocholine. Samples for the CS included drinking water, urine, hair, and dust; both studies included food (duplicate plate, composited 4-day food samples from participants). Except for AsB and As(V), the levels for As species measured in the food and drinking water samples were very low or nonexistent. The analytical methods used for measuring As species were sensitive to < 1 ppb. During the analysis of food and drinking water samples, chromatographic peaks appeared that contained As, but they did not correspond to those being quantified. Thus, in some samples, the sum of the individual As species levels was less than the total As level measured because the unknown forms of As were not quantified. On the other hand, total As was detectable in almost all samples (> 90%) except for hair (47%), indicating that the analytical method was sufficiently sensitive. Population distributions of As concentrations measured in drinking water, food (duplicate plate), dust, urine, and hair were estimated. Exposures to total As in food for children in the CS were about twice as high as in the general R5 population (medians of 17.5 ppb and 7.72 ppb, respectively). In addition, AsB was the most frequently detected form of As in food eaten by the participants, while As(V) was only rarely detected. Thus, the predominant dietary exposure was from an organic form of As. The major form of As in drinking water was As(V). Spearman (rank) correlations and Pearson (log-concentration scale) correlations between the biomarkers (urine, hair) and the other measures (food, drinking water, dust) and urine versus hair were performed. In the NHEXAS CS, total As and AsB in the food eaten were significantly correlated with their levels in urine. Also, levels of As(V) in drinking water correlated with DMA and MMA in urine. Arsenic levels in dust did not show a relationship with urine or hair levels, and no relationship was observed for food, drinking water, and dust with hair. Urine samples were collected on days 3, 5, and 7 of participants' monitoring periods. Total As levels in urine were significantly associated across the three pairwise combinations--i.e., day 3 versus day 5, day 3 versus day 7, and day 5 versus day 7. Because the half-life of As in the body is approximately 3 days, this suggests that some exposure occurred continually from day to day. This trend was also observed for AsB, suggesting that food is primarily responsible for the continual exposure. DMA and MMA in urine were also significantly correlated but not in all combinations.

Predicted intake of trace elements and minerals via household drinking water by 6-year-old children from Kraków, Poland. Part 2: Cadmium, 1997–2001

Between 1997 and 2001, samples of drinking water (DW) were collected in about 600 households and pre-schools by a double sampling method, early in the morning (stagnant water, W1) and in the evening (flushed water, W2). The study group included about 300 5-7-year-old children living in urban (metropolitan, U) and peripheral (P) areas of Kraków and rural (R) areas in southern Poland. Cadmium concentrations were estimated by the GF-AAS method with Zeeman background correction. Mean cadmium concentrations in water did not vary substantially by year. Moreover, there was no difference between P and R group (p > 0.05). The geometric mean (GM) and 95% confidence interval (CI) of cadmium concentrations in W2 was 0.13 (0.01-1.72) microg l(-1) for U group, while for combined (P&R) non-urban group (NU) it was 0.31 (0.02-6.24) microg l(-1) (p < 0.001). Significant differences between cadmium in W1 and W2 samples were evident from the ratio of cadmium concentration in W1 to W2, i.e. R1,2; its difference (W1 - W2), i.e. D1,2; or relative difference 100 x (W1 - W2)/W1, i.e. D1,2%. For NU sites D1,2, D1,2% and R1,2 values (GM) were 0.25 microg l(-1), 34% and 2.19, respectively, and for U sites 0.19 microg l(-1), 50% and 3.49, respectively. Parameter D1,2 was not site dependent (p > 0.05) and exhibited a plateau at 0.44 microg l(-1). The WHO and Polish limit of cadmium in DW (3 microg l(-1)) was exceeded in W2 samples from 0.5, 5.8 and 10.0% of households from the U, P and R areas, respectively. The predicted cadmium intake with W2 by children was (GM) 0.68 and 2.06% of PTWI for U and NU sites, respectively. However, these contributions were higher for W1 samples by coefficient R1,2. For the cases exceeding the cadmium limit, the predicted cadmium intake with DW contributed to PTWI by 27.4-29.1%. The study proved that contamination of water with cadmium in plumbing is significant, independent of the site type and period. This contamination should be considered as a factor in public health protection programmes with special attention to children. An easy approach to limit the intake of cadmium from DW by about half would be to discard some of the first drawn portion of water from pipes after overnight or longer break of usage.

Concentrations of lead and mercury in multimedia samples from homes near the former Clark Air Base, Philippines

We measured lead and mercury in samples collected from 31 homes in communities near the former Clark Air Base, Philippines during May and October 2002. Sample media included water used for drinking and cooking, house dust and entryway soil. Composite samples of 15 food items purchased at local markets were also collected. Samples were analyzed for total lead (Pb) and total mercury (Hg) to evaluate the relative importance of each media to residential exposure concentrations in the community adjacent to Clark (Community A) versus a control community 5 km away (Community B). In general, we measured low (e.g. background) to undetectable levels of the target analytes in all media sampled with two important exceptions. First, the Hg concentrations we measured in canned mackerel composites, which were within the range reported for mackerel from other locations worldwide, may pose a risk to pregnant women who are frequent consumers (e.g. one or more cans per day). Second, we measured Pb above the USEPA residential screening concentration (400 mug/g) in dust and soil from two homes, illustrating the need for periodic residential lead monitoring in these and other communities in the Philippines. We found no significant difference between Communities A and B with respect to Pb and Hg concentrations in water or food, although we were not able to detect very low levels of Pb in most of the foods we sampled because of trace Pb contamination added during sample homogenization. Although the Pb levels we measured in dust and soil from Community A homes were higher on average than Community B homes, the levels in both communities were low (e.g. background) thus we did not investigate the difference further. To our knowledge, these are the first reported measurements of Pb in house dust in the Philippines. The concentrations of Pb we measured in house dust were significantly higher than those in entryway soil from both communities, adding empirical support to the assertion that yard soil should not be considered a proxy for house dust in exposure studies in the Philippines or elsewhere.

Gender-related difference, geographical variation and time trend in dietary cadmium intake in Japan

OBJECTIVES

The present analysis was initiated to examine possible gender-dependency, geographic variation, and time-dependent changes in dietary intake of cadmium (Cd-F) among general populations in Cd-non-polluted areas in Japan. The role of rice as Cd-F source was also within the scope.

METHODS

Two databases on Cd and nutritional analyses were re-visited. Both databases were established through collection of 24-h food duplicate portion samples from residents in areas with no known Cd pollution, and contained information on Cd and energy contents in the duplicate portion, together with daily rice consumption, the gender, the age and the location of the residence of each sample donor. The first and the second databases were established through surveys in the years around 1980 on 564 cases and around 1995 on 702 cases, respectively. The two databases were combined for evaluation by multiple regression (MRA) and other analyses.

RESULTS

The analyses showed that men tended to take more Cd than women, more clearly so in the 1980 survey than in the 1995 survey. When Cd-F in the 1995 survey was compared with that in the 1980 survey, a substantial decrease was observed, e.g. by 30% (from 37.5 to 26.2 microg/day) in case of women. Cd-F values varied subject to the survey sites in a wide range (e.g. from 20 to 86 microg/day among women in the 1980 survey). In MRA with Cd-F as a dependent variable and survey sites and food intake factors (e.g. rice and energy intakes) as independent variables, the survey sites could explain more than 53% and 35% of total variation in Cd-F in the 1980 and 1995 surveys, respectively. Rice consumption was also influential to Cd-F in both surveys with partial correlation coefficients of 0.36 and 0.21, respectively, the influence being stronger in the 1980 survey than in the 1995 survey. A significant correlation was detected between the 1980 and 1995 survey results both in Cd-F and in rice consumption.

CONCLUSION

Geographic and gender-related differences, and time-dependent decrease in dietary Cd intake in Japan were detected through analyses of food duplicate-based databases. The leading role of rice as dietary Cd source was also observed.

Environmental, dietary, demographic, and activity variables associated with biomarkers of exposure for benzene and lead

Classification and regression tree methods represent a potentially powerful means of identifying patterns in exposure data that may otherwise be overlooked. Here, regression tree models are developed to identify associations between blood concentrations of benzene and lead and over 300 variables of disparate type (numerical and categorical), often with observations that are missing or below the quantitation limit. Benzene and lead are selected from among all the environmental agents measured in the NHEXAS Region V study because they are ubiquitous, and they serve as paradigms for volatile organic compounds (VOCs) and heavy metals, two classes of environmental agents that have very different properties. Two sets of regression models were developed. In the first set, only environmental and dietary measurements were employed as predictor variables, while in the second set these were supplemented with demographic and time-activity data. In both sets of regression models, the predictor variables were regressed on the blood concentrations of the environmental agents. Jack-knife cross-validation was employed to detect overfitting of the models to the data. Blood concentrations of benzene were found to be associated with: (a) indoor air concentrations of benzene; (b) the duration of time spent indoors with someone who was smoking; and (c) the number of cigarettes smoked by the subject. All these associations suggest that tobacco smoke is a major source of exposure to benzene. Blood concentrations of lead were found to be associated with: (a) house dust concentrations of lead; (b) the duration of time spent working in a closed workshop; and (c) the year in which the subject moved into the residence. An unexpected finding was that the regression trees identified time-activity data as better predictors of the blood concentrations than the measurements in environmental and dietary media.

Acute and chronic arsenic toxicity

Arsenic toxicity is a global health problem affecting many millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water and may also occur from mining and other industrial processes. Arsenic is present as a contaminant in many traditional remedies. Arsenic trioxide is now used to treat acute promyelocytic leukaemia. Absorption occurs predominantly from ingestion from the small intestine, though minimal absorption occurs from skin contact and inhalation. Arsenic exerts its toxicity by inactivating up to 200 enzymes, especially those involved in cellular energy pathways and DNA synthesis and repair. Acute arsenic poisoning is associated initially with nausea, vomiting, abdominal pain, and severe diarrhoea. Encephalopathy and peripheral neuropathy are reported. Chronic arsenic toxicity results in multisystem disease. Arsenic is a well documented human carcinogen affecting numerous organs. There are no evidence based treatment regimens to treat chronic arsenic poisoning but antioxidants have been advocated, though benefit is not proven. The focus of management is to reduce arsenic ingestion from drinking water and there is increasing emphasis on using alternative supplies of water.

Predicted intake of trace elements and minerals via household drinking water by 6-year-old children from Kraków (Poland). Part 1: lead (year 2000)

A population of 232 children living in urban, peripheral and rural areas of southern Poland was included in the study. Household drinking water was collected twice a day, early in the morning and in the evening. The lead (Pb) concentration was estimated by a graphite furnace-atomic absorption spectroscopy (GF-AAS) method. The geometric mean of Pb concentration in drinking water in 2000 for evening samples was 0.68, 1.24 and 2.28 microg x l(-1) for urban, peripheral and rural areas, respectively, while for morning samples it was 1.42, 2.16 and 2.97 microg x l(-1). These areas differed significantly (p < 0.05) and odds ratio for peripheral versus urban areas was 1.6. The difference of Pb concentrations in the morning and evening water was significant (p < 0.001). The mean ratio was 1.8 and the median difference 0.8 microg x l(-1). The predicted contribution of drinking water to the Pb intake by 6-year-old children living in urban, peripheral and rural areas was 1.2, 2.0 and 5.6% of the provisional tolerable weekly intake (PTWI) respectively. For the 4.3-11.1% of children, the Pb concentration in water > 10 microg x l(-1) and in these cases the predicted Pb intake with drinking water contributed to PTWI by 22.3-30.0%. The simple test introduced in this study, the analysis of morning and evening water samples, proved that contamination of water in the plumbing is significant and common. The above parameters can be applied to routine quality control of drinking water performed in the households. The in-house water contamination should be considered as a factor in public health protection programmes with special attention to children.

Metals in drinking water from new housing estates in the Sydney area

Metals in drinking water were measured in 95 new houses less than 18 months old in the Sydney metropolitan area. Three samples (first-flush, post-first-flush, and fully flushed water) were collected from each house, and "control" samples from the five Sydney Water points that supplied the houses, a total of 326 samples. They were analyzed for Pb, Cu, Mn, Zn, Cd, and Al. At the supply points, the levels of all metals were at or below Australian Drinking Water Guidelines (ADWG). In the houses, metal levels varied. Of the first-flush samples, Pb was above ADWG in 60% and above US EPA Guidelines in 81%, Cu was above ADWG in 12%, and Cd was above ADWG in 4%. Of the post-first-flush samples, Pb was above ADWG in 24%, Cu was above ADWG in 18%, Cd was above ADWG in 1%, and Zn was above ADWG in 1%. The other metal contaminants (Mn and Al) were within ADWG. In fully flushed water, the levels of all metals were well below ADWG.

National Human Exposure Assessment Survey: analysis of exposure pathways and routes for arsenic and lead in EPA Region 5

The National Human Exposure Assessment Survey (NHEXAS) Phase I field study conducted in EPA Region 5 (Great Lakes Area) provides extensive exposure data on a representative sample of approximately 250 residents of the region. Associated environmental media and biomarker (blood, urine) concentration data were also obtained for the study participants to aid in understanding of the relationships of exposures to both contaminant pathways and doses. Besides fulfilling the primary NHEXAS objectives, the NHEXAS data provided an opportunity to explore secondary usages, such as examining pathway to route of exposure relationships. A generic type of structural equation model was used to define the anticipated relationships among the various data types for both arsenic (As) and lead (Pb). Since, by design, only a few participants provided data for all sample types, implementing this model required that some media concentrations (outdoor air and soil) be imputed for subjects with missing information by using measurements collected in the same geographic area and time period. The model, and associated pairwise correlations, generally revealed significant but weak associations among the concentrations, exposures, and doses; the strongest associations occurred for the various air measurements (indoor versus outdoor and personal). The generally weak associations were thought to be partly due to the absence of complete coverage of nonresidential environmental media and to nonsynchronization of relevant measurement times and integration periods of collection across the various sample types. In general, relationships between the NHEXAS questionnaire data and the various concentration, exposure, and body-burden measures were also weak. The model results and the modeling exercise suggest several ways for optimizing the design of future exposure assessment studies that are aimed at supporting structural modeling activities.

An assessment of the data quality for NHEXAS--Part I: Exposure to metals and volatile organic chemicals in Region 5

A National Human Exposure Assessment Survey (NHEXAS) was performed in U.S. Environmental Protection Agency (U.S. EPA) Region V, providing population-based exposure distribution data for metals and volatile organic chemicals (VOCs) in personal, indoor, and outdoor air, drinking water, beverages, food, dust, soil, blood, and urine. One of the principal objectives of NHEXAS was the testing of protocols for acquiring multimedia exposure measurements and developing databases for use in exposure models and assessments. Analysis of the data quality is one element in assessing the performance of the collection and analysis protocols used in NHEXAS. In addition, investigators must have data quality information available to guide their analyses of the study data. At the beginning of the program quality assurance (QA) goals were established for precision, accuracy, and method quantification limits. The assessment of data quality was complicated. First, quality control (QC) data were not available for all analytes and media sampled, because some of the QC data, e.g., precision of duplicate sample analysis, could be derived only if the analyte was present in the media sampled in at least four pairs of sample duplicates. Furthermore, several laboratories were responsible for the analysis of the collected samples. Each laboratory provided QC data according to their protocols and standard operating procedures (SOPs). Detection limits were established for each analyte in each sample type. The calculation of the method detection limits (MDLs) was different for each analytical method. The analytical methods for metals had adequate sensitivity for arsenic, lead, and cadmium in most media but not for chromium. The QA goals for arsenic and lead were met for all media except arsenic in dust and lead in air. The analytical methods for VOCs in air, water, and blood were sufficiently sensitive and met the QA goals, with very few exceptions. Accuracy was assessed as recovery from field controls. The results were excellent (> or = 98%) for metals in drinking water and acceptable (> or = 75%) for all VOCs except o-xylene in air. The recovery of VOCs from drinking water was lower, with all analytes except toluene (98%) in the 60-85% recovery range. The recovery of VOCs from drinking water also decreased when comparing holding times of < 8 and > 8 days. Assessment of the precision of sample collection and analysis was based on the percent relative standard deviation (% RSD) between the results for duplicate samples. In general, the number of duplicate samples (i.e., sample pairs) with measurable data were too few to assess the precision for cadmium and chromium in the various media. For arsenic and lead, the precision was excellent for indoor, and outdoor air (< 10% RSD) and, although not meeting QA goals, it was acceptable for arsenic in urine and lead in blood, but showed much higher variability in dust. There were no data available for metals in water and food to assess the precision of collection and analysis.