电子垃圾拆解区土壤-农作物系统中镉元素的空间分布特征及其风险评价

随着电子垃圾的与日俱增，电子垃圾拆解活动导致的土壤重金属污染受到众多研究者的关注.为了探究电子垃圾拆解区周边土壤-农作物系统中镉的污染状况和空间分布特征，本研究采集了171对土壤和农作物样品进行系统解析.结果表明，根茎类、叶菜类、茄果类和水果类农作物土壤中镉含量分别为（1.292±0.647）、（1.010±0.201）、（0.921±0.125）和（0.861±0.135） mg·kg^-1，均值分别是浙江省土壤镉含量背景值的10.0、7.8、7.1和6.3倍，是农用地土壤污染风险筛选值的4.31、3.4、3.07和2.72倍，说明镉在土壤中累积明显.而农作物只有少部分超过食品安全限值，而且不同种类农作物对镉的富集能力的大小顺序为：叶菜类 > 根茎类 > 茄果类 > 水果类.单因子污染指数和潜在生态风险评价结果显示，研究区土壤镉污染严重且有高度的潜在生态风险.健康评价模型发现，手-口摄入重金属是造成当地居民健康风险的主要途径，而且重金属镉暴露对儿童造成的健康风险高于成人，但是该地区单一重金属镉污染暂时不会威胁到当地居民的身体健康.Moran''s I指数以及克里格插值结果揭示了镉具有显著的空间自相关性，存在明显的空间分布格局和局部空间聚集现象，且高值主要集中在电子垃圾拆解区周围，与电子垃圾拆解活动存在显著相关性.

Spatial Distribution Characteristics and Risk Assessment of Cadmium Pollution in Soil-crops system of an E-waste Dismantling Area

With the rapid development of electronic technology, soil heavy metal contamination caused by electronic waste dismantling activities has attracted the attention of many researchers. To investigate the contamination status and spatial distribution of Cd in soil-crop systems around an e-waste dismantling area, 171 pairs of soil and crop samples were collected for analysis. The concentrations of cadmium in root vegetable soil, leaf vegetable soil, solanaceous vegetable soil, and orchard soil were (1.292±0.647), (1.010±0.201), (0.921±0.125), and (0.861±0.135) mg·kg^-1, respectively. The average values of cadmium in these four soil types were 10.0, 7.8, 7.1, and 6.3 times the background values of soil Cd in Zhejiang Province, respectively, and 4.31, 3.4, 3.07, and 2.72 times the risk screening values for soil contamination of agricultural land, clearly indicating cadmium accumulation in the soil. However, only a small percentage of crops contained cadmium levels that exceeded food safety limits. Moreover, different types of crops showed different capacities for cadmium enrichment and can be ranked accordingly: leaf vegetables > root vegetables > solanaceous vegetables > fruits. The single factor pollution index and the potential ecological risk assessment revealed severe Cd contamination in the study area, with a high potential ecological risk. Cadmium exposure posed a higher health risk for children than for adults. However, the single heavy metal cadmium pollution index does not indicate a threat to local residents at this time. Moran''s I index and kriging interpolation results revealed that Cd has significant spatial autocorrelation, with high values mainly concentrating around the e-waste dismantling area, indicating a significant correlation with e-waste dismantling activities.