... toxiclevels in their drinking water, probably as a consequence of increased agriculturalirrigation. In recent years the toxic potential, both carcinogenic and noncarcino-genic, of arsenic in drinking ... drinking-water arsenic have provided opportuni-ties to delineate the risks of excess drinking-water arsenic. The largest studyreviewed 40,421 persons using contaminated water, compared with 75 00 ... ( 17, 18). There isconvincing experimental work in animals supporting the concept that arsenic hasan immunomodulating effect (19,20) and this may explain the effectiveness ofarsenic-containing...