Assessment of ametryn contamination in river water, river sediment, and mollusk bivalves in São Paulo state, Brazil.

São Paulo state, Brazil, is one of the main areas of sugar cane agriculture in the world. Herbicides, in particular, ametryn, are extensively used in this extensive area, which implies that this herbicide is present in the environment and can contaminate the surface water by running off. Thereby, residues of ametryn were analyzed in samples of river water an river sediment and in freshwater bivalves obtained from the rivers Sapucaí, Pardo and Mogi-Guaçu in São Paulo State, Brazil. Samples were taken in the winter of 2003 and 2004 in two locations in each river. The specimens of freshwater bivalves collected and analyzed were Corbicula fluminea, an exotic species, and Diplodon fontaineanus, a native species. Additionally, the evaluation of the ability of bioconcentration and depuration of ametryn by the freshwater bivalve Corbicula fluminea was also performed. Ametryn concentrations in the samples were measured by liquid chromatography coupled to mass spectrometry. Residues of ametryn in water (50 ng/L) and in freshwater bivalves (2-7 ng/g) were found in the Mogi-Guaçu River in 2004, and residues in river sediments were found in all rivers in 2003 and 2004 (0.5-2 ng/g). The observation of the aquatic environment through the analysis of these matrixes, water, sediment, and bivalves, revealed the importance of the river sediment in the accumulation of the herbicide ametryn, which can contaminate the biota.

Bioaccumulation of atrazine in freshwater bivalves Anodontites trapesialis (Lamarck, 1819) and Corbicula fluminea (Müller, 1774).

The bioaccumulation of atrazine in bivalves is expected due to its wide use in agriculture and its moderate water solubility (33 mg/l). To assess the capacity of bioaccumulation, we performed a laboratory study in which two bivalves species (Anodontites trapesialis and Corbicula fluminea) were exposed to atrazine (concentrations of 0.06 to 0.34 microg/ml) during 48 h. The results showed that both bivalve species were able to bioaccumulate atrazine in their tissues. In another experiment, groups of bivalves from the specie A. trapesialis were exposed to atrazine at the concentration of 1 mug/ml and different organs of these animals were analyzed. The visceral mass, foot and mantle plus siphon showed the highest values of atrazine bioaccumulation.

Poluiçäo por metais pesados na bacia do rio Sapucaí-Mirim(nordeste do Estado de Säo Paulo, Brasil), pela indústria do couro / Heavy-metal polluition in basin of Sapucaí-Mmirim river (northeast of Säo Paulo State, Brazil), by hide industry

Contamination of the limnic environment is occuring at a fast rate all over the world due to the wide industrial expansion and, at the same time, to the lack of infrastructure for previous treatment of effluents that are dumped into fresh water sources, significantly contributing to the high rates of pollution affecting small and large rivers close to urban centers. The objective of the present study was to analyze the sediment and water of the Sapucaí-Mirim River, an important river in the Northeasten part of the State of Säo Paulo that receives industrial effluents from Franca and Säo Joaquim da Barra, where the major source of pollution is the leather industry which mainly uses Cr for tanning. In the present study we investigated the presence of the metals Cd, Cr, Cu, Pb and Zn at he sites where the Ribeiräo dos Bagres stream empties into the Sä Joaquim stream and the Sapucaí-Mirim River. High metal levels were detected in both regions, with no significant differences between them. The differences detected were loca, with the highest indices being found in the tributaries of the Sapucaí-Mirim River. The metals detected in the water were limited to Cr and Zn, with levels of the order of 0.006 ug/ml to 0.168 ug/ml Cr and 0.002 ug/ml to 0.033 ug/ml Zn. All the metals analyzed were detected in the sediment, with Cr and Zn again being present at highest concentrations. Cr ranged from 17.800ug/g to 242.425 ug/g and Zn ranged from 142.000 ug/g to 1024.000 ug/g. With respect to Cr, the contamination in the region studied was attributed to the leather industry for the manufacturing of shoes