Oral exposure to inorganic arsenic: evaluation of its carcinogenic and non-carcinogenic effects

Abstract

Inorganic arsenic, which is extensively metabolised in humans into even more toxic methylated arsenicals, is a potent carcinogen, causing tumours of the skin, lung, urinary bladder, and other organs. It also induces a number of non-cancer effects. Consumption of drinking water highly contaminated by arsenic causes serious health problems in some countries in southeastern Asia, and arsenic poses problems for drinking-water safety world-wide. Existing risk assessments are based on epidemiological studies from regions with high exposure concentrations (in the mg/L range). It is a matter of debate whether these findings are useful at predicting arsenic-induced effects at low concentrations. In recent years numerous epidemiological studies on cancer and non-cancer effects of inorganic arsenic have been published. This work aims at reviewing recent toxicological and epidemiological data on inorganic arsenic with emphasis on effects at low exposure concentrations. Information obtained from epidemiological studies is supplemented with mechanistic data from in vitro and in vivo studies. Various modes of action for arsenic carcinogenicity are discussed. The information gathered was used to evaluate the reliability of existing cancer-risk assessments and to improve current assessments of non-cancer health effects. A tolerable daily dose, based on epidemiological studies on arsenic-induced skin disorders, is presented.

Editor’s Highlight: Interactive Genotoxicity Induced by Environmentally Relevant Concentrations of Benzo(a)Pyrene Metabolites and Arsenite in Mouse Thymus Cells

“…However, many populations in USA and elsewhere are exposed to unregulated drinking water sources that are in excess of 100 ppb (Rahman et al, 2006;Sherwood et al, 2013). The trivalent from of inorganic arsenic, arsenite (As þ3 ), has been associated with many diseases such as diabetes, skin lesions, and cancers (Argos et al, 2010;Schuhmacher-Wolz et al, 2009;Vahter, 2008). One of the primary genotoxic mechanisms of As þ3 is the inhibition of DNA repair (Faita et al, 2013).…”

Quality Evaluation of Different Brands of Bottled Water Sold in Uyo Metropolis

“…[23,24] Long term consumption of arsenic associated with development of skin conditions and circulatory system problems in addition to increased risk of cancer of the bladder, lungs, skin, kidney, nasal passages, liver and prostrate. [23,24,25] Samples A, B, D, E, G and L were devoid of any microorganism. However, sample A had earlier failed the pH test while L contained phenol above the normal range.…”

The control of histone methylation and gene expression by oxidative stress, hypoxia and metals

“…Given its natural abundance and industrial use, arsenic's environmental impact is felt by nearly 150 million people in at least 70 countries [61]. Arsenic has been identified as a causal agent in human skin, lung, and bladder cancers and some epidemiological studies have also implicated As in the development of liver and prostate cancers [62][63][64][65][66][67]. Furthermore, arsenic exposure has also been associated with non-carcinogenic health outcomes, including cardiovascular disease, neurologic deficits, neuro-developmental deficits in childhood, and hypertension [68][69][70][71][72].…”