Influência da toxicidade da água e do sedimento dos rios São Joaquim e Ribeirão Claro na bacia do Corumbataí / Influence of water and sediment toxicity of the São Joaquim and Ribeirão Claro Rivers on the Corumbataí River Basin

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The Corumbataí river basin located on Central region in São Paulo State is composed by part of Anâlandia, Corumbataí, Rio Claro, Itirapina, Ipeúna, Charqueada and Piracicaba municipality. The principals affluents rivers are Passa Cinco, Ribeirão Cabeça and Ribeirão Claro that have influence on water characteristics of Corumbataí river. The toxicity test has been recommended as an efficient tool for biomonitoring and evaluation of water and sediment quality. With the aim of evaluate and understand the decrease of water and sediment qualities of Corumbataí river five sampling sites were selected: two on Ribeirão Claro river, two on Corumbataí river and one on São Joaquim river. Ecotoxicity tests were performed with Hydra attenuata, Pseudokirchneriella subcapitata, Chironomus xanthus, Lactuca sativa and Dapnhia magna. For evaluation o IQA, were carried out physical, chemical and biology determinations as well chemical elements quantification by ICP-MS, such as: Be, Al, Na, Mg, Ca, K, V, Mn, Fe, Cr, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sb, Ba, Hg, Pb, Th, Tl and U. The water samples were collected every three mouth from April 2006 to May 2007. The chemical elements quantification results were compared with values standardized by CONAMA 357/05 Resolution. The Al, Fe, Hg e Pb concentration were over the ones recommended. The physical, chemical and biology assays showed that the dissolved oxygen, total phosphorus, ammonia nitrogen, biochemical oxygen demand and fecal coliforms were out of the standard recommendation. The IQA evaluation classified all water samples from São Joaquim River as Bad, the Ribeirão Claro three water samples were Bad, one Good and another Improper. So it showed the importance of these affluents on the decrease of Corumbatai river water quality. All the water and sediment samples showed toxicity at least for one organism tested, mainly for H. attenuata, P. subcapitata e C. xanthus. The H. attenuata sensity were directly affected by fecal coliforms, Cu, Ag, Ni and Zn, meanwhile the P. subcapitata were affect by Zn, Na, DBO and lowest level of OD, as obtained by redundancy analysis (RDA) on R statistics program. The chemical elements Al and Fe were present on water and sediment sample, over the recommend concentration of CONAMA 357/05 Resolution for rivers of Class 2 as the same for the Mn, which had high concentration after rain. On the other hand the elements Be, V, Cr, Co, Ni, As, Cu, Cd, Sb, Ba, Pb, Zn and U were below or near the limits. The sediment showed the chemical elements in this order: Mn >Zn >Ba >Pb >Cu >V >Cr >Co >Ni >As >U >Be >Ag >Cd >Se >Hg >Sb, when the Al and Fe where not considered. The São Joaquim and Ribeirão Claro rivers had a negative influence on Corumbataí river water quality

ASSUNTO(S)

bioensaio sediment iqa qualidade de água chemical elements metals water quality elementos químicos iqa bioassay metais sedimento

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