广州市蔬菜中重金属污染特征研究与评价

蔬菜是人们日常生活中必不可少的食物,但蔬菜受重金属污染会对人体健康造成直接的威胁.于广州市12个区(市)采集116个蔬菜样品,检测分析Cu、Zn、Pb、Cd、Ni、Cr这6种元素,通过单因子评估、内梅罗综合指数分析广州市蔬菜中重金属的超标因子与污染特征,采用暴露风险分析评价食用当地种植蔬菜引起重金属对人体的健康风险.结果表明,8种蔬菜中Cu与Zn的含量未超标;Cr的超标率高达91.67%;Pb超标蔬菜为莴苣、丝瓜、番茄和胡萝卜,超标率高达35.71%,以胡萝卜超标最为严重;Cd超标的蔬菜为番茄,超标率达31.25%;Ni超标的蔬菜包括油麦菜、空心菜与菜心,超标率最高为8.33%.8种蔬菜污染程度表现为:空心菜、油麦菜、菜心、白萝卜和胡萝卜均处于警戒级,而莴苣、丝瓜和番茄则处于安全级别;4类蔬菜的重金属综合污染程度呈现叶菜类肉质根类茎类菜茄果类的趋势.健康风险评估表明,广州市居民中日常多食用空心菜、菜心和油麦菜的人群重金属累积的健康风险较高,且经膳食摄入重金属Cr对人体健康可能会造成危害,摄入Cd对人体具有潜在的健康风险.经口摄入蔬菜重金属对儿童可能造成的暴露风险要高于成年人.

Characteristics and Evaluation of Heavy Metal Pollution in Vegetables in Guangzhou

Vegetable is an indispensible component of human daily diet,and contamination of vegetables by heavy metals directly threatens human health.In this study,116 vegetable samples were collected from 12 administrative districts of Guangzhou City for analysis of six heavy metals,Cu,Zn,Pb,Cd,Ni,Cr.A combination of single factor evaluation and Nemero Index analysis was employed to determine specific heavy metals exceeding allowable standards and analyze the characteristics of pollution.Risk of exposure was utilized to assess human health risks originating from eating locally planted vegetables contaminated by heavy metals.The results showed that contents of Cu,Zn in the 8 sorts of vegetables were below the standards of maximum allowable content and the contents of heavy mental Cr of up to 91.67% vegetable samples were higher than their standard.Lettuce sativa var.angustana Irish,Luffa acutangula L.,Lycopersicon esculentum Mill.and Daucus carota L.were the 4 species of Pb exceeding vegetables,with the exceed ratio reaching up to 35.71% and Daucus carota L.exceeded the target value most seriously.Only the content of Cd in Lycopersicon esculentum Mill.was over-standard,with the rate of 31.25%.And the highest rate of over-standard of the content of Ni in 3 species of vegetables,which included Lactuca sativa L.,Ipomoea aquatica Forsk and Brassica parachinensis,reached 8.33%.For the contamination level of the eight kinds of vegetable,Lactuca sativa L.,Ipomoea aquatica Forsk,Brassica parachinensis,Raphanus sativus L.and Daucus carota L.were put into the class of alarming,while Lettuce sativa var.angustana Irish,Luffa acutangula L.and Lycopersicon esculentum Mill.were classified as secure.Heavy metals'' comprehensive pollution degree of 4 species of vegetables presented a trend of leafy vegetables >rootstalk vegetables >stem vegetables >solanaceous fruits.Health risk assessment showed that Guangzhou citizens eat more frequently Ipomoea aquatica Forsk and Lactuca sativa L.and Brassica parachinensis were prone to higher accumulation of heavy metals,and the dietary intake of heavy metal Cr might cause harm to human health and intake of Cd would bring potential health risk to the human body.Risk of exposure to heavy metal through oral ingestion of vegetables was proved to be higher for children than adults.