Arsenic exposure assessment of children living in a lead mining area in Southeastern Brazil Avaliação da exposição de crianças ao arsênio em área de mineração de chumbo na Região Sudeste do Brasil

Environmental contamination by arsenic compounds in the Ribeira River Valley, São Paulo, Brazil has already been observed. Lead mining and refining activities had been carried on since late colonial times and finished recently, at the end of 1995. The source of As in the region is known to be mainly from arsenopirite geological presence in the lead ore. Chronic exposure to arsenic compounds may cause peripheral vascular disorders, hyperpigmentation, hiperkeratosis and cancer of the skin, bladder, lung, liver and other internal organs. The purpose of this study was to assess children exposure to arsenic from environmental sources in the region. Urine samples from children between 7 to 14 years old were collected at the following localities: Cerro Azul (Paraná); urban areas of Ribeira (São Paulo) and Adrianópolis (Paraná); Vila Mota neighborhood (rural area of Adrianópolis) and Serra neighborhood (Iporanga, São Paulo), identified as groups 1, 2, 3 and 4, respectively. Group 1 was considered as non-exposed control group. Toxicologically relevant forms of As were determined by atomic absorption spectrometry with hydride generation system. The median values of urine arsenic levels obtained in groups 1, 2, 3 and 4 were respectively: 3.60, 6.30, 6.41 e 8.94μg/L. Arsenic Poisoning; Mining; Environmental Exposure Introduction Several studies carried out in India, China, Taiwan, Chile and Argentina have shown that longterm environmental exposure to high arsenic levels, mainly through drinking water, can increase the incidence of skin, lung, liver and bladder cancer, as well as cause the occurrence of a severe debilitating arterial vascular disease (black foot disease, described in Taiwan) 1,2,3,4,5,6,7. Absorption of arsenic by humans depends on the nutritional status, concentration and duration of the exposure, as well as on the synergistic and antagonistic relationships with other substances present in water, like humic acid. Malnutrition tends to increase susceptibility to arsenic from environmental contamination 2,8. Toxicity of arsenic depends on its chemical form. In fish and seafood, arsenic is present basically in non-toxic organic forms, such as arsenobetaine and arsenocoline. Both are very stable forms of arsenic that are not metabolized in the organism after absorption, and are directly excreted by the kidneys. The total amount of arsenic in urine is strongly influenced by arsenic ingestion through diet 9,10. In humans, inorganic arsenic compounds are metabolized into trivalent and pentavalent organic arsenicals. Toxicity hierarchy of arsenic compounds decreases from arsenite > MMAIII > DMAIII > (AsIII) > arsenate (AsV) > MMAV > DMAV > TMAO 11,12,13,14. Trimethylarsine oxide (TMAO) is ARTIGO ARTICLE Sakuma AM et al. 392 Cad. Saúde Pública, Rio de Janeiro, 26(2):391-398, fev, 2010 not found in human urine 12. Therefore, speciation studies must be done in arsenic exposure