Longitudinal Investigation of Exposure to Arsenic, Cadmium, and Lead in Drinking Water

Department of Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
Environmental Health Perspectives (Impact Factor: 7.98). 08/2000; 108(8):731-5. DOI: 10.1289/ehp.00108731
Source: PubMed


Arsenic, cadmium, and lead have been associated with various forms of cancer, nephrotoxicity, central nervous system effects, and cardiovascular disease in humans. Drinking water is a well-recognized pathway of exposure to these metals. To improve understanding of the temporal dimension of exposure to As, Cd, and Pb in drinking water, we obtained 381 samples of tap and/or tap/filtered water and self-reported rates of drinking water consumption from 73 members of a stratified random sample in Maryland. Data were collected at approximately 2-month intervals from September 1995 through September 1996. Concentrations of As (range < 0.2-13.8 microg/L) and Pb (< 0.1-13.4 microg/L) were within the ranges reported for the United States, as were the rates of drinking water consumption (median < 0.1-4.1 L/day). Cd was present at a detectable level in only 8.1% of the water samples. Mean log-transformed concentrations and exposures for As and Pb varied significantly among sampling cycles and among respondents, as did rates of drinking water consumption, according to a generalized linear model that accounted for potential correlation among repeated measures from the same respondent. We used the intraclass correlation coefficient of reliability to attribute the total variance observed for each exposure metric to between-person and within-person variability. Between-person variability was estimated to account for 67, 81, and 55% of the total variance in drinking water consumption, As exposure (micrograms per day), and Pb exposure (micrograms per day), respectively. We discuss these results with respect to their implications for future exposure assessment research, quantitative risk assessment, and environmental epidemiology.

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Available from: David Macintosh, Jul 28, 2014
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    • "To evaluate the hypothesis that metals are prospectively related to DNA methylation and hydroxymethylation levels, we examined the association of baseline metal exposure biomarkers with visit 3 global DNA methylation and global DNA hydroxymethylation. For arsenic, under constant conditions of exposure over time, urinary concentrations and metabolism biomarkers have been fairly constant, as previously shown in our study population (Navas-Acien et al. 2009) and in previous studies measuring arsenic in private and public drinking water systems over long periods of time (Karagas et al. 2001; Ryan et al. 2000; Steinmaus et al. 2005). Given this background, evaluating the association of arsenic exposure and metabolism with epigenetic measures in visits 1 and 3 allowed us to evaluate the consistency of the associations assuming constant arsenic exposure and metabolic processes. "
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    Full-text · Article · Apr 2014 · Environmental Health Perspectives
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    • "We also confirmed that individual well concentrations of inorganic arsenic do not vary over long periods of time. These results concur with past studies that analyzed datasets within the USA with at least 25 wells with at least five measurements per well (Focazio et al. 2000; Ryan et al. 2000; Karagas et al. 1998; Meliker et al. 2008; Steinmaus et al. 2005; Seiler 2004). Steinmaus et al. (2005) assessed 759 wells in Nevada over 20 years and found a strong correlation (r = 0.85; 95 % CI 0.81–0.88) "
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    ABSTRACT: Consumption of inorganic arsenic in drinking water at high levels has been associated with chronic diseases. Risk is less clear at lower levels of arsenic, in part due to difficulties in estimating exposure. Herein we characterize spatial and temporal variability of arsenic concentrations and develop models for predicting aquifer arsenic concentrations in the San Luis Valley, Colorado, an area of moderately elevated arsenic in groundwater. This study included historical water samples with total arsenic concentrations from 595 unique well locations. A longitudinal analysis established temporal stability in arsenic levels in individual wells. The mean arsenic levels for a random sample of 535 wells were incorporated into five kriging models to predict groundwater arsenic concentrations at any point in time. A separate validation dataset (n = 60 wells) was used to identify the model with strongest predictability. Findings indicate that arsenic concentrations are temporally stable (r = 0.88; 95 % CI 0.83-0.92 for samples collected from the same well 15-25 years apart) and the spatial model created using ordinary kriging best predicted arsenic concentrations (ρ = 0.72 between predicted and observed validation data). These findings illustrate the value of geostatistical modeling of arsenic and suggest the San Luis Valley is a good region for conducting epidemiologic studies of groundwater metals because of the ability to accurately predict variation in groundwater arsenic concentrations.
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    • "This approach usually requires an assumption that arsenic concentrations in drinking water are stable over time and that study subjects do not consume water from other sources. Support for these assumptions has been found in several study populations (Navas-Acien et al. 2009b; Ryan et al. 2000). "
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