The Research On The Transport And Trans-formation Of HCH In Typical Soils Of Guanzhong Basin

Hexachlorocyclohexane(HCH) is one of the organo-chlorine pesticides which have serious threat to the environment. It has great harm to the human's health and the whole ecosystem. HCH was added to the POPs list by the EU in August 2004. There are different residues in the soils of most areas still, although the use of HCH has been banned for decades. Soil is the most important environmental mediator for pesticides transport and trans-formation in the environment. Pesticides can volatilize into the atmosphere from the surface soil; They can be absorbed by crops and accumulate in the plants; They can also move into groundwater by the means of eluviation or move into surface waters with runoff. Currently the residue and pollution are still not be studied systematically in the grain and cotton production regions in China with a high yield, where a high level of HCH pesticide was used from 1960s to 1980s. For these reasons, it is significant to research the residue, transport and trans-formation of HCH in the typical soils for controlling the HCH pollution.On the basis of investigating the regions topographical features and soils distribution pattern, a soil profile was selected and the loess plateau-loess, second bottom-silty clay and flood plain-silty soil samples were respectively collected at Xingping stretch of Weihe River in the vertical direction along the Weihe River in April 2005. The adsorption performance of HCH is studies in different soils through the batch adsorption test on the basis of analyzing the physicochemical property of soil and determining the HCH residue. The transport and trans-formation of HCHs with time and depths, the adsorption and accumulation of HCHs and the isomers during the crop growth stages will be studied through the cultivation simulation experiments. The main results are as followed:(1) The concentration of HCHs in the Guangzhong cultivated soils ranges from 1.419 to 77.308μg/kg, lower than Chinese Environmental Quality Standard for Agricultural Soils(HCH<500ug/kg). There were more HCHs residues in flood plain-silty soil than in loess plateau, second terrace-loess and second bottom-silty clay.(2) The results show that the adsorption conforms to the equilibration isotherm of Henry...