鄱阳湖平原区农田土壤重金属Cd、Hg空间特征及潜在风险影响因素探析

为了解鄱阳湖平原区农田土壤重金属的空间特征,探析其潜在生态风险及影响风险状况的因子,采用地统计学、潜在生态风险指数法、Person相关分析及地理探测器方法,分析研究区农田土壤重金属镉(Cd)、汞(Hg)的空间分异特征、潜在生态风险评价及风险状况影响因素。结果表明,研究区土壤重金属Cd、Hg均为中等程度的变异,空间分布差异较为明显。丰城大部分地区Cd含量均在江西省土壤元素背景值与我国农田土壤污染风险筛选值之间。Hg含量由南向北逐渐升高并超过江西省土壤元素背景值,但未达到全国风险管控值水平。Cd的潜在生态风险水平以轻微级别为主,Hg则以中等级别为主。在综合潜在生态风险方面,大部分地区被划分为低风险区,而中度风险区分布较为分散。重金属Cd、Hg综合潜在生态风险指数(RI)与土壤pH值、全磷、海拔、坡度以及距河流或道路的距离具有显著相关性(P<0.05)。影响综合潜在生态风险指数的第一个显著因子为全磷≤0.4 g·kg^-1,其次为pH值5.5~6.0。本研究对鄱阳湖平原区农田土壤重金属污染的监测与治理、维护生态环境安全及人类健康具有重要的现实意义。

Spatial Variation in Cadmium and Mercury and Factors Influencing Their Potential Ecological Risks in Farmland Soil in Poyang Lake Plain,China

To explore the spatial variation of cadmium (Cd) and mercury (Hg) in farmland soils in Poyang Lake Plain, and to investigate their potential ecological risks and risk impacting factors, geostatistics, potential ecological risk index method, Pearson correlation analysis and geographic detectors were used to investigate potential ecological risk assessment and influencing factors. The results showed that the Cd and Hg were all moderately mutated, and the spatial distribution differences were obvious. Cd concentrations were between the regional background level in Jiangxi province and national risk screening value in China. Hg concentrations gradually increased from south to north and exceeded the background value in Jiangxi Province, but did not reach the national risk screening value in China. The potential ecological risk level of Cd was predominantly low, while Hg is mainly moderate. In terms of comprehensive potential ecological risks, most areas were classified as low-risk areas, while the distribution of medium-risk areas was dispersed. The comprehensive potential ecological risk index of Cd and Hg was significantly correlated with soil pH, total phosphorous, elevation, slope, and distance from river or road (P values<0.05). The first significant factor of the comprehensive potential ecological risk index was total phosphorus, which was less than 0.4 g·kg^-1 and followed by pH 5.5~6.0. This study has practical significance in monitoring and controlling heavy metal pollution in farmland soil in Poyang Lake plain, and maintaining ecological environment safety and human health.