几类有机污染物的微塑料/水分配系数的线性溶解能关系模型

水体中的微塑料会吸附其中的有机污染物,影响有机污染物和微塑料的环境归趋和生态毒性。研究微塑料对有机污染物的吸附行为,对于评价有机污染物和微塑料的环境赋存、迁移及生物有效性有重要意义。污染物在微塑料与水之间的平衡分配系数(Kd),是表征微塑料对有机污染物吸附能力的重要参数。实验方法难以逐个测定众多有机污染物的Kd值,有必要发展其预测模型。本研究搜集了有机污染物的线性溶解能关系(LSER)参数及Kd值,构建了可预测有机污染物在聚丙烯微塑料与海水、聚乙烯微塑料与海水、聚乙烯微塑料与淡水之间Kd值的LSER模型。模型具有良好的拟合优度(R2adj介于0.794~0.903)、稳健性(Q2LOO和Q2BOOT分别介于0.763~0.863和0.720~0.804)和预测能力(R2ext和Q2ext分别介于0.886~0.971和0.825~0.954),能够用于预测多氯联苯、多环芳烃、六氯环已烷和氯苯类有机污染物的Kd值。

LSER Models for Several Classes of Organic Pollutants Partitioning between Microplastics and Water

Organic pollutants in the aquatic environment can be sorbed by microplastics, and this sorption could affect the environmental fate and ecotoxicity of both microplastics and organic pollutants. It is of importance to investigate the sorption of organic pollutants to microplastics for assessing the environmental occurrence, migration and bioavailability of both organic pollutants and plastic debris. The equilibrium coefficient of organic pollutants partitioning between microplastics and water (K_d) indicates sorption capacity. Experimentally determination of K_d values is costly, laborious and time intensive. It is necessary to develop in silico models for predicting K_d values. In this study, the linear solvation energy relationship (LSER) molecular parameters and K_d values of organic pollutants were collected. LSER models were developed for K_d of organic pollutants partitioning between polypropylene and sea water, polyethylene and sea water, and polyethylene and fresh water. For the developed models, the adjusted determination coefficient (R²_adj) range from 0.794 to 0.903; the leave-one-out cross-validated correlation coefficient (Q² (Q²_LOO) and bootstrap method correlation coefficient (Q² (Q²_BOOT) range from 0.763 to 0.863 and from 0.720 to 0.804, respectively; the external R²(R²_ext) and Q²(Q²_ext) range from 0.886 to 0.971 and from 0.825 to 0.954, respectively. Thus, the developed models have high goodness of fit, robustness and predictive ability, and can be used to predict K_d values of organic chemicals including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, hexachlorocyclohexanes and chlorobenzenes.