Studies On Residue And Dietary Exposure Risk Assessment Of Pesticides Applied In Apple

A total of 282 apple samples were randomly collected from two main apple superior producing areas, including the Bohai bay（Liaoning, Shandong and Hebei） and the Northwest loess plateau（Shaanxi, Shanxi and Henan） in this study. Carbendazim, thiophanate-methyl, imidacloprid, chlorbenzuron, abamectin, methomyl, diflubenzuron, emamectin benzoate and ethylenethiourea residues were detected in apple by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） under multiple reaction monitoring mode. Carbendazim, thiophanate-methyl, chlorbenzuron, imidacloprid and ethylenethiourea were selected for pesticide residual level analysis. The professional risk assessment software @Risk, based on Monte Carlo simulations, was used to evaluate the dietary intake risk in this study. First, data on the 5 pesticides residual content in 282 apple samples were collected for distribution fitting, which was checked by three statistical test methods — the Chi-squared test, the Anderson-Darling test and the Kolmogorov-Smirnov test; the optimum fitting distribution was selected from the results. A probabilistic evaluation model was built to estimate the health risks for the population. The purpose of this study was to ascertain pesticides residue level in domestic apple and quantify the dietary intake risk for the general population consuming apple with pesticide residues. This study will provide references for the apple quality safety supervision and allocating public resources in rationally by the government, and for carrying out the work of fruits quality and safety risk assessment systemically in the future.According to the present study, conclusions could be summarized as follows:1. The pesticides residual detectable rates were relatively high in Chinese apples. The vast majority of samples pesticide residues were at lower levels, and the proportion was reduced gradually in a trend with the increase of residual concentration. The carbendazim, thiophanate-methyl, chlorbenzuron, imidacloprid residual concentrations of all the 282 samples tested were under MRLs. The exceeded rate of ethylenethiourea was just 1.4%. Apple samples from different provinces and superior producing areas showed obvious differences. From the detectable rate and the average of residual levels: the detectable rate of carbendazim was 81.9%, which was still the most frequently detectable pesticide and close attention should be paid by Henan and Shandong provinces and Bohai bay producing areas; the detectable rate of thiophanate-methyl was 52.1%, and close attention should be paid by Shandong and Liaoning provinces and Bohai bay producing areas; the detectable rate of chlorbenzuron was 31.2%, and close attention should be paid by Hebei and Henan provinces and Bohai bay producing areas; the detectable rate of imidacloprid was 39.0%, and close attention should be paid by Shanxi and Liaoning provinces and Bohai bay producing areas; the detectable rate of ethylenethiourea was 80.9%, and close attention should be paid by Henan and Shaanxi provinces and Bohai bay producing areas. In the matter of multiple residues in one samples, the proportion of samples with more than 2 pesticides residue were in the following order: Henan > Shandong > Shanxi > Liaoning > Hebei > Shaanxi and Bohai bay > Northwest loess plateau.2. The health risks for the Chinese population consuming apples with carbendazim, thiophanate-methyl, chlorbenzuron, imidacloprid and ethylenethiourea were acceptable. The dietary intake risks for the different regions and different genders in one age group had no obvious differences. Generally speaking, females faced higher health risks than males and urban residents faced higher health risks than rural residents. Difference of dietary intake risk in different age groups was clear. The pesticides dietary intake risks of the kids（aged 2 to 6） and children（aged 7 to 13） were significantly higher than that of other groups, so that they were the vital monitoring objects.The chronic dietary intake risks for different age groups consuming apples were low even at the higher exposure percentile（P99.5）: the chronic dietary intake risks of carbendazim were 2.8600%¹6.2300% and vital attention should be paid by Henan and Shandong provinces and Bohai bay producing areas; the chronic dietary intake risks of thiophanate-methyl were 0.0225%⁰.5970% and vital attention should be paid by Shandong and Henan provinces and Bohai bay producing areas; the chronic dietary intake risks of chlorbenzuron were 0.0019%⁰.0175% and vital attention should be paid by Henan and Hebei provinces and Bohai bay producing areas; the chronic dietary intake risks of imidacloprid were 0.1019%⁰.9930% and vital attention should be paid by Liaoning and Hebei provinces and Bohai bay producing areas; the chronic dietary intake risks of ethylenethiourea were 1.0850%⁹.8300% and vital attention should be paid by Liaoning and Shaanxi provinces and Bohai bay producing areas.The acute dietary intake risks for different age groups consuming apples were low even at the higher exposure percentile（P99.5）: the acute dietary intake risks of carbendazim were 1.5600%⁷.9600% and vital attention should be paid by Henan and Shandong provinces and Northwest loess plateau producing areas; the acute dietary intake risks of imidacloprid were 0.3400%¹.0580% and vital attention should be paid by Shanxi and Liaoning provinces and Northwest loess plateau producing areas; the acute dietary intake risks of ethylenethiourea were 0.9420%².9900% and vital attention should be paid by Liaoning and Shaanxi provinces and Northwest loess plateau producing areas.3. The focus was different in different provinces and producting areas. Hebei should paid vital attention to the chlorbenzuron residual level and the chronic dietary intake risks of chlorbenzuron and imidacloprid. Henan should paid vital attention to the carbendazim, chlorbenzuron, and ethylenethiourea residual level; the chronic and acute dietary intake risks of carbendazim; and the chronic dietary intake risks of thiophanate-methyl and chlorbenzuron. Shandong should paid vital attention to the carbendazim and thiophanate-methyl residual level; the chronic and acute dietary intake risks of carbendazim; and the chronic dietary intake risks of thiophanate-methyl. Shanxi should paid vital attention to the imidacloprid residual level and its acute dietary intake risks. Shaanxi should paid vital attention to the ethylenethiourea residual level and its chronic and acute dietary intake risks. Liaoning should paid vital attention to the thiophanate-methyl and imidacloprid residual level and the chronic and acute dietary intake risks of imidacloprid and ethylenethiourea. Bohai bay should paid vital attention to the carbendazim, thiophanate-methyl, chlorbenzuron and imidacloprid residual level and their chronic dietary intake risks. Northwest loess plateau should paid vital attention to the ethylenethiourea residual level and the acute dietary intake risks of carbendazim, imidacloprid and ethylenethiourea.4. Based on the e MRL, MRL of carbendazim, thiophanate-methyl, imidacloprid and ethylenethiourea in apples were proposed to be 2.6 mg·kg^-1, 7.0 mg·kg^-1, 5.0 mg·kg^-1 and 0.2 mg/kg respectively.