天津市郊蔬菜重金属污染评价与特征分析

Metals Influencing the Level of Heavy Metal Contamination of Vegetables in Tianjin City as Derived by Principal Components Analysis

由于长期污水灌溉的影响,天津市郊蔬菜普遍受到重金属污染的冲击,为此对采自天津市郊的5大类21个品种、171个蔬菜样品的重金属进行了分析,对单项污染指数法计算的评价结果进行了统计,运用主成分分析法计算了各重金属元素的综合主成分得分,得出天津市郊蔬菜重金属污染程度Cd>As>Pb>Zn>Cu>N i的分析结果。在此基础上,对各类蔬菜重金属污染的特征进行了分析和研究。结果表明,各类蔬菜重金属污染的特征大体相同,都以Cd和As污染为主,且各类蔬菜中Cd和As的变异系数都较高,Pb和Zn污染程度都相对较低,且变异系数也都较低,显示出天津市郊蔬菜重金属污染来源的一致性。

The level of heavy metal contamination of vegetables in Tianjin caused by long-term wastewater irrigation was investigated.171 samples were collected from five sampling stations in Tianjin in 2002.Cadmium,arsenic,lead,zinc,copper and nickel in vegetable were measured.Obtained data set was subjected to statistical evaluation.Principle component analysis was used to identify the metals which predominately influence the level of heavy metal contamination of vegetables.The results showed in the following order: Cd>As>Pb>Zn>Cu>Ni.,the metals influenced the level of heavy metal contamination of vegetables.The vegetables in Tianjin are mainly contaminated by cadmium and arsenic.