Evaluation of Water Environmental Quality in a Shallow Urban Lake

South Lake in Handan City,typical of shallow urban lake with only 1.3m water depth on the average,was studied in this paper for evaluating the status of water quality by methods of single-factor appraisal,comprehensive pollution index and nutrient index. With the water quality monitoring involving 11 sampling sites all over the Lake which began from April to October 2013,and the analytic data of water quality,the evaluation was carried out in accordance with the related national standard Environmental Quality Standard for Surface Water(GB3838-2002). Results showed that nitrogen and phosphorus were the main pollution factors to be controlled in South Lake as all the data from the monitoring sites indicated concentrations of both TN and TP exceeded the limits of ClassⅤ in GB3838-2002. According to the field survey,emissions of domestic sewage and industrial wastewater and the dumping of garbage on the lake-shore were the main sources causing water pollution, with the pollution indexes being 3.0 and 2.2 respectively. The appraisal based on comprehensive nutrient indexes showed that the Lake,as a whole,still remained at the slight eutrophication level,while in the places close to pollution sources the situation was aggravated to median level.