Occurrence, Source Apportionment, and Risk Assessment of Organophosphate Esters in Zhuozhang River, North China

As the primary substitutes for traditional brominated flame retardants, organophosphate esters (OPEs) are widely employed in industrial manufacturing and consumer products, and they have been detected in most rivers across China. The Zhuozhang River, a major tributary of the Haihe River, is situated in a region characterized by intensive anthropogenic activities and water scarcity. Nevertheless, research on OPE contamination and its associated environmental impacts in the Zhuozhang River basin remains limited. To address this knowledge gap, this study investigated the occurrence, sources, and ecological risks of 12 OPEs in water samples collected from representative sites, including major reservoirs, upstream river sections, main river channels, and wastewater treatment plants. The results showed that tris(2-chloroethyl) phosphate (TCEP) and triethyl phosphate (TEP) were the dominant compounds by mass, with concentrations ranging from 1108 to 1977 ng/L and 202 to 238 ng/L in the mainstream. Ecological risk assessment using the RQ method revealed that EHDPP and TDCIPP fall into the moderate-risk category. The positive matrix factorization (PMF) model was applied to explore the sources of OPEs. The results show that plastic-related industries most likely serve as the dominant contributors to OPE contamination.