Determinação da contaminação por chumbo em Boquira (BA) em decorrência da extração mineral

• Autor(a) principal: Fernandes, Tamara Grisolia
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/7143
• topic: Waste; Contamination; Lead; Ecotoxicity; TCLP; Rejeito; Contaminação; Chumbo; Ecotoxicidade; TCLP; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::MINERALOGIA

The extraction and processing of lead ore in a large scale made since mid-1950 in Boquira (BA), besides decades of great activity and economic relevance, also left an extensive pile of waste formed by irregular disposal and outside environmental standards. This study is aimed at providing an analysis of contamination left in the region, considering that the lead, once reaching the ground, can remain there indefinitely. Knowing that the contact of human beings with lead can cause several health problems and even genetic alterations, samples of the reject which is available and untreated until nowadays, were collected in order to compose a study of characterization of the contamination, distinguishing its composition in the collecting points. At first, a mineralogical characterization of collected samples was performed, revealing the presence of cerussite (PbCO3, anglesite(PbSO4) and a few quantity of galena (PbS). Chemical analysis revealed high lead content in the samples, with a range of 6962.25 ppm to 22279.2 ppm, much higher values than the reference ones on the list of CONAMA 420 2009 (maximum of 900 ppm). However, these data alone are not able to infer the bioavailability of the metal in the soil, it is necessary to evaluate how that contact with living organisms with it may be harmful (lethal or sub- lethal). Thus, ecotoxicity tests on Eisenia foetida earthworms showed that, although not lethal, contact with lead caused sub lethal effects on the tested organisms. According to the American Society for Testing and Materials (ASTM), sub- lethal effects in a soil test are indicative of toxicity effect, such as changes in growth, behavior, reproduction and physiological processes, and others. Having said that, there was a gradual weight loss of organisms exposed to the metal in the soil, in relation to the increasing of the concentration. The Toxicity Characteristic Leaching Procedure - TCLP and the essays to determinate the amount of organic matter in the samples added information about the availability of the metal in the soil, revealing that the quantity of lead available in all samples is superior to the recommended for waste by EPA, exceeding the limit of 5 mg Pb/L (EPA,1990)