Phthalate and non-phthalate plasticizers co-occur in soils and reshape microbial carbon metabolism

Phthalate esters (PAEs) are widely used plasticizers with well-documented ecological effects. The increasing use of non-phthalate plasticizers (NPAEs) as alternatives to PAEs has resulted in their co-occurrence in the environment, yet their co-contamination and microbial impacts in soils influenced by plastic production remain poorly understood. Here, a field survey around a plastic industrial area revealed that concentrations of PAEs (306-10,718 ng g^-1) and NPAEs (20.3-380 ng g^-1) in factory soils were an order of magnitude higher than those in nearby farmlands and villages. Di-2-ethylhexyl phthalate (DEHP, 17.6-9280 ng g^-1) and acetyl tributyl citrate (ATBC, 1.19-233 ng g^-1) were the dominant PAE and NPAE compounds, respectively. A 28-day microcosm experiment examined their combined effects on soil bacterial communities and functions. DEHP contamination individually enriched aromatic degradation pathways (i.e., benzoate/styrene degradation), whereas DEHP-ATBC co-contamination inhibited the aromatic degradation pathway, potentially associated with altered microbial carbon-utilization preferences, with Sphingomonas as a key functional taxon. Co-contamination also suppressed core carbon metabolism (i.e., citrate cycle), and enriched the ribosome pathway, indicating a shift toward fast‑growing, metabolically streamlined taxa. These findings provide the first evidence that PAE-NPAE co-contamination reshapes microbial carbon metabolism and impairs aromatic compound degradation, underscoring the need for mixture-based risk assessment for plasticizers.