噻唑锌对大型溞的急性及慢性毒性效应

噻唑锌是中国自主创新研制的高效噻二唑类有机锌杀菌剂，主要防治作物细菌性病害。为评价其对水生生物的危害，以大型溞Daphnia magna为研究对象，采用半静态法，将大型溞暴露于不同质量浓度的噻唑锌中，通过48 h和21 d暴露试验，分别研究了噻唑锌对大型溞的急性和慢性毒性效应，同时采用高效液相色谱 (HPLC) 分析方法进行了噻唑锌实际浓度分析，确保试验过程中噻唑锌浓度保持在可接受范围内。结果表明:噻唑锌对大型溞的48 h-EC₅₀值为213.3 μg/L，剂量-效应方程为y = 3.08x ? 7.10 (r为0.93)；持续暴露21 d，一定浓度噻唑锌对大型溞有明显的毒性效应，其中4.26 μg/L浓度组对大型溞的各项生命指标均有显著影响 (P < 0.05)，与溶剂对照组相比，F₀代大型溞单雌总产溞数和产胎数平均减少53.45%和31.15%，首胎时长平均延迟2.75 d，并可显著降低蜕壳次数，抑制溞体生长。所有观测指标中，噻唑锌对大型溞F₀代单雌总产溞数、单雌产胎数和21 d体长的最高无可观察效应浓度 (NOEC) 为2.13 μg/L。同时，F₁代染毒各处理组的单雌总产溞数和产胎数均有明显减少，溞体生长受抑制，但与溶剂对照组均没有显著性差异。在F₁代大型溞恢复试验中，各观测指标与对照组相比均无显著差异，说明噻唑锌对大型溞子代影响不明显。研究结果表明，噻唑锌对亲代大型溞的生长发育和繁殖能力有不良影响，存在一定的水生生态风险。

Acute and chronic toxicities of zinc thiazole to Daphnia magna

Zinc thiazole is a high-efficiency thiadiazole organic zinc bactericide developed in China. Its main application is to control bacterial diseases of crops. The acute-chronic toxicity and conducted the offspring contamination and recovery tests of zinc thiazole to Daphnia magna by exposure tests at 48 h and 21 d were evaluated. The acute toxicity results indicated that zinc thiazole had high toxicity against D. magna. The 48 h-EC₅₀ value was 213.3 μg/L and the dose-effect relationship was y = 3.08x?7.10 (r = 0.93). 21 days after the exposure, each life index of D. magna changed significantly (P < 0.05) at the 4.26 μg/L group. After comparing with the vehicle, the total number of offspring per female and the number of brood per female of F₀ generation were decreased by 53.45% and 31.15%, respectively. The first reproduction time was also delayed by an average of 2.75 d. The number of cumulative molts were significantly reduced and shortened body length showed up. Among all the indexes, the no observed effect concentration(NOEC) of the total number of offspring per female, the number of brood per female and body length in F₀ generation was exposure to 2.13 μg/L zinc thiazole for 21 d. The total number of offspring per female and the number of brood per female of F₁ generation were significantly reduced, and the growth of D. magna was obviously inhibited, but there was no significant difference between the contamination and the control. F₁ recovery group had good resilience and had no significant difference in activity indexes versus the control. This study revealed that zinc thiazole can adversely impact on the reproduction and the development ability of D. magna, and showed certain risks to the aquatic ecology.