广东汕头市农业土壤和蔬菜铅含量及健康风险评估

Investigation in Shantou city,Guangdong,over the lead content in the soil and vegetables

重金属元素铅的危害已经引起人们的广泛关注,为了得到汕头市土壤及蔬菜铅污染的状况,选取了该市115个土壤样品及34个蔬菜样品进行铅含量分析。研究发现,汕头市土壤样品铅含量差异较大,最高含量为110 mg/kg,最低含量则为12.1 mg/kg,极差达到97.9 mg/kg。56.52%的土壤样品铅含量超过国家土壤环境质量标准,表明该市土壤铅污染存在普遍性,且各区(县)土壤铅含量极不均匀。汕头市蔬菜样品铅含量全部超过国家食品卫生标准(GB14935—94),不同蔬菜品种对铅的富集能力均较强,蔬菜样品铅最低含量为5 mg/kg,最高含量为85 mg/kg,分别为国家标准限值的5倍和425倍。经分析认为,该市铅污染源主要来自工业"三废"排放、大量含铅农药的使用、汽车尾气排放以及大气沉降等。还对汕头市民通过食用蔬菜而导致的铅暴露进行了健康风险评估,结果表明该市居民使用蔬菜存在较大的健康风险。

The present paper is to introduce its authors＇ investigation of the pollution caused by the over-content of Pb in the soil and vegetables produced in Shantou city, Guangdong. In order to make the assessment more objective and assurable, we have collected and tested 115 soil and 34 vegetable samples considered to be Pb pollution affected. The results of our investigation found that the Pb content in the soil samples tested are varied greatly （from the maximum content of 110 mg/kg to the minimum-12.1 mg/kg）. The results also indicate that 56.52 % of all the soil samples prove to be excessively leadladen according to the State Soil Environment Quality Standard. Furthermore, the given investigation shows that Pb pollution in soils is an all-pervasive problem. Meanwhile, the Pb content in vegetable samples also reveal excessive when measured by the State Food Sanitary Standard. Thus, the result indicates that the environment has been strongly affected by the human and social activities. In addition, the main source of Pb proves to come from industrial wastes, lead-con- tained pesticide as well as waste gas left-over by the motor vehicle transportation, etc. What is more, the industrial and traffic pollution also contribute to the high Pb content in the soil and vegetables. More accurately speaking, our investigation indicates that the lowest Pb content in vegetables is 5 mg/kg whereas the highest content is 85 mg/kg, which means 25 times and 425 times higher than the data stated in the national standard （0.2 mg/kg）. At the end of the paper, the health risk of lead exposure through vegetable consumption was also made, which proves that, the risk indexes of all vegetables are higher than the state stipulated safety level. That is to say, the potential health threat that is likely to cause has to be paid attention to.