Arsenic in groundwater in Bangladesh: A geostatistical and epidemiological framework for evaluating health effects and potential remedies

TLDR

The method offers a framework that can incorporate improved data as it becomes available, though current estimates remain uncertain. The study investigates Bangladesh’s arsenic‑contaminated groundwater crisis and evaluates drilling deeper wells as a potential remedy. Geostatistical mapping of arsenic concentrations, census‑based exposure estimation, and dose‑response modeling from West Bengal and Taiwan data are combined to estimate health effects, and the impact of deeper wells is assessed. Projected long‑term exposure could cause about 1.2 million hyperpigmentation cases, 600 000 keratosis cases, 125 000 skin cancers, and 3 000 annual internal‑cancer deaths, but replacing 31 % of wells with deeper ones could reduce these effects by roughly 70 % if deep‑well arsenic remains low.

Abstract

This paper examines the health crisis in Bangladesh due to dissolved arsenic in groundwater. First, we use geostatistical methods to construct a map of arsenic concentrations that divides Bangladesh into regions and estimate vertical concentration trends in these regions. Then, we use census data to estimate exposure distributions in the regions; we use epidemiological data from West Bengal and Taiwan to estimate dose response functions for arsenicosis and arsenic‐induced cancers; and we combine the regional exposure distributions and the dose response models to estimate the health effects of groundwater arsenic in Bangladesh. We predict that long‐term exposure to present arsenic concentrations will result in approximately 1,200,000 cases of hyperpigmentation, 600,000 cases of keratosis, 125,000 cases of skin cancer, and 3000 fatalities per year from internal cancers. Although these estimates are very uncertain, the method provides a framework for incorporating better data as it becomes available. Moreover, we examine the remedy of drilling deeper wells in selected regions of Bangladesh. By replacing 31% of the wells in the country with deeper wells the health effects of drinking groundwater arsenic could be reduced by approximately 70% provided that arsenic concentrations in deep wells remain relatively low.