Levels of persistent organic pollutants (POPs) in the Antarctic atmosphere over time (1980 to 2021) and estimation of their atmospheric half-lives

Abstract

Abstract. Persistent organic pollutants (POPs) are synthetic compounds that were intentionally produced in large quantities and have been distributed in the global environment, originating a threat due to their persistence, bioaccumulative potential, and toxicity. POPs reach the Antarctic continent through long-range atmospheric transport (LRAT). In these areas, low temperatures play a significant role in the environmental fate of POPs, retaining them for a long time due to cold trapping by diffusion and wet deposition, acting as a net sink for many POPs. However, in the current context of climate change, the remobilization of POPs that were trapped in water, ice, and soil for decades is happening. Therefore, continuous monitoring of POPs in polar air is necessary to assess whether there is a recent re-release of historical pollutants back to the environment. We reviewed the scientific literature on atmospheric levels of several POP families (polychlorinated biphenyls – PCBs, hexachlorobenzene – HCB, hexachlorocyclohexanes – HCHs, and dichlorodiphenyltrichloroethane – DDT) from 1980 to 2021. We estimated the atmospheric half-life using characteristic decreasing times (TD). We observed that HCB levels in the Antarctic atmosphere were higher than the other target organochlorine pesticides (OCPs), but HCB also displayed higher fluctuations and did not show a significant decrease over time. Conversely, the atmospheric levels of HCHs, some DDTs, and PCBs have decreased significantly. The estimated atmospheric half-lives for POPs decreased in the following order: 4,4' DDE (13.5 years) > 4,4' DDD (12.8 years) > 4,4' DDT (7.4 years) > 2,4' DDE (6.4 years) > 2,4' DDT (6.3 years) > α-HCH (6 years) > HCB (6 years) > γ-HCH (4.2 years). For PCB congeners, they decreased in the following order: PCB 153 (7.6 years) > PCB 138 (6.5 years) > PCB 101 (4.7 years) > PCB 180 (4.6 years) > PCB 28 (4 years) > PCB 52 (3.7 years) > PCB 118 (3.6 years). For HCH isomers and PCBs, the Stockholm Convention (SC) ban on POPs did have an impact on decreasing their levels during the last decades. Nevertheless, their ubiquity in the Antarctic atmosphere shows the problematic issues related to highly persistent synthetic chemicals.

Indirect Impact of Eutrophication on Occurrence, Air–Water Exchange, and Vertical Sinking Fluxes of Antibiotics in a Subtropical River

“…These antibiotics exhibit ionic properties in the elevated pH, which is indirectly induced by the eutrophication in the Pearl River. Organic species originating from the ocean can enter the atmosphere via two principal mechanisms: the generation of sea spray aerosols through bubble bursting and wind shear, − along with the release of volatile organic compounds from the ocean surface. − Studies have illustrated that phytoplankton biomass significantly influences aerosol particles generation through wave breaking in both sea and lake environments, leading to an enrichment of matter at the air–water interface. − The aerosolization of phytoplankton cells and fragments occurs across a size spectrum ranging from fine (<2.5 μm) to coarse (2.5–10 μm), with microalgal abundance in the atmosphere varying from 10 –4 to 10 4 cells m –3 . , This work revealed that antibiotics transfer to the atmosphere primarily through aerosolization, controlled by phytoplankton biomass. By linearly plotting the concentrations in aerosol-phase concentrations of antibiotics C air against the biomass, negative correlations between C air and phytoplankton biomass were observed in general (Figures a).…”