Use of geographic information system (GIS) in the characterization of the Cunha Canal, Rio de Janeiro, Brazil: effects of the urbanization on water quality.

The Cunha Canal Watershed, located in the city of Rio de Janeiro, suffered an intense environmental degradation over the last decades caused mainly by the rapid urban growth. However, this pronounced growth deteriorated the existing socio-environmental problems. This article intended to assess the pollution of the waters of Cunha Canal, caused by the disposal of domestic sewage and industrial effluents. The data analyzed were monitored in two different periods. Chemical parameters such as dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total phosphorus and amonniacal nitrogen were measured. The results show that the water of Cunha Canal is altered and degraded, probably due to the intense urbanization of the watershed environs. Increase in the water quality was not observed. Therefore, an alternative to reduce the pollution in the area could be the construction of a sewage treatment plant. [ABSTRACT FROM AUTHOR]