Characteristics And Risk Assessment Of Organophosphorus Pesticide Contamination Of Different Cropping Systems Located At The Minjiang River Downstream

When the organochlorine pesticides(OCPs) have been disabled, organophosphorus (OPPs)pesticide appeared. Because of the high efficiency and low toxicity characteristics of OPPs, it has been widely used as the alternatives of OCPs at home and obroad. But in recent years, with the depth of research, scholars have found OPPs can easily residue in soil. Although the toxicity of some OPPs is not high, its metabolism or hydrolysis product of highly toxic pesticides in the soil form of volatilization into the atmosphere, but also to cause pollution of surface water,drinking water sources, soil organic phosphorus pesticide contaminated soil environmental studies focus.According to previous investigations of our research team, field experiments were conducted in Minjiang River downstream, southwest of China. Four typical cropping systems including M1:ginger-corn-sweet potato, M2:corn-stem mustard, M3:rice, and M4:ginger-onion-lettuce selected and cultivated from April to November in2010. With affected by four cropping systems, the variations of Mevinphos, IBP, Parathion-methyl, Fenitrothion, Bromophos, Isocarbophos, Phenthoate, Methidathion in soils and the accumulation and transfer characteristics of them from soils to the crops were investigated. A brief analysis of the part of the safety of agricultural products consumption and the risk to human health hazards. Comprehensive evaluation of the four agricultural cropping patterns on soil organicphosphorus pesticides scavenging capacity and crop consumption part of the security aspects of ecological restoration efficiency. The results were as follows:(1)Follow the time-varying of the total concentration of residual organophosphorus pesticides in the soil, the variation in M1is April>November>July>September> August, in M2is April> July> August> November> September, in M3is July> April> August> September> November, in M4is July> August> September> April> November. With affected by four cropping systems, the concentration of organophosphorus OPPs residual in soils in M1between April and November is Phenthoate>Methidathion>IBP> Isocarbophos> Bromophos> Phenthoate> Mevinphos> Fenitrothion, in M2is IBP> Isocarbophos> Bromophos> Phenthoate> Parathion-methyl> Mevinphos> Fenitrothion> Methidathion, in M3is IBP> Isocarbophos> Bromophos> Fenitrothion> Parathion-methyl>Phenthoate>Mevinphos=Methidathion, in M4is Phenthoate>IBP> Bromophos> Isocarbophos> Fenitrothion> Parathion-methyl> Methidathion> Mevinphos.(2)With affected by four cropping systems, Organophosphorus pesticide residues in the crop system changes as Ye> soil> roots> stems, leafy vegetables> root vegetables> fruit category.(3) Assessment of crops under different cropping systems on the remediation of polluted soileffects, and calculate that which the restorative effects of the order of the M4> M3> M2>M1, to determine the agricultural soils, the effect of planting pattern must repair the organophosphorus pesticide contamination.(4)In the four cropping systems, only ginger, sweetpotatoes, corn, mustard, lettuce were detected organophosphorus pesticide residues, the toxicity on the human body is about5.54×10-10.This indicates that three person may poison in a population of one billion.