基于主成分分析法的湖库型饮用水源地富营养化状况评价——以攀枝花市胜利水库为例

Eutrophication Evaluation of Reservoirs Based on Principal Component Analysis-Taking Shengli Reservoir in Panzhihua City as an Example

为进一步分析湖库型饮用水源地水质和营养状态变化规律,采用2014~2019年期间胜利水库水质监测数据,利用主成分分析法对主要水质参数变化趋势、相关性及主要影响因素进行分析,同时运用主成分分析法和综合营养状态指数对两种评价方法水库营养化状态进行评价。结果表明,胜利水库水体中Chla和NH3-N随着时间变化呈上升趋势,TP和CODMn随时间变化呈下降趋势;水质状态为Ⅱ~Ⅲ类;水库营养状态处于中营养及以上。主成分分析结果显示,水库中营养状态变化的主要驱动因子(特征值大于0.8)为BOD5、TN、TP;与常规的综合营养状态法相比,主成分分析法得出的评价结果更为明显和可靠。总氮是造成水体富营养化的主要因子,减缓富营养化应重点关注氮元素的输入和输出。强化湖库周边农村环境综合整治,控制农业面源污染,加快推进农村生活污水治理,防止湖库水质进一步恶化,保障饮用水水源安全。

In order to analyze the changing rules of water quality and nutritional status of lake-reservoir drinking water source,the water quality monitoring data of Shengli Reservoir from 2014 to 2019 were used to analyze the changing trend,correlation and main influencing factors of main water quality parameters by using principal component analysis.At the same time,principal component analysis and comprehensive nutrition status method were used to evaluate the reservoir trophic state.The results showed that the Chla and NH3-N concentrations increased with time while the TP and the CODMn concentrations decrease with time.The water quality of Shengli reservoir belonged to classⅡ~Ⅲ,and the nutrient status of the reservoir is in the medium nutrition.The main component analysis results showed that the main restricting factors related to the changes of algae and nutrient status turn out to be BOD5、TN and TP.Compared with the normal comprehensive nutrition status method,the results of the principal component analysis method were more obvious and reliable.TN pollution is the main factor causing eutrophication of water body,more attention should be paid to the input and output of nitrogen elements to reduce eutrophication.Strengthen the comprehensive rural environment management,control non-point pollution of agriculture,and accelerate the development of rural sewage treatment to prevent further deterioration of the water quality,and ensure the safety of drinking water sources.