the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Levels of persistent organic pollutants (POPs) in the Antarctic atmosphere over time (1980 to 2021) and estimation of their atmospheric half-lives.
Thais Luarte
Victoria Antonieta Gómez-Aburto
Ignacio Poblete-Castro
Eduardo Castro-Nallar
Nicolás Hunneus
Marco Molina-Montenegro
Claudia Egas
Germán Azcune
Andrés Pérez-Parada
Rainier Lohmann
Pernilla Bohlin-Nizzetto
Jordi Dachs
Susan Bengtson-Nash
Gustavo Chiang
Karla Pozo
Cristóbal Galbán-Malagón
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. 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 net sink for many POPs. However, in the current context of climate change, remobilization of POPs trapped for decades in water, ice, and soil, 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 POPs families (polychlorinated biphenyls PCBs, hexachlorobenzene HCB, hexachlorocyclohexanes HCHs, and DDT) from 1988 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 OCs, but HCB also displayed higher fluctuations and did not show a significant decrease over time. Conversely, the atmospheric levels of HCHs, and 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), while 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 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.
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Thais Luarte et al.
Status: final response (author comments only)
- RC1: 'Comment on acp-2023-25', Anonymous Referee #1, 25 Feb 2023
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RC2: 'Comment on acp-2023-25', Anonymous Referee #2, 28 Feb 2023
General Comments
This manuscript reviewed literatures for the atmospheric concentrations of several classes POPs in the Antarctica from 1988 to 2021. Temporal trends were evaluated for DDT, DDD PCBs, HCHs and HCB according to the effective ban of SC. Atmospheric half-life times of these POPs were estimated using characteristic decreasing times (TD). The results showed that the ban of SC significantly influenced the levels of HCHs and PCBs, while HCB showed increasing concentrations in some publications, and longer half-life time than other POPs. The impact of climate change on the POPs levels was discussed. Increasing temperature can cause remission of POPs from the surface, and other biogeochemical processes. Overall, the manuscript have been well documented, and addressed to the emerging concern for POPs in the Antarctic. I would suggest it can be accepted with some revision.
Specific comments
L116-118, including only articles written in English; excluding from the analysis references that do not refer to a good quality assurance and quality control during the chemical analysis, or if the levels of field blanks were not reported.
Please give more detail description for “good quality assurance and quality control during the chemical analysis” applied for literature selection
L121-122, data obtained from active and passive sampling
As data from both active and passive sampling were collected in this work, although the authors stated no clear variation between these two data sets, I guess it is worth to compare the data between active sampling and passive sampling in this review, and give a suggestion for future monitoring program.
L189-197, spatial distribution of HCB, a-HCH, b-HCH, and g-HCH isomers was discussed in this section. Please give more discussion for the significant spatial differences of HCB and a-HCHs between East and West Antarctica.
Citation: https://doi.org/10.5194/acp-2023-25-RC2
Thais Luarte et al.
Thais Luarte et al.
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