Environmental fate of Persistent Organic Pollutants (POPs) during the austral summer in Antarctica

The environmental fate of persistent organic pollutants (POPs) depends on their physicochemical properties and the processes of exchange between different environmental compartments. In this context, diffusive air-water exchange is an important process that influences the levels of semi-volatile organic compounds in aquatic systems through volatilization and atmospheric deposition. On the other hand, once POPs reach the water column, they can remain in the dissolved phase and revolatilize or bind to particles rich in organic matter (phytoplankton), passing to the particulate phase. During this phase, POPs can follow two routes that strongly influence their environmental fate. One of them is the transfer of these pollutants to higher trophic levels, thus causing a biomagnification of these pollutants through the trophic network. Another alternative is that POPs can be exported to deep waters, which are then pumped into the biological pump, thus preventing the transfer of these compounds. In Antarctica, there is scarce information about both processes, which is a problem if we take into account that the polar regions act as a final sink for these compounds. It have been described that, during periods of high productivity (i.e. blooms), POPs are effectively transferred to sediments due to high biological pump flows, in relation to the bioaccumulation and biomagnification of these compounds in living organisms. This process was reported in Antarctica by Galbán-Malagón et al., 2018, however the samples came from different places, being susceptible to an ineffective quantification of the POPs levels present in the environment. Furthermore, to date, studies that have assessed the POPs cycle in aquatic systems have been carried out in terms of organic carbon extrapolated to POPs, so the environmental fate of POPs in the Southern Ocean is still uncertain. Considering the existing knowledge gaps on POPs in Antarctica and the lack of full understanding of their fundamental patterns, the main objective of this study is to assess the environmental fate of POPs, such as Polychlorinated biphenyls (PCBs) and Organochlorine pesticides (OCPs), in periods of «blooms» in Antarctica. To address this, it is proposed to sample air, water, sinking particles, phytoplankton and zooplankton with simultaneous and fixed-point sampling, in order to calculate air-water exchange, sedimentation flows and bioaccumulation (BAF), bioconcentration (BCF) and biomagnification (BMF) factors and, consequently, to increase knowledge about the environmental fate of these compounds during periods of blooms in the Southern Ocean.