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This study conducted the first extensive and comprehensive investigation of the regional‐scale sedimentary polycyclic aromatic hydrocarbons (PAHs) concentration, flux, and budget in the continental shelves of the Eastern China Marginal Seas (ECMSs). Surface sediment samples from multiple sites were collected and assessed, and the latest data from current research were assessed. The spatial distribution pattern of PAHs in the ECMSs was significantly influenced by the regional hydrodynamics, sediment properties (grain‐size, total organic carbon [TOC] content, and sedimentation rate), and anthropogenic impacts. Relatively higher PAHs concentrations occurred in areas with fine‐grained sediment. Results of source apportionment found that the relative proportions of PAHs showed significant regional variation, mainly influenced by socioeconomic differences between north and south China. The PAHs burial flux in the study area ranged from 11.2 to 1308 ng cm−2 yr−1 with an average value of 101 ± 104 ng cm−2 yr−1. The area‐integrated sedimentary PAHs burial flux across the ECMSs was 494 t yr−1. A mass budget calculation revealed that riverine input and atmospheric deposition were the most significant sources contributing, 28.4% and 71.6%, respectively. The study demonstrated that net PAHs transportation occurs between the Bohai Sea (BS) and Yellow Sea (YS), with a flux of approximately 10.2 t yr−1. PAHs were also transported from YS to the East China Sea (ECS), due to water exchange between the YS and ECS. Additionally, substantial amounts of PAHs in the inner shelf of the ECS were transported out of the shelf area due to cross‐shelf plume.

Fourteen surface water and nine surface sediment samples were collected from the Peacock River and analyzed for organochlorine pesticides (OCPs) by gas chromatograph-electron capture detector (GC-ECD). All the analyzed organochlorine pesticides, except o,p'-DDT, were detected in sediments from the Peacock River; but in the water samples, only β-HCH, HCB, p,p'-DDD, and p,p'-DDT were detected at some sites. The ranges for total OCPs in the water and sediments were from N.D. to 195 ng l( - 1) and from 1.36 to 24.60 ng g( - 1), respectively. The only existing HCH isomer in the water, β-HCH, suggested that the contamination by HCHs could be attributed to erosion of the weathered agricultural soils containing HCHs compounds. Composition analyses showed that no technical HCH, technical DDT, technical chlordanes, endosulfans, and HCB had been recently used in this region. However, there was new input of γ-HCH (lindane) into the Peacock River. The most probable source was water flowing from Bosten Lake and/or agricultural tailing water that was returned directly into the Peacock River. DDT compounds in the sediments may be derived mainly from DDT-treated aged and weathered agricultural soils, the degradation condition was aerobic and the main product was DDE. HCB in the sediment might be due to the input from Bosten Lake and the lake may act as an atmospheric deposition zone. There was no significant correlation between the concentrations of OCPs (including ∑HCH, ∑DDT, chlordanes, endosulfans, HCB and total OCPs) and the content of fine particles (<63 μm). The concentrations of OCPs were affected by salinity.

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