基于微藻运动性的海洋污染物生态毒性效应研究

Study on the ecological toxicity effect of marine pollutants based on microalgal motility trait

海洋污染生态毒性效应研究是认识和评价海洋环境质量现状及其变化趋势的重要依据。发展快速、有效的测试方法和指标对于防治污染、保护海洋环境具有重要意义。作者以海洋微藻运动性作为生理指标研究了典型海洋污染物的生态毒性效应。在本实验所测试的浓度范围内,铜(0~4.41 μmol/L)和苯酚(0~9.03 mmol/L)分别在 2 h 内对亚心型扁藻(Platymonas subcordiformis)的能动性,包括运动方式、运动能力和游泳速度产生了一定的影响,且都呈现良好的剂量-效应关系。经 Logistic 模型拟合分析求得铜和苯酚对亚心型扁藻的 2 h-EC50分别为 2.21 μmol/L^2.65 μmol/L 和 4.47 mmol/L^5.71 mmol/L。在联合毒性实验中,铜和苯酚混合后,对亚心型扁藻的 2h-EC50>1TU,其联合毒性效应方式表现为拮抗作用。上述结果与传统毒性试验(包括微藻 72 h 生长抑制试验, 24 h^48 h 大型蚤静止试验和 96 h 鱼类死亡试验)结果均是可比的,但相对所需测试时间较短,表明微藻运动性作为一种新型的生物测试指标可以对海洋污染物生态毒性(包括单一和联合毒性)进行快速、有效的评价。

Analyzing the ecological toxicity effects of marine pollution forms an important basis for the reorganiza- tion and evaluation of marine environment quality and its trend. The development of rapid and efficient bioassay methods and indicators is extremely significant for preventing pollution and protecting the marine environment. This study investigated the toxicity of typical marine pollutants using the motility of marine microalgae as a physiological trait. When Platymonas subcordiformis was exposed to single copper (0 4.41 μmol/L) or phenol (0 9.03 mmol/L), the algal motility, including the movement mode, the mobile ability, and the swimming speed, demonstrated a good dose response relationship. The 2 h EC50 values of copper and phenol to P. subcordiformis obtained by logistic model simulation were 2.21 2.65 μmol/L and 4.47 5.71 mmol/L, respectively. In the combined toxicity test, when P. subcordiformis was exposed to the mixture of phenol and copper at different TUs, the 2 h EC50 values were larger than 1 TU. This result indicated that the interaction between copper and phenol in terms of their toxicity to P. subcordiformis was antagonistic. These findings were found to be generally consistent with the toxic- ity data derived from traditional tests (e.g., 72 h microalgal growth inhibition, Daphnia immobility, and 96 h fish mortality). Compared with such lengthy toxicity tests, investigating toxicity based on motility requires a shorter test time. Therefore, this new indicator can be a rapid and effective bioassay trait to measure both single and combined toxicities of marine pollutants.