设施番茄和黄瓜田土壤中农药残留及其对蚯蚓的急性风险

为评价设施蔬菜田土壤中残留农药对蚯蚓的急性危害风险,在山东省济阳县蔬菜基地,分别选择番茄和黄瓜连作种植区,于产中、产后及后茬产中三个时期采集耕层土壤,应用超高效液相色谱串联质谱法评估土样中噻虫嗪、噻虫胺、多菌灵、吡虫啉、阿维菌素、噻唑膦、甲基异柳磷、克百威和三羟基克百威的残留,并通过风险商值法评价其对蚯蚓的急性风险。结果表明:在39个设施番茄土壤中,噻虫嗪、噻虫胺和吡虫啉的检出率(检出浓度均值)均较高,分别为90%(0.107 mg·kg~(-1)dw)、79%(0.100 mg·kg~(-1)dw)和49%(0.233 mg·kg~(-1)dw);在30个设施黄瓜土壤中,噻虫嗪(63%,1.18 mg·kg~(-1)dw)和吡虫啉(57%,0.126 mg·kg~(-1)dw)的检出率和检出浓度均值均较高。在95%的番茄土样及97%的黄瓜土样中,目标农药对蚯蚓的急性风险商值小于1。在3例土壤中发现风险商值大于1,包括2例吡虫啉和1例噻虫胺,应用风险商值逆推,吡虫啉和噻虫胺对蚯蚓的土壤安全阈值分别为1.07和0.593 mg·kg~(-1)dw。研究表明,所调查区域设施蔬菜土壤中目标农药对蚯蚓的急性风险总体较低,对于高风险农药应监测其土壤残留浓度,确保低于安全阈值。

Acute risks of pesticide residues in greenhouse tomato and cucumber field soil to earthworms

The present study investigated the pesticide residues in the soil of greenhouse vegetables and estimated their acute risk to earthworms. Soil samples were collected from the greenhouses where tomato and cucumber are planted in Jiyang County, Shandong Province of China at the following three periods, the middle and after the growing season and the middle of the next growing season. Pesticide residues of thiamethoxam, clothianidin, carbendazim, imidacloprid, abamectin, fosthiazate, isofenphos-methyl, carbofuran, and 3-hydroxycarbofuran were determined using ultra-fast-tandem mass spectrometry(UFLC-MS/MS), and then the risk quotient(RQ)method was used to assess the risks of the detected pesticides to earthworms. In 39 soil samples from the greenhouse tomato field, the most frequently detected chemicals were thiamethoxam(90%), clothianidin(79%), and imidacloprid(49%)at mean detected concentrations of 0.107, 0.100, and 0.233 mg·kg^-1 dw, respectively. Thiamethoxam and imidacloprid were detected in 63% and 57% of the 30 soil samples from the greenhouse cucumber field, with mean detected concentration of 1.18 and 0.126 mg·kg^-1 dw, respectively. In 39 soil samples from the greenhouse tomato field, 95% of the RQs were <1, whereas in 30 soils from the greenhouse cucumber field, 97% were <1. Imidacloprid in two soils and clothianidin in one soil posed unacceptable risks to earthworms. The safety threshold concentration for earthworms was 1.07 and 0.593 mg·kg^-1 dw for imidacloprid and clothianidin, respectively. The target pesticide residues rarely posed high risks to earthworm in the investigated samples, but the safety threshold concentration should be applied to protect the earthworm from high-risk pesticides.