Arsenic exposure assessment of children living in a lead mining area in Southeastern Brazil

ARTIGO ARTICLE 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 Alice Momoyo Sakuma 1 Eduardo Mello De Capitani 2 Bernardino Ribeiro Figueiredo 3 Franca Durante de Maio 1 Monica Maria Bastos Paoliello 4 Fernanda Gonçalves da Cunha 5 Maria Cristina Duran 1 1 Instituto Adolfo Lutz, São Paulo, Brasil. 2 Centro de Controle de Intoxicações, Universidade Estadual de Campinas, Campinas, Brasil. 3 Instituto de Geociências, Universidade Estadual de Campinas, Campinas, Brasil. 4 Centro de Ciências da Saúde, Universidade Estadual de Londrina, Londrina, Brasil. 5 Companhia de Pesquisas de Recursos Minerais, Rio de Janeiro, Brasil. Correspondence M. M. B. Paoliello Departamento de Patologia, Análises Clínicas e Toxicológicas, Centro de Ciências da Saúde, Universidade Estadual de Londrina. Av. Robert Koch 60, Londrina, PR 86038-440, Brasil. Abstract Introduction 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. 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 Arsenic Poisoning; Mining; Environmental Exposure Cad. Saúde Pública, Rio de Janeiro, 26(2):391-398, fev, 2010 391 392 Sakuma AM et al. not found in human urine 12. Therefore, speciation studies must be done in arsenic exposure evaluation studies. Chemical speciation aims to assess exposure to toxic, and low or non-toxic forms of arsenic. Several analytical techniques may be used for speciation studies, such as high performance liquid chromatography (HPLC) coupled with flow injection-hydride generation atomic absorption spectrometry (HG AAS) 15,16, or inductively coupled plasma mass spectrometry detection (ICP MS) 17. Guo et al. 18 have proposed methods for detecting only the toxicological relevant species using cystein and HG AAS. Arsenic is excreted mainly through the renal system. Therefore, the urine is the best biological specimen for assessing recent exposure to this element 19,20. According to Hinwood et al. 21, there is no need for 24-hour urine sampling to assess environmental inorganic arsenic exposure. There are no significant differences between the urinary inorganic arsenic concentrations for the different sample types, whether results are adjusted by urine creatinine or not 22. Gong et al. 23 performed studies on urine physical-chemical stability for arsenic determination and observed that samples remain stable for up to 114 days when kept at -20oC. In Brazil there are few studies assessing environmental arsenic contamination in mining areas. In the State of Amapá, in the northern part of the country, aquifers in a manganese mining and milling operation in Serra do Navio are contaminated due to high arsenic levels occurring in industrial waste that is stocked nearby. Nevertheless, water samples from residential areas showed arsenic levels on average below 10mg/L 24. In the Ribeira de Iguape river valley, located in the southern region of the State of São Paulo and east of the State of Paraná, Brazil, Silva 25 found abnormal arsenic levels in river sediments, possibly due to illegal unloading of mining waste in the rivers and also due to natural arsenic contamination. In Nova Lima, in the Southeast Region of Brazil, the Morro Velho Mining Company has been unloading gold mining and milling waste directly into the Cardoso stream, contributing to arsenic contamination of the environment 26. The Ribeira de Iguape river valley has a long and rich history of mining activities that goes back to late colonial times. The environmental impact of these activities regarding metal contamination of water, soil and sediment, has been assessed in recent years mainly focused on lead and arsenic concentrations 25,27. In the median part of the valley soils and rocks rich in arsenic can be found, principally Cad. Saúde Pública, Rio de Janeiro, 26(2):391-398, fev, 2010 in a geologic outcrop named Faixa Piririca, geographically located between the cities Iporanga and Eldorado, in São Paulo State. That region did not suffer a direct impact from the operation of the lead refining plant located upstream in Adrianópolis, Paraná. Nevertheless, soils with up to 2,000mg/kg can be found in that region due to the weathering of host rocks and gold seams containing sulfides and arsenopirite 28,29. The objective of the present study was to assess the arsenic ex (...truncated)