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Shedding light on the invisible: addressing the potential for groundwater contamination by plastic microfibers

  • Viviana ReEmail author
Open Access
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Abstract

The processes of microplastic fiber pollution in groundwater are unknown. The recent research on this contaminant threat is generally focused on surface waters (mainly oceans and rivers), while aquifer contamination is only marginally mentioned as an issue needing further investigation. Synthetic microfibers can be introduced into soils in different ways (e.g. wastewater treatment plants or greywater discharge, septic tank outflows, direct injection of contaminated water in cases of managed aquifer recharge, losing streams, etc.), and can thus reach aquifer systems due to leaching or infiltration in soil pores. Microfibers can then adsorb persistent bioaccumulative and toxic chemicals, which include persistent organic pollutants and metals, and become a carrier of harmful substances in the aquifer system, hence contributing to the overall contamination in both urban and rural areas. For this reason, it is of paramount importance, not only to assess the occurrence and fate of microplastic fibers in groundwater, but also to study the role of microplastics as carriers of contaminants within the aquifer and to advance standardization and organization of monitoring campaigns. Only by addressing these key challenges can hydrogeologists contribute to the state of the art on microplastic pollution and ensure that groundwater is not neglected in the environmental assessments tackling this contaminant of emerging concern.

Keywords

Emerging pollutants Microplastic Groundwater monitoring Water-resources conservation Contamination 

Lumière sur l’invisible: s’attaquer au potentiel de contamination des eaux souterraines par des microfibres plastiques

Résumé

Les processus de pollution par les fibres micro-plastiques dans les eaux souterraines sont inconnus. Les recherches récentes sur cette menace de contaminants sont généralement axées sur les eaux de surface (principalement les océans et les rivières), tandis que la contamination des aquifères n’est que marginalement mentionnée comme une question nécessitant des recherches plus approfondies. Les microfibres synthétiques peuvent être introduites dans les sols de différentes manières (par ex. rejets de stations de traitement d’eaux usées ou rejets d’eaux grises, sorties de fosses septiques, injection directe d’eau contaminée dans les cas de gestion de la recharge d’aquifère, perte de cours d’eau, etc.) et peuvent ainsi atteindre les systèmes aquifères en raison de lessivage ou d’infiltration dans les pores du sol. Les microfibres peuvent ensuite adsorber des produits chimiques persistants, bio-accumulatifs et toxiques, qui comprennent les polluants organiques persistants et les métaux, et deviennent porteuses de substances nocives dans les systèmes aquifères, contribuant ainsi à la contamination générale aussi bien dans les zones urbaines que dans les zones rurales. Pour cette raison, il est d’une importance primordiale, non seulement d’évaluer l’occurrence et le devenir des fibres micro-plastiques dans les eaux souterraines, mais aussi d’étudier le rôle des micro-plastiques en tant que porteurs de contaminants dans l’aquifère et de faire progresser la normalisation et l’organisation de campagnes de suivi. Ce n’est qu’en abordant ces principaux défis que les hydrogéologues contribuent à l’état de l’art sur la pollution par les micro-plastiques et veillent à ce que les eaux souterraines ne soient pas négligées dans les évaluations environnementales qui s’attaquent à ce contaminant de préoccupation émergente.

Arrojando luz sobre lo invisible: abordar el potencial de contaminación de las aguas subterráneas por microfibras de plástico

Resumen

Se desconocen los procesos de contaminación por fibras microplásticas en el agua subterránea. La investigación reciente sobre esta amenaza de contaminantes se centra generalmente en las aguas superficiales (principalmente los océanos y los ríos), mientras que la contaminación de los acuíferos se menciona sólo marginalmente como un tema que requiere mayor investigación. Las microfibras sintéticas pueden introducirse en los suelos de diferentes maneras (por ejemplo, en plantas de tratamiento de aguas residuales o descarga de aguas grises, desagües de fosas sépticas, inyección directa de agua contaminada en casos de recarga de acuíferos gestionados, pérdida de corrientes, etc.) y, por lo tanto, pueden llegar a los sistemas acuíferos debido a la lixiviación o infiltración en los poros del suelo. Las microfibras pueden entonces adsorber productos químicos bioacumulativos y tóxicos persistentes, que incluyen contaminantes orgánicos persistentes y metales, y convertirse en portadores de sustancias nocivas en el sistema acuífero, contribuyendo así a la contaminación general tanto en zonas urbanas como rurales. Por esta razón, es de suma importancia, no sólo evaluar la ocurrencia y el destino de las fibras microplásticas en las aguas subterráneas, sino también estudiar el papel de los microplásticos como portadores de contaminantes dentro del acuífero y avanzar en la estandarización y organización de campañas de monitoreo. Sólo abordando estos desafíos clave pueden los hidrogeólogos contribuir al estado del arte de la contaminación microplástica y asegurar que las aguas subterráneas no sean descuidadas en las evaluaciones ambientales que abordan este contaminante de interés emergente.

揭示不可见污染问题:解决塑料微纤维污染地下水的可能性

摘要

地下水中微塑性纤维污染的过程尚不清楚。最近关于该污染物威胁的研究通常集中在地表水(主要是海洋和河流),而含水层污染仅略微被提到是需要进一步调查的问题。合成微纤维可以不同方式进入土壤(例如废水处理厂或灰水排放,化粪池出流,管理的含水层补给或河流补给地下水等情况下直接补给污染水),因此由于土壤孔隙中浸出或渗透作用污染水可以进入含水层系统。而且微纤维可以吸附包括持久性有机污染物和金属之类的持久性生物蓄积性和有毒的化学物质,并成为含水层系统中有害物质的载体,从而导致城市和农村地区的整体污染。因此至关重要的是,不仅要评估地下水中微塑料纤维的产生和归趋,还要研究微塑料作为含水层内污染载体的作用,并推进监测项目的标准化和组织。只有解决了这些关键问题,水文地质学家才能对微塑性污染的现有技术做出贡献,并确保在解决新出现污染的环境评估中地下水不会被忽视。

Iluminando o invisível: abordando o potencial de contaminação da água subterrânea por microfibras de plástico

Resumo

Os processos de poluição de fibra de microplástico em águas subterrâneas são desconhecidos. A pesquisa recente sobre essa ameaça de contaminantes é geralmente focada em águas superficiais (principalmente oceanos e rios), enquanto a contaminação de aquíferos é apenas marginalmente mencionada como uma questão que necessita de investigação adicional. As microfibras sintéticas podem ser introduzidas nos solos de diferentes maneiras (por exemplo, estações de tratamento de águas residuais, vazamentos de tanques sépticos, injeção direta de água contaminada em casos de recarga gerenciada de aquíferos, influência de córregos, etc.) e podem atingir sistemas aquíferos devido à lixiviação ou infiltração nos poros do solo. As microfibras podem, então, adsorver substâncias químicas bioacumulativas e tóxicas persistentes, que incluem poluentes orgânicos persistentes e metais, e se tornarem portadoras de substâncias nocivas no sistema aquífero, contribuindo assim para a contaminação geral em áreas urbanas e rurais. Por essa razão, é de suma importância não apenas avaliar a ocorrência e o destino das fibras de microplásticos nas águas subterrâneas, mas também estudar o papel dos microplásticos como portadores de contaminantes no aquífero e avançar na padronização e organização das campanhas de monitoramento. Somente abordando esses desafios chave, os hidrogeólogos podem contribuir para o estado da arte sobre a poluição por microplásticos e garantir que as águas subterrâneas não sejam negligenciadas nas avaliações ambientais que tratam desse contaminante de preocupação emergente.

Introduction

It is the age of plastics and the debate over microplastics pollution has never been more relevant, however a full understanding of its impacts on the natural environment is still far from being reached. Plastic is ubiquitous and, most importantly, everlasting, as practically no biological organism in the Earth’s ecosystem has sufficiently evolved to readily consume it (Crawford and Quinn 2017). This implies that everyone has to deal with the side effects of plastic wastes released and accumulating in the natural environment over time (Barnes et al. 2009; UNEP and GRID-Arendal 2016). A recent study (Geyer et al. 2017) estimated that up to 2017, 8,300 million metric tons (Mt) of virgin plastics have been produced, and that of the approximately 6,300 Mt of plastic waste generated before 2015, only a very small percentage had been recycled or incinerated (9 and 12% respectively), while 79% had accumulated in landfills or the natural environment. The same study affirms that if current production and waste management trends continue, by 2050, about 12,000 Mt of plastic waste will be in landfills or in the environment. Together with these forms of plastic, which are mainly packaging, bottles and single-use plastic items, another issue of increasing concern is microplastics, which are defined as plastic particles smaller than 5 mm in length (Arthur et al. 2008). Microplastics are generally divided into two major categories: (1) primary microplastics intentionally manufactured for use in cosmetics, personal care products, industrial processing (e.g. sandblasting), textile applications, synthetic clothes production, domestic and industrial washing processes of fabrics (Gregory 1996; Fendall and Sewell 2009; Browne et al. 2011) that, being too small to be filtered by waste water treatment plants (WWTPs), can be introduced directly into oceans through direct runoff; and (2) secondary microplastics, as those typically generated by degradation and fragmentation of larger pieces of plastics (due to the exposure to ultraviolet light from the sun and/or by mechanical means such as tidal waves; Gregory and Andrady 2003), hence the ones referred to when talking about marine litter (Avio et al. 2016).

First reported in the 1970s in the Sargasso Sea in the North Atlantic (Carpenter and Smith 1972), microplastics have since then been found in several beach sediments worldwide (e.g. Thompson et al. 2004; Costa et al. 2010; Browne et al. 2011; Van Cauwenberghe et al. 2013; Nor and Obbard 2014). Therefore, their abundance in the marine environment, and associated increasing interest from both the scientific community and civil society, has meant that microplastics are gradually passing from being considered a contaminant of emerging concern to being recognized as an emerged threat (Avio et al. 2016). However, it is only recently that the impact of primary microplastics, and microfibers in particular, has started to be acknowledged (Browne et al. 2011). Given that a recent investigation (Tyree and Morrison 2017) estimated that 1 Mt of microplastic fibers are discharged into wastewater each year, where more than half evade treatment and escape into the environment, it is clear that microplastics are an issue that cannot be underestimated and require a strong engagement from the scientific community to avoid further negative consequences due to the lack of knowledge and of complete systematic research.

As the study of microplastics is a relatively new area of investigation, several challenging open questions still need to be addressed (Eerkes-Medrano et al. 2015; Geissen et al. 2015; Avio et al. 2016; Henry et al. 2019), including: (1) assessing microplastics occurrence and distribution in the natural environment, and, particularly in groundwater (as most of the studies focus on seawater, and only recently on surface waters); (2) understanding their transport pathways and factors that affect their distribution; (3) defining the methods for their accurate detection and quantification, including specifics on measurements and the standardization of analytical procedures; and (4) evaluating the extent and relevance of their impacts on both aquatic life and human health.

As a result, a full comprehension of the impact of primary microplastics on the natural environment is still far from being reached and, with regard to freshwater resources, research is in its early stages, while a coordinated monitoring of surface water and groundwater is not yet achieved, but urgently required (Geissen et al. 2015). The invisibility of groundwater makes it difficult to understand, study and manage, and often, as in the case of emerging pollutants, research only develops when the contamination issue has already occurred. It is under these premises, that this review article aims at contributing to highlight the gaps and challenges to be addressed on microplastics contamination in groundwater resources, with a special focus on synthetic microfibers.

Microfibers: an invisible threat

Fibers are defined as natural or synthetic substances that are significantly longer than wide, and that are often used in the manufacture of other materials (Harper 2017). Apart from asbestos, most of the natural fibers commonly employed in industrial applications are considered to be of no danger to human health (WHO 1986; Fig. 1), although the increasing concern about the biological and environmental impacts of synthetic fibers is driving new research addressing their eco-toxicological effects (Crawford and Quinn 2017, and references therein; Tyree and Morrison 2017).
Fig. 1

Classification of natural and synthetic fibers. Modified from Jawaid and Khalil (2011) highlighting in red the fibers with acknowledged toxicity, in green those with no risk, and in orange the fibers with suspected (or still under investigation) toxicity

As regards natural fibers, asbestos is probably the most studied, due to its natural abundance and toxicity. Asbestos is the generic designation for a group of naturally occurring minerals that are formed of thin fibers: chrysotile (the most commonly used form), actinolite, amosite, anthophyllite, crocidolite and tremolite (Strunz 2001). Consisting of separable fibers that are heat-resistant, strong and flexible enough to be spun and woven, these minerals have been widely used in buildings (e.g. fireproofing, acoustic and thermal insulation), automotive parts, tiles, cement and textiles (e.g. special cloths and garments which are resistant to heat and corrosive elements). Even though nowadays the carcinogenic effect of long-term exposure to, and associated inhalation of, asbestos is widely recognized (and mainly attributed to fiber dimensions; International Agency for Research on Cancer 1977; WHO 1986; Madl et al. 2010), some items are still widely debated in the scientific community. For example, based on the World Health Organization definition (WHO 2000), the current regulations only focus on long asbestos fibers (LAF: length: L ≥ 5 μm, diameter: D < 3 μm and L/D ratio > 3), while short asbestos fibers (SAF: length (L < 5 μm;) are still not taken into account (Boulanger et al. 2014). In addition, since most of the research focuses on airborne asbestos, another open concern is the clear assessment of the health effects of the direct ingestion of asbestos in drinking-water (e.g. Polissar et al. 1983; Di Ciaula and Gennaro 2016), as proven by its absence in drinking-water guidelines (WHO 2013).

Synthetic microfibers are defined as a type of plastic, made up of various synthetic polymers (e.g. polyester, acrylic and nylon fibers), fibrous in shape, and smaller than 1 mm to 1 μm in length (Crawford and Quinn 2017; Fig. 2a). Recent studies have highlighted a significant increase in the production of synthetic fibers to supply the growing demand of the clothing and cleaning products sectors (Qin 2014; Fig. 2b), with polyester alone accounting for over 40 Mt/year (Aizenshtein 2015), and it has been proven that synthetic textiles can shed numerous microfibers during conventional washing (Hartline et al. 2016).
Fig. 2

a Fibers captured on a 20-μm filter. Photo: Shreya Sonar, Bren School of Environmental Science and Management at UCSB, USA (Patagonia 2017); b Historical and projected fiber production (in million metric tons, Mt) from 1980 to 2025 (source Qin 2014)

The scope of this problem is evidenced by the growing attention of the productive sector itself, as in the case of Patagonia, a company selling outdoor clothing marketed as sustainable, which recently commissioned the University of California (USA) to assess the amount of microfibers released from outerwear during washing. Using the company’s sale numbers, the researchers (Bruce et al. 2017) extrapolated that about 100,000 jackets are in use worldwide each year, and washing them would produce enough plastic to make 11,900 grocery bags. When released into the natural environment, being too small to be filtered in WWTPs, the microfibers can end up in seas and oceans, thus contributing to marine litter (e.g. Mintenig et al. 2017; Henry et al. 2019; Magni et al. 2019). In particular, it has been estimated that these tiny fibers make up 85% of human debris on shorelines across the globe (Browne et al. 2011), and were also recently found in seawater and in fish caught worldwide (e.g. Rochman et al. 2015; Barrows et al. 2018; Gago et al. 2018 and references therein), in table salt (Yang et al. 2015), in beer (Liebezeit and Liebezeit 2014; Kosuth et al. 2018), and even in drinking water (Eerkes-Medrano et al. 2018; Tyree and Morrison 2018; Schymanski et al. 2018; Koelmans et al. 2019).

As a consequence of their abundance and ubiquity it is likely that synthetic microfibers are to become the next big issue to threaten water quality and wildlife, and there is growing concern about their potential danger to human health, to such an extent that the media are gradually beginning to call them “the new asbestos” (Tyree and Morrison 2017). However, if, on the one hand, the toxicity of asbestos fibers is mainly given by their physical properties, and particularly their sharpness and microscopic size which enables them to pierce cell wall membranes, interfere with DNA, and hence potentially lead to cancer (Ruosaari et al. 2008), the harmfulness of microfibers is principally attributed to chemical processes. In fact, microfibers can absorb persistent bioaccumulative and toxic (PBT) chemicals, which include persistent organic pollutants (POPs) and metals (Rios et al. 2007; Teuten et al. 2009; Pirc et al. 2016), hence enabling the uptake of toxic elements via consumption (Koelmans et al. 2016). Several studies have already reported the negative impact of microplastics on both freshwater invertebrates and fish, where ingestion of plastic microfibers was shown to cause physiological stress and signs of tumor formation (Eerkes-Medrano et al. 2015 and references therein). This has led to new concerns being raised about the possible health issues that may occur from human consumption of aquatic fauna and seafood (e.g. Sussarellu et al. 2016; Watts et al. 2015; Huerta Lwanga et al. 2016; Watts et al. 2016). In addition, a recent study (Liebmann et al. 2018) detected microplastic residues in human stool samples from eight different geographic regions (Austria, Finland, United Kingdom, Italy, Japan, the Netherlands, Poland and Russia), highlighting both the ubiquitous nature of the issue, and the potential impact of such an emerging contamination.

Despite the fact that to date no studies have shown that microfibers cause health problems in humans, and toxicological hazards associated with plastic microfibers ingestion are still not fully known (Galloway et al. 2016; Crawford and Quinn 2017), it is reasonable to assume that understanding the potential of microfibers as a vector for the introduction of contaminants in human bodies is only a question of time and advances in scientific research.

Microfibers in groundwater: invisible contaminants in the hidden component of the water cycle

Groundwater is the world’s most important source of available freshwater supplying more than 2 billion people with safe water for domestic, drinking, agricultural and industrial purposes in both developing and industrialized nations worldwide. In addition, in many rural areas, groundwater is often the main freshwater source for both domestic and agricultural uses (Re and Zuppi 2011), providing farmers and local households with, generally free, supplies in close proximity to the users, and commonly without the need for complex treatment (Morris et al. 2003). Approximately 38% of global irrigated areas rely on groundwater resources (Siebert et al. 2013), which has led to a 10-fold increase of groundwater extraction for agricultural irrigation over the last 50 years (WWAP 2016). Undoubtedly one of the main consequences of this high aquifer dependency is that any contamination of these waters can have serious repercussions on the local population, both directly, when groundwater is used for drinking purposes, and indirectly, when used for irrigation. Even though the international hydrogeological community is quite active in promoting actions targeted toward the long-term protection of global aquifer systems (IAH 2017), the hidden nature of groundwater makes it difficult to study and manage, and hampers the implementation of sound science-based management practices, especially when emerging issues are at stake, which is the case with microplastics pollution. In fact, despite the growing number of investigations targeted at surface waters, at present, there is a limited knowledge on possible plastic microfibers’ presence and transport in aquifer systems. In fact, only a few studies targeted their occurrence in groundwater (e.g. e.g. Bouwman et al. 2018; Mintenig et al. 2019; Panno et al. 2019), while the presence of microscopic plastic fibers in tap water coming from underground sources was revealed for the first time only recently (Tyree and Morrison 2017). As a result of this lack of knowledge, groundwater still does not appear in literature on microfibers, as evidenced by some of the most cited publications on the present state-of-the-art research on microfibers pollution (Fig. 3; Bruce et al. (2017), nor in the legislation dealing with plastic contamination reduction, as in the case of the European plastics strategy (European Commission 2017), currently being prepared to help countries improve recycling, cut marine litter, and remove potentially dangerous chemicals.
Fig. 3

Conceptual box model of microfibers distribution, displaying observed and theorized pathways of microfibers transfer in the environment and biome. Modified from Bruce et al. (2017) with the addition of the red rectangles highlighting the steps where microfibers could enter the aquifer systems and be transported along the groundwater flow

Indeed, if natural microfibers such as asbestos can be present and move through soil and groundwater (Willenbring 2016), it is reasonable to hypothesize that synthetic microfibers will not be much different and could also be transported to, and within, aquifer systems.

For example, synthetic microfibers can be introduced into soils in different ways, either via land-applied WWTPs’ biosolids (Habib et al. 1998; Zubris and Richards 2005; Rillig 2012; Murphy et al. 2016), or via direct discharge of greywater (i.e. untreated wastewater generated in households from all streams except for toilets, i.e. sinks, showers, baths and washing machines) out of septic tanks (National Academies of Sciences, Engineering, and Medicine 2016). In both cases, water can leach into the soil and create a pathway for microfibers to reach the aquifer system (Hurley and Nizzetto 2018), or they can accumulate in the soil and be subsequently remobilized by heavy rains and/or irrigation.

In addition, since effluents from industrial processes and WWTPs are often discharged into local river systems, surface-groundwater interactions (e.g. in the presence of losing streams recharging groundwater) potentially provide a pathway for microfibers to enter into aquifer systems (Fig. 4a) and should also be addressed. The direct injection of contaminated water into the underground system can also occur, as in cases of managed aquifer recharge (MAR) using WWTP effluent (Fig. 4b). Indeed, if these contamination pathways are not adequately assessed, microfibers and associated PBT chemical compounds can enter the aquifer system without control and, in the case of groundwater used for drinking and agricultural purposes, can potentially cause more harm than ingestion via fish and seafood. This is, firstly, because the amount of water a person drinks per day, both directly and indirectly (e.g. sodas, beer, juices etc.), is generally considerably higher than the quantity of fish and seafood consumed, and, secondly, because the pathway from the source to the tap is much shorter than the possible intake of microplastics via the food chain (Fig. 5).
Fig. 4

Schematic representation of possible indirect pathways of microfiber transport in groundwater: a losing stream and b managed aquifer recharge (MAR, with treated water from WWTPs injected directly into the aquifer via an injection well). Blue arrows represent surface-water recharging groundwater; red arrows highlight the possible pathway for microfibers entering in to the supply well. (Modified from Government of Western Australia 2017)

Fig. 5

Scheme of the potential mechanisms for plastic microfibers intake for humans. Dashed black line: food intake; blue line: drinking intake

It seems therefore of great relevance to assess the occurrence of microfibers in aquifer systems, and to try to understand the possible harmful effects on human health due to plastic ingestion. To this end, a full understanding of transport dynamics and the assessment of how the morphology of the fibers can affect their movements along the flow paths are key issues that still need to be addressed.

The review of the known unknowns (i.e. items recognized by the scientific community as needing investigation) and the unknown unknowns (i.e. items not already present or still not adequately addresses in the scientific literature) of both synthetic and natural microfibers highlights the existing gaps in the field. It also highlights the challenges for the international community of hydrogeologists to go beyond the state of the art on contaminant hydrogeology (Table 1), thus supporting an effective and long-term protection of global groundwater resources.
Table 1

Summary of the state-of-the-art research on microfibers which underline the challenges that hydrogeologists can address

Type of microfiber

Size

Color

Mobility in groundwater

Toxicity

Epidemiology

Diffusion

Environmental relevance

Natural microfibers (e.g. asbestos)

Known known

Known known

Known unknown

Known known (inhalation),

Known unknown (ingestion)

Known known

Known known

Known known

Synthetic microfibers

Known known

Known known

Unknown unknown

Unknown unknown

Unknown unknown

Unknown unknown

Unknown unknown

Known knowns are items already addressed in the international literature and/or well understood). Known unknowns are items recognized by the scientific community as needing investigation). Unknown unknowns are items not fully addressed and identified as gaps in the scientific literature. (Sources: Lemen et al. 1980; Tweedale and McCulloch 2004; Boulanger et al. 2014; Avio et al. 2016; Miranda and de Carvalho-Souza 2016; Crawford and Quinn 2017)

Challenges and opportunities

The vulnerability of groundwater resources to anthropogenic pressure, associated with their crucial role in sustaining human activities and natural ecosystems, requires sound actions targeted at groundwater protection and management. Therefore, pioneering investigations are required for an early identification of potential sources of contamination, before the problem is too widespread that only decontamination actions can be implemented.

The issue of synthetic microfiber pollution in groundwater is still far from being addressed, as the potential for aquifer contamination is only marginally mentioned in the recent literature on microplastic pollution. This means that in most cases, groundwater is only mentioned as a possible receptor of microfibers due to leaching and/or transfer in the biopores (e.g. Hohenblum et al. 2015; Huerta Lwanga et al. 2016, 2017; Rillig et al. 2017; Chae and An 2018; Eerkes-Medrano et al. 2018; He et al. 2018; Henry et al. 2019), while only a limited number of studies have attempted to assessed their presence in groundwater bodies (e.g. Bouwman et al. 2018; Mintenig et al. 2019).

It is under these premises, that the international hydrogeological community should address the following challenges:
  1. 1.

    Determine the occurrence of microfibers in groundwater and study their transport mechanisms along the flow paths. In particular, it will become fundamental to focus on the unknown processes associated to the fate and occurrence of microfibers in groundwater, thus contributing to the long-term protection of the natural environment and human health.

    To this end, understanding transport mechanisms will be the first step towards demonstrating the potential impact that microfibers present in surface water can have on the underground system. Assessing microfibers’ movement within different porous media would hence permit researchers to determine aquifer vulnerability to this emerging contaminant.

     
  2. 2.

    Assess the role of microplastics as carriers of contaminants within the aquifer. In particular, the analysis should focus on those classes of pollutants that have already been demonstrated to interact with microplastics (e.g. DDT, perfluoroalkylates, polycyclic aromatic hydrocarbons, polychlorinated biphenyl phthalates; Crawford and Quinn 2017), and potentially present in both industrial and agricultural sites.

     
  3. 3.

    Define a standardized procedure for microfibers sampling and monitoring in groundwater. This will represent a strong contribution to the research field since, at present, accurate detection and quantification techniques, including protocols for measurements and analyses, are still missing (Avio et al. 2016). Indeed, the creation of a standardized methodology in the development stage of this new research field would optimize any future research efforts, avoiding the biases due to methodological discrepancies, the lack of uniformity in the information, and associated issues in results comparisons. This would not only facilitate the replicability of any research and experiment, but also the communication to the civil society and policy makers, a fundamental requisite for the development of new regulations on microfibers contamination reduction. A homogenization of sampling procedures and analytical techniques, thus resulting from multidisciplinary collaboration with surface hydrologists, biologists and ocean scientists, that are already performing microfibers analyses in surface-water samples using spectroscopic analysis—e.g. Fourier Transform Infrared Spectroscopy (FTIR) or Raman spectroscopy (e.g. Habib et al. 1998; Liebezeit and Liebezeit 2014; Löder et al. 2015; Wiesheu et al. 2016; Hartline et al. 2016) will be necessary.

     

Addressing these challenges will therefore enable sound pollution assessments at the catchment scale, and will favor the inclusion of the hidden component of the water cycle starting at the earliest stages of this new branch of contaminant hydrology.

Notes

Acknowledgements

The author would like to thank Prof. Elisa Sacchi (University of Pavia, Italy) for the critical review of the manuscript and Ms. Jo Oddie for the English review. The open access publication of this manuscript was supported by the InRoad funding scheme of the University of Pavia, Italy.

References

  1. Aizenshtein EM (2015) Global and Russian output of polyester fibres in 2013. Fibre Chem 47:1–7CrossRefGoogle Scholar
  2. Arthur C, Baker J, Bamford H (2008) Proceedings of the international research workshop on the occurrence, effects and fate of microplastic marine debris. NOAA Technical Memorandum NOS-OR&R-30, NOAA, Silver Spring, MD, 49 ppGoogle Scholar
  3. Avio CG, Gorbi S, Regoli F (2016) Plastics and microplastics in the oceans: from emerging pollutants to emerged threat. Mar Environ Res 128:2–11CrossRefGoogle Scholar
  4. Barnes DKA, Galgani F, Thompson RC, Barlaz M (2009) Accumulation and fragmentation of plastic debris in global environments. Philos Trans R Soc B 364:1985–1998CrossRefGoogle Scholar
  5. Barrows PW, Cathey SE, Petersen CW (2018) Marine environment microfiber contamination: global patterns and the diversity of microparticle origins. Environ Pollut 237:275–284CrossRefGoogle Scholar
  6. Boulanger G, Andujar P, Pairon JC, Billon-Galland MA, Dion C, Dumortier P, Brochard P, Sobaszek A, Bartsch P, Paris C, Jaurand MC (2014) Quantification of short and long asbestos fibers to assess asbestos exposure: a review of fiber size toxicity. Environ Health 13:59CrossRefGoogle Scholar
  7. Bouwman H, Minnaar K, Bezuidenhout C, Verster C (2018) Microplastics in freshwater environments. WRC report 2610/1/18, Water Resources Commission. http://www.wrc.org.za/. Accessed Dec 2018
  8. Browne MA, Crump P, Niven SJ, Teuten E, Tonkin A, Galloway T, Thompson R (2011) Accumulation of microplastic on shorelines worldwide: sources and sinks. Environ Sci Technol 45:9175–9179CrossRefGoogle Scholar
  9. Bruce NJ, Hartline N, Karba SN, Ruff B, Sonar S (2017) Microfiber pollution and the apparel industry. http://brenmicroplastics.weebly.com/uploads/5/1/7/0/51702815/bren-patagonia_final_report.pdf. Accessed Aug 2017
  10. Carpenter EJ, Smith KL (1972) Plastics on the Sargasso Sea surface. Science 175:1240–1241CrossRefGoogle Scholar
  11. Chae Y, An Y-C (2018) Current research trends on plastic pollution and ecological impacts on the soil ecosystem: a review. Environ Pollut 240:387–395CrossRefGoogle Scholar
  12. Costa MF, Ivar do Sul JA, Silva-Cavalcanti JS, Araújo MCB, Spengler A, Tourinho PS (2010) On the importance of size of plastic fragments and pellets on the strandline: a snapshot of a Brazilian beach. Environ Monit Assess 168:299–304CrossRefGoogle Scholar
  13. Crawford CB, Quinn B (2017) Microplastic pollutants. Elsevier, Amsterdam, 336 ppGoogle Scholar
  14. Di Ciaula A, Gennaro V (2016) Possible health risks from asbestos in drinking water. Epidemiol Prev 40:472–475Google Scholar
  15. Eerkes-Medrano D, Thompson RC, Aldridge DC (2015) Microplastics in freshwater systems: a review of the emerging threats, identification of knowledge gaps and prioritisation of research needs. Water Res 75:63–82CrossRefGoogle Scholar
  16. Eerkes-Medrano D, Leslie HA, Quinn B (2018) Microplastics in drinking water: a review and assessment of an emerging concern. Curr Opin Environ Sci Health 7.  https://doi.org/10.1016/j.coesh.2018.12.001
  17. European Commission (2017) Strategy on plastics in a circular economy. http://ec.europa.eu/smart-regulation/roadmaps/docs/plan_2016_39_plastic_strategy_en.pdf. Accessed August 2017
  18. Fendall LS, Sewell MA (2009) Contributing to marine pollution by washing your face: microplastics in facial cleansers. Mar Pollut Bull 58:1225–1228CrossRefGoogle Scholar
  19. Gago J, Carretero O, Filgueiras AV, Viñas L (2018) Synthetic microfibers in the marine environment: a review on their occurrence in seawater and sediments. Mar Pollut Bull 127:365–376CrossRefGoogle Scholar
  20. Galloway TS, Cole M, Lewis C (2016) Interactions of microplastic debris throughout the marine ecosystem. Nature Ecol Evolut 1:0116CrossRefGoogle Scholar
  21. Geissen G, Mol H, Klumpp E, Umlauf G, Nadal M, van der Ploeg M, van de Zeea SEATM, Ritsem CJ (2015) Emerging pollutants in the environment: a challenge for water resource management. Int Soil Water Conserv Res 3:57–65CrossRefGoogle Scholar
  22. Geyer R, Jambeck JR, Law KL (2017) Production, use, and fate of all plastics ever made. Sci Adv 3(7):e1700782CrossRefGoogle Scholar
  23. Government of Western Australia (2017) Managed aquifer recharge. http://www.water.wa.gov.au/urban-water/water-recycling-efficiencies/managed-aquifer-recharge. Accessed Sept 2017
  24. Gregory M (1996) Plastic ‘scrubbers’ in hand cleansers: a further (and minor) source for marine pollution identified. Mar Pollut Bull 32(12):867–871CrossRefGoogle Scholar
  25. Gregory MR, Andrady AL (2003) Plastics in the marine environment. In: Andrady AL (ed) Plastics and the environment. Wiley, Hoboken, NJCrossRefGoogle Scholar
  26. Habib D, Locke DC, Cannone LJ (1998) Synthetic fibers as indicators of municipal sewage sludge, sludge products, and sewage treatment plant effluents. Water Air Soil Pollut 103:1–8CrossRefGoogle Scholar
  27. Harper D (2017) Online etymology dictionary. http://www.etymonline.com/. Accessed Aug 2017
  28. Hartline N, Bruce NJ, Karba SN, Ruff EO, Sonar SU, Holden PA (2016) Microfiber masses recovered from conventional machine washing of new or aged garments. Environ Sci Technol 50:11532–11538CrossRefGoogle Scholar
  29. He D, Luo Y, Lu S, Liu M, Song Y, Lei L (2018) Microplastics in soils: analytical methods, pollution characteristics and ecological risks. TrAC Trends Anal Chem 109:163–172CrossRefGoogle Scholar
  30. Henry B, Laitala K, Kleppb IG (2019) Microfibres from apparel and home textiles: prospects for including microplastics in environmental sustainability assessment. Sci Total Environ 652:483–494CrossRefGoogle Scholar
  31. Hohenblum P, Liebmann B, Liedermann M (2015) Plastic and microplastic in the environment, vol 201. Environment Agency Austria, Umweltbundesamt, Vienna, 29 ppGoogle Scholar
  32. Huerta Lwanga E, Gertsen H, Gooren H, Peters P, Salánki T, van der Ploeg M, Besseling E, Koelmans AA, Geissen V (2016) Microplastics in the terrestrial ecosystem: implications for Lumbricus terrestris (Oligochaeta, Lumbricidae). Environ Sci Technol 50:2685–2691CrossRefGoogle Scholar
  33. Huerta Lwanga E, Gertsen H, Gooren H, Peters P, Salánki T, van der Ploeg M, Besseling E, Koelmans AA, Geissen V (2017) Incorporation of microplastics from litter into burrows of Lumbricus terrestris. Environ Pollut 220:523–531CrossRefGoogle Scholar
  34. Hurley RR, Nizzetto L (2018) Fate and occurrence of micro(nano)plastics in soils: knowledge gaps and possible risks. Curr Opin Environ Sci Health 1:1–62CrossRefGoogle Scholar
  35. IAH (2017) The International Association of Hydrogeologists website. https://iah.org/. Accessed Aug 2017
  36. International Agency for Research on Cancer (1977) Monographs on the evaluation of the carcinogenic risk of chemicals to man: asbestos, 14th edn. IARC, Lyon, FranceGoogle Scholar
  37. Jawaid M, Khalil HPSA (2011) Cellulosic/synthetic fibre reinforced polymer hybrid composites: a review. Carbohydr Polym 86:1–18CrossRefGoogle Scholar
  38. Koelmans AA, Bakir A, Burton GA, Janssen CR (2016) Microplastic as a vector for chemicals in the aquatic environment. Environ Sci Technol 50:11532–11538CrossRefGoogle Scholar
  39. Koelmans AA, Nor NHM, Hermsen E, Kooi M, Miniteng SM, De France J (2019) Microplastics in freshwaters and drinking water: critical review and assessment of data quality. Water Res 155:410–422CrossRefGoogle Scholar
  40. Kosuth M, Mason SA, Wattenberg EV (2018) Anthropogenic contamination of tap water, beer, and sea salt. PLoS One 13(4):e0194970CrossRefGoogle Scholar
  41. Lemen RA, Dement JM, Wagoner JK (1980) Epidemiology of asbestos-related diseases. Environ Health Perspect 34:1–11CrossRefGoogle Scholar
  42. Liebezeit G, Liebezeit E (2014) Synthetic particles as contaminants in German beers. Food Addit Contam 31:1574–1578CrossRefGoogle Scholar
  43. Liebmann B, Köppel S, Königshofer P, Bucsics T, Reiberger T, Schwab P (2018) Assessment of microplastic concentrations in human stool: preliminary results of a prospective study. Int. Conference on Emerging Contaminants (EMCON), 25–28 June 2018, Oslo, NorwayGoogle Scholar
  44. Löder MGJ, Kuczera M, Mintenig S, Lorenz C, Gerdts G (2015) Focal plane array detector-based micro-Fourier-transform infrared imaging for the analysis of microplastics in environmental samples. Environ Chem 12:563–581CrossRefGoogle Scholar
  45. Madl AK, Carosino C, Pinkerton KE (2010) Particle toxicities. In: Yost G (ed) Comprehensive toxicology, 2nd edn. Elsevier, New YorkGoogle Scholar
  46. Magni S, Binelli A, Pittura L, Avio CG, Della Torre C, Parenti CC, Gorbi S, Regoli F (2019) The fate of microplastics in an Italian wastewater treatment plant. Sci Total Environ 652:602–610CrossRefGoogle Scholar
  47. Mintenig SM, Int-Veena I, Löder MGJ, Primpke S, Gerdts G (2017) Identification of microplastic in effluents of waste water treatment plants using focal plane array-based micro-Fourier-transform infrared imaging. Water Res 108:365–372CrossRefGoogle Scholar
  48. Mintenig SM, Löder MGJ, Primpke S, Gerdts G (2019) Low numbers of microplastics detected in drinking water from ground water sources. Sci Total Environ 648:631–635CrossRefGoogle Scholar
  49. Miranda DD, de Carvalho-Souza GF (2016) Are we eating plastic-ingesting fish? Mar Pollut Bull 103:109–114CrossRefGoogle Scholar
  50. Morris BL, Lawrence ARL, Chilton PJC, Adams B, Calow RC, Klinck BA (2003) Groundwater and its susceptibility to degradation: a global assessment of the problem and options for management. Early warning and assessment report series, RS. 03–3. United Nations Environment Programme, NairobiGoogle Scholar
  51. Murphy F, Ewins C, Carbonnier F, Quinn B (2016) Wastewater treatment works (WwTW) as a source of microplastics in the aquatic environment. Environ Sci Technol 50:5800–5808CrossRefGoogle Scholar
  52. National Academies of Sciences, Engineering and Medicine (2016) Using graywater and Stormwater to enhance local water supplies: an assessment of risks, costs, and benefits. The National Academies Press, Washington, DC, 420 ppGoogle Scholar
  53. Nor NH, Obbard JP (2014) Microplastics in Singapore’s coastal mangrove ecosystems. Mar Pollut Bull 79:278–283CrossRefGoogle Scholar
  54. Panno SV, Kelly WR, Scott J, Zheng W, McNeish RE, Timothy NH, Hoellein J, Baranski EL (2019) Microplastic contamination in karst groundwater systems. Groundwater 57:189–196CrossRefGoogle Scholar
  55. Patagonia (2017) The cleanest line. https://www.patagonia.com/blog/2017/02/an-update-on-microfiber-pollution/. Accessed August 2017
  56. Pirc U, Vidmar M, Mozer A, Kržan A (2016) Emissions of microplastic fibers from microfiber fleece during domestic washing. Environ Sci Pollut Res 23:22206–22211CrossRefGoogle Scholar
  57. Polissar L, Severson RK, Boatman ES (1983) Cancer risk from asbestos in drinking water: summary of a case-control study in western Washington. Environ Health Perspect 53:57–60CrossRefGoogle Scholar
  58. Qin Y (2014) Global fibres overview. Synthetic Fibres Raw Materials Committee Meeting at APIC, Pattaya City, Thailand, May 2014Google Scholar
  59. Re V, Zuppi GM (2011) Influence of precipitation and deep saline groundwater on the hydrological systems of Mediterranean coastal plains: a general overview. Hydrol Sci J 56:966–980CrossRefGoogle Scholar
  60. Rillig MC (2012) Microplastic in terrestrial ecosystems and the soil? Environ Sci Technol 46:6453–6454CrossRefGoogle Scholar
  61. Rillig MC, Ingraffia R, de Souza Machado AA (2017) Microplastic incorporation into soil in agroecosystems. Front Plant Sci 8:1805CrossRefGoogle Scholar
  62. Rios LM, Moore C, Jones PR (2007) Persistent organic pollutants carried by synthetic polymers in the ocean environment. Mar Pollut Bull 54:1230–1237CrossRefGoogle Scholar
  63. Rochman CM, Tahir A, Williams SL, Baxa DV, Lam R, Miller JT, Teh F–C, Werorilangi S, Swee J, Teh SJ (2015) Anthropogenic debris in seafood: plastic debris and fibers from textiles in fish and bivalves sold for human consumption. Sci Rep 5:14340CrossRefGoogle Scholar
  64. Ruosaari S, Hienonen-Kempas T, Puustinen A, Sarhadi VK, Hollmén J, Knuutila S, Saharinen J, Wikman H, Anttila S (2008) Pathways affected by asbestos exposure in normal and tumour tissue of lung cancer patients. BMC Med Genet 2008(1):55Google Scholar
  65. Schymanski D, Goldbeck C, Humpf HU, Fürst P (2018) Analysis of microplastics in water by micro- Raman spectroscopy: release of plastic particles from different packaging into mineral water. Water Res 129:154–162CrossRefGoogle Scholar
  66. Siebert S, Henrich V, Frenken K, Burke J (2013) Update of the digital global map of irrigation areas (GMIA) to version 5. FAO, RomeGoogle Scholar
  67. Strunz H (2001) Mineralogical tables: chemical-structural mineral classification system, 9th edn. Schweizerbart, Berlin, 870 ppGoogle Scholar
  68. Sussarellu R, Suquet M, Thomas Y, Lambert C, Fabioux C, Pernet MEJ, Le Goïc N, Quillien V, Mingant C, Epelboin Y, Corporeau C, Guyomarch J, Robbens J, Paul-Pont I, Soudant P, Huvet A (2016) Oyster reproduction is affected by exposure to polystyrene microplastics. Proc Natl Acad Sci USA 113:2430–2435CrossRefGoogle Scholar
  69. Teuten EL, Saquing JM, Knappe DR, Barlaz MA, Jonsson S, Björn A, Rowland SJ, Thompson RC, Galloway TS, Yamashita R, Ochi D, Watanuki Y, Moore C, Viet PH, Tana TS, Prudente M, Boonyatumanond R, Zakaria MP, Akkhavong K, Ogata Y, Hirai H, Iwasa S, Mizukawa K, Hagino Y, Imamura A, Saha M, Takada H (2009) Transport and release of chemicals from plastics to the environment and to wildlife. Philos Trans R Soc Lond B Biol Sci. 364:2027–2045 Google Scholar
  70. Thompson RC, Olsen Y, Mitchell RP, Davis A, Rowland SJ, John AWG, Mcgonigle D, Russell AE (2004) Lost at sea: where is all the plastic? Science 304:838CrossRefGoogle Scholar
  71. Tweedale G, McCulloch J (2004) Chrysophiles versus chrysophobes: the white asbestos controversy, 1950s–2004. Isis 95:239–259CrossRefGoogle Scholar
  72. Tyree C, Morrison D (2017) INVISIBLES: the plastic inside us. https://orbmedia.org/stories/Invisibles_plastics/multimedia. Accessed September 2017
  73. Tyree C, Morrison D (2018) Plus plastic: microplastics found in global bottled water. https://orbmedia.org/stories/plus-plastic/text. Accessed December 2018
  74. UNEP and GRID-Arendal (2016) Marine litter vital graphics. United Nations Environment Programme, NairobiGoogle Scholar
  75. Van Cauwenberghe L, Vanreusel A, Mees J, Janssen CR (2013) Microplastic pollution in deep-sea sediments. Environ Pollut 182:495–499CrossRefGoogle Scholar
  76. Watts AJR, Urbina MA, Corr S, Lewis C, Galloway TS (2015) Ingestion of plastic microfibers by the crab Carcinus maenas and its effect on food consumption and energy balance. Environ Sci Technol 49:14597–14604CrossRefGoogle Scholar
  77. Watts AJR, Urbina MA, Goodhead R, Moger J, Lewis C, Galloway TS (2016) Effect of microplastic on the gills of the shore crab Carcinus maenas. Environ Sci Technol 50:5364–5369CrossRefGoogle Scholar
  78. WHO (1986) Asbestos and other natural mineral fibres. Environmental Health Criteria, WHO, Geneva, 35 ppGoogle Scholar
  79. WHO (2000) Air quality guidelines for Europe, second edn. European series no. 91, WHO, Geneva, 288 ppGoogle Scholar
  80. WHO (2013) Asbestos in drinking-water background document for development of WHO guidelines for drinking-water quality. In: Guidelines for drinking-water quality, vol 2, 2nd edn. WHO, GenevaGoogle Scholar
  81. Wiesheu AC, Anger PM, Baumann T, Niessner R, Ivleva NP (2016) Raman microspectroscopic analysis of fibers in beverages. Anal Methods 8(28):5722–5725CrossRefGoogle Scholar
  82. Willenbring J (2016) The fate of Asbestos in soil: remediation prospects and paradigms. In: Proceedings of the 2016 American Chemical Society meeting, Philadelphia, PA, Aug. 22, 2016. https://semspub.epa.gov/work/01/593287.pdf. Accessed August 2017
  83. WWAP (2016) The United Nations world water development report 2016: water and jobs. UNESCO, ParisGoogle Scholar
  84. Yang D, Shi H, Li L, Li J, Jabeen K, Kolandhasamy P (2015) Microplastic pollution in table salts from China. Environ Sci Technol 49:13622–13627CrossRefGoogle Scholar
  85. Zubris KAV, Richards BK (2005) Synthetic fibers as an indicator of land application of sludge. Environ Pollut 138:201–211CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Department of Earth and Environmental SciencesUniversity of PaviaPaviaItaly
  2. 2.Department of Earth SciencesUniversity of PisaPisaItaly

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