基于多作物中吡唑醚菌酯的环境行为评估长期膳食风险

    Environment fate of the pyraclostrobin for long-term dietary risk assessment in multiple crops

    • 摘要: 农药环境行为及其风险评估是农产品质量安全与生态健康领域重点关注问题,为明确典型农用化合物吡唑醚菌酯在农作物中的行为特征及其暴露风险差异,该研究结合中国农作物主产区分布,运用确定性和概率性双风险模型评估吡唑醚菌酯长期膳食风险,结果表明,吡唑醚菌酯在小麦、花生、黄瓜和西瓜上的原始沉积量高达0.209 mg/kg,半衰期为1.9~9.9 d。作物秸秆中的残留浓度(0.187~75.291 mg/kg)远大于籽粒(≤0.096 mg/kg)。通过膳食途径造成的吡唑醚菌酯暴露会对消费人群造成不可接受的慢性风险,风险商值为123.959%~406.415%。城镇人群的风险显著大于乡村人群(P<0.05),且风险商值随年龄的递增而降低。概率性模型被进一步引入以量化风险评估的不确定性。该研究根据多作物中吡唑醚菌酯残留水平的概率分布,预警其存在高潜在的长期膳食暴露风险。乡村儿童群体的摄入风险明显高于其他群体,需重点关注。

       

      Abstract: Pyraclostrobin is one of the most prevalent strobilurin fungicides from the broad-spectrum control of fungal diseases. The ever-increasing pesticides with the active ingredient of pyraclostrobin have been put into the agroecosystem in recent years. The survival of non-targeted organisms and the by-effects on human health can be induced by pyraclostrobin biomagnification within the food web. This study aims to elaborate on the fate characteristics and risk magnitude of pyraclostrobin after large-scale application that contributed to agroecosystem sustainability and dietary rationality. The registered crops included wheat, peanut, watermelon, and cucumber in the main production areas in China. The tracing of pyraclostrobin was performed on the multiple crop matrices using the self-developed ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Some measurements were used to validate the specificity, linearity, matrix effect (ME), accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). LOD and LOQ were estimated to be 0.0001-0.0004, and 0.001 mg/kg for the wheat grains, wheat straw, peanut kernels, peanut straw, cucumber, and watermelon matrices, respectively. The average recoveries of the target analyte ranged from 81.2% to 112.2% for all fortification levels. The precision values were associated with the analytical methods. The relative standard deviations (RSD) were 0.7% to 18.1% for the pyraclostrobin in all matrices. The fate characteristics of pyraclostrobin were elucidated using the verified storage stability. Some parameters were selected to represent the occurrence, pharmacokinetics dissipation, and terminal magnitude of pyraclostrobin, including the original depositions, half-lives, and terminal magnitude. The concentrations of pyraclostrobin were attached the maximum of <0.001, ≤0.209, ≤0.048 mg/kg 2 h after the last application in peanut kernels, cucumber and watermelon, respectively, and 0.005-0.043 mg/kg 7 d after last application in the wheat grain. Significant differences were observed in the degradation dynamics of pyraclostrobin among different crops, with half-life of 1.9-4.7 d in watermelon, 2.6-7.5 d in cucumber, and 5.9-9.9 d in wheat grain. There was no half-life of peanut kernels without detecting the pyraclostrobin in any samples. The terminal level of pyraclostrobin in the wheat and peanut straws (0.187-75.291 mg/kg) was much higher than that in the edible part, including the wheat grain and peanut kernel (≤0.096 mg/kg). The long-term dietary risks of pyraclostrobin were further clarified for the population with the different regions, gender, and age using the supervised trials median residues (STMR) for the investigated crops that were recommended by the large-scale field trials. The risk quotients (RQ) were assessed as 123.959%-406.415% by the deterministic model, indicating out of the acceptable range. The risk quotients were inversely correlated to the age of the population. The children group was subjected to the greatest long-term risks of pyraclostrobin exposure from the dietary pathway. The population subgroup location in rural (RQ, 146.799%-406.415%) suffered more serious exposures than that in urban (123.959%-374.217%). A probabilistic model was further introduced for a more accurate estimation of dietary exposure. The total chronic risks (RQ) caused by consuming wheat grain and watermelon ranged from 0.025% to 11.309% from the 50 percentile to the 99.9 percentile, far less than 100%, indicating no potential risks for the population. The unacceptable chronic risk magnitude of pyraclostrobin was determined, according to the probabilistic distribution in the residual levels of the above four crops. Anyway, the hazard effects of pyraclostrobin from dietary pathways should be emphasized in daily life, especially for rural children group.

       

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