U.S. Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN, 55804, USA.
U.S. Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN, 55804, USA.
Aquat Toxicol. 2019 Jun;211:18-28. doi: 10.1016/j.aquatox.2019.03.008. Epub 2019 Mar 8.
The survival and growth of juvenile fathead minnows were investigated at various combinations of waterborne exposure to arsenate and of dietborne exposure to oligochaete worms which had been exposed to inorganic arsenic. Previous work with rainbow trout established that dietborne arsenic can reduce fish growth at environmentally relevant concentrations and could be more important than waterborne exposures. This was found to be less true for fathead minnows, which were less sensitive to dietborne exposures than rainbow trout, while being as or more sensitive to waterborne exposures. When assessed on the basis of accumulation of total As by the fish, further differences between fathead minnows and rainbow trout were evident. Fathead minnows accumulated relatively more arsenic from water versus diet than trout, and the accumulations at which growth effects occurred in minnows were different for dietborne and waterborne exposure, whereas they were the same for trout. These results suggest complex relationships involving arsenic speciation, toxicokinetics, and toxicodynamics, and underscore a need for care in relating effects information to real-world exposures. The present study also demonstrated the challenges in testing and interpreting growth effects in long-term exposures to fish, because the expression of toxicity can be confounded by the relationship of fish growth to size, the feeding regime, and wet weight versus dry weight relationships.
研究了在水中暴露于砷酸盐和通过饮食暴露于已接触无机砷的寡毛类蠕虫的不同组合对幼年黑头呆鱼的存活和生长的影响。之前对虹鳟鱼的研究表明，饮食中的砷可以在与环境相关的浓度下降低鱼类的生长速度，而且比水暴露更为重要。然而，这对于黑头呆鱼来说并不那么正确，与虹鳟鱼相比，它们对饮食暴露的敏感性较低，而对水暴露的敏感性则相同。根据鱼类对总砷的积累来评估，黑头呆鱼和虹鳟鱼之间存在进一步的差异。与鱼相比，黑头呆鱼从水中和饮食中积累的砷相对较多，而且在 minnows 中发生生长效应的积累水平因饮食和水暴露而不同，而在 trout 中则相同。这些结果表明涉及砷形态、毒代动力学和毒效动力学的复杂关系，并强调需要谨慎将影响信息与实际暴露联系起来。本研究还表明，在对鱼类进行长期暴露测试和解释生长效应方面存在挑战，因为毒性的表达可能会受到鱼类生长与大小、饲养制度以及湿重与干重关系的影响。
