对二甲苯对褐牙鲆(Paralichthys olivaceus)幼鱼的毒性效应研究

采用急性和28 d慢性暴露试验研究了海洋典型危险化学品对二甲苯对褐牙鲆幼鱼的致死效应和生长抑制效应,并测定了遗传毒性、神经毒性以及免疫毒性效应相关的毒理学评价指标。研究结果表明:对二甲苯对褐牙鲆幼鱼的96 h-LC50为45.7 mg·L~(-1),根据国家环保局水和废水监测分析方法编委会规定的化学物质对鱼类毒性分级标准,属于中等毒性,浓度高于2.3 mg·L~(-1)的暴露能显著抑制褐牙鲆幼鱼的生长;4.6和9.2 mg·L~(-1)浓度组观察到对二甲苯暴露28 d后褐牙鲆肝脏中的丙二醛含量与DNA损伤程度显著升高,脑组织中乙酰胆碱酯酶(Ach E)活力被明显抑制;9.2 mg·L~(-1)浓度组暴露28 d后,褐牙鲆幼鱼体内总血细胞数量和溶菌酶活力显著降低。这些结果表明较高浓度的对二甲苯长期作用可导致褐牙鲆幼鱼的氧化胁迫,造成其肝脏毒性损伤并产生神经毒性与免疫毒性。本实验结果为了解对二甲苯对鱼类的毒性作用机制以及对二甲苯的海洋生态风险评估提供了科学依据。

Toxicological Effects of p-Xylene on the Juvenile Flounder (Paralichthys olivaceus)

Acute and sub-chronic toxicity tests using juvenile marine flounder Paralichthys olivaceus were conducted, in order to evaluate the toxicological effects of one of the most typical hazardous and noxious substances, p-xylene. The toxicological effects studied in the present study include the acute lethal effect, growth inhibition, as well as biomarkers which could indicate the genotoxicity, neurotoxicity and immunotoxicity of p-xylene. The results showed that the 96 h LC₅₀ of p-xylene on juvenile P. olivaceus was 45.7 mg L^-1. Exposure to p-xylene with concentration no less than 2.3 mg L^-1 caused significant growth inhibition of the juveniles. MDA content and DNA damage in fish liver was significantly increased and the activity of AChE in fish brain was significantly inhibited after 4.6 and 9.2 mg L^-1 p-xylene exposure for 28 days. Exposure to 9.2 mg L^-1 p-xylene for 28 days caused significant reduce of total hemocyte counts and lysozyme activity. These results indicated that the long-term effect of p-xylene lead to oxidative stress and DNA damage, as well as neurotoxicity and immunotoxicity. The results presented in this study provided data for marine ecotoxicological assessment of p-xylene and could contribute to a better understanding of the toxicological mechanism of p-xylene in fish.