Chromosomal aberrations in arsenic-exposed human populations: a review with special reference to a comprehensive study in West Bengal, India

Abstract

For centuries arsenic has played an important role in science, technology, and medicine. Arsenic for its environmental pervasiveness has gained unexpected entrance to the human body through food, water and air, thereby posing a great threat to public health due to its toxic effect and carcinogenicity. Thus, in modern scenario arsenic is synonymous with “toxic” and is documented as a paradoxical human carcinogen, although its mechanism of induction of neoplasia remains elusive. To assess the risk from environmental and occupational exposure of arsenic, in vivo cytogenetic assays have been conducted in arseniasis-endemic areas of the world using chromosomal aberrations (CA) and sister chromatid exchanges (SCE) as biomarkers in peripheral blood lymphocytes. The primary aim of this report is to critically review and update the existing in vivo cytogenetic studies performed on arsenic-exposed populations around the world and compare the results on CA and SCE from our own study, conducted in arsenic-endemic villages of North 24 Parganas (district) of West Bengal, India from 1999 to 2003. Based on a structured questionnaire, 165 symptomatic (having arsenic induced skin lesions) subjects were selected as the exposed cases consuming water having a mean arsenic content of 214.96 µg/l. For comparison 155 age-sex matched control subjects from an unaffected district (Midnapur) of West Bengal were recruited. Similar to other arsenic exposed populations our population also showed a significant difference (P < 0.01) in the frequencies of CA and SCE between the cases and control group. Presence of substantial chromosome damage in lymphocytes in the exposed population predicts an increased future carcinogenic risk by this metalloid.

Assessment of arsenic toxicity using Allium/Vicia root tip micronucleus assays

“…The results of the present study showed that arsenic exposure caused genotoxicity in plant cells, which is consistent with the earlier reports in a variety of cultured human cells [33][34][35], animals [16,36], and arsenic-exposed human populations [37,38].…”

BRCA2-dependent homologous recombination is required for repair of Arsenite-induced replication lesions in mammalian cells

“…This could then explain the increased level of chromosomal aberrations seen in As[III] exposed individuals. Indeed some reports suggest that the level of chromosomal damage in exposed individuals can be used to predict future risk of cancer (64). …”

Synergistic effect of folic acid and vitamin B12 in ameliorating arsenic-induced oxidative damage in pancreatic tissue of rat

“…Arsenic contamination has reached an alarming proportion in various districts of West Bengal, an eastern state of India, and in Bangladesh, so much so that it has been earmarked as bthe biggest arsenic calamity in the worldQ [1][2][3][4]. A large number of people from this area are endemically exposed to arsenic-contaminated groundwater due to drinking of tube well water containing arsenic level above World Health Organization's maximum permissible limit of 50 Ag/L [5].…”