Analysis of spatiotemporal evolution characteristics of water quality in Nanyi Lake and pollution sources
Based on water quality sampling and monitoring data,this paper carries out water quality evaluation of Nanyi Lake.Single factor evaluation and comprehensive evaluation methods are adopted to analyze the spa-tiotemporal evolution of water quality.Cluster analysis and principal component analysis are used to identify the main factors influencing the lake water quality and determine the main sources of pollution.The results of single factor evaluation show that the water quality of Nanyi Lake from 2013 to 2021 was all in class Ⅳ and below.The evaluation results of comprehensive water quality labeling method show that the water quality of Nanyi Lake fluctuated,and the water quality was in class Ⅲ on the whole,mainly manifested as nitrogen and phosphorus pollution,and the inflow of rivers had a great impact on the water quality of the lake.The main factors influencing water quality during flood season(June to August)were total nitrogen(TN),ammonia ni-trogen and five-day biochemical oxygen demand(BOD5),which mainly came from agricultural runoff,aqua-culture in outer lakes and domestic sewage sources.In non-flood season(January to May and September to December),the main influencing factors were ammonia nitrogen,TN,permanganate index CODMn(chemical oxygen demand),chlorophyll a and total phosphorus(TP),which were mainly affected by domestic sewage and internal source pollution of lake bottom.This study provides a theoretical reference for the formulation of water quality improvement plan in the lake area from the perspective of multiple pollution sources control.
NETL
NSTL
万方数据
