Population models are increasingly being used to extrapolate individual-level effects of chemicals, including metals, to population-level effects. For metals, it is also important to take into account their bioavailability to correctly predict metal toxicity in natural waters. However, to our knowledge, no models exist that integrate metal bioavailability into population modeling. Therefore, our main aims were to 1) incorporate the bioavailability of copper (Cu) and zinc (Zn) into an individual-based model (IBM) of rainbow trout (Oncorhynchus mykiss), and 2) predict how survival-time concentration data translate to population-level effects. For each test water, reduced versions of the general unified threshold model of survival (GUTS-RED) were calibrated using the complete survival-time concentration data. The GUTS-RED individual tolerance (IT) showed the best fit in the different test waters. Little variation between the different test waters was found for 2 GUTS-RED-IT parameters. The GUTS-RED-IT parameter “median of distribution of thresholds” (m_w) showed a strong positive relation with the Ca²⁺, Mg²⁺, Na⁺, and H⁺ ion activities. Therefore, m_w formed the base of the calibrated GUTS bioavailability model (GUTS-BLM), which predicted 30-d x% lethal concentration (LCx) values within a 2-fold error. The GUTS-BLM was combined with an IBM, inSTREAM-Gen, into a GUTS-BLM-IBM. Assuming that juvenile survival was the only effect of Cu and Zn exposure, population-level effect concentrations were predicted to be 1.3 to 6.2 times higher than 30-d laboratory LCx values, with the larger differences being associated with higher interindividual variation of metal sensitivity. The proposed GUTS-BLM-IBM model can provide insight into metal bioavailability and effects at the population level and could be further improved by incorporating sublethal effects of Cu and Zn. Environ Toxicol Chem 2021;40:2764–2780. © 2021 SETAC

中文翻译：

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在鱼类种群模型中整合金属的生物利用度

人口模型越来越多地用于将包括金属在内的化学品的个体水平影响外推至人口水平影响。对于金属，考虑其生物利用度以正确预测天然水中的金属毒性也很重要。然而，据我们所知，不存在将金属生物利用度整合到人口建模中的模型。因此，我们的主要目标是 1) 将铜 (Cu) 和锌 (Zn) 的生物利用度纳入基于个体的虹鳟鱼 ( Oncorhynchus mykiss ) 模型 (IBM)) 和 2) 预测生存时间浓度数据如何转化为人口水平的影响。对于每种测试水，使用完整的生存时间浓度数据校准通用统一生存阈值模型 (GUTS-RED) 的简化版本。GUTS-RED 个体耐受性 (IT) 显示出在不同测试水域中的最佳拟合。对于 2 个 GUTS-RED-IT 参数，发现不同测试水之间的差异很小。GUTS-RED-IT 参数“阈值分布中位数”( m _w ) 与 Ca ²⁺、Mg ²⁺、Na ⁺和 H ⁺离子活性呈强正相关。因此，m _w形成了校准的 GUTS 生物利用度模型 (GUTS-BLM) 的基础，该模型在 2 倍误差内预测了 30-d x % 致死浓度 (LC x ) 值。GUTS-BLM 与 IBM inSTREAM-Gen 组合成 GUTS-BLM-IBM。假设青少年存活是铜和锌暴露的唯一影响，人口水平的影响浓度预计比 30 天实验室 LC x值高 1.3 至 6.2 倍，较大的差异与金属敏感性的个体间差异较大有关. 所提出的 GUTS-BLM-IBM 模型可以深入了解金属生物利用度和群体水平的影响，并且可以通过结合铜和锌的亚致死效应来进一步改进。环境毒物化学2021；40:2764–2780。© 2021 SETAC