绿色石化项目邻近海域表层沉积物PAHs分布及年际变化

Distribution and interannual changes of PAHs in surface sediments from the adjacent waters of the green petrochemical project

为评估绿色石化项目运营前后的环境变化,于2018—2021年连续4年对项目所在地鱼山岛邻近海域的表层沉积物多环芳烃(PAHs)进行了调查。结果表明,PAHs含量为16.9~178.0μg·kg^(-1),平均值为75.9±24.0~102.6±41.4μg·kg^(-1),4年来整体呈下降趋势,与国内其他海区相比,总体含量较低;各组分平均值为4环PAHs>5环PAHs>3环PAHs>6环PAHs>2环PAHs。调查海域表层沉积物以粉砂为主,PAHs的空间分布受到多种因素的综合影响。调查海域PAHs来源相对稳定,年际差异较小,主要来源于石油、木柴、煤炭等燃烧产物的远距离迁移。依据沉积物质量基准法评价,调查海域沉积物PAHs生态风险水平较低。绿色石化项目在建设期及投产期未引起邻近海域沉积物PAHs的增加,但随着项目持续运营,其对周边生态环境的影响需持续关注。

To evaluate the environmental changes before and after the operation of the green petrochemical project,polycyclic aromatic hydrocarbons(PAHs)in the surface sediments of the adjacent sea area of Yushan Island where the project is located,were investigated and monitored for four consecutive years from 2018 to 2021.The results showed the total PAHs contents ranged from 16.9 to 178.0μg·kg^(-1)with the average content of 75.9±24.0-102.6±41.4μg·kg^(-1),showing an overall downward trend over the past four years,with a lower overall concentration compared to other sea areas in China.The average content of different PAHs components in the investigated surface sediments from high to low were:4 rings PAHs,5 rings PAHs,3 rings PAHs,6 rings PAHs and 2 rings PAHs.The surface sediments of the surveyed sea area was mainly composed of silt,and the spatial distribution of PAHs was influenced by various factors.The sources of PAHs in the surveyed sea area were relatively stable,with small interannual differences,mainly originating from the long-distance migration of combustion products of substances such as oil,firewood,and coal.According to the sediments quality baseline method evaluation,the ecological risk level of PAHs in the surveyed sea area sediments was relatively low.The green petrochemical project did not cause an increase in PAHs of sediments in adjacent sea areas during the construction and production periods.However,as the project continues to operate,its impact on the surrounding ecological environment still needs to be continuously monitored.