广州市流溪河流域农产品重金属污染特征与评价

Characteristics and Evaluation of Heavy Metal Contamination of Agricultural Products in Liuxi River Basin of Guangzhou City

【目的】以广州市流溪河流域农产品为研究对象,研究农产品重金属污染特征与评价,旨在掌握流溪河流域周边农产品重金属含量特征及污染现状,为保障农产品安全提供基础数据。【方法】采集流溪河流域63个农产品样品,采用单项与综合污染指数法,开展农产品重金属Cd、Hg、As、Pb、Cr、Cu、Zn、Ni含量的调查和分析,并进行农产品质量分级。【结果】流溪河流域农产品中重金属Cd、Hg、As、Pb、Cr、Cu、Zn、Ni的平均含量分别为0.02、0.001、0.03、0.04、0.16、1.15、6.00、0.15 mg/kg,均低于食品中规定的限值。但个别监测点位的农产品重金属Cd和Cr存在超标现象,超标率均为2.41%,其中,Cd超标点位存在于新鲜水果类和谷物类,Cr超标点位仅存在于谷物类。除Cu、Zn和Ni不参与污染评价外,其余各重金属的单项污染指数均值小于1,单项污染指数从高到低依次为Pb>Cr>Cd>As>Hg。同时,重金属综合污染指数范围为0.06~1.30,均值为0.28,说明流溪河流域农产品整体处于清洁(安全)水平,占比为92.77%。处于警戒线水平和轻污染水平的占比分别为6.02%和1.20%,主要存在于谷物类农产品中,其点位主要分布于流溪河山庄和太平水质监测断面之间。【结论】广州市流溪河流域农产品总体处于安全水平,但新鲜水果类和谷物类农产品中个别监测点位仍存在超标现象,尤其对于上游的谷物类农产品,建议加强监测和重点关注。

【Objective】The study was carried out to explore characteristics and evaluation of heavy metal contamination of agricultural products in Liuxi River basin,aiming to master the characteristics and pollution status of heavy metal contents of agricultural products in Liuxi River basin and provide basic data for ensuring the safety of agricultural products.【Method】Sixty-three agricultural product samples in Liuxi River basin were collected to investigate and analyze the heavy metals contents of Cd,Hg,As,Pb,Cr,Cu,Zn and Ni in agricultural products by methods of single pollution index and complex pollution indices,and the quality of agricultural products was graded.【Result】The average contents of heavy metals Cd,Hg,As,Pb,Cr,Cu,Zn and Ni in agricultural products in Liuxi River basin were 0.02,0.001,0.03,0.04,0.16,1.15,6.00 and 0.15 mg/kg,respectively,which were all under the food limit values.However,the contents of heavy metals of Cd and Cr in agricultural products of some areas were above the limit values,both with the exceeding standard rate of 2.41%.Among them,the excessive points of Cd were found in fresh fruits and cereals,while the excessive points of Cr were only found in cereals.Except that Cu,Zn and Ni were not involved in the pollution evaluation,the single pollution indexes of other heavy metals were all less than 1,and the single pollution index from high to low was showed as Pb>Cr>Cd>As>Hg.At the same time,the comprehensive pollution indices of heavy metals ranged from 0.06 to 1.30,with an average value of 0.28,which indicated that the agricultural products in Liuxi River basin were at a clean (safe) level generally,with a proportion of 92.77%.The proportions of the warning line and light pollution level were 6.02% and 1.20% respectively,which mainly existed in cereals,and the distribution of these samples was mainly between the water quality monitoring section of Liuxi River Villa and Tai Ping.【Conclusion】The agricultural products in Liuxi River basin of Guangzhou city are generally at a safe level.However,some monitoring points of fresh fruit and cereal agricultural products still exceed the standard,especially for upstream cereal agricultural products.It is suggested that monitoring should be strengthened and close attention be paid.