A review of organophosphate esters in Chinese agricultural soil–crop systems: Structure-oriented occurrence, bioaccumulation, and phytotoxicity

Abstract

Organophosphate esters (OPEs) are pervasive industrial additives that accumulate in agricultural soils, which serve as the primary interface for transfer into food crops. Despite their ubiquity, systematic insights into contamination profiles, soil–crop relationships, and biological effects remain insufficient for accurate risk assessment. Focusing on datasets from China, this review synthesizes the occurrence, bioaccumulation, and phytotoxicity of chlorinated (Cl-), alkyl-, and aryl-OPEs in agroecosystems. Reported contamination levels in Chinese agricultural soils exhibit pronounced spatial heterogeneity, with significantly higher concentrations in agriculturally intensive eastern regions (such as Liaoning, Tianjin, and Zhejiang province), driven by intensive wastewater irrigation and plastic mulch application. OPE levels in crops generally correlate with soil concentrations, though the relationship is modulated by compound-specific properties and plant species. Contamination patterns follow a specific hierarchy (vegetables > cereals > other crops), with ΣCl-OPEs typically dominating. Bioaccumulation of OPEs is largely governed by octanol–water partition coefficient (logKow) and molecular weight (MW), resulting in preferential partitioning of Cl-OPEs into hydrophilic compartments, alkyl-OPEs into structural matrices such as cell walls, and aryl-OPEs into lipid-rich root tissues. Biotransformation proceeds via coordinated phase I and phase II pathways, involving hydroxylation, hydrolysis, and conjugation reactions. Cl-OPEs tend to undergo dichlorination, aryl-OPEs form more polar metabolites, and alkyl-OPEs yield structurally diverse transformation products. Chronic exposure to OPEs and their metabolites induces oxidative stress, growth inhibition, and photosynthetic disruption in plants, potentially exceeding intrinsic detoxification capacities. Overall, this review highlights the structure-governed environmental fate and biological effects of OPEs in soil–crop systems and underscores the importance of integrating congener-specific prioritization, soil–plant transfer assessment, and transformation product monitoring for improved risk management in agricultural environments.