污染场地土壤重金属的生物可给性及毒性研究

近年来，生物可给性被用于评估场地土壤污染健康风险，然而不同场地类型重金属生物可给性差别巨大，生物可给态重金属的人体健康危害效应仍然鲜见报道.本研究以浙江温岭某电子拆解厂为研究区，分析比较了5个场地土壤（S1-S5）中Zn、Cu、Cd、Pb的生物可给性并探究生物可给态重金属对人小肠上皮细胞的毒性效应机制.结果表明，场地土壤Cd和Cu污染较为严重，含量分别为4.84，438.52mg/kg.4种重金属在胃阶段生物可给性范围分别为2.10%~48.28%、4.84%~33.73%、16.04%~42.81%、1.81%~15.71%，小肠阶段为2.05%~36.91%、13.17%~22.23%、10.19%~23.10%、0.60%~2.69%，可见胃阶段的生物可给性低于小肠阶段.对于肠相生物可给态重金属暴露人体肠道上皮细胞后，除样点S4外，细胞活力均显著性下降.此外，样点S3和S5土壤提取液对超氧化物歧化酶活力影响较小，但显著抑制过氧化氢酶活力，并且该样点对DNA产生损伤.通过研究电子拆解厂土壤生物可给性以及其毒性效应，以为我国场地土壤重金属健康风险评估提供科学依据.

Bioaccessibility and their toxic effects of heavy metal in field soils from an electronic disassembly plant

Recently, bioaccessibility of metals has been applied for assessing the health risk of field soils, however the bioaccessibility of metals is varied and there are few studies on the toxic effects of bioaccessible metals on human body. In this study, fives soil samples (S1-S5) from an electronic disassembly plant in Wenling, Zhejiang Province were sampled. The total concentrations and bioaccessibility of Zn, Cu, Cd and Pb in the soils were determined. Moreover, the toxic effects of bioaccessible heavy metals on human intestinal epithelial cells were also evaluated. The results demonstrated that all samples were polluted by Cd, Pb, Zn, and Cu, with the greatest concentrations of Cd (4.84mg/kg) and Cu (438.52mg/kg). The bioaccessibility of the four heavy metals in the gastric and intestinal phase was 2.10%~48.28%, 4.84%~33.73%, 16.04%~42.81%, 1.81%~15.71%, and 2.05%~36.91%, 13.17%~22.23%, 10.19%~23.10%, 0.60%~2.69%, respectively. In general, the bioaccessibility of four heavy metals in the gastric phase was lower than that in the intestine phase. After exposure to intestinal bioaccessible extracts of different soils for 24h, cell viability significantly decreased except for sample S4. In addition, there was no significant change in SOD activity after treatment with S3 and S5samples, but CAT activity was decreased. Furthermore, DNA damage was trigged by those samples. To investigate the bioaccessibility and its toxic effects of fields soils, this study provides a scientific basis for the health risk assessment of soil in China.