Polychlorinated naphthalenes in Chinese coastal ecosystems: A review of their distribution, sources, and potential risks

Polychlorinated naphthalenes (PCNs) are a class of persistent organic pollutants (POPs) known for their persistence, toxicity, and bioaccumulative properties. This review summarizes the analytical methods, spatial distribution, emission sources, and associated risks of PCNs in Chinese coastal environments. PCNs in marine sediments are frequently detected along the mid-northern coastline of China, while concentrations of PCNs in marine biota are of less spatial variation. Source analyses indicate that combustion processes and unintentional releases from industrial thermal activities are the primary contributors. To assess potential risks from PCNs, toxic equivalent quotient (TEQ) is a commonly used tool, and the PCN TEQ values showed a generally decreasing trend in coastal sediments from south to north. To address the potential rise in unintentional PCN emissions, further research is needed to investigate their spatial and temporal dynamics across environmental matrices, particularly in seawater and sediment cores. Additionally, environmental modeling is essential to simulate the multimedia behavior and marine fate of PCNs, contributing to a more comprehensive understanding of their environmental impact and facilitating systematic risk assessments. © 2025 Elsevier Ltd