Geodisponibilidade de metais pesados na área de confluência dos Rios Piranhas e Seridó/RN.

Abstract

The present work has the objective of identifying the geoavailable chemical elements in the confluence region of Rios Piranhas and Seridó, in the cities of Caicó, Timbaúba dos Batistas and São Fernando, located in the state of Rio Grande do Norte. The chain sediment, soil and rock samples were analyzed using a commercial kit from SGS/Geosol laboratories. The kit analyzes using ICP – MS (Inductively Coupled Plasma - Mass Spectrometer) 32 elements (Ag, Ba, Be, Cd, Cr, Cu, Li, Mo, Ni, Sc, Sr, Zn, Zr, Y, Co, Pb, Sb, V, Bi, Sn, W, La, B, Al, Ca, Fe, K, Mg, Mn, Na, P and Ti) and the gold by fire assay / Atomic Absorption. The resulting information in each one of the collection environments was treated statistically aiming to compare the tenors of the elements in relation to the data universe and in relation to the quality parameters settled by national and international institutions. The same samples were also examined spatially, with the help of geographic information systems software (Arc Gis 9.3 and MapInfo 10), which proportioned the identification of the dispersion sources of metals associated with the places of mineral exploration of the gold mining being conducted in Anastacia, Tapera, Ponta de Serrra, Simpático, Caifás, Serra dos Patos and Serra do Rodrigues (which was the object area of the exploration). Two other dispersion sources of metals deserve special attention, since they are not formed in places of mining exploration and might represent the location of a Mineral Deposit of gold not yet explored. The work identifies the geoavailable works in concentrations higher than those recommended by CONAMA for sediment through Resolution 344 of March 25th of 2004, chemicals such as: As, Cd, Pb, Cr, Cu and Ni. In the soil of Anastacia, Tapera and Ponta de Serra regions, the As reaches 301 ppm which is much higher than the reference values, calling special attention to health implications. Heavy metals Arsenic, Cadmium, Lead and Chrome, geoavailable in the confluence area of Piranhas river and Seridó, from the mining of gold, cause malignancies, as it's pointed from many national and international scientists and health organizations and form enough justify to be blamed for cancer death of 50% of São Fernando population, between 50 and 65 years old, once they might be present in all the biological chain that depends, direct or indirectly, on that catchment.