Investigation And Transport&Transformation Of Pesticides In Anhui Dangshan Pear Production Environment

This paper intends to investigate the distribution difference of the insecticide residue in terms of various soil depths and seasons (spring and fall) in Dangshan crisp pear main producing areas in Dangshan Country, Anhui Province. Based on51types of insecticides, it explored3different Multi-residue test methods and acetamiprid residue method. The methods evaluate the risk of soil contamination through the quantitative analysis of GC-ECD、GC-PFPD and HPLC-VWD. In the present study,the following three methods of insecticide administration were selected: broadcast, spraying after bagging fruits, and root irrigation. The amount of residual insecticides after administration of insecticides by different methods was analyzed through an UPLC-MS/MS analytical method built in-house to detect ACE and MAP.1)The distribution of pesticides in soil characteristicsChlorpyrifos, y-HCH, p,p’-DDE, o,p’-DDT, p,p’-DDD and cyhalothrin were detected in the samples of spring collecting; Chlorpyrifos, p,p’-DDE, o,p’-DDT, p,p’-DDD, cypermethrin, cyhalothrin, fenvalerate, deltamethrin, thiophanate-methyl and carbendazim were detected in the samples which were collected in autumn. In addition to γ-HCH, the pesticide residues and detection rate of soil samples collected in the autumn were higher than the soil samples collected in spring the samples from0-20cm,20-40cm,40-60cm three different layers deep soil were detected and analyzed for pesticide residues type, residual volume and detection rate, the results showed that three indicators decreased in turn with increasing of soil depth. The highest detection rate was p,p’-DDE, accounting for43.2%of the total samples, accounting for61.3%of the sampling points, the highest residual amount of p p’-DDE reached0.885mg/kg, and the residues for it accounted for70.86%of total residual. DDTs(p,p’-DDE+o,p’-DDT+p,p’-DDD) was the main of pesticide residues in the soil accounted for81.22%of total residue.2)Effects of pesticides in soil distribution factorsThe distribution of pesticide residues in samples had obvious difference during different season and different depth of soil. Pesticide residues in the soil was higher than surface of deep soil, applying pesticide history was the main factors influencing the pesticide residues in the soil, the physical and chemical properties of soil and the pesticide itself were the key to influence the outcome of different pesticides in the soil distribution factors. In addition, the distribution was also influenced by pesticides, pesticides in soil, the dose size, farming and intercropping plants. etc.3)The risk assessment of pesticide residues in soilIn this paper, the single pollution index method and species sensitivity distribution evaluation method were used to conduct the risk assessment of pesticide residues in the soil. The results of single pollution index method showed that HCHs was pollution-free overall, no risk of soil pollution, DDTs’index was greater than1, making the environment had a certain potential risks, belongs to the slightly polluted.The species sensitivity distribution evaluation showed that, in the soil of Dangshan County’s orchards, HCHs residues in soil didn’t have ecological risk to the invertebrate animals, DDTs’residues in soil existed great risk to organisms and birds in this area,some regions detection of residual risk value more than190mu g/kg, for mammals having a certain influence.Additionally, Dangshan County’s soil was priority with sand, water soluble pesticides would easily through irrigation and rainwater removed to deep soil and groundwater.The detection found that high levels of DDTs residues in deep soi, pesticide pollution had polluted the deep soil and given pollution to groundwater.4)Transport and transformation of acephate and its metabolite methamidophosin in pearThis study showed that ACE was absorbed by leaf and root of pear trees, transferred within the tree, and finally reached fruits. It indicated that the leaf and root absorbance was not the main way by which ACE and MAP residues were accumulated in pear fruits. Of the three methods, the use of spraying after bagging fruits was found to be more safe as it could avoid direct spraying of ACE on the fruits, and this method could be recommended to improve the quality and safety of pear fruits.