基于最优尺度地理探测的长三角有机污染物时空分布驱动因素分析

场地污染对人体健康和生态环境造成了严重危害,理解其时空分布规律是污染评估和场地修复的基础.为此基于场地采样数据,利用最优尺度地理探测器分析长三角地区有机污染物时空分布规律及其驱动因素.结果表明:①长三角场地有机污染物空间分布存在显著的尺度效应,其最佳地理探测尺度格网为8000 m；②长三角污染物空间分布的主控因子最主要来源于生物场,其次来源于化学场；③在土壤0~20 cm深度,蔗糖酶含量、脲酶含量、微生物量氮、全氮含量和离子交换量等对有机污染物空间分布的解释力较大.在土壤20~40 cm深度,对有机污染物空间分布解释力较强的因子是土壤湿度、人口和全氮含量等.随着土壤深度的加深,水动力场的因子解释力增强.④春季里人口、全氮含量和多酚氧化酶含量等对有机污染物空间分布解释力较强.秋季里有机污染物的空间分布更复杂,因子之间表现出更强烈的非线性增强现象和双因子增强现象.

Driving Factors Analysis for Spatial-Temporal Distribution of Organic Pollutants in the Yangtze River Delta Based on the Optimal-scale Geographical Detector

Site contamination has caused serious harm to human health and the ecological environment, so understanding its spatial and temporal distribution patterns is the basis for contamination assessment and site remediation. For this reason, this study analyzed the spatial-temporal distribution patterns of organic pollutants and their driving factors in the Yangtze River Delta based on site sampling data using the optimal-scale geographical detector. The analysis results showed that:① There was a significant scale effect in the spatial distribution of organic pollutants in the Yangtze River Delta, and its optimal geographic detection scale grid was 8 000 meters. ② The main control factor of the spatial distribution of pollutants in the Yangtze River Delta originated mostly from the biological field, followed by the chemical field. ③ At the depth of 0-20 cm of soil, the explanatory power of sucrase content, urease content, microbial nitrogen amount, total nitrogen content, and cation exchange amount were stronger for the spatial distribution of organic pollutants. At the soil depth of 20-40 cm, the factors with stronger explanatory power on the spatial distribution of organic pollutants were soil moisture, population, and total nitrogen content. With the deepening of soil depth, the explanatory power of the factors of the hydrodynamic field increased. ④ Population, total nitrogen content, and polyphenol oxidase content had stronger explanatory power for the spatial distribution of organic pollutants in the spring. The spatial distribution of organic pollutants was more complex in autumn, and the factors showed stronger enhanced-nonlinear and enhanced-bi phenomena.