异噻唑啉酮类杀菌剂对黑斑蛙胚胎和蝌蚪的急性毒性

异噻唑啉酮类杀菌剂1,2-苯并异噻唑-3-酮（BIT）和甲基异噻唑啉酮（MIT）虽已在多种行业中广泛使用，但目前有关其毒性尤其对水体中生物毒性的数据还较少。鉴于BIT和 MIT在水体中普遍存在，本文研究了这两种污染物对两栖动物黑斑蛙胚胎和蝌蚪的急性毒性。黑斑蛙胚胎和蝌蚪分别暴露系列浓度的BIT和 MIT，观察化学品对其生长、发育和运动的影响，计算96小时半数致死浓度（96 h-LC₅₀）和96小时半数致畸浓度（96 h-TC₅₀），确定最小生长抑制浓度（MCIG）。结果发现，BIT对黑斑蛙胚胎的96 h-LC₅₀和96 h-TC₅₀分别为2.99 mg?L^-1和0.60 mg?L^-1，MCIG小于0.40 mg?L^-1，对蝌蚪的96 h-LC₅₀为6.44 mg?L^-1。MIT对黑斑蛙胚胎的96 h-LC₅₀和96 h-TC₅₀分别为5.30 mg?L^-1和2.36 mg?L^-1，MCIG为2.59 mg?L^-1，对蝌蚪的96 h-LC₅₀为7.58 mg?L^-1。根据《化学农药环境安全评价准则报批稿》中两栖动物蝌蚪急性毒性的分级标准，判定BIT和MIT的毒性等级为中等。该毒性数据为异噻唑啉酮类杀菌剂的环境管理提供参考。

Acute Toxicity of Isothiazolinone Biocides to Rana nigromaculata Embryos and Tadpoles

1, 2-benzisothiazolin-3-one (BIT) and methylisothiazolinone (MIT) are isothiazolinone biocides that are widely used in various industries, but their toxicity has still been unclear. Considering their ubiquitous pollution in water, we investigated the acute toxicity of BIT and MIT to Rana nigromaculata embryos and tadpoles. By exposing embryos and tadpoles to different concentrations of BIT and MIT, we observed the growth and motor ability of embryos and tadpoles, and calculated 96 h-LC₅₀, 96 h-TC₅₀, and the minimum concentration to inhibit growth (MCIG). 96 h-LC₅₀ and 96 h-TC₅₀ of BIT to embryos were 2.99 mg?L^-1 and 0.60 mg?L^-1, respectively, with a MCIG value less than 0.40 mg?L^-1. 96 h-LC₅₀ of BIT to tadpoles was 6.44 mg?L^-1. 96 h-LC₅₀ and 96 h-TC₅₀ of MIT to embryos were 5.30 mg?L^-1 and 2.36 mg?L^-1, respectively, with a MCIG value of 2.59 mg?L^-1. 96 h-LC₅₀ of MIT to tadpoles was 7.58 mg?L^-1. According to Guidelines on Environmental Safety Assessment for Chemical Pesticides, BIT and MIT are medium toxic to Rana nigromaculata embryos and tadpoles. These results can provide a reference for environmental management of isothiazolinone biocides.