Zhang Lilan, Niu Junfeng, Wang Yujuan, Shi Jianghong, Huang Qingguo
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
Chemosphere. 2014 Nov;114:114-20. doi: 10.1016/j.chemosphere.2014.03.099. Epub 2014 May 13.
Rotifers play an important role in the dynamics of freshwater and coastal marine ecosystems, and are also important tools for assessing toxicity in aquatic environments. In this study, the effects of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) on the population growth rate and resting egg production of rotifer Brachionus calyciflorus were investigated. Reproductive bioassays indicated that PFOS increased the rotifer population growth rate at the concentration ⩽2.0 mg L(-1), and inhibited it at higher concentrations. For PFOA, the inhibition of population growth rate was observed when the concentration was greater than 4.0 mg L(-1). Exposure to PFOS (0.25 mg L(-1)) or PFOA (2.0 mg L(-1)) increased the mictic ratios of unexposed rotifer offspring. Population variation and increased mictic ratios were likely the two major factors leading to decline of resting egg production. The resting eggs formed under exposure to PFOA/PFOS in the range of 0.125-2.0 mg L(-1) showed higher hatching percentages in the control medium than that without PFOA/PFOS exposure. When the resting eggs were formed in the control medium and incubated in media with different levels of PFOA/PFOS, higher hatching percentages were induced by PFOS but lower hatching percentages induced by PFOA. The effects on the hatching rate of resting eggs with PFOA/PFOS exposure during the hatching period were greater than those with exposure during resting egg formation period, and the effect of PFOS was greater than that of PFOA. Both PFOA and PFOS exhibited slight effect on the hatching pattern.
轮虫在淡水和沿海海洋生态系统的动态变化中发挥着重要作用，也是评估水生环境毒性的重要工具。在本研究中，调查了全氟辛烷磺酸（PFOS）和全氟辛酸（PFOA）对萼花臂尾轮虫种群增长率和休眠卵产量的影响。生殖生物测定表明，PFOS在浓度≤2.0 mg L(-1)时提高了轮虫种群增长率，而在较高浓度时则抑制了该增长率。对于PFOA，当浓度大于4.0 mg L(-1)时观察到种群增长率受到抑制。暴露于PFOS（0.25 mg L(-1)）或PFOA（2.0 mg L(-1)）会增加未暴露轮虫后代的混交率。种群变化和混交率增加可能是导致休眠卵产量下降的两个主要因素。在0.125 - 2.0 mg L(-1)范围内暴露于PFOA/PFOS形成的休眠卵，在对照培养基中的孵化率高于未暴露于PFOA/PFOS的情况。当休眠卵在对照培养基中形成并在含有不同水平PFOA/PFOS的培养基中孵化时，PFOS诱导的孵化率较高，而PFOA诱导的孵化率较低。在孵化期暴露于PFOA/PFOS对休眠卵孵化率的影响大于在休眠卵形成期暴露的影响，且PFOS的影响大于PFOA。PFOA和PFOS对孵化模式的影响均较小。
