Accounting for Molecular Weight Distribution Dynamics in the Environmental Fate Assessment of Water-Soluble Polymers

Water-soluble polymers (WSPs) are widely used in industrial and agricultural applications, as well as in consumer products. After use, they may be released into both engineered and natural environments, where their fate is governed by transfer and transformation processes which are strongly influenced by their molecular weight distribution (MWD). Unlike traditional low molecular weight organic chemicals, WSPs are ensembles of molecules with varying chain lengths. This work suggests the use of Monte Carlo (MC) simulations to model shifts in MWDs resulting from abiotic and biotic chain scission reactions in receiving environments. We specify key factors influencing chain-scission selectivity, including chain-end scissions, molecular weight-dependent scissions, and site-specific scissions. Experimental validation of MC simulation predictions presents analytical challenges, requiring high-resolution MWD characterization of WSPs and reliable extraction techniques from complex environmental matrices. MC simulations may play a pivotal role not only in identifying the most relevant molecular weight (MW) ranges for targeted analysis but also in predicting and elucidating environmental chain scission processes.