The Distribution Of Organophosphorus Pesticide In Soil-Maize System And Health Risk Assessment From Typical Black Soil Region In Jilin Province

Organophosphorus pesticidewas commonly used in agriculture for pest prevention in China. The long-term use of organophosphorus pesticide could result in soil pollution. The pesticides residues in agricultural products could abovecorresponding standards and may threat human health. The organophosphorus pesticides contents were analyzed by GC-FPD(gas chromatograph-flame photometric detector). This research studied soil organophosphorus pesticides contents and space distribution in Yushu County, a representative agricultural area in the black soil region, Jilin Province, Northeast China. The research also studied the relationship between soil chemical properties and soil organophosphorus pesticides. The rearch assessed the chronic and acute health risk due to maize consumption. The results can provide critical proof and data for reducing maize pesticide residues and ensuring agricultural products safe.The total twelve kinds of organophosphorus pesticides contents in agricultural soils ranged from 162.98 g/kg to 305.85 g/kg, with a mean value of 244.61 g/kg. The main detected organophosphoruspesticides contents were 48.27, 38.08, 37.99 and 30.43 g/kgfor omethoate, methamidophos, diazinon and phorate,respectively, with detection rates of 100%. The high organophosphorus pesticides contents were located in northwest of Yushu County, while the low organophosphorus pesticides contents were located in middle, southwest and northeast of Yushu County. Moreover, there was little region of high organophosphorus pesticideslocated in southeast of Yushu County.Soil properties significantly affected soil organophosphorus pesticides contents. Soil acidition and high soil water content may decrease degradation of organophosphoruspesticides. Soil organophosphorus pesticideswere easily absorbed by high soil organic matter content. Soil erosion easily made organophosphorus pesticides move in sloping farmland region.The organophosphorus pesticides can be detected in 120 cm depth of soil, while the organophosphorus pesticides contents decreased with the soil depth increase. The organophosphorus pesticides were mainly distributed in 0.25-1mmand <0.25 mm soil aggregates in surface soil of 0-10 cm depth.The average total eleven organophosphorus pesticides contents in maize decreased in the following order: leaf(68.0!g/kg)> root(34.7!g/kg)> stem(31.8!g/kg)> grain(5.2!g/kg). The detection rates of combined organophosphorus pesticides contents decreased in the following order: leaf(96.4%)> stem(83.6%)= root(83.6%)> grain(67.3%). The results indicated that maize leaf was polluted easily by organophosphorus pesticides. The detection rates and contents of organophosphorus pesticides in maize grainswere smallest among different maize organs.The organophosphorus pesticides contents in maize grain were not above corresponding maximum residue limit(MRL)laid down by the Standardization Administration of China. Owing to resistance of pests in the processof pest prevention, some mixed organophosphorus pesticides were applied commonly in maize. In present study, 29.1% maize grains samples contained more than one organophosphorus pesticide, while 38.2% samples detected one organophosphorus pesticide and only 32.7% samples did not detected any organophosphorus pesticides.It was conclude that inhabitants who expose average organophosphorus pesticides levels may not pose significant chronic health risk if the residents expose single or combined organophosphorus pesticides. The acute health risk for children was higher than that for adults. It was conclude that acute health risks associated with organophosphorus pesticides level exposure for adults and children in Yushu County were insignificant if the residents only ingest maize grains.