西藏地区蔬菜及产地环境重金属污染风险分析与评价

Risk Analysis and Evaluation of Heavy Metals Pollution in Vegetables and Producing Areas in Tibet

文章通过对西藏拉萨和昌都2地(市)蔬菜生产基地蔬菜及产地环境开展重金属污染风险分析与评价,进而为提高农产品质量安全水平、强化农产品质量安全监管提供数据和技术支撑。在拉萨市(城关区、达孜县、堆龙县和曲水县)与昌都市(昌都县、察雅县和八宿县)共选择11个蔬菜生产基地作为样品分析监测点,分别对蔬菜(含食用菌)及产地环境样品进行采集,采用三重四级杆电感耦合等离子体质谱法对340个蔬菜和土壤样品中5种常见重金属含量进行检测分析,主要包括汞(Hg)、铅(Pb)、砷(As)、镉(Cd)、铬(Cr)。拉萨和昌都2地(市)蔬菜生产基地土壤中Pb、Hg和Cd含量均存在不同程度的超标,其中Pb超标率分别为51.2%和45.2%;Hg超标率分别为23.3%和66.7%;Cd超标率分别为25.6%和60.5%;2地(市)土壤中As和Cr均未超标。拉萨蔬菜基地蔬菜中Hg未检出,Pb、As、Cd和Cr均有检出,但其含量均未超过食品卫生标准限量值;昌都蔬菜基地蔬菜中Hg、Pb、As、Cd和Cr均有检出,其中Pb和Hg在根茎类、瓜类、茄果类蔬菜中存在不同程度的超标,其他重金属未超标。昌都地区、拉萨达孜县和城关区蔬菜基地土壤均受到不同程度的重金属污染,已不再适宜开展蔬菜安全生产;拉萨堆龙县和曲水县土壤未受重金属污染,适合进行蔬菜安全生产。拉萨地区各生产基地所生产蔬菜重金属综合污染指数均小于0.7,总体均处于清洁状态,但部分蔬菜基地也需要关注和治理;昌都地区蔬菜基地所生产蔬菜综合污染指数均大于0.7,甚至大于1,属于警戒级水平和轻度污染水平,应引起高度重视并积极治理。

The pollution status of heavy metals in vegetables and producing bases in these areas is understood through the risk analysis and evaluation of heavy metal pollution in vegetables and producing areas in the production bases in Qmado and Lhasa,Tibet.Thus providing data and technical supports for improving the quality and safety level of agricultural products and strengthening the quality and safety supervision of agricultural products.In Lhasa(Chengguan District,Dazi County,Duilong County and Qushui County)and Qmado(Qmado County,Chaya County and Basu County),11 sample collection monitoring points were set,including 11 vegetable production bases.The vegetables(including edible fungi)and environmental samples from monitoring sites were collected,The contents of common heavy metals in 340 samples were detected by triple four-pole inductively coupled plasma mass spectrometry;Monitoring indicators include Cd,Pb,As,Cr and Hg.The Pb,Hg and Cd in the soil of vegetable production bases in Lhasa and Qmado exceeded the standard in varying degrees,among them the Pb exceeding standard rate was 51.2%and 45.2%,respectively;The Hg exceeding standard rate was 23.3%and 66.7%,respectively;The Cd exceeding the standard rate was 25.6%and 60.5%,respectively.The As and Cr in the soil of the two areas did not exceed the standard.The Hg of vegetables in Lhasa vegetable base were not detected,and the Pb,As,Cd and Cr were all detected,but the contents did not exceed the limit value of food hygiene standard.The Hg,Pb,As,Cd and Cr of vegetables in Qmado vegetable base were detected,among which the Pb and Hg exceeded the standard in Rhizome,Melon and Solanum vegetables,and the others did not exceed the standard.The soil of vegetable base in Qmado area and Lhasa Dazi County and Chengguan District has been polluted by heavy metals to varying degrees,which was not suitable for the safe production of vegetables.The soil of Duilong County and Qushui County in Lhasa was not polluted by heavy metals and it was suitable for the safe production of vegetables.The composite pollution index of vegetable heavy metals produced in Lhasa production bases was less than 0.7,and the overall pollution index was in a clean state,but some bases need attention and treatment.The composite pollution index of vegetables produced in vegetable base of Qmado area was greater than 0.7 or even greater than 1,which belonged to the level of warning and mild contamination;it should be paid attention to and actively treated.