25%乙基多杀菌素水分散粒剂对陆生生物的急性毒性及环境风险评估

    Acute toxicity and environmental risk assessment of 25% spinetoram water dispersible granules for terrestrial organisms

    • 摘要: 乙基多杀菌素是一种广谱高效的绿色生物农药,在害虫综合防治中具有良好的应用前景,其在环境中的残留可能对陆生生物生存、生长和繁殖等方面产生不利影响。为明确25%乙基多杀菌素水分散粒剂对日本鹌鹑(Coturnix japonica)、意大利蜜蜂(Apis mellifera L.)、家蚕(Bombyx mori)、玉米螟赤眼蜂(Trichogramma ostriniae)、七星瓢虫(Coccinella septempunctata)和赤子爱胜蚓(Eisenia foetida)的急性毒性和初级风险,对上述6种非靶标陆生生物进行了急性毒性测试和初级风险评估。毒性试验结果表明:25%乙基多杀菌素水分散粒剂对日本鹌鹑急性经口7 d半数致死剂量(7 d-LD50)为1510.3 mg a.i./kg bw,对意大利蜜蜂的急性经口毒性和急性接触毒性(48 h-LD50)分别为0.267 和0.060 μg a.i./蜂,对家蚕的急性毒性96 h半数致死浓度(96 h-LC50)为0.22 mg a.i./L,对玉米螟赤眼蜂的急性毒性24 h半数致死用量(24 h-LR50) > 562.5 g a.i./hm2,对七星瓢虫的急性毒性13 d-LR50 > 168.75 g a.i./hm2,对蚯蚓的急性毒性14d-LC50 > 100 mg a.i./kg 干土。风险评估结果表明,25%乙基多杀菌素水分散粒剂在喷施场景下以最高推荐施用量使用时,对鸟类和土壤生物的初级风险可接受,对蜜蜂(风险商值RQ = 47)、家蚕喷雾场景下的最外围桑树(RQ = 5636 > 1)和次外围桑树(RQ = 343 > 1)以及非靶标节肢动物的农田内(危害商HQin = 1027 > 5)和农田外(HQoff = 24.29 > 5)喷雾场景风险均不可接受,,并对不可接受的风险提出相应的风险降低措施,以达到保护非靶标环境生物的目的。同时,也可开展田间试验进行高级风险评估,从而获得更接近实际的风险评估结果,降低评估结果的不确定性。

       

      Abstract: Spinetoram is a broad-spectrum and highly effective biological pesticide with promising applications in integrated pest management. However, its application or residue in the environment may adversely affect the survival, growth, and reproduction of terrestrial organisms. In order to evaluate the acute toxicity and primary risk of 25% spinetoram water dispersible granules to Japanese quail (Coturnix japonica), honeybee (Apis mellifera L.), silkworm (Bombyx mori), trichogrammatid (Trichogramma ostriniae), seven-spotted ladybird(Coccinella septempunctata) and earthworm (Eisenia foetida), acute toxicity tests and primary risk assessments were performed for the above six non-target terrestrial organisms. The results of the toxicity tests showed that the acute oral median lethal dose (7 d-LD50) of 25% spinetoram water dispersible granules for Japanese quail was 1510.3 mg a.i./kg bw, and the acute oral and acute contact 48 h-LD50 for honeybees were 0.267 and 0.060 μg a.i./bee. The acute median lethal concentration (96 h-LC50) for the silkworms was 0.22 mg a.i./L. The acute median lethal application rate (24 h-LR50) for trichogrammatids was greater than562.5 g a.i./hm2, and the acute 13 d-LR50 for ladybirds was greater than 168.75 g a.i./hm2. 14 d-LC50 for earthworms was greater than 100 mg a.i./kg dry soil. The results of the risk assessment showed that when 25% spinetoram water- dispersible granules were used at the highest recommended application rate in the spraying scenario, it had acceptable primary risks to birds and soil organisms, and unacceptable risks to bees (risk quotient, RQ = 47), silkworms in spray scenarios for the outermost (RQ = 5636 > 1) and second outermost mulberry trees(RQ = 343 > 1), and for non-target arthropods in -field and off-field exposure scenarios (hazard quotient, HQin = 1027 > 5, HQoff = 24.29 > 5). For unacceptable risks, mitigation measures were proposed to protect non-target environmental organisms. Additionally, field trials were recommended to conduct higher-tier risk assessments to obtain more realistic risk results, thereby reducing uncertainties in the evaluation.

       

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