es9b03006_si_001.pdf (2.22 MB)
Snow Amplification of Persistent Organic Pollutants at Coastal Antarctica
journal contribution
posted on 2019-07-25, 16:35 authored by Paulo Casal, Gemma Casas, Maria Vila-Costa, Ana Cabrerizo, Mariana Pizarro, Begoña Jiménez, Jordi DachsMany legacy and emerging persistent
organic pollutants (POPs) have
been reported in polar regions, and act as sentinels of global pollution.
Maritime Antarctica is recipient of abundant snow precipitation. Snow
scavenges air pollutants, and after snow melting, it can induce an
unquantified and poorly understood amplification of concentrations
of POPs. Air, snow, the fugacity in soils and snow, seawater and plankton
were sampled concurrently from late spring to late summer at Livingston
Island (Antarctica). Polychlorinated biphenyls (PCBs) and organochlorine
pesticides (OCPs) concentrations in snow and air were close to equilibrium.
POPs in soils showed concentrations close to soil–air equilibrium
or net volatilization depending on chemical volatility. Seawater–air
fugacity ratios were highly correlated with the product of the snow–air
partition coefficient and the Henry’s law constant (KSA H’), a measure of snow amplification
of fugacity. Therefore, coastal seawater mirrored the PCB congener
profile and increased concentrations in snowmelt due to snowpack releasing
POPs to seawater. The influence of snowpack and glacier inputs was
further evidenced by the correlation between net volatilization fluxes
of PCBs and seawater salinity. A meta-analysis of KSA, estimated as the ratio of POP concentrations in snow
and air from previously reported simultaneous field measurements,
showed that snow amplification is relevant for diverse families of
POPs, independent of their volatility. We claim that the potential
impact of atmospheric pollution on aquatic ecosystems has been under-predicted
by only considering air–water partitioning, as snow amplification
influences, and may even control, the POP occurrence in cold environments.