Water pollution assessment and health risk analysis of Puzhehei Lake

School of geography and ecotourism, Southwest Forestry University, Kunming 650224, China

^* Corresponding author: ww0592@gmail.com

Abstract

Puzhehei Lake is located in Wenshan Prefecture, Yunnan Province. Water pollution assessment is of great significance for the pollution control of the lake and the sustainable development of the basin. This study evaluates the water pollution and eutrophication status of three sampling points (upstream, middle and downstream) of Puzhehei Lake based on single factor evaluation method, comprehensive pollution index method and improved comprehensive pollution index method based on entropy weight method, and analyzes the water health risk. The results show that the water quality of the three sampling points is sub-class V using the single factor evaluation method. The water quality evaluation result based on the traditional comprehensive pollution index method shows that the water quality of the three sampling points belongs to heavy pollution. By contrast, the improved comprehensive pollution index method based on entropy weight method shows that the water quality of Leshui Cave belongs to class V, while the water quality of Puzhehei Village and Karst Wetland Park belongs to class V. According to the comprehensive evaluation method, the water quality of the three sampling points before and after correction is ranked from good to bad as follows: Leshui Cave, Karst Wetland Park and Puzhehei Village. The water bodies of Leshui Cave and Puzhehei Village are moderately nutritious, and the water bodies of Karst Wetland Park are oligotrophic. The chemical carcinogens health risk in water at the three sampling points exceeded the standard seriously, and the risk ranking was as follows: Karst Wetland Park > Leshui Cave > Puzhehei Village, in which Cr exceeded the standard seriously. The non carcinogenic health risk are low, and the risk ranking is Puzhehei Village > Leshui Cave > Karst Wetland Park. In the future water quality control, we should focus on the strict control of TN and TP in rivers entering the lake.