新乡市某电池厂附近污灌农田重金属污染特征与分类管理

在河南省新乡市某电池厂东南污灌农田区不同距离处挖掘土壤剖面6个，高密度采集剖面样品，并在污灌农田区和电池厂西部不同距离处采集表层混合样12个，共获得土壤样品238份，同时在污灌农田区采集粮食样品13份.用ICP-MS法测定Cd、Ni、Pb、Cr、Cu和Zn含量，AFS法测定Hg和As含量，并对土壤重金属的垂直迁移、污染状况、来源及污染农田的分类管理进行了探讨.结果表明：污灌农田耕层Cd平均含量均高于其风险管制值（GB 15618-2018），其他重金属几乎全部低于筛选值.Cd是最主要的致污因子，其他重金属对土壤污染的贡献可以忽略.耕层Cd、Ni和As含量随着距电池厂距离的增加呈递减趋势.大多数剖面中Cd、Ni、Cr、Cu、Zn和As含量呈现不同程度的表聚性，Pb含量自上而下逐渐递减，Hg含量上下基本一致.污灌农田Cd、Ni和As主要来自污灌，同时受电池厂的干湿沉降影响，是工业源重金属；Cu、Zn、Cr和Pb属于农业源重金属；Hg是自然和人为混合源重金属.根据土壤环境质量类别及农产品质量综合确定距离电池厂大约3.5 km以内的污灌农田属于严格管控类农用地，应尽快禁止食用农产品的种植，代之以苗圃、林地.

Heavy metal pollution and classification management of sewage irrigation farmland around a battery factory in Xinxiang, Henan Province

Six soil profiles were selected at different distances of sewage irrigation farmland located in the southeast of a battery factory in Xinxiang City, Henan Province, and their soil samples were collected by high density in each profile. Also, 12 topsoil mixture samples (0~20 cm) were collected in the sewage irrigation farmland and the west of the battery factory at different distances. Totally, 238 soil samples and 13 food samples were collected in the sewage irrigation farmland. Concentrations of Cd, Ni, Pb, Cr, Cu and Zn in soil samples were determined using inductively coupled plasma mass-spectrometry (ICP-MS), while Hg and As concentrations were measured by atomic fluorescence spectrometry (AFS). The pollution levels, vertical migration, sources of heavy metals in soils were analyzed, and the classification management of polluted farmland were explored. The results show that the average concentrations of Cd in topsoils of the sewage irrigation farmland are higher than its risk control value (GB 15618-2018), while almost all other heavy metals are below their risk screening values. Thus, Cd is the most important pollutant for study area. Generally, the average concentrations of Cd, Ni and As in the topsoils show a decreasing trend with the increasing distance away from the battery factory. The metals Cd, Ni, Cr, Cu, Zn and As in most profiles are mainly concentrated in the surface layer, while Pb concentrations present a gradual decrease trend from top to bottom, and Hg concentrations have no clear change in profiles. Cd, Ni, and As in soils are mainly from sewage irrigation, together with dry-wet deposition of particles from the battery factory. Cu, Zn, Cr and Pb concentrations in soils are strongly affected by agricultural activities, and Hg comes from natural and anthropogenic sources. According to the soil environmental quality category and the quality of agricultural products, strict control measures should be implemented for the farmland within 3.5 km away from the battery factory. The planting of edible agricultural products should be banned as soon as possible and replaced by nurseries and woodlands.