QUADRAT DTP CASE: Modelling the fate of persistent organic pollutants (POPs) in the Northwest European Shelf ecosystem with a suite of high-resolution numerical models

Introduction/Background:
Persistent organic pollutants (POPs) are chemical substances that are resistant to environmental degradation through chemical, biological, geological and physical processes.
POPs enter coastal waters from various diffuse and point sources, located near the coast or originating from further inland.

There are many classes of POPs which have been produced for multiple purposes, including pesticides in agriculture, coolants and insulators in industry, flame retardants, pharmaceuticals, consumer and personal products from households. They can be produced by combustion processes, and are found in waste and seepage and leakages from dump sites and landfills.

POPs persist in the environment – they often have half-lives of tens of years in water and sediment, can undergo long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and have potentially significant impacts on human health and the environment. For example, Desforges et al. (2018) found that polychlorinted biphenyl (PCB, a class of POP used in industry) concentrations found in killer whales can be 100 times safe levels, resulting in severely damaged reproductive organs, cancer and damage to the immune system. The study predicts the collapse of the global killer whale population from PCB pollution. The Northwest European Shelf has been identified as a region of higher trophic level (animal) exposure to PCBs (e.g. Handoh & Kawai, 2014).

POPs tend to be either hydrophobic (lipophilic) or hydrophilic (lipophobic), that is they tend to either be water hating or water soluble (see O’Driscoll et al. 2013 for examples of hydrophobic v. hydroplhilic POPs). Hydrophobic POPs sorb to organic matter in the ocean: they can settle with detritus (dead-matter) in sediment and can be recycled with nutrients before entering the food chain, or they can sorb directly to plankton. So they enter the food chain either directly or indirectly, where they bioaccumulate and biomagnify up the food chain, thus are a threat to the ecosystem and its services.

Project:
The major objective of this work is to study POP exchange processes at lower trophic levels (LTLs phyto- and zoo-plankton) in the Northwest European Shelf ocean ecosystem as part of an integrated and holistic investigation into the cycling, pathways and fate of POPs within the shelf and coastal system. To accomplish this, the student will further develop the state-of-the-art model described by O’Driscoll et al. (2013) to simulate these processes, thereby quantifying the spatio-temporal variability of the processes acting within each of the major ocean sub-systems (water, sediment and ecosystem).

The proposed modelling approach will extend the model of O’Driscoll et al. (2013) to include POP exchange processes in phytoplankton (uptake, depuration, growth, and metabolism rates) and zooplankton (same as phytoplankton and egestion in faeces and eggs). Rate constants depend on a number of variables and will be calculated/chosen for key plankton species.
Hydrodynamic, biogeochemical and ecosystem model results are used from existing NERC National Oceanographic Centre model runs (e.g. NEMO-ERSEM, https://noc.ac.uk/science/research-areas/marine-systems-modelling).
The project is not only science driven but will contribute to national and international efforts to mitigate against ocean pollution, especially ecosystems under pressure from stressors.

More project details are available here: https://www.quadrat.ac.uk/projects/case-modelling-the-fate-of-persistent-organic-pollutants-pops-in-the-northwest-european-shelf-ecosystem-with-a-suite-of-high-resolution-numerical-models/

How to apply: https://www.quadrat.ac.uk/how-to-apply/

Please note: applications should be submitted directly to QUADRAT and not to Queen’s University Belfast.