摘要:
为了对防污漆杀生活性物质敌草隆的环境毒性进行评估，根据《沉积物-水体中摇蚊生命周期毒性试验—水体加标法或沉积物加标法》(OECD-233)，以底栖生物花翅摇蚊为试验对象，通过添加敌草隆的上覆水溶液(浓度设置为1.22 mg·L-1、1.94 mg·L-1、3.08 mg·L-1、4.88 mg·L-1、7.74 mg·L-1和12.26 mg·L-1)对两代花翅摇蚊先后进行暴露，研究其对摇蚊孵化、发育、羽化和繁殖等阶段的影响。结果显示，敌草隆对亲代花翅摇蚊及其子代的羽化率产生抑制，EC在50值分别为7.56 mg·L-1和5.24 mg·L-1，子代对敌草隆的耐受性有所降低；还对亲代和子代发育率产生抑制，EC50分别为5 mg·L-1和4.33 mg·L-1，表明子代对敌草隆的敏感性增加；敌草隆能够影响两代花翅摇蚊的雌雄性别比率，浓度-效应曲线均呈倒“U”型；另外，随着暴露浓度的增加，两代花翅摇蚊所产卵的孵化率均下降，亲代和子代的EC50分别为2.53 mg·L-1和10.4 mg·L-1，提示子代所产卵对敌草隆的抗性增强；同样地，敌草隆对两代花翅摇蚊的繁殖力均有抑制作用，亲代EC50值为1.99 mg·L-1，子代EC50为2.68 mg·L-1。总之，敌草隆暴露对花翅摇蚊上述生活史各阶段均能造成不利影响，其中在羽化和发育阶段可观察到敌草隆毒性的累积，而就卵的孵化率而言，子代所产卵较母代所产卵对敌草隆表现出一定程度的抗性。
Abstract:
To evaluate environmental toxicity of Diuron, a biocidally active substance commonly used in antifouling paints, the two generation life-cycle toxicity of Chironomus kiiensis was conducted according to the OECD testing guideline 233, namely Sediment-Water Chironomid Life-Cycle Toxicity Test Using Spiked Water or Spiked Sediment. Chironomus kiiensis, one of sediment-dwelling organisms, fully covering the parental generation (P generation) and the offspring generation (F1 generation), were exposed to Diuron which was added to overlying water at the concentrations of 1.22 mg·L-1, 1.94 mg·L-1, 3.08 mg·L-1, 4.88 mg·L-1, 7.74 mg·L-1 and 12.26 mg·L-1, respectively. The adverse effects of Diuron on Chironomus kiiensis were observed at different life stages such as hatching from eggs, development, emergence and reproduction. It was found that Diuron could inhibit the emergence ratio of both generations, with EC50 at 7.56 mg·L-1 for P generation and 5.24 mg·L-1 for F1 generation, implying that the tolerance to Diuron lowered in the secondary generation. The development rates decreased in the exposed groups for both generations, with EC50 at 5 mg·L-1 for P generation and 4.33 mg·L-1 for F1 one, indicating that the latter was more sensitive to Diuron. The sex ratios of Chironomus kiiensis were also influenced by Diuron, showing an inverse U-shaped concentration-effect curve for both generations. Besides, the hatching ratio of eggs spawned by P generation declined with the increasing concentrations, so did that by F1 generation; EC50 at 2.53 mg·L-1 for P generation and 10.4 mg·L-1 for F1 generation gave a clue that eggs spawned by F1 generation were of higher resistance to Diuron. Similarly, the fecundity of both generations was compromised by Diuron exposure, with EC50 at 1.99 mg·L-1 for P generation and 2.68 mg·L-1 for F1 generation. In conclusion, Diuron could produce adverse effects on Chironomus kiiensis at different life stages. Wherein, the influence of Diuron on emergence and development could be passed from P generation to F1 generation, and however, with regard to hatching ratio, eggs spawned by F1 generation were found to be more resistant to Diuron than those spawned by P generation.
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