Análise de espécies químicas presentes no caranguejo-uçá, Ucides cordatus (Linnaeus, 1763) enquanto bioindicador da contaminação de manguezais do estuário do Rio Subaé - Bahia (Brasil) por metais tóxicos

Abstract

A Company of lead processing, which operated in the city of Santo Amaro – Ba between the years of 1960 and 1993 caused a huge contamination by toxic metals in this area. Considering the risks associated to the contamination, this work was developed using Ucides cordatus as a biomarker of the contamination of toxic metals in this area by the use of mineral compounds from different crab’s organs and tissues. The animals were collected at six different points of collection in the estuary of Subae River in five trips. Organs and tissues of the animals were submitted to a previous procedure for chemical analysis by acid digestion using nitric acid, and hydrogen peroxide under heating in a digester block. The determinations of Cu, Fe, Zn, Pb, Ni, Cd, Mn, Mg, P, S, K and Ca were made by a simultaneous inductively coupled plasma optical emission spectrometer (ICP OES). Among the findings, it was pointed out differences between the concentration of these metals in male and female animals. In addition, differences in the concentrations of these metals were found between animals in different stages of sexual maturation. At all points of collection, animals were found with the concentrations of these metals above the accepted by current laws by at least, one metal. The highest concentrations of the toxic metals were found in the gills, followed by hepatopancreas, and muscle tissue. Levels of contamination for Pb reached values near to 16.4 times uppon the accepted limit by current laws; thus it represents ecologic risks, and risk to the population who lives in Santo Amaro-BA. According to the findings, levels of contamination were found among the collected animals, and the contamination is related to historic events in this area.