2015, 34(4): 325-330.
doi: 10.11932/karst20150403
Abstract:
This paper studies the residual pesticides in orchard soils in the catchment of Lijiang River, with the intention of providing valuable suggestions for the development of Guilin International Tourist Resort.The surface soils from the vineyard, the citrus orchard and the peach garden in the Lijiang watershed were sampled to analyze the residual levels of 27 kinds of organochlorine pesticides (OCPs) and organophosphorus pesticides (OPPs). With the method of time succession sequence instead of spatial sequence ,their risks were assessed by using maximum residual limits (MRLs) in Environmental Quality Standard for Soils (GB15618-1995) and Farmland Environmental Quality Evaluation Standard for Edible Agricultural Products(HJ 332-2006), as well as extraneous maximum residue limits(EMRLs) in National Food Safety Standard-Maximum Residue Limits for Pesticides in Food(GB2763-2014). The results show that the concentrations of all 6 OPPs, including methamidophos ,acephate ,dipterex ,dimethoate ,parathion-methyl and malathion, fall below the reported limit ranges; and alike case occurs in 16 out of 21 OCPs analyzed, including toxaphene, atrazine, alachlor,hexachlorobenzene (HCB), alpha-hexachlorocyclohexane (α-HCH), gamma-hexachlorocyclohexane (γ-HCH), delta-hexachlorocyclohexane (δ-HCH), heptachlor, heptachlorepoxide, aldrin, α-chlordane, γ-chlordane, dieldrin, endrin, o,p-DDT, and p,p-DDD. The contents of Dichlorodiphenyltrichloroethane(DDTs),p,p-DDE,p,p-DDT, hexachlorocyclohexane(HCHs) and beta-hexachlorocyclohexane (β-HCH) are below the range of 0.50-10.67 ng/g, 0.50-8.32 ng/g, 0.70-2.35 ng/g, 0.50-0.64 ng/g and 0.50-0.64 ng/g, respectively, with point detection percentages of 68.8%, 68.8%, 6.3%, 6.3% , 6.3%, which are originated from historic usage of the chemical DDT and HCH. The detection percentages are 33%, 25% and 100% for DDTs and 0%, 0% and 6.3% for HCHs in the peach garden and the vineyard and the citrus orchard, respectively. On the basis of topsoil OCPs and OPPs residual levels and according to the soil environmental quality standard GB15618-1995, the soils in three orchards reach the first class which is suitable for the cultivation of safe agricultural products such as citrus, grape, peach and etc.in the Lijiang area.
