南疆棉花转产区土壤和农产品中邻苯二甲酸酯(PAEs)污染分析和评价

Contamination and risk assessment of phthalates in soils and agricultural products after cotton cultivation in southern Xinjiang, northwest China

为评估棉花转产地区农产品中邻苯二甲酸酯(PAEs)风险,在新疆传统棉花种植区域(阿克苏市、沙雅县、新和县和库车县),采集94对农产品-土壤样品,40个农田地膜残留样品,进行17种PAEs含量水平分析和来源解析。结果表明,阿克苏地区土壤样品中17种PAEs累积含量范围为0～1 622μg·kg^(-1),平均含量180.2μg·kg^(-1),检出率95.7%,阿克苏地区农产品样品中17种PAEs累积含量范围为0～2430.1μg·kg^(-1),平均含量190.6μg·kg^(-1),检出率93.6%。阿克苏地区残膜量0.1～42.1 kg·hm^(-2),残膜膜厚5.6～6.85μm,破碎度6.4～30.3 mg·块^(-1)。相关性分析结果表明新疆阿克苏地区农产品ΣPAEs与土壤ΣPAEs呈正相关(R=0.529,P<0.01),土壤、蔬果中的ΣPAEs和棉花种植时间上未发现相关性(P>0.05),土壤ΣPAEs和农膜残留量呈正相关(R=0.767,P=0.044),和破碎度(R=0.778,P<0.01)及农膜厚度(R=0.786,P=0.021)呈负相关,提示南疆棉花转产区PAEs污染关键控制点是降低农田残膜量。

To assess the risk of phthalate esters(PAEs)in agricultural products after long-term cotton planting,94pairs of soil-fruit/vegetables and40mulch film residues were collected from the traditional cotton planting area including Akesu,Shaya,Xinhe,and Kuche counties in southern Xinjiang Uygur Autonomous Region.Residue levels of17kinds of PAEs were determined,and source analysis was carried out.High detection rates of95.7%and93.6%of PAEs were observed in soils and agricultural products,respectively.Total phthalates content in soils ranged from0to1622μg·kg^-1with an average content of180.2μg·kg^-1.Total phthalates content in agricultural products ranged from0to2430.1μg·kg^-1with an average content of190.6μg·kg^-1.AverageΣPAEs in vegetables(220.1μg·kg^-1)was higher than that in fruits(182.3μg·kg^-1).PAE content of agricultural products in the four counties was,in decreasing order:Shaya(297μg·kg^-1)>Xinhe(273μg·kg^-1)>Kuche(119.3μg·kg^-1)>Akesu(65μg·kg^-1);and a similar pattern was observed in soils:Shaya(305.1μg·kg^-1)>Xinhe(143.5μg·kg^-1)>Kuche(122.6μg·kg^-1)>Akesu(115.8μg·kg^-1).DEP and DEHP contributed more than71.1%of the total PAEs in soil samples,and DMP,DEP,and DEHP contributed more than86.4%of that in agricultural products.ΣPAEs of root vegetables(534.7μg·kg^-1)was significantly higher than those of other fruits and vegetables.Human exposure assessment,based on daily intake of contaminated agriproducts and dose for reproductive toxicity,indicated no reproductive damage after long term exposure.The mulch film residues in Akesu Region ranged from0.1to42.1kg·hm^-2,mulch film thickness from5.6to6.85μm,and degree of size breakages from6.4to30.3mg·piece-1.Correlation analysis indicated thatΣPAEs in agricultural products(n=94)was positively correlated(R=0.529,P<0.01)withΣPAEs in soils(n=94)at the0.01level.No correlation was observed betweenΣPAEs in soils or agricultural products and the time of cotton planting(P>0.05),however,positive correlation betweenΣPAEs in soils and mulch film residues(R=0.767,P=0.044)was observed at the0.05level.ΣPAEs in soils were negatively correlated with the degree of size breakages(R=0.778,P<0.01),and the mulch film thickness(R=0.786,P=0.021).The correlation analysis results suggest that reducing the mulch film residues in farmland is the critical control point of PAEs pollution in Xinjiang cotton planting area.