Quality of drinking water and high incidence rate of esoph-ageal cancer in Golestan Province of Iran: a probable link

ABSTRACT

Golestan Province in northern Iran is known to be a high-risk area for esophageal cancer [EC]. Of a long list of multiple risk factors, this study focuses on a possible link between the epidemiologic patterns of EC and the anomalous concentration of some ions and elements in the drinking water sources. A total of 183 samples from 45 villages covering a wide range of EC mortality rates are collected and analyzed. The results demonstrate that NO3, SO42, Sb, and Sr exceed the recommended maximum concentration level [MCL] in drinking water. This is more prominent in the villages with high esophageal cancer mortality rate, suggesting a possible link between EC incidence and water quality. Se concentration in drinking water increases from low to the high EC areas, a finding contrary to the expected trend. It is concluded that Se deficiency does not play a major role in the etiology of EC in the Golestan Province. The statistical results obtained from Mann-Whitney and Kruskal-Wallis tests along with cluster analysis are consistent with the observed trend of EC mortality rate in Golestan Province