Persistent organic pollutants (POPs) in deep-sea sediments of the tropical western Pacific Ocean

Persistent organic pollutants (POPs) are toxic compounds that can persist for extended periods in the environment. The marine environment is considered an important sink for POPs. However, information regarding POPs in deep-sea environments remains limited. In this study, surface sediments from depths below 2,000 m were collected in the western Pacific Ocean to analyze polycyclic aromatic hydrocarbons (PAHs), organic pesticides, and polychlorinated biphenyls (PCBs). The concentrations of PAHs were highest (5.2–24.6 ng g−1 dw). Hexachlorocyclohexanes (HCHs) were the predominant organic pesticide (30–1,730 pg g−1 dw). Dicofol, chlorpyrifos, and malathion were detected only at a few sites. PCBs were not detected in the study area. A principal component analysis with multiple linear regression (PCA-MLR) indicated that PAHs in sediments mainly originated from biomass and coal combustion (∼62%) and petrogenic (∼38%) sources. This study revealed the distribution and potential sources of POPs in sediments of a deep-sea region in the western Pacific Ocean. Further studies of the transformations, sedimentation, and biological interactions of POPs are needed to better understand the fates of POPs in the marine environment and the ecological risks they pose. [Display omitted] •PAHs, PCBs and pesticides were analyzed in sediments of the western Pacific.•PAHs were the most abundant compounds while PCBs were not detected.•PAH concentrations were orders of magnitude greater than pesticide concentrations.•PAHs likely came mostly from biomass combustion and petrogenic sources.