Avaliação da concentração de metais tóxicos em amostras de sedimentos dos reservatórios do complexo Billings (Guarapiranga e Rio Grande)

LARISSA SOUZA SILVA, FRANCISCO JORGE FERREIRA, DÉBORA INÊS TEIXEIRA FÁVARO

Abstract


The objective of this study was to evaluate the concentration of toxic metals Cd, Cr, Cd, Hg, Ni, Pb and Zn and semi metal As and some other metals in bottom sediment samples collected in the Billings System (including the Rio Grande and the Guarapiranga Reservoirs), in two sampling campaigns. To evaluate the levels of anthropogenic contamination, the enrichment factor (EF) and geoaccumulation index (IGeo) were calculated, and oriented values TEL and PEL established by CCME (Canadian Council of Ministers of The Environment) and adopted by CETESB (Environmental Company of Sao Paulo State) were applied. In general, the elements As, Cr, Cu, Ni, Pb and Zn presented values above PEL for most sampling points, resulting in classification of bad quality of the sediments analyzed. The metals Cd and Hg were between TEL and PEL levels for most sampling points, in both campaigns. Billings Reservoir showed the worst situation in relation to the toxic metal concentration levels. The EF presented enrichment for Al, Ba, Fe, Mn, Sb and Se in the points analyzed, indicating possible contribution of anthropogenic origin. The IGeo values indicated contamination of Ba, Sb and Se. This study evidenced the need for frequent monitoring of the sediment quality in the Billings, Guarapiranga and Rio Grande Reservoirs as an indispensable procedure for periodic evaluation of the basin quality, considering their importance for Metropolitan Region of São Paulo water supply.


Keywords


Toxic Metals; Sediment; Billings Complex.



DOI: http://dx.doi.org/10.21715/GB2358-2812.2017301037

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