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.

SUBMITTER: Nuckols JR 

PROVIDER: S-EPMC3230387 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature