Analyses of micronuclei in exfoliated epithelial cells from individuals chronically exposed to arsenic via drinking water in Inner Mongolia, China

The groundwater in Bayingnormen (Ba Men), located in Central West Inner Mon golia, China, is naturally contaminated with arsenic at concentrations rang ing from 50 mug/L to 1.8 mg/L. Various adverse health effects in this regio n, including cancer, have been linked to arsenic exposure via drinking wate r. A pilot study was undertaken to evaluate frequencies of micronuclei (MN) , as measures of chromosomal alterations, in multiple exfoliated epithelial cell types from residents of Ba Men chronically exposed to arsenic via dri nking water, Buccal mucosal cells, airway epithelial cells in sputum, and b ladder urothelial cells were collected from 19 residents exposed to high le vels of arsenic in drinking water (527.5 +/- 24 mug/L), and from 13 control residents exposed to relatively low levels of arsenic in drinking water 4. 4 +/- mug/L). Analytical results from these individuals revealed that MN fr equencies in the high-exposure group were significantly elevated to 3.4-fol d over control levels for buccal and sputum cells, and to 2.7-fold over con trol for bladder cells (increases in MN frequency significant at p <.001 fo r buccal cells; p <.01 for sputum cells; p <.05 for bladder cells). When sm okers were excluded from high-exposure and control groups the effects of ar senic were observed to be greater, although only in buccal and sputum cells ; approximately 6-fold increases in MN frequency occurred in these tissues. The results indicate that residents of Ba Men chronically exposed to high levels of arsenic in drinking water reveal evidence of genotoxicity in mult iple epithelial cell types; higher levels of induced MN were observed in bu ccal and sputum cells than in bladder cells.