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Abstract：
Worldwide, cyanobacterial blooms have been increasing in intensity and frequency, with toxic cyanobacteria sometimes dominant throughout the year in many freshwater bodies. Since the coexistence of more than one type of cyanotoxins in freshwater environments is a common phenomenon, studies on the joint effects of these toxins would be very useful. In this study, the single and combined effects of two cyanotoxins with different modes of action (hepatotoxic and neurotoxic) on the survival (lethal exposure) and feeding (sublethal exposure) of the cladoceran Daphnia magna were investigated. With the single exposures, it was observed that both the survival and feeding activity of the daphnids were impaired by the hepatotoxic and neurotoxic extracts at environmentally relevant concentrations. In the combined exposures, both survival and feeding rate endpoints showed a good fit to the independent action model. For the acute assay and 24h exposure period in the feeding inhibition test, there was no interaction between components of the hepatotoxic and neurotoxic extracts, although a slight tendency to a synergistic deviation could be seen in the feeding rates. On the other hand, for the 4h post-exposure period, a synergistic deviation was found in feeding rates at all mixture concentrations tested. Hence, the combined exposure of hepatotoxins and neurotoxins should also be taken into account in risk assessments of freshwater bodies, since the mixture of these toxins can result in more severe post-exposure effects on the feeding of daphnids than the sum of those expected for single exposures.
摘要：
全球,蓝藻水华的强度和频率一直在增加，有毒的蓝细菌有时全年在许多淡水体内占主导地位。由于淡水环境中一种以上的氰基毒素共存是一种普遍现象，研究这些毒素的联合作用将是非常有用的。在这项研究中,研究了两种具有不同作用方式（肝毒性和神经毒性）的氰化毒素对克拉多角虫大型蚤的存活（致死性暴露）和摄食（亚致死性暴露）的单一和联合作用。随着单次曝光，观察到，在环境相关浓度下，肝毒性和神经毒性提取物会损害水蚤的存活和摄食活性。在组合曝光中，存活率和摄食率终点均显示出与独立作用模型的良好拟合.对于摄食抑制试验中的急性测定和24h暴露期，肝毒性和神经毒性提取物的成分之间没有相互作用，尽管在喂食率方面可以看到轻微的协同偏差趋势。另一方面,对于暴露后的4h，在所有测试的混合物浓度下，喂食率都存在协同偏差。因此，在淡水水体的风险评估中也应考虑肝毒素和神经毒素的联合暴露，因为这些毒素的混合物会导致更严重的暴露后对水蚤的摄食影响比预期的单一暴露的总和。
