Pollution Characteristics Of Heavy Metals In Vegetables And Drinking Water In Taiyuan

Heavy metal pollution is getting more and more attention.In this study,the heavy metal contents of vegetables and drinking water samples collected from urban and rural areas of Taiyuan city was detected by ICP-MS.On this basis,the pollution characteristics of heavy metals in vegetables and drinking water of Taiyuan city were analyzed.The pollution sources were analyzed by multivariate statistical analysis method,and the US EPA health risk assessment model was used to evaluate the exposure and health risk of intaking vegetable and drinking water.The main conclusions are as follows:(1)The contents of Pb,Cd,Hg,As,Ni,Cr,Cu and Zn in 11 kinds of vegetables in Taiyuan city were 0.002-1.132,0.0003-0.459,0.0001-0.078,0.0002-0.207,0.004-2.463,0.002-1.831,0.037-5.474,0.092-29.977 mg·kg-1,respectively.The contents of heavy metals in different types of vegetables vary greatly,and the contents of Pb,Cd,Hg,As,Cr,Cu and Zn in edible fungus vegetables are higher than those in other types of vegetables.The contents of Ni in sprout vegetables are high,while those of Pb,As,Ni,Cu and Zn in taproot and guac vegetables are low.According to the current national food hygiene and health standards,the exceeding rates of Pb,Cd,Hg,Ni,Cr and Zn were 11.8%,1.3%,10.6%,16%,2.6% and 2.0%,respectively.As and Cu were not exceeded.(2)The single pollution index was 1.13 for Hg of cabbage,1.22 for Ni of legume,3.68 for Ni of sprout vegetables and 1.18 for Pb of potato,which exceeded the safety line by 1.0,while the heavy metals in other vegetable categories was not exceed the safety line.The nemero comprehensive pollution indexes of melons,leafy greens,solanaceous fruits,edible fungi,aquatic vegetables and root vegetables are at the safe level,and those of cabbage,Onions,garlic,beans and tubers are at the alert level.The pollution degree ofsprout vegetables is heavier than that of other vegetables,reaching the level of moderate pollution,which should be taken seriously.(3)The mean estimated daily intake(EDI)values of Pb,Cd,Hg,As,Ni,Cr,Cu and Zn ingested by adults through vegetables were 5.20E-4,6.14E-5,3.66E-5,6.34E-5,0.0014,2.99E-4,0.0083 and 0.036 mg·(kg·d)-1,which were all lower than reference dose(Rf D)values.The total risk values of heavy metals in vegetables in Taiyuan city were arranged in the order of As > Cu > Pb > Hg > Zn > Cr > Ni > Cd,and the hazard index(HI)of edible fungi and sprouts vegetables was greater than 1,indicating that the consumption of edible fungi and sprouts vegetables may cause potential health risks.The HI value of other vegetables was less than 1,suggesting no potential health risks.(4)The heavy metal content in drinking water in Taiyuan city increased in the oder of Ba > Zn > Cr > Cu > Mn > Ni > As > Pb > Cd,and the over standart rates of Cr,Ba and Ni in drinking water samples were 0.803%,39.759%,and 0.402%,respectively.On the pollution sources of the heavy metal elements in the drinking water,they could be classified into four categories,that is,Cu,Pb and Zn being a category,Mn and Ni being a group,and As,Cr and Ba being a one,and Cd itself being a one.(5)Ingestion was the major pathway of heavy metals exposure in drinking water in Taiyuan.The total non-carinogenic and carinogenic health risks of 10 heavy metals in drinking water through ingestion and dermal contact in urban areas for adult were higher than those of rural areas.The health risk of Cr through ingestion in drinking water exceeded the maximum risk acceptable level for human recommended by EPA,while those of other heavy metals through ingestion and dermal contact were all lower than the safe level.