纳米二氧化钛对佳乐麝香所引起的沙蚕(Perinereis aibuhitensis)神经毒性的影响

Influences of nano-TiO_2 on the neurotoxicity induced by galaxolide in the polychaeta Perinereis aibuhitensis

为探讨新兴有机和无机复合污染对海陆交错带关键性物种沙蚕的生态毒理学效应,在实验室条件下,考察了双齿围沙蚕(Perinereis aibuhitensis)毒理学指标(致死率和乙酰胆碱酯酶活性)与污染物[佳乐麝香(HHCB)和纳米二氧化钛(纳米TiO_2)]浓度间的关系。单一污染胁迫结果显示:HHCB和纳米TiO_2对P.aibuhitensis均具有潜在生理毒性。通过8 d的P.aibuhitensis致死率与污染物浓度间关系得到HHCB的半致死浓度(LC50)为313.21 mg·L-1,纳米TiO_2的LC50为27.09 mg·L-1。P.aibuhitensis乙酰胆碱酯酶(ACh E)活性随HHCB浓度增加而降低,即ACh E抑制率随其浓度增加而增加。与单一HHCB处理的沙蚕ACh E活性相比,纳米TiO_2的存在使其ACh E活性显著降低。研究结果表明,纳米TiO_2可以促进沙蚕ACh E对HHCB的敏感性,进而加重HHCB对P.aibuhitensis的神经毒性。因此,ACh E可以作为一种有效的潜在生物标志物,用来表征环境中新兴污染物的神经毒性;纳米TiO_2作为新型环境修复材料在使用时一定要考量其可能带来的复合污染毒性效应。

The number of reports on the eeotoxicological effects of emerging contaminants, especially emerging organic and inorganic combined contaminants, on estuary keystone species（polychaeta） is low. To understand the influence of these contaminants better, the relationships between toxicological indices （mortality and acetylcholinesterase （ AChE ） activity） and concentrations of contaminants （galaxolide （HHCB） and nano-TiO2） were examined in Perinereis aibuhitensis under laboratory conditions. The results of single contaminant stress in- dicated that the contaminants potentially were physiologically toxic to P. aibuhitensis. The estimated LC50（8 d） for HHCB and nano-TiO2 derived from the relationships between mortality and single contaminant concentrations were 313.21 mg· L^-1 and 27.09 mg· L-1, respectively. The AChE activity of P. aibuhitensis was decreased, namely, the inhibition rate of AChE increased with an increase of the single HHCB ex- posure concentrations. However, the AChE activity of combined contaminants was significantly lower than that of single HHCB stress owing to the addition of nano-TiOv The results implied that nano-TiO2 enhanced the sensitivity of AChE to HHCB, which exacerbated the neurotoxicity of HHCB to P. aibuhitensis. Thus, AChE had potential for becoming a useful biomarker of the neurotoxicity of emerging contami- nants in the environment. The potential toxic effects of combined contamination should be paid more attention in the utilization of nano-TiO2 as a new material for environmental remediation.