丘陵平原过渡区土壤农药残留特征及评价——以四川省五通桥区为例

Investigation and Assessment on Soil Residual Pesticide Contamination in the Mountain-Hilly Transitional Zone:A Case from Wutongqiao District in Sichuan

【目的】研究丘陵平原过渡区土壤农药残留特征,为其农业生产布局及土壤污染防治提供科学依据。【方法】以四川省五通桥区为例,利用气相色谱法检测丘陵平原过渡区103个样点的土壤样品中六六六(HCHs)、滴滴涕(DDTs)和10种有机磷农药(OPPs)残留量,利用地统计方法和GIS技术,评价研究区域内的土壤农药残留空间分布特征。【结果】94%的样品中HCHs含量符合国家二级标准(50～500μg·kg-1),70%的样品中DDTs含量符合国家一级标准(<50μg·kg-1)。10种OPPs中杀螟硫磷和溴硫磷超标率最高,检出率分别达到60.40%和55.45%。【结论】区内HCHs和DDTs残留不会影响正常的农业生产安全,OPPs存在一定程度的污染。不同功能区、自然乡镇农药残留分布差异较大,岷江两岸以及丘陵/河流冲积平原区之间农药残留分布差异较小。

[Objective] Characteristics of soil residual pesticides in the hilly-plain transitive zone was investigated to provide a scientific basis for optimal agricultural zoning and control of polluted soil. [ Method] Benzene hexachloride （HCHs）, dichlorodiphenyltrichoroethane （DDTs） and organophosphorus pesticides （OPPs） in 103 soil samples collected from Wutongqiao district of Sichuan were detected by gas chromatography （GC）. Spatial distribution characteristics of residual pesticide in soils of transitional zone from mountain to plain was evaluated by employing the methods of GIS and geostatistical techniques. [Result] HCHs concentration in 94% of soil samples was in the range of the 2nd level of National Soil Environment Quality Standard （GB 15618-1995） （50-500 μg·kg^-1）. Similarly, DDTs concentration in 70% of soil samples accorded with the 1 st level of National Soil Environment Quality Standard （GB15618-1995） （〈50 μg·kg^-1）. Fenitrothion and bromohos were detected in 60.4% and 55.5% of all samples, which were higher than those of the rest of OPPs. [Conclusion] Residual HCHs and DDTs in soils of the studied region were safe for agriculture, while residual OPPs were harmful for agriculture to a certain extent. From the spatial distribution map of residual pesticide drawn by ArcGIS 9.0 software, obvious difference was found among different function zones and towns, however, little difference was found among alluvial plains by Min River and between hilly region and plain.