东洞庭湖莲藕种植区土壤重金属污染及其对莲藕重金属含量的影响

Heavy metal contamination in soils and their impact on heavy metal content in lotus in the East Dongting Lake

通过对东洞庭湖莲藕种植区的野外调查,揭示了土壤重金属污染的潜在生态风险及其对莲藕重金属含量的影响。土壤重金属镉(Cd)、铅(Pb)、铜(Cu)、锌(Zn)含量均高于洞庭湖背景值,以Cd污染最为严重,潜在生态风险指数高,属极重度生态风险级。莲藕干物质中重金属含量较高,其中Cd、Pb含量分别达到3.43 mg·kg^(-1)和6.84 mg·kg^(-1)。不同种植区域之间,莲藕重金属含量差异显著,以君山区挂口镇的莲藕重金属含量最高。莲藕重金属含量的高低与土壤重金属含量呈显著正相关关系(P<0.01)。可见,东洞庭湖莲藕种植区土壤重金属污染是导致莲藕重金属含量过高的直接原因,建议在污染较重的区域,减少莲藕种植,开展土壤重金属污染治理,引导莲藕产业健康发展。

Based on the field investigation in lotus plantation areas in the East Dongting Lake, potential ecological risk of heavy metals in soil were estimated and their impact on heavy metal content in lotus were measured. The contents of heavy metals（Cd, Pb, Cu, Zn） in the soil were higher than background value of the Dongting Lake. Among these heavy metals, Cd was the most serious pollutant. Potential ecological risk index of heavy metals in soil was high（3551.04） and belonged to the highest class. Lotus had high heavy metal content in dry matters. The content of Cd and Pb reached to 3.43 mg·kg^（-1） and 6.84 mg·kg^（-1）, respectively. In these plantation areas, lotus had highest heavy metal content in Guakou Town, Junshan District. There was positive regression（P0.01） between heavy metal contents in lotus and those in soil, which indicated that heavy metal contamination in soil was the main reason for high heavy metal content in lotus. Therefore, some measurements, such as decreasing lotus plantation in seriously polluted areas and eliminating heavy metal pollution in soil, were suggested to guide healthy development of lotus industry.