Fuad Nafis, Williams Rebecca, Vadas Timothy M
Department of Civil and Environmental Engineering, College of Engineering, University of Connecticut, Storrs-Mansfield, CT 06269, USA.
Department of Civil, Construction and Environmental Engineering, College of Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Toxics. 2024 Aug 20;12(8):608. doi: 10.3390/toxics12080608.
The most up-to-date regulatory guidelines for establishing acute and chronic numeric limits for copper in freshwaters are based on a biotic ligand model for various species, but the model for Cu lacks data on dietary uptake. In addition, some common macroinvertebrate toxicity assay parameters are less representative of the ecosystem. We investigated the effects of diet and its type in the experimental setup and as an exposure pathway to an established amphipod (crustacean) () for Cu toxicity assays. We also investigated another overlooked aspect, the organic matter (OM) source. Our experiments compared the toxicity of pre-equilibrated and unequilibrated natural diets and a laboratory-favored diet in effluent and stormwater sources of organic matter adjusted to standard water characteristics. The experiments indicated a more toxic effect of the pre-equilibrated diet and natural dietary sources, and less toxic effects in the presence of effluent OM compared with stormwater OM, shifting LC50 or EC20 values by as much as 67% compared with the controls. The use of a pre-equilibrated natural diet in toxicity assays provides the advantage of producing toxicity data more representative of field conditions. Considering organic matter type, especially in dietary exposures, will better predict toxicity, accounting for copper complexation with OM from different sources and partitioning to the food supply. Adapting these ecologically relevant parameters in whole effluent toxicity testing or other assays will also provide safer regulatory oversite of discharges to surface waters.
制定淡水铜急性和慢性数值限值的最新监管指南基于各种物种的生物配体模型，但铜的模型缺乏饮食摄取方面的数据。此外，一些常见的大型无脊椎动物毒性试验参数对生态系统的代表性较差。我们在实验设置中研究了饮食及其类型的影响，并将其作为一种暴露途径应用于已确定的用于铜毒性试验的双壳类动物（甲壳纲）。我们还研究了另一个被忽视的方面，即有机物质（OM）来源。我们的实验比较了预平衡和未平衡的天然饮食以及实验室常用饮食在调整为标准水特征的流出物和雨水有机物质来源中的毒性。实验表明，预平衡饮食和天然饮食来源的毒性作用更强，与雨水有机物质相比，流出物有机物质存在时的毒性作用较小，与对照组相比，半数致死浓度（LC50）或半数效应浓度（EC20）值变化高达67%。在毒性试验中使用预平衡的天然饮食具有产生更能代表现场条件的毒性数据的优势。考虑有机物质类型，尤其是在饮食暴露中，将能更好地预测毒性，这涉及到铜与不同来源的有机物质的络合以及在食物供应中的分配。在全流出物毒性测试或其他试验中采用这些与生态相关的参数，也将为向地表水排放提供更安全的监管监督。
