Health Effects of Naturally Radioactive Water Ingestion: The Need for Enhanced Studies

BACKGROUND: Radiological pollution is a potentially important aspect of water quality. However, relatively few studies have been conducted to document its possible health effects. OBJECTIVE: In this commentary we discuss available epidemiological findings and related data from experimental studies concerning the health effects of naturally radioactive water ingestion. DISCUSSION: Despite modest epidemiological evidence of uranium nephrotoxicity and radium effects on bone, available data are not sufficient to quantify the health effects of naturally occurring radionuclides in water. Methodological limitations (exposure measurement methods, control for confounding, sample size) affect most studies. Power calculations should be conducted before launching new epidemiological studies focusing on late pathological outcomes. Studies based on biomarkers of exposure and adverse effects may be helpful but should involve more specific molecules than biomarkers used in previous studies. Experimental data on ingestion of drinking water are limited to uranium studies, and there is some disagreement between these studies about the nephrotoxicity threshold. CONCLUSION: Further experimental and enhanced epidemiological studies should help to reduce uncertainties resulting from dose estimation to dose-response characterization.