Arsenic occurrence in Brazil and human exposure

Abstract

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 microg/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.

Estudo da especiação de arsênio inorgânico e determinação de arsênio total no monitoramento ambiental da qualidade de águas subterrâneas

“…Estas amostras foram coletadas no interior das minas do Chico Rei (CR) e Passagem (PM), situadas em Ouro Preto, e Passagem de Mariana, respectivamente, no Quadrilátero Ferrífero -MG, onde há a contaminação natural e antropogênica por As de águas, solos e sedimentos de rios, relacionada com a mineração secular de ouro. 14,15 Em cada local de amostragem foram coletadas seis alíquotas de água, de 200 mL, que foram filtradas através de uma membrana de acetato de celulose de 0,45 µm (Millipore) e colocadas em tubos de centrifuga esterilizados. Em uma das alíquotas foram medidos diretamente, in situ, o pH, Eh, a condutividade e a temperatura das tabela 1.…”

Arsenic: behavior in the environment, plant uptake mechanisms and human health risks

“…Furthermore, pesticides, herbicides, wood preservatives, burning of fossil fuels, fertilizers, smelting of gold, lead, copper and nickel, and production of iron and steel are the main anthropogenic sources of As (Mandal;Suzuki, 2002). surface water bodies with values higher than10 µg L -1 have been verified by studies of human exposure in the Quadrilátero Ferrífero area, Minas Gerais state (Figueiredo, 2006) and in the municipality of Santana, Amapá state (Figueiredo et al, 2007). The main source of contamination at these sites is the mining of metals, mainly gold, iron and manganese.…”

Arsenic in drinking water: sources, occurrence and health effects (a review)

“…When comparing the As urine levels of these patients with the ones of healthy subjects, Ruiz-Navarro et al (1998) did not find any statistical difference, indicating that regulation of As in the human body is independent of these diseases. Figueiredo et al (2007) summarized previous studies in a series of Brazilian zones highly impacted by mining (Au, Pb-Zn, …), where water run-off was found with total As up to 2,980 lg/l and As(III) up to 86 lg/l; they discussed these data and complementary human monitoring (urine, hairs) on various populations, according to various factors including local climate. Concerning As concentration in urine, Ma and Le (1998) observed that the ingestion of arsenosugars-containing food (like i.e.…”