Work

Co-occurrence of multiple contaminants: Unentangling adsorption behaviour in agricultural soils

Year: 2025

Type: article

Abstract: The cooccurrence of pesticides, pharmaceuticals, and MPs has resulted in combined toxicity and high risk to ecosystems and human health. Unfortunately, the understanding of interactions among these cooccurring pollutants in soil is still limited. This study focused on adsorption behaviour of pesticide mixture (chlorpyrifos (CPF), pendimethalin (PDM) and pyraclostrobin (PCS)) in three soils (sandy soil (S1), loamy soil (S2), and clay soil (S3)) to examine the absorption behaviour of pesticides in the presence of pharmaceutical compound albendazole (ALB) and starch-based microplastics (MPs). The results showed that ALB significantly decreased the adsorption of CPF, PDM, and PCS by 29% - 41% in S1. The adsorption of CPF (+20%) and PCS (+101%) in S2 were significantly (p < 0.05) enhanced but PDM (-22%) adsorption were inhibited by ALB. ALB also significantly (p < 0.05) promoted the CPF and PCS adsorption in S3 by 39% and 120%, respectively, while didn’t change PDM adsorption. In soil-MP matrices, ALB significantly reduced the adsorption of CPF (-25%), PDM (-26%), and PCS (-21%) in S1-MP matrix, but no significant change in S2 and S3-MP matrices was observed. Moreover, MPs significantly increased the adsorption of pesticide mixture by 78%-340%, but reduced ALB adsorption by 11-24% in soils. Further, regardless of ALB presence, the correlation analysis suggested that Kd of pesticides showed positive correlation (p < 0.01) to soil organic matter, specific surface area, and clay content in soil matrices without MP-contamination, while no significantly positive correlation between Kd of pesticides and soil properties was observed in soil-MPs matrices. This study indicates that the cooccurring pollutants could alter the adsorption behaviour of pesticides in soil, and thereby affect their bioavailability and mobility in soil ecosystem. Further study is urgently needed to assess the toxicity of cooccurrence multi-contaminants, as well as their potential transport to other environmental compartments.

Source: Environmental Pollution

DOI: 10.1016/j.envpol.2025.126118