Estimating Water Supply Arsenic Levels in the New England Bladder Cancer Study

Abstract

Background: Ingestion of inorganic arsenic in drinking water is recognized as a cause of bladder cancer when levels are relatively high (≥ 150 µg/L). The epidemiologic evidence is less clear at the low-to-moderate concentrations typically observed in the United States. Accurate retrospective exposure assessment over a long time period is a major challenge in conducting epidemiologic studies of environmental factors and diseases with long latency, such as cancer.Objective: We estimated arsenic concentrations in the water supplies of 2,611 participants in a population-based case–control study in northern New England.Methods: Estimates covered the lifetimes of most study participants and were based on a combination of arsenic measurements at the homes of the participants and statistical modeling of arsenic concentrations in the water supply of both past and current homes. We assigned a residential water supply arsenic concentration for 165,138 (95%) of the total 173,361 lifetime exposure years (EYs) and a workplace water supply arsenic level for 85,195 EYs (86% of reported occupational years).Results: Three methods accounted for 93% of the residential estimates of arsenic concentration: direct measurement of water samples (27%; median, 0.3 µg/L; range, 0.1–11.5), statistical models of water utility measurement data (49%; median, 0.4 µg/L; range, 0.3–3.3), and statistical models of arsenic concentrations in wells using aquifers in New England (17%; median, 1.6 µg/L; range, 0.6–22.4).Conclusions: We used a different validation procedure for each of the three methods, and found our estimated levels to be comparable with available measured concentrations. This methodology allowed us to calculate potential drinking water exposure over long periods.

Assessing Exposure and Health Consequences of Chemicals in Drinking Water: Current State of Knowledge and Research Needs

“…Several methods can be used in combination, tailored to the availability of data; for example, in a recent study on the long-term exposure to arsenic and cancer, Nuckols et al (2011) combined arsenic data from their own measurements in water samples collected at homes of the participants, data from public water utilities, and historical data for aquifers.…”

Possible Positive Selection for an Arsenic-Protective Haplotype in Humans

“…Increased concentrations of inorganic arsenic (above the World Health Organization guideline value of 10 µg/L) in drinking water are frequently found in Argentina, Bangladesh, Chile, China, Hungary, India, Mexico, Romania, Taiwan, and different parts of the United States [International Agency for Research on Cancer (IARC) 2004; Nuckols et al 2011; Sanders et al 2012]. Arsenic contamination occurs mainly through leakage from arsenic-containing bedrock and sediment into the drinking water (mainly groundwater).…”

Variability in the chemistry of private drinking water supplies and the impact of domestic treatment systems on water quality

“…The occurrence of high concentrations of trace elements, such as As, can be very unpredictable at the local scale, or subject to temporal variation (Ayotte et al 2015). This makes the acquisition of sample data essential to understand chemical water quality in a given area and enable lifetime exposure risks to be quantified (Hough et al 2010; Nuckols et al 2011). Globally, in areas where groundwater used as drinking water has very high As concentrations, it is recognised as a cause of high morbidity and premature mortality rates (Murcott 2012; Smith et al 2000).…”