Study On The Determination Method For Herbicides In Food And Dietary Exposure Assessment Of Chinese Population

Herbicides are the first large varieties of pesticide used nowadays. The widespread use of these compounds has increased the public concern on the presence of their residues in food. It is of significant importance to monitor herbicide residues in food and to evaluate their risk to human health.Consindering the complex matrix of the total diet samples (TDS) and the dilution effect for pollutants arised by cooking, rape, pork and dietary sample were selected as representative matrix to establish a method for quantitative determination of65herbicides by gas chromatography-mass spectrometry (GC-MS). Samples were exacted with acetonitrile and cheaned by gel permeation chromatography (GPC) combined with Carbon/NH2cartridge. Matrix-matched calibration was used for quantitation. The linearity of the external standard calibration curves was satisfied and the coefficients of determination (r) were not less than0.99. The limits of detection (LODs) were0.02～2.2μg/kg in rape,0.2～9.0μg/kg in pork and0.1～10.0μg/kg in dietary sample. The recoveries by blank spiked samples at low, medium, and high fortification levels ranged from41.1%～130.0%in various matrix, with the relative standard deviation (RSD) below24.4%. The method validation results demonstrate that the established method is sensitive and specific enough for the the analysis of herbicide residues in complex samples.The method established above was successfully applied to determine herbicides in the5th TDS samples. A total of135samples from15provines covering9kinds of diet were analysed. Only4herbicides, including chlorpropham, trifluralin, alachlor and acetochlor, were detected in6samples, with the concentration within the range of0.210～1.63μg/kg. Chlorpropham and Alachlor were detected in potatos from Zhejiang and Hunan province, separately. Trifluralin was detected in fishes from Liaoning, Shanghai and Ningxia provinces. Acetochlor was detected in beans from Heilongjiang province. The results demonstrate that the contamination of herbicids in dietary foods was limited and the contamination levels were relatively low.The dietary exposure of chlorpropham, trifluralin, alachlor and acetochlor was evaluated for Chinese population. The average dietary exposure of those4herbicdies was0.034μg/kg bw d,0.004μg/kg bw d,0.020μg/kg bw d and0.026μg/kg bw d, which accounts for0.07%,0.03%,0.20%and0.24%of ADI, respectively. Acute hazards posed by chlorpropham and trifluralin were assessed for Hunan and Zhejiang distract, seperately. The acute dietary exposure amount of chlorpropham and trifluralin was0.004μg/kg bw d and0.003μg/kg bw d, accounting for0.0008%and0.0003%of ARfD. From those results, it can be concluded that the4herbicides would not pose a risk to human health.