GEOMAR Helmholtz Centre for Ocean Research Kiel Wischhofstr. 1-3, 24148 Kiel, Germany.
Institute of Environmental Science and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan.
J Chem Inf Model. 2024 Aug 26;64(16):6492-6505. doi: 10.1021/acs.jcim.4c00574. Epub 2024 Aug 9.
We developed a Target Plastic Model (TPM) to estimate the critical plastic burden of organic toxicants in five types of plastics, namely, polydimethylsiloxane (PDMS), polyoxymethylene (POM), polyacrylate (PA), low-density polyethylene (LDPE), and polyurethane ester (PU), following the Target Lipid Model (TLM) framework. By substituting the lipid-water partition coefficient in the TLM with plastic-water partition coefficients to create TPM, we demonstrated that the biomimetic nature of these plastic phases allows for the calculation of critical plastic burdens of toxicants, similar to the notion of critical lipid burdens in TLM. Following this approach, the critical plastic burdens of baseline ( = 115), less-inert ( = 73), and reactive ( = 75) toxicants ranged from 0.17 to 51.33, 0.04 to 26.62, and 1.00 × 10 to 6.78 × 10 mmol/kg of plastic, respectively. Our study showed that PDMS, PA, POM, PE, and PU are similar to biomembranes in mimicking the passive exchange of chemicals with the water phase. Using the TPM, median lethal concentration (LC) values for fish exposed to baseline toxicants were predicted, and the results agreed with experimental values, with RMSE ranging from 0.311 to 0.538 log unit. Similarly, for the same data set of baseline toxicants, other widely used models, including the TLM (RMSE: 0.32-0.34), ECOSAR (RMSE: 0.35), and the Abraham Solvation Model (ASM; RMSE: 0.31), demonstrated comparable agreement between experimental and predicted values. For less inert chemicals, predictions were within a factor of 5 of experimental values. Comparatively, ASM and ECOSAR showed predictions within a factor of 2 and 3, respectively. The TLM based on phospholipid had predictions within a factor of 3 and octanol within a factor of 4, indicating that the TPM's performance for less inert chemicals is comparable to these established models. Unlike these methods, the TPM requires only the knowledge of plastic bound concentration for a given plastic phase to calculate baseline toxic units, bypassing the need for extensive LC and plastic-water partition coefficient data, which are often limited for emerging chemicals. Taken together, the TPM can provide valuable insights into the toxicities of chemicals associated with environmental plastic phases, assisting in selecting the best polymeric phase for passive sampling and designing better passive dosing techniques for toxicity experiments.
我们开发了一种目标塑料模型（TPM），以根据目标脂质模型（TLM）框架，估计五种类型塑料（聚二甲基硅氧烷（PDMS）、聚甲醛（POM）、聚丙烯酸酯（PA）、低密度聚乙烯（LDPE）和聚氨基甲酸酯酯（PU））中有机毒物的临界塑料负荷。通过将 TLM 中的脂水分配系数替换为塑料-水分配系数来创建 TPM，我们证明这些塑料相的仿生特性允许计算毒物的临界塑料负荷，类似于 TLM 中临界脂质负荷的概念。按照这种方法，基线（= 115）、低惰性（= 73）和反应性（= 75）毒物的临界塑料负荷范围分别为 0.17 至 51.33、0.04 至 26.62 和 1.00×10 至 6.78×10 mmol/kg 塑料。我们的研究表明，PDMS、PA、POM、PE 和 PU 与生物膜类似，可模拟化学物质与水相的被动交换。使用 TPM 预测了暴露于基线毒物的鱼类的中位致死浓度（LC）值，结果与实验值一致，RMSE 范围为 0.311 至 0.538 对数单位。同样，对于相同的基线毒物数据集，其他广泛使用的模型，包括 TLM（RMSE：0.32-0.34）、ECOSAR（RMSE：0.35）和 Abraham 溶剂化模型（ASM；RMSE：0.31），实验值与预测值之间的一致性也相当。对于低惰性化学品，预测值在实验值的 5 倍以内。相比之下，ASM 和 ECOSAR 的预测值分别在 2 倍和 3 倍以内。基于磷脂的 TLM 的预测值在 3 倍以内，辛醇在 4 倍以内，表明 TPM 对低惰性化学品的性能与这些成熟模型相当。与这些方法不同，TPM 仅需要给定塑料相的塑料结合浓度的知识即可计算基线毒物单位，而无需广泛的 LC 和塑料-水分配系数数据，这些数据对于新兴化学品通常是有限的。总的来说，TPM 可以为与环境塑料相相关的化学品的毒性提供有价值的见解，有助于选择用于被动采样的最佳聚合相，并设计用于毒性实验的更好的被动给药技术。
