In recent years, airborne microplastics have been identified in a range of remote environments. However, data throughout the Southern Hemisphere, in particular Antarctica, are largely absent to date. We collected snow samples from 19 sites across the Ross Island region of Antarctica. Suspected microplastic particles were isolated and their composition confirmed using micro-Fourier transform infrared spectroscopy (
Over the last century plastics have become one of the most ubiquitous synthetic materials in the world due to their versatility and durability. Despite their longevity, plastics degrade over time to produce microplastics (plastic particles
Airborne microplastics have been identified in atmospheric fallout in a range of urban
With a few exceptions, such as lead pollution in the late 19th century
To date there is little information available regarding the presence of airborne microplastics in Antarctica. We collected freshly fallen snow samples from the Ross Island region of Antarctica in late 2019 and analysed them to quantify the presence and abundance of microplastics. Samples were collected close to two scientific research stations (Scott Base and McMurdo Station) and from 13 field sites up to 20 km from the research stations. We identified polymer composition using micro-Fourier transform infrared spectroscopy (
Snow samples were collected in 500 mL stainless-steel bottles. A total of 19 samples were collected with 6 from locations near research stations and 13 from remote locations with minimal human disturbance (Fig.
Site locations for snow sample collections across the Ross Island region of Antarctica (S1–S19). Sample sites are marked in black, and locations of scientific research stations are shown by blue triangles. Some site markers correspond to two sampling sites due to the scale of the map. Map data sourced from
Snow samples were thawed in the sealed sample bottles at room temperature for 24–48 h prior to analysis. Thawed samples were filtered through a glass apparatus attached to a vacuum using a cellulose nitrate membrane filter (Whatman nitrocellulose membrane, 50 mm diameter, 0.45
The dried cellulose nitrate filter was transferred to a 250 mL glass beaker for a wet peroxide oxidation (WPO) digestion to remove organic material present on the filter. An Iron (Fe(II)) sulfate solution (0.05 M) was prepared by adding 7.5 g of FeSO
The digested cellulose nitrate filter was rinsed with ultra-pure water to remove any attached material. The digested filtrate was then filtered under vacuum onto a Whatman glass fibre GF/C filter (47 mm diameter, 1.2
Filter papers were initially screened using a Leica MZ125 stereomicroscope with 10
All suspected microplastics were chemically identified by micro-Fourier transform infrared spectroscopy (
Each sampling site was selected ensuring the presence of fresh snow with no visible contamination or movement in the collection area. Non-plastic sampling equipment was used to avoid contamination, and all equipment was rinsed in nearby snow prior to each sample collection. Leather gloves were worn by the sample collectors, and the sample site was selected upwind from any human movement to minimize contamination by the samplers. The lid of each sampling bottle was held without the inside being touched during sample collection to avoid human contamination. Bottles were stored upright and kept in a cool box in snow during transportation.
Two field controls were collected during sample collection: one alongside a remote field site sample and one alongside a research station sample. The two field control bottles were left open during snow sampling and filled with ultra-pure water when returned to the laboratory. They subsequently underwent the same laboratory methods as all other samples. Two method controls were prepared in stainless-steel bottles identical to the sampling bottles used for collection and were filled with ultra-pure water. These were stored in the laboratory freezer in New Zealand during sampling and underwent identical laboratory procedures as the samples to identify potential sources of contamination from the sampling bottles. For blank corrections we followed the methodology highlighted in
Method recovery tests consisted of two 500 mL samples of ultra-pure water spiked with five polyethylene (PE) beads and seven polymethyl methacrylate (PMMA) fibres sized between 500 and 2000
National Antarctic programmes provide essential clothing and field gear to staff and scientists. Some of the gear provided is mandatory whenever undertaking fieldwork or travelling outside of bases. The composition of field gear provided by the New Zealand National Antarctic programme (including base layers, mid-layers, outer layers, shoes, boot liners, gloves, bags, hats and accessories) was catalogued to determine potential local sources of synthetic particles into the Ross Island region (Table
Because samples were collected during or shortly after a single snowfall event (Fig.
Snowfall over the measurement period from the ERA5 reanalysis. These values are averaged over the sample site area (77.75–78
The ensemble configuration of HYSPLIT was used to generate 27-member back-trajectory ensembles which represent the uncertainty in the trajectories. For each ensemble trajectory, the meteorological data were offset in the
Recovery rates for spiked samples were 100 %. Across the sample controls an average of 1.5
Microplastics were found in all Antarctic snow samples with a total of 109 particles confirmed as microplastics using
Concentrations of microplastics (MP; in particles L
A total of 13 different polymer types were identified across the snow samples when compared against a spectral reference library (Supplement Fig. S2). Polyethylene terephthalate (PET) was the most frequently detected polymer type, found in 79 % of the samples, comprising 41 % of total polymers identified (Fig.
Polymer types identified across all samples.
Particles confirmed spectroscopically as microplastics were classified as fibres, fragments and films (Supplement Fig. S3). No beads were detected. Fibres were the most abundant morphotype (61 %, Fig.
Back-trajectory ensembles generated by HYSPLIT for six of the collected samples. Each of these trajectories is run for 156 h with the ensemble members generated by minor perturbations as described in Sect.
All of the samples from remote sites (S1–S13) were collected over 3 d (30 November–2 December 2019). A large snowfall event occurred 1 d prior to sampling on 30 November 2019 (Fig.
Figure
The trajectories presented in Fig.
In accordance with the climatology of the region, all of the trajectories show that the immediate source of the airflow is from the south following the Trans-Antarctic Mountains. This means that for the majority of these samples, short-term local transport is the most likely source of microplastics as the sampling sites are mostly north of the local bases (Scott Base and McMurdo Base). It is also possible that local small-scale transport processes that are not captured by HYSPLIT could play a key role in transport at this scale. For the trajectories that clearly show a Ross air stream event (sites 2, 3, 7 and 13), the most likely distant sources are the Ross and Amundsen seas as there are no manned stations or other likely sources along the trajectory path. The transport processes in this region can be very rapid with the trajectories from these sites on average covering a distance of 143 km in the first 6 h and 469 km in 24 h. With a 156 h residence time, transport over thousands of kilometres is possible.
For site 19 there is a different set of meteorological conditions causing a divergence from the results of the other samples. The corresponding trajectories show a wide range of possible sources including the Antarctic Peninsula and Weddell Sea. While these conditions are relatively rare compared with the kind of Ross air stream flow examined earlier, they still provide a possible source of microplastics. These different conditions expand the set of possible sources to include more distant sources including many other Antarctic research stations. Given that an assumed maximum residence time of 156 h leads to trajectories covering a total distance of over
Our work provides the first evidence of microplastics in Antarctic snow, and critically, the average concentration of microplastics found in this study are higher (29.4
The most frequent polymer type we detected was PET, which was found in 79 % of all samples. Approximately 60 % of all PET produced is used for synthetic fibres and 30 % for plastic bottles
Fibres were the most abundant morphotype (60 %) followed by fragments (39 %) and films (1 %, Fig.
As the size distribution of identified microplastics is skewed towards smaller particles (Fig.
Microplastics in Antarctica may originate from both local sources and long-range transport. Direct sources of microplastics to the Antarctic environment may include fragmentation of plastic equipment from research stations, clothing worn by base staff and researchers, and mismanaged waste. Microplastics may also enter the Antarctic environment via long-range transport by ocean currents
Antarctic research stations on Ross Island, Scott Base (NZ) and McMurdo Station (US) have the closest proximity to the sampling sites, up to 20 km away (Fig.
Plastic products in use at research stations (including building materials, marker flags, safety equipment and tyre rubber) may fragment with environmental exposure and be a potential local source of microplastics into the environment. General wear and weathering from clothing and outdoor equipment used in the field may introduce plastics into more remote regions away from populated bases. In addition, enhanced ultraviolet fluxes due to the Antarctic ozone hole may accelerate the fragmentation of larger plastic products into microplastics
PET was the most common polymer found in snow samples making up 41 % of total microplastics. The most common polymer found in catalogued gear was also PET, which was present in 48 % of the garments in varying percentages from 68 % to 100 %, followed by PA which was present in 30 % of the garments (Table
Marker flags used in Antarctica. Before being placed outside (left) and after they were retrieved (right). Photo credit: Evan Townsend (
Wastewater treatment plants (WWTPs) have been identified as a source of entry of microplastics to the environment worldwide
The transportation of particulates, such as dust, across the Southern Ocean and into Antarctica from other continents has been explored in previous literature, identifying mid-latitude circumpolar westerly winds dominating atmospheric transport to these regions, with Patagonia and New Zealand the most likely sources
Short-range transport of microplastics from the bases to sampling sites close by (e.g. S14–S19) is more likely than long-range transport, given the sites' proximity to research bases and the climatology of the area. Yet sites further away may have more influence from long-range transportation, showing the potential influence of both short-range and long-range inputs. HYSPLIT trajectory modelling indicates that microplastics may have travelled from the Amundsen or Ross seas to reach the remote sample sites and could possibly have come from as far as the Weddell Sea (based on hypothesized particle residence time in
Microplastic particles may have originated from local anthropogenic sources and been transported around Antarctica via a cycle of entrainment and deposition. Alternatively, microplastics may have originated from surface waters surrounding Antarctica via co-emission with sea spray
The implications of microplastics reaching remote regions such as Antarctica are vast. Antarctic organisms have adapted to extreme environmental conditions over many millions of years
Negative effects of plastic pollution in Antarctic waters have been reported since 1990 when anthropogenic products, mainly from fishing vessels, were found to be entangling fur seals
The consumption of microplastics by higher predators in the Antarctic ecosystem has also been noted, with gentoo (
Microplastics are an emerging contaminant for which appropriate controls and regulations have not been widely put in place
The findings of this study highlight the global reach of plastic pollution and identifies the need for urgency in creating successful policy to reduce its extent and effects, both globally and locally. While studies in the Antarctic region currently focus on marine microplastic pollution, future research and policy need to take a holistic approach to incorporate airborne and terrestrial impacts. The Protocol on Environmental Protection to the Antarctic Treaty (1991) aims to promote the protection of the Antarctic environment and its place in the world as a natural reserve devoted to peace and science. Growing rates of pollution across the world make this a much greater challenge, and huge transdisciplinary efforts are required to ensure this can continue to be achieved.
This study confirms the presence of microplastics in Antarctic snow. Microplastics were identified on the Ross Ice Shelf and near Scott Base and McMurdo Station at an average concentration of 29 particles L
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Catalogued material used in New Zealand Antarctic programme gear.
Characteristics of microplastics identified and sample volume. As discussed in the text, “blue” includes blue, black and navy. “Size” indicates the width for fragments and length for fibres.
Continued.
Mean distance travelled by air masses for trajectory ensembles at each of the sites and at 6, 24 and 156 h prior to sampling. Trajectories were initialized at a starting height of 2000 m; starting heights of 1000 and 500 m yielded similar results.
The microplastic data generated in this study are provided in the Appendix of this paper, including microplastic counts, sample volume, particle size, shape and polymer type. Relevant data to evaluate the conclusions of this paper are present in either the main paper, the Appendix or the Supplement.
The supplement related to this article is available online at:
Conceptualization of the study was completed by LER and SG. Methodology development was undertaken by LER, HR and SG. Field sampling was completed by ARA, ML and AJM. Investigation was undertaken by ARA, NEW and AS. Visualization was completed by ARA, NEW, ML and AS. Supervision of study was led by LER and SG. The original draft was completed by ARA and LER with review and editing completed by all authors.
The contact author has declared that neither they nor their co-authors have any competing interests.
Publisher’s note: Copernicus Publications remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
The authors thank Nicole Lauren-Manuera, Alex Nicholls, Paula Brooksby, Justin Harrison, Antarctica New Zealand, staff and students from Gateway Antarctica, and the Postgraduate Certificate of Antarctic Studies 2019 group. Alex R. Aves was supported by Gateway Antarctica's Ministry of Foreign Affairs and Trade Scholarship in Antarctic and Southern Ocean Studies. We acknowledge mana whenua, Ngāi Tūāhuriri, on whose lands our analysis and writing took place.
This research has been supported by the Marsden Fund (grant no. MFP-UOC1903).
This paper was edited by Kaitlin Keegan and reviewed by two anonymous referees.