Avaliação da qualidade da água superficial do Rio Mamanguape - Paraíba, local de ocorrência de peixes-bois marinhos (Trichechus manatus)

Abstract

The Brazil is a country which has five important biomes and the largest river system in the world. In addition, it has the richest continental biota of the planet which earned him the title of mega-diverse country. The various species of aquatic mammals, the manatee (Trichechus manatus) has constantly suffered the effects of anthropogenic factors. In this context, the sewage waste dumps and heavy metal waste, are related to the degradation of aquatic environments and animal species which live in this biome. The aims of this study was to evaluate the quality of surface water from the river Mamanguape, located in the state of Paraíba, Brazil. This place is featured by an Environmental Protection area, where manatees occur. From September 2013 to July 2014, water samples were collected in triplicate of five distinct points of the river. In order to determine the Most Probable Number of fecal coliform the technique of multiple tubes was used. The reading of the samples for the research of mercury metal was performed through the System of Flow Injection Analysis, whereas for the other metals was performed, by Optical Emission Spectrometry with Inductively Coupled Plasma. In the research of thermotolerant coliforms, the contamination of some points, but always, values below to that recommended by the legislation was observed. Mercury, cadmium and chromium metals, were not detected, conversely copper, nickel, manganese, zinc and iron were detected, in low concentrations. On the other hand, aluminum and lead were found in concentrations above that allowed by the legislation. In conclusion, the water of the Mamanguape River presenting levels of salinity and pH within the limits previously established and low levels of contamination by fecal coliforms. The water samples of the Mamanguape River herein evaluated presented contamination by heavy metals, demonstrating the need of implementation of programs to monitor the collection sites. This measure could identify the likely source of contamination, considering that they are bioconcentrated in marine biota and may cause alterations in the food chain and consequently on the manatee.