Ecotoxicological and microbiological assessment of drainage channel of Santos (SP) estuarine system Raiane Fernandes Elias, Kalel Henrique Ferro de Oliveira, Camilo Dias Seabra Pereira

Abstract

In the current management of human activities in coastal areas it is difficult to reconcile economic development with the maintenance of ecological quality. In the region of Santos ( state of São Paulo) can be cited the expansion of industrial, real estate and port activities, resulting from the ampliation of the largest port in Latin America (Santos), the petrochemical megapolo of Cubatão and more recently the activities of the pre-salt oil exploration as important factors of change in environmental quality. The urban drainage systems contribute to dump pollutants in the Estuary, compromising its use for fishing, recreation and protection of aquatic biota. The present study aimed to evaluate the microbiological contamination and toxicity of water in the region of the Santos Basin market, and see if this causes a significant negative influence on the navigation channel of Santos, which receives water coming from the drainage channels of the urban municipality of Santos and ends in the left margin of it. For that, samples were taken monthly from water at 4 points in the channel Santos market basin, and from two points in the navigation channel of the estuary (in this place for 9 months), during the period of one year. The samples were tested for chronic toxicity of short duration with Lytechinus variegatus and microbiological analyzes for fecal coliform. With the exception of points 1, 2 and 4 of December, points 3 and 4 of February and the points of April, all samples collected within the urban drainage channel of the basin showed toxicity. The results of chronic toxicity tests showed that for 7 months, 2 points evaluated in the navigation channel of the estuary of Santos, presented a CEO <6.25%. Regarding the colimetric assays, of the 9 months analyzed in the Santos navigation estuary channel, only on the September, March and May samples, the results of both points is presented below the threshold set. In all samples collected within the urban drainage channel, the limit of 1000 fecal coliforms per 100ml of sample, established by CONAMA Resolution 357/2005 was exceeded. It was verified that with certain exceptions related to weather patterns, there is a continuing source of contamination in the region. The results indicate the influence of the waters of the Basin Market in changing the environmental quality of adjacent estuarine zone. These results will contribute to environmental risk and public health assessment, providing a basis for future sanitation policies in the region.