Chlorpyrifos

Chlorpyrifos, as a broad-spectrum organophosphorothioate insecticide, has a principal mechanism of toxicity by inactivation of acetylcholinesterase at nerve junctions^[1].

In vitro test it exhibited that In agricultural soils under field conditions,half-lives are shorter. The mean water-soil adsorption coefficient(Koc) of chlorpyrifos is 8,216 mL/g^[2]. The 24-h LC10 and LC50 values of chlorpyrifos for embryos were 0.89 and 11.8 μg/L, respectively. And the 24-h LC10 and LC50 values of chlorpyrifos for larvae were 0.53 and 21.7 μg/L, respectively; the 48-h LC10 and LC50 for larvae were 0.04 and 5.47 μg/L, respectively. Moreover, in the aquatic environment ,1 μg/L of chlorpyrifos may adversely affect the development and the reproduction of banded gourami^[3].

In vivo efficacy test it shown that there is a similar sensitivity to orally administered chlorpyrifos with LD50s ranging from 8 to > 400 mg/kg body weight in amphibians, birds, and mammals. There is also no observed effect concentrations to be greater than 1 mg/kg food in long-term chronic feeding studies in birds and mammals^[1]. In addition, the exposure to environmentally relevant chlorpyrifos with 0.03, 0.06 and 0.12 μg/L increased precopulatory guardian behavior time, amplexus reformulation after exposure and the number of ovigerous females in the amphipod Hyalella curvispina^[4]. Exposure to 500 μg/L chlorpyrifos for 15 days, there is no consistent obvious effect in both male and female gonado-somatic index^[5].

References:

[1] Barron MG, et al. Ecotoxicology of chlorpyrifos. Rev Environ Contam Toxicol. 1995;144:1-93.

[2] Solomon KR, et al. Properties and uses of chlorpyrifos in the United States. Rev Environ Contam Toxicol. 2014;231:13-34.

[3] Sumon KA, et al. Acute toxicity of chlorpyrifos to embryo and larvae of banded gourami Trichogaster fasciata. J Environ Sci Health B. 2017 Feb;52(2):92-98.

[4] Negro CL, et al. Effects of Chlorpyrifos Over Reproductive Traits of Three Sympatric Freshwater Crustaceans. Bull Environ Contam Toxicol. 2021 May;106(5):759-764.

[5] Sumon KA, et al. Effects of long-term chlorpyrifos exposure on mortality and reproductive tissues of Banded Gourami (Trichogaster fasciata). J Environ Sci Health B. 2019;54(7):549-559.

毒死蜱作为一种广谱有机硫代磷酸酯类杀虫剂,其主要致毒机制是通过使神经接头处的乙酰胆碱酯酶失活^[1]。

体外试验表明,在田间条件下的农业土壤中,半衰期较短。毒死蜱的平均水-土壤吸附系数（Koc）为8,216 mL/g^[2]。毒死蜱对胚胎的 24 小时 LC10 和 LC50 值分别为 0.89 和 11.8 μg/L。毒死蜱对幼虫的24小时LC10和LC50值分别为0.53和21.7 μg/L；幼虫的 48 小时 LC10 和 LC50 分别为 0.04 和 5.47 μg/L。此外,在水生环境中,1 μg/L的毒死蜱可能会对带状吻口鱼的发育和繁殖产生不利影响^[3]。

体内药效试验表明,口服毒死蜱具有相似的敏感性,LD50s范围为8至>；两栖动物、鸟类和哺乳动物的 400 mg/kg 体重。在鸟类和哺乳动物的长期长期喂养研究中也没有观察到大于 1 mg/kg 食物的影响浓度^[1]。此外,暴露于环境相关的浓度为 0.03、0.06 和 0.12 μg/L 的毒死蜱会增加交配前的守卫行为时间、暴露后的 amplexus 重新形成以及端足类 Hyalella curvispina^[4] 中产卵雌性的数量。 500 μg/L毒死蜱暴露15天,对男女性腺体细胞指数无一致的明显影响^[5]。