The Distribution And Risk Assessment Of Organochlorine Pesticides Residues In Farmland Soils And Grains In Anhui Province, China

The distribution and the risk of8kinds of organochlorine pesticides (α-HCH, β-HCH, γ-HCH, δ-HCH, op′-DDE, pp′-DDD, α-endosulfan and chlorothalonil) in farmland soil and grains from19sampling sites in Anhui province were studied by ultrasonic method and GC/ECD. The results were as follows:(1)In Anhui farmland topsoil(0~20cm), the concentration of OCPs was varied from ND to23.75μg/kg, among which pp′-DDD and γ-HCH were the major pollutants,and the mean concentrations were13.83μg/kg for pp′-DDD and13.49μg/kg for γ-HCH Compared with the investigation result in1990, the mean concentration of HCH showed a significant decreasing trend, while which was relatively higher in Anhui province than that in other regions. The mean concentrations of OCPs, HCHs and pp’-DDD in topsoil were48.58μg/kg,28.64μg/kg and13.83μg/kg respectively, which were below the China National Soil Environmental Quality Standards (GB15618-1995). Therefore the soil samples investigated in this study were less polluted and could reach first standard (<50μg/kg).(2) In Anhui farmland soil profile (0~50cm), the concentration of OCPs was20.30~117.84μg/kg with its average of50.00μg/kg. Of which PP’-DDD and γ-HCH were the major pollutions, which ranged from ND to43.39μg/kg and from ND to74.48μg/kg, and the mean concentrations were14.39μg/kg for pp′-DDD and14.33μg/kg for γ-HCH moreover, the detection rates of pp′-DDD and γ-HCH were98.92%and97.85%, respectively the concentration of OCPs in soil profiles was that the third/four-layer was high, while the fifth layer was low. Distribution of organochlorine pesticide residues had different trends in soil profile at every sampling point, which was caused by a variety of reasons. HCHs were more in the third, fourth. HCH was higher in the fourth layer of Qingyang point (90.71μg/kg) and the third layer of Juchao points(68.26μg/kg), which were all beyond the China National soil environmental quality standards (>50μg/kg), and low the secondary standard (<500μg/kg).(3) The concentration of HCHs isomers showed that: γ-HCH was the major pollutions. It could be found that the concentration of HCHs isomers was in the order of γ-HCH>δ-HCH>α-HCH>β-HCH.(4) The average of OCPs residues was22.14μg/kg in grains, in which β-HCH and γ-HCH had the highest detection rate (91.67%), and the average of γ-HCH residues amounted to10.57μg/kg. The residues of OCPs in grains were far below EMRLs of the current international food codex (EMRLs≤100μg/kg), so it would not harm to the health of consumers.(5) The results of risk analysis were as follows: HCHs and DDTs had no risk in Anhui farmland soil by single-factor evaluation γ-HCH of most samples was no risk to fish, while they had certain ecological risks to other organisms by means of species sensitivity distributions (SSD). DDTs(OP’-DDE+PP’-DDD) of every point were some biological ecological risk The results of health risk assessment showed that the residues of organochlorine pesticide were very low health risk in Anhui farmland soils and grains, which would not cause harm to human health.