Ashauer Roman, Boxall Alistair B A, Brown Colin D
Environment Department, University of York, Heslington, York, YO10 5DD, United Kingdom.
Environ Sci Technol. 2007 Aug 1;41(15):5528-34. doi: 10.1021/es062977v.
Aquatic nontarget organisms are typically exposed to sequential pulses of contaminants with fluctuating concentrations. We use the semimechanistic threshold damage model (TDM) to simulate survival of the aquatic invertebrate Gammarus pulex after sequential pulsed exposure to carbaryl and compare itto a simpler model based on time-weighted averages (TWA). The TDM is a process-based model and we demonstrate how to parametrize it with data from an uptake and elimination experimenttogether with data from a survival experiment with sequential pulses. The performance of the two models is compared by the fit to the first survival experiment and the simulation of another, independent survival experiment with different exposure patterns. Measured internal concentrations in the first survival experiment are used to evaluate the toxicokinetic submodel of the TDM. The TDM outperforms the TWA model, facilitates understanding of the underlying ecotoxicological processes, permits calculation of recovery times (3, 15, and 25 days for pentachlorophenol, carbaryl and chlorpyrifos respectively) and enables us to predict the effects of long-term exposure patterns with sequential pulses or fluctuating concentrations. We compare the parameters of the TDM for carbaryl, pentachlorophenol and chlorpyrifos and discuss implications for ecotoxicology and risk assessment.
水生非靶标生物通常会接触到浓度波动的连续污染物脉冲。我们使用半机理阈值损伤模型（TDM）来模拟水生无脊椎动物蚤状溞在连续脉冲暴露于西维因后的存活情况，并将其与基于时间加权平均值（TWA）的更简单模型进行比较。TDM是一个基于过程的模型，我们展示了如何根据摄取和消除实验的数据以及连续脉冲存活实验的数据对其进行参数化。通过对第一个存活实验的拟合以及对另一个具有不同暴露模式的独立存活实验的模拟，比较了这两个模型的性能。第一个存活实验中测得的体内浓度用于评估TDM的毒代动力学子模型。TDM的性能优于TWA模型，有助于理解潜在的生态毒理学过程，允许计算恢复时间（五氯苯酚、西维因和毒死蜱分别为3天、15天和25天），并使我们能够预测连续脉冲或浓度波动的长期暴露模式的影响。我们比较了西维因、五氯苯酚和毒死蜱的TDM参数，并讨论了其对生态毒理学和风险评估的意义。
