Population density and occurrence of freshwater gastropod species in the Paca River, Caraguatatuba, SP, Brazil Beverllyn Marinho Franco, Judith Font Batalla

Abstract

The body of water known to the population as the Paca river (Caraguatatuba-SP), runs through the neighborhoods of Jaqueira and Tinga in the city of Caraguatatuba shows signs of pollution, resulting from the disposal of solid waste by the population directly in the course of the river. By observing the aesthetic conditions of the river, it is verified that the water quality of the river is compromised due to the eviction of untreated evictions of the residents and even of commercial establishments. These actions end up deteriorating the conditions of the water and the habitat of many organisms, running the risk still of the river end up becoming vehicle of transmission of pathogenic diseases for the population. In order to verify the effluent contamination, water samples from the Paca River were collected to perform the physicochemical analyzes. The results showed the presence of fecal coliforms, approximately 23,300/100 ml. Among the physicochemical parameters analyzed, ammoniacal nitrogen, as well as faecal coliforms, exceeded the maximum limit of 5.6 mg/l allowed by CONAMA resolution 357 presented a concentration of 12.6 mg/l. With regard to the population density of gastropods were found representatives of the genus Pomaccea sp., Biomphalaria sp., Lymnea sp. and Physa sp.