Análise da qualidade da água de um estuário urbano

Abstract

Urban tropical estuaries are susceptible to environmental impacts of anthropogenic origin, mainly due to the availability of excess nutrients, mainly due to domestic effluents discharged into the estuary, often due to the lack of a more adequate option. The present work aims to analyze the interannual variations in water quality of the urban tropical estuary of the Capibaribe River, located in the city of Recife - Pernambuco (Brazil), identifying changes in water quality during 2004 to 2012, considering the seasonality (dry and rainy periods), as well as comparing the possible differences between two sampling points (referred to as "upstream" and "downstream"). The physical-chemical variables (salinity, pH, turbidity, temperature, dissolved oxygen, biochemical oxygen demand, ammonia, phosphorus and color) were analyzed by the CPRH Basin Monitoring Program. The largest sources of variance are related to the factors of the season and sampling point (p <0.05). Ammonia (mean 1.51 ± 2.54 mg L-¹) and phosphorus (mean 0.45 ± 0.32 mg L-¹) presented the majority of their values above that recommended by current legislation. Hypoxia and / or anoxia records occurred for the analyzed period, being more common in rainy seasons. It is found that the greatest vulnerability is present upstream of the estuary during the dry season.