Dissolved Ni concentrations inhibiting the growth of juvenile great pond snails (Lymnaea stagnalis) have been documented to vary from about 1 to 200 µg L⁻¹ Ni. This variability makes L. stagnalis either a moderately sensitive or the most sensitive freshwater species to chronic Ni exposure tested to date. Given the role of sensitive species in environmental risk assessment frameworks, it is particularly important to understand this variability, i.e., to characterize the factors that modulate Ni toxicity and that may confound toxicity test outcomes when uncontrolled. In the present study, we tested if this variability was due to analytical (growth calculation: biomass versus growth rate), environmental (water quality), lab‐specific practices, and/or snail population differences among earlier studies. Specifically, we reanalyzed previously published Ni toxicity data and conducted additional measurements of Ni aqueous speciation, short‐term Ni uptake, and chronic Ni toxicity with test waters and snail cultures used in previous studies. Corrections for Ni bioavailability and growth calculations explained a large degree of variability in the published literature. However, a residual 16‐fold difference remained puzzling between 2 studies: Niyogi et al. (2014) (low ECxs) and Crémazy et al. (2018) (high ECxs). Indeed, differences in metal bioavailability due to water chemistry, lab‐specific practices, and snail population sensitivity could not explain the large variation in Ni toxicity in these 2 very similar studies. Other potentially important toxicity‐modifying factors were not directly evaluated in the present work: test duration, diet, snail holding conditions, and snail age at onset of testing. The present analysis highlights the need for further studies to elucidate 1) the mechanisms of growth inhibition in Ni‐exposed L. stagnalis and 2) the important abiotic and biotic factors affecting this biological response. Until these processes are understood, substantial uncertainties will remain about inclusion of this species in Ni environmental risk assessment. Integr Environ Assess Manag 2020;16:983–997. © 2020 SETAC

中文翻译：

---

一个神秘的故事：当蜗牛失败时，镍是多变的，调查了镍对大池塘蜗牛的毒性变化。

业已证实，抑制幼大塘蜗牛（Lymnaea stagnalis）生长的溶解Ni浓度范围为1至200 µg L ^-1 Ni。这种变异性使胸骨乳杆菌迄今已测试的对慢性镍暴露的中度敏感或最敏感的淡水物种。考虑到敏感物种在环境风险评估框架中的作用，特别重要的是要了解这种变异性，即表征调节镍毒性的因素，并且在不受控制时可能混淆毒性测试结果。在本研究中，我们测试了这种差异是否是由于早期研究之间的分析性（增长计算：生物量与生长速率），环境（水质），特定于实验室的实践和/或蜗牛种群差异引起的。具体来说，我们重新分析了先前发表的Ni毒性数据，并使用先前研究中使用的试验水和蜗牛培养物对Ni的水形态，短期Ni摄取和慢性Ni毒性进行了其他测量。镍生物利用度和生长计算的校正解释了已发表文献中的很大程度的变异性。但是，两项研究之间仍然存在16倍的残差：Niyogi等。（2014）（低ECx）和Crémazy等。（2018）（高ECx）。确实，由于这两种非常相似的研究，由于水化学，实验室特定操作和蜗牛种群敏感性引起的金属生物利用度差异无法解释镍毒性的巨大差异。在本工作中，未直接评估其他可能重要的毒性改变因素：测试持续时间，饮食，蜗牛的保持状况和测试开始时的蜗牛年龄。本分析强调需要进一步研究阐明1）镍暴露下生长抑制的机制葡萄球菌和2）影响这种生物反应的重要非生物和生物因素。在不了解这些过程之前，对于将此类物质纳入Ni环境风险评估仍将存在很大的不确定性。Integr环境评估管理2020； 16：983–997。©2020 SETAC