某农药厂废弃场地六六六和滴滴涕污染分布特征及风险评价

Distribution and Risk Assessment of HCH and DDT in an Abandoned Pesticide Factory Site

研究了某农药厂废弃场地土壤中六六六(α,β,γ,δ-HCH)和滴滴涕(p,p'-DDT,o,p'-DDT,p,p'-DDD,p,p'-DDE)的污染分布特征,并对其进行了风险评价.从该场地72个点位的0～400 cm深度土壤中共采集了232个样品,分析表明六六六残留含量为2.6～80 130μg/kg,滴滴涕残留含量为未检出～54 350μg/kg,均表现出垂直迁移的特性.该场地六六六和滴滴涕均有明显降解,六六六各异构体所占质量分数为α-HCH(56.9%)>β-HCH(23.3%)>γ-HCH(14.0%)>δ-HCH(5.8%),DDT及代谢物所占质量分数为p,p'-DDT(42.1%)>p,p'-DDD(27.0%)>o,p'-DDT(18.0%)>p,p'-DDE(12.9%),该场地土壤不存在新的六六六和滴滴涕输入源.该场地作为居住用地开发不会对居民造成非致癌风险,但对小孩的非致癌风险值明显要高于成人;该场地存在致癌风险的可能,且对成人致癌风险值高于小孩.有必要对该废弃场地进行土壤修复和治理.

The distribution of HCH（α,β,γ,δ-HCH） and DDT（p,p′-DDT,o,p′-DDT,p,p′-DDD,p,p′-DDE）in an abandoned pesticide factory site was studied,and its risk assessment was carried out.232 soil samples were collected from the field 72 points of 0-400 cm depth.Analysis showed that the residual content of HCH and DDT in soil were 2.6-80 130 μg/kg and non-detected-54 350 μg/kg respectively,and showed the characteristics of vertical migration.Both HCH and DDT degraded significantly in this site.The percentages of HCH isomers were α-HCH（56.9%）β-HCH（23.3%）γ-HCH（14.0%）δ-HCH（5.8%）,and the percentages of DDT and its metabolites were p,p′-DDT（42.1%）p,p′-DDD（27.0%）o,p′-DDT（18.0%）p,p′-DDE（12.9%）.There is no new input source of HCH and DDT at the site soil.The site as a residential land development will not be adverse on residents of non-cancer risk,but non-carcinogenic risk to children is significantly higher than that of adults.At this site,there exists the possibility of cancer risk,and the cancer risk to adults is higher than that to children.Remediation and treatment was necessary for the soil of the site.