渤海海洋油气区邻近海域水质时空分布特征

Spatial and temporal distribution characteristics of seawater quality near the offshore oil and gas exploration zone in the Bohai Sea

利用2015-2020年渤海14个海洋油气区邻近海域表层海水污染要素监测结果,结合主成分综合评价法、相关性分析及空间可视化等方法分析了渤海海洋油气区邻近海域水质时空分布特征及污染贡献。结果表明:渤海中部油气区邻近海域水质状况优于辽东湾和渤海湾;位于辽东湾湾顶的油气区1号邻近海域海水水质综合评价结果最差,位于辽东湾湾口的油气区4号邻近海域结果最好,这可能与二者受陆源输入和水动力条件影响差异较大有关;此外,与汞(Hg)相比,化学需氧量(COD)、石油类、镉(Cd)含量受陆源输入的影响较大,油气平台排海污染物对海水中污染要素贡献较小,其携带COD、石油类的贡献率分别低于陆源输入的0.02%、6%,Hg、Cd远远低于陆源输入的7%、3%。

The spatial and temporal distribution characteristics and pollution contribution of seawater quality near the offshore oil and gas exploration zone in the Bohai Sea were analyzed by combining the methods of principal component comprehensive evaluation,correlation analysis,and spatial visualization based on the monitoring results of surface seawater pollution factors near 14 offshore oil and gas exploration zones in the Bohai Sea from 2015 to 2020.The results revealed that the seawater quality near the offshore oil and gas exploration zone in the central Bohai Sea was better than in Liaodong Bay and Bohai Bay.The comprehensive evaluation results of seawater quality near No.1 offshore oil and gas exploration zone at the top of Liaodong Bay were the worst,while the results near No.4 offshore oil and gas exploration zone at the mouth of Liaodong Bay were the best,which could be attributed to the significant influence of land-based inputs and hydrodynamic conditions near No.1 offshore oil and gas exploration zone.Furthermore,in comparison to mercury(Hg),landbased input had a significant impact on the levels of chemical oxygen demand(COD),petroleum,and cadmium(Cd).Pollutants discharged from oil and gas platforms contributed little to the pollution elements in the surface seawater near the offshore oil and gas exploration zone in the Bohai Sea,and COD and petroleum fluxes into the sea were less than 0.02%and 6%of the land-based inputs,respectively,while Hg and Cd were far less than 7%and 3%of the land-based inputs,respectively.