Ostras do gênero Crassostrea como bioindicadores de poluição aquática na Ilha de São Luís – MA

Abstract

This study aimed to use biochemical biomarkers associated with microbiological analysis to assess gender Crassostrea oysters as water pollution indicator, in addition to analyzing the microbiological quality of water and socioeconomic and hygienic sanitary issues on oyster seller. Thus, we analyzed in december 2013 to january 2015, 64 water samples of 64 oysters and oyster Crassostrea genus sample extraction sites collected in municipalities of São Luís Island - MA to quantify the enzymatic activity of biochemical biomarker glutathione-stransferase (GST) and catalase (CAT) by spectrophotometry. To evaluate the quality of hygienic sanitary oysters were used official analytical methods for determination of total coliforms and thermotolerant Most Probable Number - MPN, quantification of mesophilic aerobic bacteria and research Aeromonas spp. For the determination of total Coliforms and E. coli in water samples was used the technique of chromogenic and fluorogenic enzyme substrate ONPG / MUG. At the same time, we interviewed 19 oyster seller using semistructured questionnaire addressing socioeconomic and hygienic sanitary perception issues. The results indicated that in the rainy season and the dry season the activity of glutathione stransferase enzyme was higher in oysters of the Port of Cumbique. As for the oysters of the Port of Pau Laying area, this activity was almost nil during the rainy season. For the catalase enzyme activity the highest levels occurred in oysters of the Port of Cumbique, in both periods (wet and dry), Cais da Raposa in the rainy season, followed by Port of Braga in the dry season. In relation to water, 100% of the samples analyzed in both periods, showed levels of total Coliforms (Ct) and E. coli, 69% of oyster samples showed Ct, 47% thermotolerant coliforms (CT) and 8.33% E. coli in the rainy season. While in the dry season 57% of the oysters showed Ct, CT 39% and 21,42% E. coli. In relation to water, 100% of the samples analyzed in both periods, showed levels of total coliforms (Ct) and E. coli, 69% of oyster samples showed Ct, 47% thermotolerant coliforms (CT) and 8.33% E. coli in the rainy season. Furthermore, 47% of the samples of oysters were contaminated by bacteria of the genus Aeromonas, and all confirmed for A. hydrophila. The counts of heterotrophic bacteria mesophilic ranged from 8 x 102 ± 6 x 102 to 2,8 x 104 ± 4,7 x 104. As the questionnaires showed that the oyster seller belonged exclusively to men with estimated average of 33 years old, most of it from other Maranhão municipalities that are not part of the São Luís Island. Most have incomplete primary education, are married or in a stable relationship. They have little idea about the hygienic care to be adopted for the marketing of oysters. The data obtained showed that the change of enzymatic activity of glutathione s-transferase in oysters analyzed is indicative of adverse effects of contaminants carted to the water bodies in São Luís Island, especially in the area of the Port of Pau Laying. These oysters are with inadequate higienicossanitária quality for consumption and can be an important vehicle for foodborne pathogens such as A. hydrophila and E. coli. The water of oyster collection sites are within the microbiological standards set by law. The oyster collection mining activity is an important source of income for the community, but is performed without technological resources and artisan method.