Introduction
Antarctica was first discovered in 1820, and this was swiftly followed by periods of seal and whale exploitation in the region (Pearson et al. Reference Pearson, Zarankin, Salerno, Oliva and Ruiz-Fernández2020). Following the end of the Heroic Age of Antarctic exploration, between ca. 1897 and 1922, levels of scientific activity were low until the preparations for the International Geophysical Year 1957/58 commenced, which saw the construction of a series of research facilities at locations around the continent (Berkman Reference Berkman2002). However, the inter-war period saw a substantial shore and ship-based whaling industry develop in the Antarctic Peninsula region (Brown Reference Brown1963).
Since that time, human activities in the Antarctic region have increased, exerting increasing pressure on this once-pristine environment (Bargagli Reference Bargagli2008, Caruso et al. Reference Caruso, Bergami, Singh and Corsi2022). A notable consequence of the increase in human activity is microplastic (particles smaller than 5 mm in size) pollution, which is a particular concern regarding the marine environment due to the challenges of removing such litter once it has been introduced and due to the potential impacts of microplastics on marine species and ecosystems (Rowlands et al. Reference Rowlands, Galloway and Manno2021).
Numerous sampling campaigns have confirmed the presence of microplastics in the Antarctic environment (Tirelli et al. Reference Tirelli, Suaria, Lusher, Rocha-Santos, Costa and Mouneyrac2022). These campaigns have found microplastics in both terrestrial (Aves et al. Reference Aves, Revell, Gaw, Ruffell, Schuddeboom and Wotherspoon2022, Jones-Williams Reference Jones-Williams2025) and marine environments (Waller et al. Reference Waller, Griffiths, Waluda, Thorpe, Loaiza and Moreno2017). Plastic pollution has been identified in near-surface marine samples (Cincinelli et al. Reference Cincinelli, Scopetani, Chelazzi, Lombardini, Martellini and Katsoyiannis2017, Isobe et al. Reference Isobe, Uchiyama-Matsumoto, Uchida and Tokai2017, Absher et al. Reference Absher, Ferreira, Kern, Ferreira, Christo and Ando2019, Lacerda et al. Reference Lacerda, Rodrigues, van Sebille, Rodrigues, Ribeiro and Secchi2019, Suaria et al. Reference Suaria, Perold, Lee, Lebouard, Aliani and Ryan2020, Leistenschneider et al. Reference Leistenschneider, Burkhardt-Holm, Mani, Primpke, Taubner and Gerdts2021) as well as in seafloor sediments (Van Cauwenberghe et al. Reference Van Cauwenberghe, Vanreusel, Mees and Janssen2013, Munari et al. Reference Munari, Infantini, Scoponi, Rastelli, Corinaldesi and Mistri2017, Reed et al. Reference Reed, Clark, Thompson and Hughes2018, Cunningham et al. Reference Cunningham, Ehlers, Dick, Sigwart, Linse, Dick and Kiriakoulakis2020).
Microplastics, if introduced into the environment, pose multiple risks to Antarctic marine ecosystems (Teuten et al. Reference Teuten, Saquing, Knappe, Barlaz, Jonsson and Björn2009, Sarkar et al. Reference Sarkar, Diab and Thompson2023). These particles can act as carriers of toxic chemicals, including additives from plastic production and persistent organic pollutants absorbed from surrounding waters (Campanale et al. Reference Campanale, Massarelli, Savino, Locaputo and Uricchio2020). Direct ingestion by marine organisms can cause physical blockages in digestive systems and facilitate the transfer of toxic compounds into tissues (Wright et al. Reference Wright, Thompson and Galloway2013). Beyond the immediate physical effects, microplastics disrupt biological processes through endocrine interference and tissue damage, while their integration into food webs alters feeding behaviours and creates cascading ecological impacts (Egbeocha et al. Reference Egbeocha, Malek, Emenike and Milow2018, Nelms et al. Reference Nelms, Galloway, Godley, Jarvis and Lindeque2018). Notably, the presence of microplastics has been observed in Antarctic marine species, from smaller organisms, such as Antarctic krill (Euphausia superba; Wilkie Johnston et al. Reference Wilkie Johnston, Bergami, Rowlands and Manno2023, Zhu et al. Reference Zhu, Liu, Chen, Liao, Yu and Jin2023) and amphipods (Jones-Williams et al. Reference Jones-Williams, Galloway, Cole, Stowasser, Waluda and Manno2020), to top predators such as fish (Cannon et al. Reference Cannon, Lavers and Figueiredo2016), penguins (Bessa et al. Reference Bessa, Ratcliffe, Otero, Sobral, Marques and Waluda2019) and seabirds (Auman et al. Reference Auman, Woehler, Riddle and Burton2004).
Microplastics in Antarctica are sourced both locally and through ocean current transfer from outside the region (Aves et al. Reference Aves, Revell, Gaw, Ruffell, Schuddeboom and Wotherspoon2022). While the Antarctic Circumpolar Current (ACC) has traditionally been viewed as a barrier limiting the long-distance transport of debris from lower latitudes, studies have shown that it is more permeable than previously thought, allowing some plastic debris to cross into the Southern Ocean (Clarke et al. Reference Clarke, Barnes and Hodgson2005, Thompson Reference Thompson2008, Fraser et al. Reference Fraser, Kay, DU Plessis and Ryan2017). Local sources of microplastic that may pollute the Antarctic environment are likely to come primarily from national scientific research facilities and tourism and fisheries vessels (Cincinelli et al. Reference Cincinelli, Scopetani, Chelazzi, Lombardini, Martellini and Katsoyiannis2017, Munari et al. Reference Munari, Infantini, Scoponi, Rastelli, Corinaldesi and Mistri2017, Hunter et al. Reference Hunter, Thorpe, McCarthy and Manno2024). Each source requires individual investigation to generate detailed information about microplastic release patterns from specific economic activities, enabling the development of more targeted and specialized mitigation measures. This study focuses specifically on microplastic release from wastewaters discharged by scientific stations in Antarctica.
As per the Council of Managers of National Antarctic Programs (COMNAP; COMNAP 2024), Antarctica has 102 research facilities encompassing 76 scientific stations, 5 refuges, 2 laboratories, 3 depots, 11 camps and 5 airfield camps. These facilities are operated by 31 nations. Daily operations within these facilities may contribute microplastics through wastewater, primarily in the form of microbeads, from personal/hygiene products such as toothpaste, shampoos, shower gels, detergents, cosmetics and fibres produced during the washing of synthetic textiles (Browne et al. Reference Browne, Crump, Niven, Teuten, Tonkin, Galloway and Thompson2011, Waller et al. Reference Waller, Griffiths, Waluda, Thorpe, Loaiza and Moreno2017). Cosmetic products typically contain microbeads constituting between 0.5% and 6.0% of the product, with an average size of 250 μm (Zitko & Hanlon Reference Zitko and Hanlon1991, GESAMP Reference Kershaw2015). A single washing load can release over 7 000 000 fibres into the water (Napper & Thompson Reference Napper and Thompson2016, De Falco et al. Reference De Falco, Gullo, Gentile, Di Pace, Cocca and Gelabert2018). Associated microplastics can subsequently enter wastewater systems and potentially the environment if not treated properly (Magnusson & Norén Reference Magnusson and Norén2014, Murphy et al. Reference Murphy, Ewins, Carbonnier and Quinn2016).
The issue of microplastic release in wastewaters from research stations in Antarctica can be addressed through prevention measures to minimize their release and/or by implementing robust wastewater treatment systems (WWTSs) to treat wastewaters. WWTSs operate through the removal of physical, chemical and biological pollutants in three main stages (i.e. primary, secondary and tertiary treatment processes; Crini & Lichtfouse Reference Crini, Lichtfouse, Crini and Lichtfouse2018, Sun et al. Reference Sun, Dai, Wang, van Loosdrecht and Ni2019). In the primary stage, methods such as mechanical processes, maceration and sedimentation are employed to eliminate solid wastes, fats, oils and grease from the wastewater stream. The secondary stage involves converting dissolved biological matter into a solid mass using waterborne microorganisms, which can be disposed of or reused. The methods used here include activated sludge, fluidized bed reactors, filter beds, biological aerated filters or membrane biological reactors (Krzeminski et al. Reference Krzeminski, Tomei, Karaolia, Langenhoff, Almeida and Felis2019). Tertiary treatment focuses on disinfecting treated water using chemical or physical methods such as microfiltration, chemical precipitation, chlorine, ultraviolet (UV) radiation or ozone, before discharging the final effluent into the natural environment (de Boer et al. Reference de Boer, González-Rodríguez, Conde and Moreira2022).
Although WWTSs are not primarily designed for microplastic waste removal, they can effectively capture microplastic particles during settling, aeration and filtration processes. Current studies suggest that primary WWTSs can remove between ~35% and 98.4% of microplastics (Prata Reference Prata2018, Sun et al. Reference Sun, Dai, Wang, van Loosdrecht and Ni2019). Following primary treatment, secondary WWTSs can contribute to further reductions of 0.2–14% of original total microplastics (Hu et al. Reference Hu, Gong, Wang and Bassi2019, Iyare et al. Reference Iyare, Ouki and Bond2020). Removal efficiency levels fluctuate depending on factors such as treatment techniques, influent volume and microplastic dimensions. Lastly, some tertiary WWTS techniques can further decrease microplastic content to as low as 0.2% relative to initial content after primary and secondary treatment (Ngo et al. Reference Ngo, Pramanik, Shah and Roychand2019, Reza et al. Reference Reza, Riza, Abdullah, Hasan, Ismail and Othman2023).
The internal practices and policies of scientific stations, as well as the operations of WWTSs in Antarctica, remain weak at this time. Disposal of all waste types within the Antarctic Treaty area is considered through the Protocol on Environmental Protection to the Antarctic Treaty, which was signed in 1991 and entered into force in 1998. Through Annex III to the Protocol, entitled ‘Waste disposal and waste management’, minimum standards regarding sewage treatment and disposal into the Antarctic environment were established, with no mandatory regulations in place requiring scientific facilities to treat their wastewaters any more than via simple maceration (Connor Reference Connor2008).
In recent years, the problem of microplastic pollution in Antarctica has started to gain more attention. The issue of microplastic pollution was first presented to a meeting of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) Working Group on Ecosystem Monitoring and Management in 2016 (CCAMLR 2016), where the assessment of the presence and impacts of microplastics and nanoplastics (size: 1 nm–1 μm) on Antarctic marine biota was discussed. Since then, plastic pollution has been considered within the Committee for Environmental Protection and Antarctic Treaty Consultative Meetings (ATCM; ATCM 2019). In 2019, a non-binding resolution was agreed upon entitled ‘Reducing plastic pollution in the Antarctic and Southern Ocean’ that encouraged parties to eliminate personal care products containing microplastic beads in the Antarctic Treaty area, share information on methods to reduce microplastic release from wastewater systems, support greater monitoring of plastic pollution, invite the Scientific Committee on Antarctic Research (SCAR) to report on any new information on the risks of plastic pollution and consider the issue of plastic release in any future revisions of the Annexes to the Protocol (https://www.ats.aq/devAS/Meetings/Measure/705).
To date, little economic and policy analysis has been conducted to support ATCM policy decisions on microplastic release in Antarctica. The objective of this paper is to identify the most economically efficient solution to mitigate and reduce microplastic pollution production in wastewaters and their release in the Antarctic environment as a result of research and science support activities. First, we estimated the release of microplastics into the Antarctic environment as a result of scientific activities at the continent’s research facilities. Second, a cost-efficiency analysis (CEA) was performed whereby different microplastic waste management options designed to mitigate the problem were evaluated.
Materials and methods
Microplastic pollution from scientific facilities’ wastewaters
Estimation of the potential production of microplastics in wastewaters
For this analysis, the two major sources of microplastic in wastewaters were considered (i.e. hygiene products and laundry). To estimate the amount of microplastics produced from an Antarctic research facility in wastewater each year
$({M}^{prod(s)}$
; mg/year), three inputs were required: 1) the quantity of microplastics contained in personal care products used per person
$({M}_{(P)}^{prod}$
; mg/person/day) and laundering
$({M}_{(L)}^{prod}$
; mg/person/day), 2) the mean population size in each Antarctic facility
$\left({p}^s\right)$
and 3) the number of days spent by the population in each facility
$\left({t}^s\right)$
. Once these inputs were obtained, the potential production of microplastics in wastewater was estimated using Equation 1.
$$\begin{align}\left({M}_{(P)}^{prod}+{M}_{(L)}^{prod}\right)\ast {p}^s\ast {t}^s={M}^{prod(s)} \end{align}$$
Here, the subscript
$^{\prime }s^{\prime }$
represents the scientific facility in question. To estimate the total amount of microplastics produced by all the facilities, we simply summed the microplastic production from each facility, as depicted in Equation 2.
$$\begin{align}\sum \limits_{s=1}^{102}{M}^{prod(s)}\end{align}$$
Finding primary data for these inputs was challenging, as there are currently no empirical data on the quantities of microplastic production or accumulation at Antarctic wastewater treatment stations due to day-to-day activities. To estimate potential contributions, we therefore used published rates of microplastic generation per person from other regions (from hygiene products and laundering) and applied these rates to scientific bases in Antarctica, a method also suggested by Waller et al. (Reference Waller, Griffiths, Waluda, Thorpe, Loaiza and Moreno2017). Although the Antarctic ecosystem is unique, our method is based on the assumption that scientists stationed there maintain similar daily life patterns as in their home countries. However, it is important to note that these estimates can vary depending on individual habits, product choices and specific station protocols. Despite this variability, existing data from non-Antarctic regions provide the best available proxies for assessing microplastic release from these stations, given the current lack of Antarctica-specific measurements. However, to address uncertainties, we considered three levels of microplastic production: low, medium and high. The medium estimate represented the mean production rate presented in all of the published studies considered for a given microplastic source, whereas the low and high estimates were derived from studies that provided the lowest and highest microplastic production rates, respectively. Estimations of the rates of microplastic production from the use of personal care products ranged from 2.4 to 27.5 mg/person/day, based on studies by Gouin et al. (Reference Gouin, Avalos, Brunning, Brzuska, Kaumanns and Konong2015) and Napper et al. (Reference Napper, Bakir, Rowland and Thompson2015). Similarly, estimates of synthetic fibres produced through laundering vary, with studies reporting between 107 and 1286 mg/day/person (Browne et al. Reference Browne, Crump, Niven, Teuten, Tonkin, Galloway and Thompson2011, Napper & Thompson Reference Napper and Thompson2016, Pirc et al. Reference Pirc, Vidmar, Mozer and Kržan2016, Hernandez et al. Reference Hernandez, Nowack and Mitrano2017, De Falco et al. Reference De Falco, Gullo, Gentile, Di Pace, Cocca and Gelabert2018, Reference De Falco, Di Pace, Cocca and Avella2019, Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Cai et al. Reference Cai, Yang, Mitrano, Heuberger, Hufenus and Nowack2020).
Population data and data on the time spent by that population at each facility were sourced from the COMNAP database (COMNAP 2022), which detailed the peak population in each of the scientific facilities and the level of occupancy by personnel during the summer and winter. Antarctica contains 41 permanent facilities (i.e. operational year-round) and 61 summer facilities that are generally open for a maximum of 5 months annually. The level of station occupancy and duration of opening are dependent upon the scientific and logistical requirements of the nation operating the facility each year. As detailed information on occupancy was not available for all of the facilities under consideration, the following assumptions were made: during the 5 months of summer, peak population was reached, while during the 7 months of winter, ~25% of the peak population was assumed to be residing in each facility. Therefore, to calculate the number of person-days on the station, for summer-only facilities the peak population was multiplied by 151 days (i.e. 5 months), whereas for year-round facilities the peak population was multiplied by 151 days (i.e. 5 months) plus 25% of the peak population present for the remainder of the year (i.e. 7 months or 214 days).
Estimation of the potential level of microplastic release into the environment (encompassing areas of permanent ice and the marine environment)
Once the potential amount of microplastics produced by facilities was calculated, we calculated the proportion that was not treated and likely to be released into the environment. To achieve this, the microplastic removal efficiency of each facility’ WWTSs was estimated. The removal efficiency rate estimate depended mainly upon the presence and characteristics of the WWTSs installed at each facility.
The plastic released from each facility was estimated using Equation 3.
$$\begin{align}{M}^{prod(s)}-\left({M}^{prod(s)}\ast {E}^s\right)={M}^{rel(s)}\end{align}$$
As shown earlier, the amount of microplastics removed by the WWTSs annually can be estimated by multiplying by the amount of microplastics produced within the facility each year
$({M}^{prod(s)})$
by the microplastic waste removal efficiency of a facility
$({E}^s$
; %). This allows estimation of the potential release of microplastics into the environment from a given facility each year
$({M}^{rel(s)}$
; mg/year).
At facilities without any WWTSs, it was assumed that all microplastics produced on station from personal products and laundering were released into the environment.
The total amount of microplastics released into the Antarctic environment was estimated by summing the amounts released from each facility, as represented in Equation 4.
$$\begin{align}\sum \limits_{s=1}^{102}{M}^{rel(s)}\end{align}$$
Data for the calculation of microplastic release were collected as follows. To estimate the efficiency of microplastic removal, a comprehensive list of wastewater treatment methods used at Antarctic facilities was compiled based on data collected from the COMNAP survey (COMNAP 2022). This survey was developed with the support of a scientific group and the COMNAP, and it was distributed to managers of 84 scientific facilities in Antarctica to gain insights into the WWTSs within each facility. Out of the 84 facilities about which information was sought, survey data were received for 66 of them. Among these responses, 46 facilities reported the presence of WWTSs. Within this group of 46 facilities, 31 indicated the installation of tertiary WWTSs, primarily through ozone and UV treatment. Eight facilities had only primary and secondary WWTSs, while seven were solely filtering waste at the primary level before releasing it into the Antarctic environment. However, due to confidentiality agreements, detailed data on the filtration systems used by each facility and country cannot be provided. Therefore, the results have been presented on a regional basis rather than on a station-by-station basis (i.e. East Antarctica, Antarctic Peninsula, Ross Sea region and Queen Maud Land).
Due to the absence of data for some facilities, it was assumed that microplastics from these facilities were directly released into the environment. In addition, in the calculations, it was assumed that if a facility had a WWTS, then the system was operational throughout the year. However, at some facilities, despite WWTSs having been installed, national operators may choose not to operate them year-round, particularly during periods of reduced population, such as the winter season.
After collecting data on the type of WWTSs installed by each facility, a literature review was conducted to estimate the average removal efficiency associated with each treatment method. At present, there is a lack of data and understanding regarding the potential removal of microplastics through WWTSs installed in Antarctica. However, detection of microplastics in WWTS effluents has been reported throughout the world, including in Asia, Europe, the USA, Australia, China and Russia (Prata Reference Prata2018). Antarctica’s research facilities, which employ similar primary WWTSs, mainly include methods such as screening, grit removal, sedimentation and settling tanks. These techniques are particularly effective at removing larger microplastics, specifically those sized between 1000 and 5000 μm (Lofty et al. Reference Lofty, Muhawenimana, Wilson and Ouro2022), with an estimated mean removal efficiency of 71% (Talvitie et al. Reference Talvitie, Mikola, Koistinen and Setälä2017a, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Lares et al. Reference Lares, Ncibi, Sillanpää and Sillanpää2018, Wang et al. Reference Wang, Maier, Horn, Holländer and Aschemann2018, Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019, Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Zhang et al. Reference Zhang, Haward and McGee2020). In facilities with secondary WWTSs in place along with a primary system, the overall mean removal efficiency varies by method: coagulation and flotation achieve 89.0% (Wang et al. Reference Wang, Zheng, Zhu, Brewer and Brown2017, Zhang et al. Reference Zhang, Haward and McGee2020), activated sludge achieves 87.2% (Talvitie et al. Reference Talvitie, Mikola, Setälä, Heinonen and Koistinen2017b, Lares et al. Reference Lares, Ncibi, Sillanpää and Sillanpää2018, Simon et al. Reference Simon, van Alst and Vollertsen2018, Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019), aeration achieves 78.1% (Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Simon et al. Reference Simon, van Alst and Vollertsen2018, Liu et al. Reference Liu, Yuan, Di, Li and Wang2019), membrane bioreactors achieve 90.2% (Talvitie et al. 2017, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Lares et al. Reference Lares, Ncibi, Sillanpää and Sillanpää2018, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019), secondary settling tanks achieve 97.0% (Dris et al. Reference Dris, Gasperi, Tassin, Wagner and Lambert2018, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019) and anaerobic-anoxic-aerobic (A2O) treatments achieve 54.7% (Murphy et al. Reference Murphy, Ewins, Carbonnier and Quinn2016, Jia et al. Reference Jia, Chen, Zhao, Li, Nie and Ye2019, Liu et al. Reference Liu, Yuan, Di, Li and Wang2019, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019, Edo et al. Reference Edo, González-Pleiter, Leganés, Fernández-Piñas and Rosal2020).
For facilities with tertiary WWTSs, the percentage of microplastics removed in the first two stages is observed, and then stage-wise removal efficiency is applied based on the tertiary treatment method used. The estimated mean removal efficiencies for tertiary treatment methods are as follows: sand filtration/rapid filtration achieves 61.0% (Talvitie et al. Reference Talvitie, Mikola, Koistinen and Setälä2017a, Mintenig et al. Reference Mintenig, Int-Veen, Löder, Primpke and Gerdts2017, Wang et al. Reference Wang, Zheng, Zhu, Brewer and Brown2017, Pivokonsky et al. Reference Pivokonsky, Cermakova, Novotna, Peer, Cajthaml and Janda2018, Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019, Zhang et al. Reference Zhang, Haward and McGee2020), ultrafiltration achieves 41.7% (Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Liu et al. Reference Liu, Jinlan, Liu, Guo, Zhang and Yao2020, Tadsuwan & Babel Reference Tadsuwan and Babel2022), reverse osmosis achieves 25.0% (Wang et al. Reference Wang, Zheng, Zhu, Brewer and Brown2017, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017), activated carbon achieves 47.6% (Wang et al. Reference Wang, Zheng, Zhu, Brewer and Brown2017, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Pivokonsky et al. Reference Pivokonsky, Cermakova, Novotna, Peer, Cajthaml and Janda2018), ozone achieves 69.8% (Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019), UV achieves 71.7% (Jia et al. Reference Jia, Chen, Zhao, Li, Nie and Ye2019, Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Easton et al. Reference Easton, Koutsos and Chatzisymeon2023), denitrification achieves 71.7% (Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Edo et al. Reference Edo, González-Pleiter, Leganés, Fernández-Piñas and Rosal2020) and membrane disk-filters achieve 79.4% (Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019, Simon et al. Reference Simon, Vianello and Vollertsen2019).
Policy analysis to reduce microplastic pollution from scientific facilities
Antarctica is governed by the 29 Consultative Parties to the Antarctic Treaty. Implementing large-scale, high-cost measures may not be feasible or acceptable. Therefore, as an initial step, we believe it could be valuable to explore low-cost, low-effort solutions that do not impose financial burdens or cause resistance from stakeholders. The financial cost of reducing the release of microplastics into the Antarctic environment was examined under five microplastic waste management options. Each management option utilized a different wastewater treatment measure or combination of measures aimed at reducing microplastic release (see Table I).
Table I. Summary of microplastic waste management options with different combinations of measures.
1o = primary; 2o = secondary; 3o = tertiary.
Management Option 1 has primary and secondary treatment only, while Management Option 2 incorporates tertiary treatment methods. Management Option 3 is similar to Management Option 1 but includes the installation of washing machine filters, which are designed to capture microplastic fibres produced during clothes laundering. Management Option 4 is similar to Management Option 1 but includes the implementation of a ban on hygiene products containing microbeads. Finally, Management Option 5 combines the installation of washing machine filters with a ban on personal hygiene products containing microbeads, but no wastewater treatment methods are employed.
To compare the proposed management options, CEA was used. CEA is a method of input-allocative efficiency analysis used to compare different policy investment scenarios by assessing and finding the optimal allocation of input in a way that minimizes cost (Camanho et al. Reference Camanho, Silva, Piran and Lacerda2024). In this study, our objective was to identify the optimal microplastic removal strategies for every dollar spent. To achieve this, the amount of microplastics produced by one individual annually was compared with the annual cost of providing wastewater treatment for that individual.
The cost-efficiency (CE) of each management option was assessed by determining the ratio of benefit received and cost spent. This was evaluated using Equation 5.
$$\begin{align}CE=\frac{E^{Y^{\prime }}}{C^{Y^{\prime }}}\times 100 \end{align}$$
This equation represents the yearly benefit (i.e. amount of microplastics removed in grams
$\left({E}^Y\right)$
per unit of cost (
${C}^Y$
)). The prime notation (‘) signifies that the data are presented on a per-person basis.
To compare each management option, we calculated the total cost and total positive outcome received per person annually with each option.
For cost data, we considered the yearly financial cost per person of a WWTS in US dollars. The total financial cost of each treatment method was estimated by dividing the fixed installation cost of a WWTS
$\left({C}_{fix}\right)$
by its lifespan
$\left(l(Y)\right)$
before it becomes obsolete and then adding this to the yearly maintenance cost
$\left({C}_{var}\right)$
. This is represented by Equation 6.
$$\begin{align}\frac{C^Y=\frac{C_{fix}}{l(Y)}+{C}_{var}}{cap}\end{align}$$
To estimate the cost of each WWTS per person, the total cost was divided by the total number of station personnel that can be supported by the WWTS
$(cap)$
. Equation 6 was applied to each management option, depending on the different costs associated with different treatment method sets.
The indicator of benefits is the amount of microplastics removed by the treatment method. To calculate this, first we calculated the average amount of microplastics produced by a single individual. This was calculated simply by dividing the total amount of microplastics produced by all stations in a year by the total population, as presented by Equation 7.
$$\begin{align}\frac{\sum {M}^{prod(s)}}{\sum {p}^s}={M}^{prod^{\prime }},\ \mathrm{where}\;s=1,\dots, 102\end{align}$$
Once we calculated the amount of microplastics produced by one person in a year, we were able to determine, for each management option, how much microplastic could be removed. The amount of microplastics removed from each management option was estimated as described below.
In Management Option 1, the total amount of microplastics produced initially underwent primary treatment. The removal efficiency rate of the primary WWTS
$\left({E}^{prim}\right)$
was multiplied by the total amount of microplastics produced per person in a year
$\left({M}^{prod^{\prime }}\right)$
. Subsequently, the remaining microplastics flowed through the secondary WWTS, where it underwent further cleaning using the removal efficiency rate of the secondary WWTS
$\left({E}^{sec}\right)$
.
In Management Option 2, wastewater underwent an additional tertiary treatment. Here, the removal efficiency of the tertiary WWTS
$\left({E}^{ter}\right)$
was applied to the remaining wastewater after it passed through the primary and secondary treatment systems.
In Management Option 3, before wastewater underwent treatment in the main WWTSs, a portion of the microplastics produced during laundry activities was removed through washing machine filters. This removal was estimated by multiplying the removal efficiency rate of the washing machine filters
$\left({E}^{filters}\right)$
by the amount of microplastics produced during laundering
$\left({M}_{(L)}^{prod^{\prime }}\right)$
. The remaining microplastics were then released into the wastewater along with the microplastics from other sources
$\left({M}_{(P)}^{prod^{\prime }}\right)$
. Subsequently, the removal efficiency rates of the primary and secondary WWTSs were applied, as explained previously.
In Management Option 4, it was assumed that with the ban on products containing microbeads there was no production of microplastics from this source. Thus, only the microplastic production from laundry underwent wastewater treatment through the primary and secondary systems. As a result, microplastic removal under Management Option 4 was the amount that was removed through primary and secondary WWTSs plus the amount that was eliminated through the ban on hygiene products with microbeads.
$$\begin{align}\left(\;{M}_{(L)}^{prod^{\prime }}\times {E}^{filters}\right)+{M}_{(P)}^{prod^{\prime }}\end{align}$$
Finally, in Management Option 5, the microplastics produced from laundering underwent treatment through washing machine filters. The remaining wastewater, along with any microplastics it may have contained, was directly released into the environment, as there were no other WWTSs in place. The total benefit received was the amount that was removed through primary and secondary wastewater treatment plus the amount that was eliminated through banning hygiene products with microbeads.
Initial inquiries showed that it would be difficult to gather data on the cost of WWTSs from each Antarctic facility. Estimates of the fixed and variable costs associated with the primary, secondary and tertiary WWTSs, as well as washing machine filters, were based on those for the WWTSs installed in Rothera Research Station, Adelaide Island, Antarctic Peninsula. Information was obtained through interviews with British Antarctic Survey estate managers. These data were then extrapolated to all other stations, assuming that the cost of WWTSs for one person at Rothera Research Station was approximately consistent across all stations.
At the time of this study, Rothera Research Station was equipped with primary, secondary and tertiary WWTSs capable of treating wastewater generated by up to 110 individuals, and it operated 11 laundering machines on which microplastic filters were being installed. The input data used for the calculations are presented in Table II.
Table II. Input data collected for wastewater treatment systems (WWTSs) at Rothera Research Station.
While the costs of all treatment levels and washing machine filters were estimated, the cost of banning products containing microbeads was assumed to be zero. In this study, only the immediate financial burdens on research stations were considered. While switching to microplastic-free hygiene products may result in minor costs or savings to national operators, these secondary financial effects or opportunity costs were beyond the scope for this study due to a lack of data and varying product pricing across countries.
A literature review was undertaken to estimate the average removal efficiency rate for each level of wastewater treatment (i.e. primary, secondary and tertiary). A total of 20 different studies were consulted to assess the influent and effluent of microplastics in various WWTS types. Based on the mean values calculated from these studies, the removal efficiencies of microplastics used in the calculations were 71% for primary WWTSs (Talvitie et al. Reference Talvitie, Mikola, Koistinen and Setälä2017a, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Lares et al. Reference Lares, Ncibi, Sillanpää and Sillanpää2018, Wang et al. Reference Wang, Maier, Horn, Holländer and Aschemann2018, Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019, Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Zhang et al. Reference Zhang, Haward and McGee2020), 92% for secondary WWTSs (Magnusson & Norén Reference Magnusson and Norén2014, Carr et al. Reference Carr, Liu and Tesoro2016, Talvitie et al. Reference Talvitie, Mikola, Koistinen and Setälä2017a,b, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Dris et al. Reference Dris, Gasperi, Tassin, Wagner and Lambert2018, Lares et al. Reference Lares, Ncibi, Sillanpää and Sillanpää2018, Simon et al. Reference Simon, van Alst and Vollertsen2018, Wang et al. Reference Wang, Maier, Horn, Holländer and Aschemann2018, Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019, Liu et al. Reference Liu, Yuan, Di, Li and Wang2019, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019, Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Zhang et al. Reference Zhang, Haward and McGee2020, Franco et al. Reference Franco, Arellano, Albendín, Rodríguez-Barroso, Quiroga and Coello2021) and 98% for tertiary WWTSs (Mintenig et al. Reference Mintenig, Int-Veen, Löder, Primpke and Gerdts2017, Reference Mintenig, Löder, Primpke and Gerdts2019, Talvitie et al. Reference Talvitie, Mikola, Koistinen and Setälä2017a, Ziajahromi et al. Reference Ziajahromi, Neale, Rintoul and Leusch2017, Pivokonsky et al. Reference Pivokonsky, Cermakova, Novotna, Peer, Cajthaml and Janda2018, Wang et al. Reference Wang, Maier, Horn, Holländer and Aschemann2018, Hidayaturrahman & Lee Reference Hidayaturrahman and Lee2019, Lv et al. Reference Lv, Dong, Zuo, Liu, Huang and Wu2019, Ma et al. Reference Ma, Xue, Ding, Hu, Liu and Qu2019, Yang et al. Reference Yang, Qiao, Lei, Li, Kang, Cui and An2019, Li et al. Reference Li, Cai and Zhang2020).
Similarly, we applied the same method to evaluate the removal efficiency of washing machine filtration. After reviewing six studies on microplastic filters, the mean removal efficiency was calculated to be 94% (Brodin et al. Reference Brodin, Norin, Hanning and Persson2018, McIlwraith et al. Reference McIlwraith, Lin, Erdle, Mallos, Diamond and Rochman2019, Napper et al. Reference Napper, Barrett and Thompson2020, Erdle et al. Reference Erdle, Parto, Sweetnam and Rochman2021, Le et al. Reference Le, Nguyen, Nguyen, Duong, Bui, Hoang and Nghiem2022, Belzagui et al. Reference Belzagui, Gutiérrez-Bouzán, Carrillo-Navarrete and López-Grimau2023).
Once the ‘yearly per person costs’ and ‘benefits’ for each management option were estimated, comparisons were made based on monetary estimates of physical outcomes, forming the basis for policy recommendations.
Results and discussion
Microplastic production and release from scientific facilities’ wastewaters
The estimates of annual microplastic production of research facilities were categorized into four regions: East Antarctica, Antarctic Peninsula, Ross Sea region and Queen Maud Land, as shown in Table III, which presents the detailed results on the quantity of microplastics produced by scientific facilities in each region.
Table III. Summary of estimated annual microplastic production at Antarctic research facilities and the quantity of microplastic released in wastewater into the environment by scientific facilities in different Antarctic regions (kg/year).
The highest amount of microplastic was produced by facilities located in the Antarctic Peninsula, which was because of the large number of facilities in the region. The Ross Sea region was the second largest producer of microplastic. Despite comprising only 13% of the total number of facilities, the region hosted 1722 individuals during the summer. Approximately half of the facilities were operated by the USA and accommodated 77% of the region’s population. The East Antarctica region had the second highest number of facilities and the third highest level of microplastic production. Lastly, Queen Maud Land had the smallest number of facilities, the lowest population and the lowest amount of microplastic production.
According to mean estimations, scientific facilities in Antarctica produced a total of 344 kg of microplastics from personal hygiene products and laundering clothes annually. Out of this, ~238 kg/year, constituting 69% of the amount produced, was released into the Antarctic environment due to the lack or limited capabilities of WWTSs currently employed at Antarctic facilities.
Despite the Antarctic Peninsula region having the highest population and number of facilities, it was not the primary region contributing to microplastic pollution in the Antarctic environment. The Ross Sea region potentially contributed the highest amount of microplastic to the environment, estimated at ~92 kg/year.
The Antarctic Peninsula region ranked as the second largest contributor to microplastic pollution. This region had a lower proportion of stations with WWTSs compared to the other regions. However, half of its facilities are seasonal, some of which host small populations of, for example, eight or fewer individuals. This renders it economically and technically unfeasible to install sewage treatment plants. Consequently, the minimal microplastic production from these populations is directly discharged into the environment.
Lastly, East Antarctica and Queen Maud Land exhibited lower microplastic release rates, estimated at ~32 and 34 kg/year, respectively, compared to the Ross Sea region and Antarctic Peninsula. The COMNAP survey data indicated that these regions had high proportions of facilities equipped with tertiary WWTSs, indicating more effective wastewater management practices.
Figure 1 provides a geographical representation of the distribution density of scientific stations in Antarctica and the corresponding quantities of microplastics produced and released by these stations. The majority of the stations are situated near the coast, increasing the likelihood of immediate marine environmental impacts.
Figure 1. Maps showing potential microplastic pollution from scientific facilities in Antarctica: (a) representation of the mass of microplastic produced at each facility per year; (b) estimation of the quantity of microplastic released into the Antarctic environment within each region (i.e. into ice shelves, ice sheets and the marine environment).
Policy analysis to reduce microplastic pollution from scientific facilities
The results of the CEA are presented in Table IV, and they illustrate the optimal investment options and the cost-efficiency for each US dollar spent across various management options.
Table IV. Cost-efficiency of different microplastic waste management options.
Management Option 5, which targeted the removal of microplastics at the source, emerged as the most cost-efficient option. This outcome is consistent with recent studies that have shown that intervening at earlier stages to minimize microplastic release is less costly and yields higher removal rates compared to options in which microplastic particles are allowed to accumulate in large quantities within wastewater, which subsequently necessitates costly cleaning processes (Vuori & Ollikainen Reference Vuori and Ollikainen2022, Hettiarachchi & Meegoda Reference Hettiarachchi and Meegoda2023). This low-cost option could be an effective solution to deal with microplastic release from stations with low populations, such as many of the facilities found in the Antarctic Peninsula.
Furthermore, both Management Option 1 (incorporating only primary and secondary WWTSs) and Management Option 4 (adding a ban on products containing microbeads alongside primary and secondary WWTSs) delivered similar levels of microplastic removal, with Management Option 4 only slightly outperforming Management Option 1. This comparable performance can be explained by the fact that both options use the same WWTSs to target the majority (estimated at 94%) of microplastics, which originate from laundering synthetic clothes. Thus, the cost of removing the major part of microplastics is similar in both options.
However, Management Option 4 merits greater attention because it completely eliminates the remaining 6% of microplastic releases by banning products containing microbeads. This additional benefit is achieved with minimal or no immediate cost to research stations, thus increasing its cost-efficiency.
Finally, Management Option 2 (incorporating primary, secondary and tertiary WWTSs) and Management Option 3 (with primary and secondary WWTSs plus installation of washing machine filters) achieve nearly identical microplastic removal rates (59.10 g/person/year). Management Option 3 proved to be more economically advantageous, as a tertiary WWTS requires significant investment compared to the installation of washing machine filters. However, these results do not intend to advocate against the importance of tertiary WWTSs. It is crucial for the facilities, especially those with large populations, such as some of those in Ross Sea region, to install tertiary-level WWTSs. This study specifically addresses microplastic waste, but it is essential to acknowledge that wastewater contains other biological and chemical pollutants that can significantly impact the Antarctic environment and its biodiversity (Akpor et al. Reference Akpor, Otohinoyi, Olaolu and Aderiye2014). Wastewater, especially from toilets, may contain pathogens such as bacteria and viruses (Lou et al. Reference Lou, Liu, Gu, Hu, Tang and Zhang2021). Tertiary WWTSs are necessary to remove these pollutants effectively. If all of these other pollutants are considered, Management Option 2 presents the highest cost-efficiency rate, as no other management option fully addresses both biological and chemical pollutants. Additionally, this study does not account for the secondary impacts of microplastics, such as the release of chemicals, which would further increase the cost-efficiency of tertiary WWTSs.
Study limitations
Several limitations should be acknowledged for future research considerations. This study focused exclusively on policy interventions targeting microplastic generation through banning personal hygiene products containing microbeads. However, other upstream prevention strategies (e.g. replacing synthetic clothing with natural fibres or reducing human presence in Antarctica) were not considered due to practical constraints. Synthetic fabrics provide essential thermal protection and safety features critical for Antarctic conditions that natural, bulky alternatives cannot currently match without compromising personnel safety. Similarly, reducing scientific presence was determined to be counterproductive to our broader scientific and environmental goals. The research conducted in Antarctica provides irreplaceable data on climate change, marine ecosystems and global environmental processes. These approaches will reduce one form of impact while potentially creating greater harms through compromised safety or scientific understanding.
Nevertheless, it remains important to further investigate the microplastic emissions associated with these upstream sources, as research stations contribute microplastic particles through multiple pathways beyond WWTSs (Frontier et al. Reference Frontier, Cole and Hughes2025). Notably, Napper et al. (Reference Napper, Parker-Jurd, Wright and Thompson2023) demonstrated that atmospheric deposition of synthetic microfibres shed during normal textile use represents a significant pathway for microplastic pollution - potentially exceeding the quantities released during laundering. Given the extensive use of synthetic clothing and equipment by scientists working in Antarctic conditions, there is probably a substantial direct release of microfibres into the environment through daily wear and tear, independent of washing processes. This significant source of contamination requires further research as our understanding of microfibre shedding patterns during daily use continues to evolve.
Furthermore, to develop a comprehensive understanding of microplastic contamination in this sensitive region, it is crucial to investigate other significant contributors - particularly tourism and fishing operations, both of which have increased substantially in recent years. Antarctic tourism has grown dramatically, with visitor numbers rising from ~8000 in the early 1990s to over 122 000 in the 2023/2024 season before the COVID-19 pandemic (International Association of Antarctica Tour Operators 2024). Each vessel carries washing machines, shower facilities and other amenities that generate wastewater. Unlike research scientific stations, these vessels typically employ less sophisticated WWTSs due to space constraints and operational limitations at sea, potentially resulting in higher concentrations of microplastic discharge directly into Antarctic waters.
Similarly, fishing activities in the Southern Ocean have intensified. These operations introduce microplastics through multiple pathways: degradation of fishing nets, wastewater from crew facilities and inadvertent release of operational waste. A study by Waller et al. (Reference Waller, Griffiths, Waluda, Thorpe, Loaiza and Moreno2017) estimated that a single fishing vessel might release up to 5.6 billion microplastic particles annually through equipment degradation alone.
Conclusion
To target the microplastic problem, it is essential to study each sector and source independently in order to be able to develop focused and efficient mitigation strategies. This study focused on estimating the potential microplastic release from scientific facilities in Antarctica and investigated possible solutions to manage wastewater flow. Annually, an estimated 238 kg of microplastic particles are released by these stations. On a continental scale - covering 14 million km2 - this amount might seem negligible. However, the continuous release of microplastics can have a significant local impact over time, particularly in areas near the stations where dilution and dispersal rates of wastewater are low.
The study has also shown that this microplastic pollution can be effectively addressed by prioritizing simple, low-cost preventative methods. Some solutions involve simple technologies such as washing machine filters and changes in behaviour at stations by placing a ban on hygiene products containing microbeads. Additionally, we recommend the general improvement of sewage treatment facilities for the long-term preservation of the Antarctic environment. Comprehensive wastewater treatment is crucial for eliminating other pollutants such as pathogens, metals, organic matter and microplastic particles.
Currently, Antarctica lacks specific regulations or a continent-wide monitoring programme to address microplastic pollution (Waller et al. Reference Waller, Griffiths, Waluda, Thorpe, Loaiza and Moreno2017). As part of the United Nations Sustainable Development Goals, the Southern Ocean Action Plan identified the improvement of waste management in this region as a critical priority (Janssen et al. Reference Janssen, Badhe, Bransome, Bricher, Cavanagh and de Bruin2022). The empirical results of this study are intended to help improve current decisions regarding microplastic waste in Antarctica.
Finally, this research offers a methodological foundation for broader applications, including future assessments of microplastic emissions from other human activities such as fisheries and tourism. Expanding this framework could help us to achieve a more comprehensive understanding of microplastic sources and guide effective protection strategies for the Antarctic environment.
Our study provides a framework to inform policy decisions on microplastic release in Antarctica and lays the foundation for improved environmental protection strategies in this sensitive region.
Acknowledgements
This paper is supporting the objectives of the SCAR ‘Plastic in the Polar Environments’ action group and the SCAR Scientific Research Programme ‘Integrated Science to Inform Antarctic and Southern Ocean Conservation’ (Ant-ICON). Natasha Gardiner, Ceisha Poirot, Jonny Stark, Peter Taylor and Sophia White are acknowledged for the production of the questionnaire to National Antarctic Programmes that subsequently provided the underlying data for this analysis.
Author contributions
Aanchal Jain: conceptualization, methodology, data curation, writing. Kevin A. Hughes: data curation, writing, supervision. Clara Manno: conceptualization, data curation, writing, supervision, resources. All authors reviewed the manuscript.
Data availability
All the data presented in this study are available in this paper.
Financial support
This work was funded by a COMNAP Fellowship and is a contribution to the UKRI-FLF project CUPIDO (MR/T020962/1). Kevin A. Hughes was supported through NERC core funding to the Environment Office of the British Antarctic Survey.
Competing interests
The authors declare none.
Open access
