Distribution Characteristics and Pollution Sources Analysis of Polycyclic Aromatic Hydrocarbons and Phthalate Esters in the Seawater of Land-Based Outlets around Zhanjiang Bay in Spring

Abstract

This study analyzed the distribution characteristics and sources of pollutants in the coastal estuaries of Zhanjiang Bay (ZJB) to provide theoretical and data support for the scientific prevention and control of bay pollution. Monitoring data from eight rivers and flood drains flowing into ZJB in March 2021 were used to analyze the composition and spatial distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) in the water bodies of the bay. The dominant components in the eight rivers and flood drains were 3–4-ring PAHs, with Bis (2-ethylhexyl) phthalate (DEHP), Diisobutyl phthalate (DIBP), and Dibutyl-O-phthalate (DBP) being the main PAE compounds. Higher pollutant levels were observed in residential areas, aquaculture zones, and industrial areas. Eigen-ratio analysis and principal component analysis were used to identify pollution sources, including atmospheric inputs (coal, petroleum products, biomass combustion products), offshore petroleum pollution, and plastic pollution sources. The assessment showed that atmospheric inputs contributed to 89.75% of the total PAHs in the bay, with coal and biomass combustion accounting for 62.12% and petroleum fuel combustion accounting for 27.63%. The content of ΣPAEs ranged from 588.43 to 1427.26 ng·L−1, with a mean value of 906.59 ng·L−1, which is at a low to medium level compared to other regions of China and abroad, indicating a medium-low level of pollution risk. The results of this study have important implications for guiding urban development, adjusting energy consumption structures, and planning pollution prevention and control measures in ZJB.