Pollution characteristics, source apportionment, and ecological risks of phthalic acid esters (PAEs) in seawater and sediments of the Bohai Sea and Northern Yellow Sea, China

Phthalic Acid Esters (PAEs) are ubiquitous persistent organic pollutants posing significant risks to marine ecosystems and human health. This study investigated PAE pollution in seawater and sediments from 23 stations in the Bohai Sea and northern Yellow Sea China in May 2023. Total PAE concentrations ranged from 314.06 to 713.61 ng/L in seawater and from 1423.74 to 3052.93 ng/g dry weight (dw) in sediments, with Diisobutyl Phthalate (DiBP), Dibutyl Phthalate (DBP), and Bis(2-ethylhexyl) Phthalate (DEHP) as dominant components. Principal Component Analysis (PCA) identified three primary sources: industrial plastic input, domestic-fishery activities, and shipping-oil and gas development, with land-based input as the core driver. Ecological risk assessment using Risk Quotient (RQ) revealed DiBP as the high-risk monomer (RQ > 10 in coastal sediments), DBP and DEHP as medium-risk, and Dimethyl Phthalate (DMP)/Diethyl Phthalate (DEP) as low-risk. High-risk areas were concentrated in estuaries, Laizhou Bay, and coastal industrial belts. This study provides regional baseline data and fundamental insights for PAE pollution management and marine ecological protection in semi-enclosed seas.