Human activities have released large quantities of neutral persistent organic pollutants (POPs) that may be biomagnified in food webs and pose health risks to wildlife, particularly top predators. Here we develop a global 3-D ocean simulation for four polychlorinated biphenyls (PCBs) spanning a range of molecular weights and volatilities to better understand effects of climate-driven changes in ocean biogeochemistry on the lifetime and distribution of POPs. Observations are most abundant in the Arctic Ocean. There, model results reproduce spatial patterns and magnitudes of measured PCB concentrations. Sorption of PCBs to suspended particles and subsequent burial in benthic marine sediment is the dominant oceanic loss process globally. Results suggest benthic sediment burial has removed 75% of cumulative PCB releases since the onset of production in 1930. Wind speed, light penetration, and ocean circulation exert a stronger and more variable influence on volatile PCB congeners with lower particle affinity such as chlorinated biphenyl-28 and chlorinated biphenyl-101. In the Arctic Ocean between 1992 and 2015, modeled evasion (losses) of the more volatile PCB congeners from the surface ocean increased due to declines in sea ice and changes in ocean circulation. By contrast, net deposition increased slightly for higher molecular weight congeners with stronger partitioning to particles. Our results suggest future climate changes will have the greatest impacts on the chemical lifetimes and distributions of volatile POPs with lower molecular weights.
1.Harvard Univ, Harvard John A Paulson sch Engn & Appuea sci, Cambridge, MA 02138 USA 2.Harvard TH Chan Sch Publ Hlth, Dept Environm Hlth, Boston, MA USA 3.MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA 4.Maine Maritime Acad, Corning Sch Ocean Studies, Castine, ME USA 5.MIT, Inst Data Syst & Soc, 77 Massachusetts Ave, Cambridge, MA 02139 USA 6.Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA
Recommended Citation:
Wagner, Charlotte C.,Amos, Helen M.,Thackray, Colin P.,et al. A Global 3-D Ocean Model for PCBs: Benchmark Compounds for Understanding the Impacts of Global Change on Neutral Persistent Organic Pollutants[J]. GLOBAL BIOGEOCHEMICAL CYCLES,2019-01-01,33(3):469-481