Risk Assessment Of Combined Exposure To Multiple Pesticide Residues In Agricultural Products

In recent years,multiple pesticide residues in a single sample are more common in the food monitoring survey,and cumulative exposure risk assessment has become a hot research topic in the field of food quality and safety.The pesticides that are used most frequently with higher exceeding rate in the fruits and vegetables.,namely carbendazim,cyhalothrin,chlorpyrifos,acetamiprid and abamectin were selected.Acute toxicity,avoidance behavior,reproduction toxicity of six compounds in different combinations to Eisenia fetida in the artificial soil were observed.According to MTT colorimetry,pesticide inhibition effects to HepG2liver cell proliferation were determined.The methods of risk assessment on combined exposure in representative countries and international organizations were studied.Taking the multiple pesticides in bayberry as an example,the combined exposure risk assessments of pesticides with same mechanism or different mechanisms were carried out.The results of combined toxicity:Combined toxicity tests to Eisenia fetida indicated that the acute toxicity of the multiple pesticides was stronger than that of the single pesticide,and the more mixed the pesticides were,the lower concentration caused a hazard.The combined pesticides of three,four,five and six components led to synergistic effect,and the toxicity enhanced with the exposure time extention.Avoidance behavior test results showed that the toxicity of different types of pesticides was consistent with their acute toxicity,and the synergistic effect of combined toxicity of two or multiple components was stronger.Through the reproduction toxicity test to Eisenia fetida,the half-effective concentration of each treatment group was lower than the half-avoidance concentration,and both are lower than the half–lethal concentration.According to MTT colorimetry,multiple pesticides inhibition results to HepG2 liver cell indicated that:most of groups in combinations produced a certain proliferation inhibition to cellseven their concentration is lower than that of the corresponding single pesticide.By comparision of methods adopted by different countries,the procedure and framework were proposed for combined expsosure risk assessment for agricultural products in China.Multiple pesticides combined exposure risk assessment for bayberry showed that:it is impossible for several pesticides groups with the same mechanism in bayberry samples revealed a signigicant risk.When at 97.5^th percentile exposure level,the hazard indexes?HI?of the pesticides with anti-androgenic effects for adults and children were both above 1,and the probability of exposure exceeding the ADI was 7.1%and 31.1%for adults and children,respectively.Followed by pyrethroids pesticides,The HI for children at the 97.5th percentile consumption level is above 1.0,and the probability of exposure exceeding the ADI was 3.8%.For the pesticides with dissimilar mechanism,exposed to binary combination of carbendazim and cyhalthrin,the HI increased 24.3%and24.4%for adults and children respectively,while exposed to ternary combination of carbendazin,chlopyriphos and acetamiprid,the HI increased by 122%,189%and 203%for adults,124%,219%and 205%for children.The actual HI was much higher than that predicated by concerntration addition models.