北京市农业区不同使用类型土壤中二噁英类分析

2005年6—7月采集了北京市农业区不同使用类型土壤样品24个,分别为蔬菜地8个、粮地8个、果园地8个,采用高分辨气质联机对17种二噁英类进行了分析.结果表明:所有样品中二噁英浓度范围为,0.26—5.74(平均值为1.51)pgI-TEQ.g-1;蔬菜地浓度范围为,0.26—5.62(平均值1.75)pgI-TEQ.g-1;粮地浓度范围为,0.45—5.74(平均值2.02)pgI-TEQ.g-1;果园地浓度范围为,0.34—2.02(平均值0.73)pgI-TEQ.g-1;三种类型中粮食地浓度最高,其次为蔬菜地,果园地浓度最低.与国外农业区土壤中的二噁英浓度相比而言,北京市相对较低.所有样品中,样品8和16浓度异常高,但是8.3%(2:24)的高浓度样品数并不代表对人体有害.由于样品24处于垃圾焚烧炉旁边,也对此进行了详细的分析.样品中二噁英类物质形态分布出现了极大的离散性,这表明农田土壤中二噁英可能是多种因素综合作用的结果,例如:除草剂的使用、秸秆等固体废弃物的焚烧、汽车尾气排放等.

STUDY PCDD/Fs IN DIFFERENT TYPE SOIL IN AGRICULTURAL FROM BEIJING CITY

In order to evaluate the contamination caused by PCDD/Fs in Beijing agricultural soil,24 different soil samples were,collected from July to June 2005,and each sample was analyzed for PCDD/Fs by high-resolution gas chromatography/high-resolution mass spectrometry.Total concentrations of PCDD/Fs in soil samples ranged from 0.26 to 5.74(mean 1.51)pg I-TEQ·g~(-1) dry wt.The range is from 0.26 to 5.62(mean 1.75)pg I-TEQ·g~(-1) dry wt in vegetable soil from 0.45 to 5.74(mean 2.02)pg I-TEQ·g~(-1) in grain soil,and from 0.34 to 2.02(mean 0.73)pg I-TEQ·g~(-1),dry wt,in orchard soil.The concentrations in grain soil was the highest,next was the vegetable,and the orchard was the lowest.Compared with other countries concentrations of PCDD/Fs in soil sample in Beijing was rather low in examined area.Basis on the guidelines for PCDD/Fs in Germany and U.S.A,site 8 and 16 were analyzed,but 8.3 %(2 of 24)could not be expected to pose human health hazards.Site 24,near a MSW incinerator,was also analyzed,the wide range of PCDD/Fs isomers detected in many locations also suggests the presence of a multitude of sources,including herbicides and solid waste incinerator,such as scrap wires,plastics,papers,straw stalk incineration at random,and emission of automobile exhaust.