Turesson Eva Ulfsdotter, Stiernström Sara, Minten Johanna, Adolfsson-Erici Margaretha, Bengtsson Bengt-Erik, Breitholtz Magnus
Department of Applied Environmental Science, Stockholm University, S-106 91 Stockholm, Sweden.
Aquat Toxicol. 2007 Jul 20;83(3):180-9. doi: 10.1016/j.aquatox.2007.04.002. Epub 2007 Apr 8.
Both freshwater and marine sediments are sinks for many anthropogenic substances. This may pose a risk to benthic and epibenthic organisms and it is crucial that toxicity tests that are available for environmental risk assessment can identify potentially adverse effects of sediment-associated substances on benthic organisms, such as harpacticoid copepods. While marine harpacticoids have been protected via a number of acute and chronic sediment tests, the freshwater harpacticoid copepod community has so far been neglected in such activities. The main aim of the present study was therefore to (a) find a suitable freshwater harpacticoid copepod, (b) establish robust laboratory mass cultures and (c) develop a chronic test for assessment of sediment-associated toxicity using spiked sediments. After several cultivation trials with a number of potential test species, the choice fell on the benthic freshwater harpacticoid copepod Attheyella crassa, a species that possesses many of the characteristic features identified as prerequisites for toxicity test organisms, e.g. it has a sexual reproduction, it is relatively easy to grow and keep in mass cultures in the laboratory, and it has a small body size. Owing to the relatively long generation time of freshwater harpacticoids (in relation to many marine harpacticoids), it was decided that the test should be separated into a development part (21 days) and a reproduction part (14 days) running in parallel. As a reference substance we used the fungicide tebuconazole, which is currently subject to risk assessment and which partitions to soil and sediment. Clear concentration-related responses were observed for all endpoints analyzed. Nauplia body length was the most sensitive endpoint with a measured time weighted LOEC(water) of 20microg/L. The corresponding LOEC(water) for larval mortality and offspring production was 65 and 62microg/L, respectively. In conclusion, A. crassa is an ecologically relevant test species for freshwater ecosystems and particularly for the cold, oligotrophic and often acidic lakes of Northern Europe. Regardless of the relatively long generation time of this species, our results clearly show that sediment-associated toxicity related to development and sexual reproduction can be assessed within 2-3 weeks exposure with the developed bioassay.
淡水和海洋沉积物都是许多人为物质的汇。这可能对底栖生物和浅海生物构成风险，对于可用于环境风险评估的毒性测试而言，至关重要的是能够识别沉积物相关物质对底栖生物（如猛水蚤）的潜在不利影响。虽然通过一些急性和慢性沉积物测试对海洋猛水蚤进行了保护，但淡水猛水蚤群落迄今为止在这些活动中一直被忽视。因此，本研究的主要目的是：（a）找到一种合适的淡水猛水蚤；（b）建立稳定的实验室大规模培养体系；（c）开发一种使用加标沉积物评估沉积物相关毒性的慢性测试方法。在用多种潜在测试物种进行了多次培养试验后，选定了底栖淡水猛水蚤粗壮阿特柔猛水蚤，该物种具有许多被确定为毒性测试生物必备的特征，例如它进行有性繁殖，相对容易在实验室大规模培养中生长和饲养，且体型较小。由于淡水猛水蚤的世代时间相对较长（与许多海洋猛水蚤相比），因此决定将测试分为并行进行的发育部分（21天）和繁殖部分（14天）。作为参考物质，我们使用了杀菌剂戊唑醇，该物质目前正在进行风险评估，且会在土壤和沉积物中分配。对于所有分析的终点均观察到了明显的浓度相关反应。无节幼体体长是最敏感的终点，测得的时间加权最低有效应浓度（水相）为20微克/升。幼虫死亡率和后代产量的相应最低有效应浓度（水相）分别为65和62微克/升。总之，粗壮阿特柔猛水蚤是淡水生态系统，特别是北欧寒冷、贫营养且常呈酸性的湖泊的一种具有生态相关性的测试物种。尽管该物种的世代时间相对较长，但我们的结果清楚地表明，通过所开发的生物测定法，在2至3周的暴露时间内即可评估与发育和有性繁殖相关的沉积物毒性。
