Arsenic occurrence in Brazil and human exposure

• Published in: Environmental geochemistry and health 2007-04, Vol.29 (2), p.109-118
• Main Authors: Figueiredo, Bernardino Ribeiro de, Borba, Ricardo Perobelli, Angélica, Rômulo Simões
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Arsenic; Arsenic - adverse effects; Arsenic - analysis; Arsenic Poisoning - epidemiology; Arsenic Poisoning - etiology; Arsenic Poisoning - prevention & control; Brazil - epidemiology; Contamination; Demography; Distribution; Drainage systems; Drinking water; environment; Environmental Exposure; Environmental Monitoring; Environmental studies; Epidemiological Monitoring; Exposure; Geochemistry; Health; Health risks; human health; Humans; Industrial Waste - analysis; Iron; Manganese; Manganese ores; Mine wastes; Mining; Nonpoint source pollution; Ores; Pollution; Pollution sources; Population studies; Public health; Sediments; Soil; Soil contamination; Soils; Surface water; Toxicity testing; Tropical climate; Water Pollutants, Chemical - adverse effects; Water Pollutants, Chemical - analysis; Water pollution; Water Purification; Water Supply; Zinc
• ISSN: 0269-4042; 1573-2983
• DOI: 10.1007/s10653-006-9074-9

Environmental exposure to arsenic (As) in terms of public health is receiving increasing attention worldwide following cases of mass contamination in different parts of the world. However, there is a scarcity of data available on As geochemistry in Brazilian territory, despite the known occurrence of As in some of the more severely polluted areas of Brazil. The purpose of this paper is to discuss existing data on As distribution in Brazil based on recent investigations in three contaminated areas as well as results from the literature. To date, integrated studies on environmental and anthropogenic sources of As contamination have been carried out only in three areas in Brazil: (1) the Southeastern region, known as the Iron Quadrangle, where As was released into the drainage systems, soils and atmosphere as a result of gold mining; (2) the Ribeira Valley, where As occurs in Pb-Zn mine wastes and naturally in As-rich rocks and soils; (3) the Amazon region, including the Santana area, where As is associated with manganese ores mined over the last 50 years. Toxicological studies revealed that the populations were not exposed to elevated levels of As, with the As concentrations in surface water in these areas rarely exceeding 10 μg/L. Deep weathering of bedrocks along with formation of Fe/Al-enriched soils and sediments function as a chemical barrier that prevents the release of As into the water. In addition, the tropical climate results in high rates of precipitation in the northern and southeastern regions and, hence, the As contents of drinking water is diluted. Severe cases of human As exposure related to non-point pollution sources have not been reported in Brazil. However, increasing awareness of the adverse health effects of As will eventually lead to a more complete picture of the distribution of As in Brazil.