安溪铁观音茶园土壤-茶叶重金属健康风险评价

Health Risk Assessment of Heavy Metals in Soil-tea System from Tieguanyin Tea Garden of Anxi County

为研究茶园土壤-茶叶系统中重金属对人体的综合健康风险,采集安溪铁观音茶园土壤和茶叶样品,用电感耦合等离子体质谱法(ICP-MS)分析测定6种重金属元素(Cr、Ni、Cu、Zn、Cd和Pb)的含量并进行健康风险评价。结果表明,茶园土壤中重金属存在不同程度的富集,其中Zn、Cd和Pb平均含量超过土壤背景值,部分地区土壤中Cd含量高于农用地土壤污染风险筛选值,可能存在污染风险。茶叶中Cr、Cd和Pb的含量均小于污染物限量值。茶叶从土壤中累积重金属的能力为Cu>Ni>Zn>Cd>Pb≈Cr。健康风险评价结果表明,各重金属元素的非致癌健康风险可接受,但存在人体可耐受的致癌风险,且主要由Cr和Pb贡献,两者贡献率之和为99.99%。土壤-茶叶系统中重金属主要通过"经口摄入"途径对人体产生健康风险。

In order to study the health risk of heavy metals in the soil-tea system through the direct exposed pathways and food chain pathways,the soil and tea samples were collected from Tieguanyin tea garden of Anxi County,and the contents of six heavy metals(Cr,Ni,Cu,Zn,Cd and Pb)in the soil and tea samples were determined by inductively coupled plasma mass spectrometry(ICP-MS).The health risk assessment model(dose-response model)recommended by US EPA was applied to evaluate the human health risk of soil heavy metals.The results showed that the heavy metals in soils were enriched in different degrees.Among them,the average contents of Zn,Cd and Pb exceeded the soil background value,and the contents of Cd in some areas were higher than the risk screening values for soil contamination of agricultural land.The contents of Cr,Cd and Pb in tea were all lower than the limit values of national standard.The accumulation ability of tea for different heavy metals was Cu>Ni>Zn>Cd>Pb≈Cr.The results of health risk assessment showed that there was no significant non-carcinogenic risk of heavy metals to adults.While there was carcinogenic risk which human could tolerate,the carcinogenic risk was mainly contributed by Cr and Pb with the total contribution rate of 99.99%.Heavy metals in the soil-tea system mainly posed the health risk to the human body through oral ingestion.