Hydrodynamic Impacts on the Fate of Polychlorinated Biphenyl 153 in the Marine Environment

• Published in: Water
• Main Authors: Elena Mikheeva, Johannes Bieser, Corinna Schrum
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2022
• Subjects: PCB; POPs; North and Baltic Sea; 1D model; pollutant modeling; Hydraulic engineering; TC1-978; Water supply for domestic and industrial purposes; TD201-500; Arctic; Sea ice
• Online Access: https://doi.org/10.3390/w14233952; https://doaj.org/article/508624978f8646ad8916f8a25c8dcaaf

Due to their long half-life, polychlorinated biphenyls (PCBs) tend to contaminate not only coastal areas, but they travel over long distances, eventually reaching remote areas such the Arctic. The physical and biogeochemical features of every coastal area govern the main distribution patterns of freshly introduced PCBs into the marine system. Some of these processes are determined by chemical properties of the individual PCB congener. Thus, atmospheric influx along with ad/absorption on non-living organic material, photolytical and biological degradation processes vary from one PCB congener to another. For a detailed fate analysis of individual congeners, we developed a new chemical model, based on the GOTM-ECOSMO-FABM model framework. Here, we exemplarily present results for PCB 153 based on 1D simulations of four regions in the North-Baltic Sea. The study area is characterized by different hydrodynamic and biogeochemical conditions. We investigate the impact of resuspension, mixing and the biological pump, sea ice and tides on the final phasal distribution of PCB 153 . Different combinations of these factors lead to the development of different areas of PCB 153 accumulation, with the formation of hotspot areas, and influence the total uptake and concentration of PCB 153 in the water column. As a result, two major dynamics determine the fate of PCB 153 in the coastal ocean: (i) Primary production leads to PCB 153 being adsorbed by organic material. Partitioning to organic material and sedimentation of organic particles removes dissolved PCB 153 from the surface ocean and increases atmospheric influx. (ii) Tidal-induced resuspension and mixing control the benthic–pelagic exchange of PCB 153 and its distribution in the water column. Depending on the resuspension regime and stratification, sediments can become a permanent (Gotland Deep, the Baltic Sea) or seasonal sink for PCB 153 . In regions with seasonal stratification and high near bottom turbulence (Northern North Sea), resuspension events can lead to ...