University of Aveiro, Department of Biology & CESAM, 3810-193, Aveiro, Portugal.
Department of Ecological Science. Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands.
Chemosphere. 2022 Mar;291(Pt 1):132751. doi: 10.1016/j.chemosphere.2021.132751. Epub 2021 Nov 1.
Chromium (Cr) has many applications in industry and day-to-day life, entering the terrestrial environment mostly from anthropogenic sources. Despite the fact that Cr is essential, it can be harmful in biota at high concentrations. Full life cycle tests (FLCt) are scarce, representing a gap for soil ecotoxicology. Hence, the effects of Cr were studied using the soil organism Enchytraeus crypticus in the 46-day FLCt and the standard 21-day enchytraeid reproduction test (ERT). FLCt hatching (day-11) and time to reach maturity (day 22-25) were the most sensitive endpoints, representing a delay, partly recovered with time. Reproduction was reduced to similar levels in both the ERT and the FLCt (EC∼320 mg Cr/kg), but survival was more affected in the ERT (LC = 377 mg Cr/kg) than in the FLC (LC = 467 mg Cr/kg). This could be due to the induction of stress response mechanisms at earlier life stages (cocoons/juveniles), providing protection to toxicity in a later stage (adults). FLCt results provided considerably more details and data points, and the additional endpoints allowed to explain the source of observed effects, e.g. a direct impact on fecundity and not only due to adult mortality. The estimated population growth curves confirmed the significant effect of 320 mg Cr/kg and onwards, reflecting the impact of Cr on both cocoon production and juvenile performance, with follow-up consequences for reproduction. An Adverse Outcome Pathway was drafted. The FLCt design is recommended as an upgrade of the current standard ERT, which could be integrated into the existing OECD ERT test guideline.
铬（Cr）在工业和日常生活中有许多应用，主要从人为源进入陆地环境。尽管铬是必需的，但在高浓度下它可能对生物群有害。全生命周期测试（FLCt）很少，这是土壤生态毒理学的一个空白。因此，使用土壤生物真涡虫在 46 天的 FLCt 和标准的 21 天真涡虫繁殖试验（ERT）中研究了 Cr 的影响。FLCt 孵化（第 11 天）和达到成熟所需的时间（第 22-25 天）是最敏感的终点，代表着延迟，随着时间的推移部分恢复。繁殖在 ERT 和 FLCt 中都降低到相似的水平（EC∼320mg Cr/kg），但在 ERT 中存活率受到的影响比在 FLCt 中更严重（LC = 377mg Cr/kg）。这可能是由于早期生命阶段（茧/幼体）诱导了应激反应机制，为后期（成虫）的毒性提供了保护。FLCt 结果提供了更多的细节和数据点，并且额外的终点允许解释观察到的效应的来源，例如对生殖力的直接影响，而不仅仅是由于成虫死亡率。估计的种群增长曲线证实了 320mg Cr/kg 及以上的显著影响，反映了 Cr 对茧生产和幼体性能的影响，对繁殖产生后续影响。起草了一个不良结局路径。建议将 FLCt 设计升级为当前标准 ERT，该 ERT 可集成到现有的 OECD ERT 测试指南中。
