摘要:
为了探究消毒副产物(DBPs)的氧化损伤和神经毒性作用,选择幼年斑马鱼作为模式生物,研究了市政污水处理厂二级出水和经次氯酸钠(NaClO)消毒后的二级出水对斑马鱼体内过氧化氢酶(CAT)活性、丙二醛(MDA)含量和乙酰胆碱酯酶(AchE)活性的影响。结果表明,暴露时间达到10 d时,MDA含量显著高于对照,且消毒后MDA含量增幅(91.43%)显著高于消毒前(44.36%);暴露时间达到15 d时,CAT活性被显著抑制,且消毒后抑制率(40.22%)显著高于消毒前(15.56%);说明消毒后暴露组对斑马鱼的氧化损伤强于消毒前。另外,消毒前后污水对AchE活性抑制率分别为38.49%和48.50%,说明消毒后污水对斑马鱼的神经毒性更大。因此,经NaClO消毒后的市政污水处理厂二级出水中DBPs对斑马鱼的抗氧化防御系统和神经系统具有潜在影响。
Abstract:
Juvenile zebrafish was chosen as a model organism to explore the oxidative damage and neurotoxicity of disinfection by-products (DBPs). The juvenile zebrafish were exposed to the chlorinated and non-chlorinated secondary effluents to test their subacute toxicity. The activities of catalase (CAT) and acetylcholinesterase (AchE) as well as malondialdehyde (MDA) contents in the exposed zebrafish were analyzed. Results showed that the MDA contents in the exposed groups were significantly higher than those in the control, after 10-days of exposure. The increase of MDA content in the chlorinated group (91.43%) was much higher than those in the non-chlorinated group (44.36%). Moreover, CAT activities in the exposed groups were dramatically inhibited after 10-days of exposure. The chlorinated group (40.22%) exerted obviously higher inhibition than non-chlorinated group (15.56%) did. Results indicated that the chlorinated secondary effluents had greater oxidative toxicity to zebrafish. In addition, the chlorinated secondary effluents also displayed higher AchE inhibition (48.50%) than the non-chlorinated group (38.49%), demonstrating the chlorinated group had greater neurotoxicity to zebrafish. In all, the DBPs formation during the secondary effluent chlorination has the potential impact on antioxidant defense system and nervous system of zebrafish.