Persistent organic pollutants (POPs) and seabirds of the East Antarctic
Creators: name: Lewis, Phoebe
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 410402
subject: Environmental assessment and monitoring

description: To assess the increasing magnitude of persistent organic pollutants (POPs) worldwide, baseline information of background levels in pristine environments such as Antarctica is essential. Polar seabird species in particular can be vulnerable to POPs exposure through their foraging habits, and information available on POPs contamination within Antarctic seabirds is lacking. POPs such as organochlorine pesticides (OCPs) are mainly transported to the region via long-range atmospheric transport (LRAT); however, local sources of POPs such as the legacy contaminants polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs, a class of brominated flame retardants - BFRs) have recently been identified, affiliated with Antarctic research stations and increasing human activity in the region.

The objectives met in this doctoral thesis have produced novel, baseline data on levels of PCBs, OCPs and BFRs, both PBDEs and some emerging contaminants, in seabirds across a significant geographical region of East Antarctica, utilising the birds' status as indicators of marine health to assess the previously unknown POPs levels and potential local secondary sources to this region. 

The early stages of this project focussed on developing a reliable, fast and targeted multi-reside extraction and analysis method for seabird blood, using selective pressurized liquid extraction (S-PLE) and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). As method validation, baseline levels of PCBs, OCPs and BFRs were determined in blood samples from seabirds local to southeast Australia: short-tailed shearwaters (Ardenna tenuirostris) from Tasmania and little penguins (Eudyptula minor) from Phillip Island, Victoria. In both species, measured levels followed the contamination pattern PCBs&gt;OCPs&gt;BFRs, consistent with studies from seabird contamination in the Northern Hemisphere, where POPs sources are predominantly industrial. Total contamination levels in each species were similar, ranging from not detected (ND) to 39.2 ng/g wet weight (ww) for short-tailed shearwaters and from ND to 33.7 ng/g ww for little penguins. Present in both species was the novel flame retardant hexabromobenzene (HBB). Little penguins had a comparatively wider range of PBDE levels than the shearwaters, suggesting there are local exposure sources of BFRs within their foraging ranges close to the nearby major city of Melbourne. Levels in both species provide important information to the local (penguins) and global (shearwaters) distribution of POPs with the marine environment. 

Using the validated blood method, an investigation within the Prydz Bay region of East Antarctica focussed on establishing baseline levels of the same contaminants in local Adélie penguins (Pygoscelis adeliae) compared to migratory species including cape petrels (Daption capense), Antarctic petrels (Thalassoica antarctica), snow petrels (Pagodroma nivea) and southern fulmars (Fulmarus glacialoides). Measured levels provided the first comprehensive baseline data for POPs contamination within East Antarctica. While levels of total OCPs and BFRs were similar for all species, Adélie penguins had the highest ¿PCB levels (4.1-361.8 ng/g ww) compared to the migratory species except the snow petrel (¿PCBs 8.0-49.3 ng/g ww). Both species remain above 60 °S for the winter months, with snow petrels feeding at a higher trophic level on deep water fish, and  the prolonged fasting of the Adélie penguins¿ egg incubation stage contributing to increased levels via lipid mobilisation. Aside from the Adélie penguins (where PCBs&gt;OCPs), total contamination patterns followed OCPs&gt;PCBs&gt;BFRs, and the presence of novel flame retardants HBB, pentabromotoluene (PBT), 2-ethyl-hexyl tetrabromobenzoate (EH-TBB) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were detected in all species, which is an indication of the growing environmental presence of these compounds. Species from Prydz Bay had BFR levels similar to those reported in Arctic seabirds. As body condition improved, BFR contamination increased for all Antarctic species, which could be due to biomagnification through their diet, however given there is no data on BFR contamination in prey species within this region, further research is needed. 

Comparisons of blood contamination levels to those found in preen oil for the same individuals showed how these compartments can integrate contamination over both spatial (preen oil) and temporal (blood) scales. The baseline preen oil concentrations strongly reflected seabird migratory pathways, with the flying seabirds showing significantly higher concentrations of all contaminants compared to the penguins. All species followed the contamination trend of OCPs&gt;PCBs&gt;BFRs, with the novel flame retardant PBT measured in both Adélie penguins and snow petrels (with mean concentrations 5.1±5.1 and 5.4±2.8 ng/g ww, respectively). Preen oil concentrations for the petrel and fulmar species (Procellaridae) were correlated with blood concentrations for a number PCB, OCP and BFR chemicals, suggesting preen oil alone would make an effective non-destructive biomonitoring technique for long-term monitoring studies. In comparison, more work investigating POPs levels in penguins (Speniscidae) is required to confirm whether similar relationships are found, however, both non-destructive sampling techniques would yield important information about POPs contamination in this species.
 
The final chapters in this doctoral thesis investigate Antarctic research station-derived sources of POPs using Adélie penguin colony soils and soils sampled from research stations Casey, Davis and Mawson. Only trace levels of POPs were detected, yet soils taken from all research stations were more highly contaminated than surrounding penguin colonies. PCBs and PBDEs were ubiquitous in all samples taken from the Australian research stations (n=18), providing evidence of local inputs of both legacy and emerging POPs to the Antarctic environment. Novel flame retardants (NBFRs) were also quantified for the first time in Antarctic soils, in samples from Mawson and Casey Station (PBEB 0.04 ¿ 5.74 ng/g dw and PBT 0.08 ¿ 0.20 ng/g dw). Contamination in penguin colony soils was likely due to the penguins' role as secondary sources of POPs, whereby they contribute contaminants via organic matter from their biological activities (breeding, guano and carcasses). Congener profiles within penguin colony soils, for PBDEs in particular, further support the hypothesis that research stations are local sources of POPs to the Antarctic environment. 

The key findings in this doctoral thesis established baseline levels of POPs contamination within seabirds local to the East Antarctic, and are an essential addition to the growing understanding of POPs contamination worldwide. The identification of preen oil as an appropriate non-destructive biomonitoring medium could yield a standardised monitoring protocol. In addition, levels of legacy and emerging POPs established in this study will allow interspecific comparison of seabird species over spatial and temporal scales, allowing for the potential identification of previously unmonitored threats to Antarctic seabird populations.