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Differential bioavailability of polychlorinated biphenyls associated with environmental particles: Microplastic in comparison to wood, coal and biochar
Abstract
Microplastic particles are increasingly being discovered in diverse habitats and a host of species are found to ingest them. Since plastics are known to sorb hydrophobic organic contaminants (HOCs) there is a question of what risk of chemical exposure is posed to aquatic biota from microplastic-associated contaminants. We investigate bioavailability of polychlorinated biphenyls (PCBs) from polypropylene microplastic by measuring solid-water distribution coefficients, gut fluid solubilization, and bioaccumulation using sediment invertebrate worms as a test system. Microplastic-associated PCBs are placed in a differential bioavailability framework by comparing the results to several other natural and anthrogenic particles, including wood, coal, and biochar. PCB distribution coefficients for polypropylene were higher than natural organic materials like wood, but in the range of lipids and sediment organic carbon, and smaller than black carbons like coal and biochars. Gut fluid solubilization potential increased in the order: coal < polypropylene < biochar < wood. Interestingly, lower gut fluid solubilization for polypropylene than biochar infers that gut fluid micelles may have solubilized part of the biochar matrix while bioaccessibility from plastic can be limited by the solubilizing potential of gut fluids dependent on the solid to liquid ratio or renewal of fluids in the gut. Biouptake in worms was lower by 76% when PCBs were associated with polypropylene compared to sediment. The presence of microplastics in sediments had an overall impact of reducing bioavailability and transfer of HOCs to sediment-ingesting organisms. Since the vast majority of sediment and suspended particles in the environment are natural organic and inorganic materials, pollutant transfer through particle ingestion will be dominated by these particles and not microplastics. Therefore, these results support the conclusion that in most cases the transfer of organic pollutants to aquatic organisms from microplastic in the diet is likely a small contribution compared to other natural pathways of exposure.
... In contrast, Beckingham and Ghosh (2017) [61] determined that PCB transfer fro MP spheres into benthic worms was much less than transfer from surrounding sediment Thaysen et al. (2020) [62] found the bidirectional transfer of PBDEs from ingested micr plastics in seabirds; contaminants in tissues could transfer onto ingested microplastic Given the diversity of MPs and their associated chemicals, generalizations are not poss ble. Since results on the desorption of chemicals from MPs are not consistent, it is n possible to conclude whether or not POPs desorbed from MPs are always harmful. ...
... In contrast, Beckingham and Ghosh (2017) [61] determined that PCB transfer from MP spheres into benthic worms was much less than transfer from surrounding sediments. Since results on the desorption of chemicals from MPs are not consistent, it is not possible to conclude whether or not POPs desorbed from MPs are always harmful. ...
... In contrast, Beckingham and Ghosh (2017) [61] determined that PCB transfer from MP spheres into benthic worms was much less than transfer from surrounding sediments. Thaysen et al. (2020) [62] found the bidirectional transfer of PBDEs from ingested microplastics in seabirds; contaminants in tissues could transfer onto ingested microplastics. ...
Plastics, including microplastics, have generally been regarded as harmful to organisms because of their physical characteristics. There has recently been a call to understand and regard them as persistent, bioaccumulative, and toxic. This review elaborates on the reasons that microplastics in particular should be considered as "toxic pollutants". This view is supported by research demonstrating that they contain toxic chemicals within their structure and also adsorb additional chemicals, including polychlorinated biphenyls (PCBs), pesticides, metals, and polycyclic aromatic hydrocarbons (PAHs), from the environment. Furthermore, these chemicals can be released into tissues of animals that consume microplastics and can be responsible for the harmful effects observed on biological processes such as development, physiology, gene expression, and behavior. Leachates, weathering, and biofilm play important roles in the interactions between microplastics and biota. Global policy efforts by the United Nations Environmental Assembly via the international legally binding treaty to address global plastic pollution should consider the designation of harmful plastics (e.g., microplastics) with associated hazardous chemicals as toxic pollutants.
... 24,26,[38][39][40][41] The vector effect is one of the major concerns in the field of plastic pollution, and is heavily debated in the research community. 26,[42][43][44] Transfer of HOCs from ingested plastics to biota has been investigated either with models accounting for a variety of exposure conditions using scenario analysis, [25][26][27]32,[45][46][47] in feeding experiments 38,41,[48][49][50][51] or in in vitro studies, [52][53][54] which mimic the organism's gastrointestinal (GI) system. While data from in vivo feeding experiments better represent the ultimate reality of nature and are essential for effects assessment, in vitro experiments provide significant advantages when determining chemical exchange rates between microplastics and gut fluid mimic. ...
... Pioneering in vitro studies have demonstrated that the desorption of plastic associated chemicals was rapid and enhanced under gut conditions compared to desorption to water only. [52][53][54] However, these previous studies have interpreted data on the desorption of chemicals in the gut fluid as a one-compartment unidirectional process. [52][53][54] In contrast, the reversibility of chemical sorption is acknowledged and taken into account for many sorbents of environmental interest, e.g., for soils and sediments 55 and for the widely used passive samplers, composed of polymers like polyethylene (PE) 56 , polyoxymethylene (POM) 57 or polydimethylsiloxane (PDMS). ...
... [52][53][54] However, these previous studies have interpreted data on the desorption of chemicals in the gut fluid as a one-compartment unidirectional process. [52][53][54] In contrast, the reversibility of chemical sorption is acknowledged and taken into account for many sorbents of environmental interest, e.g., for soils and sediments 55 and for the widely used passive samplers, composed of polymers like polyethylene (PE) 56 , polyoxymethylene (POM) 57 or polydimethylsiloxane (PDMS). 58 In the field of microplastic research however, quantifying the resorption of chemicals from the gut fluid content to plastic has been largely neglected thus far. ...
... However, risk assessments and, consequently, risk management decisions and actions carry a relatively high level of uncertainty without an understanding of bioavailability. Passive samplers (PS) of various types have been used as tools to directly sample porewater dissolved hydrophobic organic compounds (HOCs) and reliably estimate freely dissolved concentrations (C free ) in water or porewater (Jonker et al. 2020), which in turn has been shown to be a good thermodynamic metric for bioavailability assessment (Adams et al. 2007;Gschwend et al. 2011;Booij et al. 2016;Smedes et al. 2017;Beckingham and Ghosh 2017;Endo et al. 2020). Passive sampler hydrophobic organic compound (HOC) uptake has also been used as a surrogate for wholebody bioaccumulation in aquatic organisms, in both laboratory and field exposures, as reviewed in Joyce et al. (2016) and Schmidt and Burgess (2020). ...
... The primary objective of this study was to test the hypothesis of no difference in bioavailability between PCBs associated with PC dispersed in sediments and PCBs associated with field-collected sediments historically contaminated by sources other than paint. Differential bioavailability assessment provides a relative scaling of the tendency for contaminants associated with different environmental media (e.g., different types of organic matter or different manufactured materials), to be strongly sequestered, or quickly released and accumulated by organisms (Beckingham and Ghosh 2017). Investigation of differential bioavailability is facilitated by the use of PS (a uniform phase) which provide bioavailability measurements without the need to account for complex partitioning to a multitude of matrices contained in sediments. ...
... For example, decrease in PCB bioavailability by microplastics was associated with a polypropylene dose of 5% by dry wt. (Beckingham and Ghosh 2017). ...
This is the first investigation of the bioavailability of PCBs associated with paint chips (PC) dispersed in sediment. Bioavailability of PCB-containing PC in sediment was measured using ex situ polyethylene passive samplers (PS) and compared to that of PCBs from field-collected sediments. PC were mixed in freshwater sediment from a relatively uncontaminated site with no known PCB contamination sources and from a contaminated site with non-paint PCB sources. PC < 0.045 mm generated concentrations in the PS over one order of magnitude higher than coarser chips. The bioavailable fraction was represented by the polymer-sediment accumulation factor (PSAF), defined as the ratio of the PCB concentrations in the PS and organic carbon normalized sediment. The PSAF was similar for both field sediments. The PSAFs for the field sediments were ~ 50–60 and ~ 5 times higher than for the relatively uncontaminated sediment amended with PC for the size fractions 0.25–0.3 mm and < 0.045 mm, respectively. These results indicate much lower bioavailability for PCBs associated with PC compared to PCBs associated with field-collected sediment. Such information is essential for risk assessment and remediation decision-making for sites where contamination from non-paint PCBs sources is co-located with PCB PC.
... Further, other factors that influence the uptake of chemicals from ingested particles, such as gut residence time, can also vary between fibers and other types of microplastics. Another important consideration for future investigations is the bioavailability of microfiber-sorbed contaminants compared to other exposure pathways [136,142,143]. For example, Beckingham and Ghosh [142] demonstrated that the PCB uptake from microplastic spheres into benthic worms was much lower than the uptake from surrounding sediments. ...
... Another important consideration for future investigations is the bioavailability of microfiber-sorbed contaminants compared to other exposure pathways [136,142,143]. For example, Beckingham and Ghosh [142] demonstrated that the PCB uptake from microplastic spheres into benthic worms was much lower than the uptake from surrounding sediments. Further, Thaysen et al. [143] reported evidence of the bidirectional transfer of PBDEs from ingested microplastics in seabirds, where in some cases highly contaminated tissues may be a source of contaminants to ingested microplastics. ...
Microfibers are the most prevalent microplastics in most terrestrial, freshwater, and marine biota as well as in human tissues and have been collected from environmental compartments across most ecosystems and species sampled worldwide. These materials, made of diverse compound types, range from semi-synthetic and treated natural fibers to synthetic microfibers. Microfibers expose organisms across diverse taxa to an array of chemicals, both from the manufacturing process and from environmental adsorption, with effects on organisms at subcellular to population levels. Untangling the physical versus chemical effects of these compounds on organisms is challenging and requires further investigations that tease apart these mechanisms. Understanding how physical and chemical exposures affect organisms is essential to improving strategies to minimize harm.
... Lower brominated congeners had high assimilation rates while higher brominated congeners did not transfer, suggesting they may be too tightly adsorbed onto the plastic or unable to be assimilated. Beckingham and Ghosh [26] demonstrated uptake of PCBs from microplastic into benthic worms, but PCB uptake from sediments was much greater than from MPs. Juveniles of the fish Sparus aurata were exposed to virgin vs. weathered MPs [27]. Results indicated there was some cellular stress from virgin MPs, but greater stress from ...
... Lower brominated congeners had high assimilation rates while higher brominated congeners did not transfer, suggesting they may be too tightly adsorbed onto the plastic or unable to be assimilated. Beckingham and Ghosh [26] demonstrated uptake of PCBs from microplastic into benthic worms, but PCB uptake from sediments was much greater than from MPs. Juveniles of the fish Sparus aurata were exposed to virgin vs. weathered MPs [27]. Results indicated there was some cellular stress from virgin MPs, but greater stress from weathered MPs. ...
Microplastics have become a topic of considerable concern and intensive study over the past decade. They have been found everywhere in the oceans, including the deepest trenches and remotest parts of the Arctic. They are ingested by many animals and some are incorporated into tissues. There is considerable effort in studying what effects they have on marine life. It has become clear that when water samples are collected in ways that prevent most long thin particles from escaping through pores of a net, the most abundant type of microplastics found in water and sediments are microfibers (fibers with dimensions less than 5 mm). The major source of these pollutants is synthetic textiles, such as polyester or polyamides, which shed microfibers during their entire life cycle. Microfibers are released during textile manufacturing, everyday activities (e.g., washing, drying, wearing) and final disposal. The complexity of microfiber release mechanisms and of the factors involved make the identification and application of ways to reduce the inputs of microfibers very challenging. A comprehensive approach is strongly needed, taking into account solutions at a number of levels, such as re-engineering textiles to minimize shedding, applying washing machine filters, developing advanced wastewater treatment plants and improving the management of textile wastes. To harmonize and make mandatory the solutions identified, a variety of potential government policies and regulations is also needed.
... Micro(nano)plastics are hydrophobic and are attracted to adsorptive sites of biochar due to hydrophobic interactions in the aqueous media (Beckingham and Ghosh, 2017;Fu et al., 2021;Wang et al., 2021a). Fig. 1 shows the overall biochar interactions with microplastics based on different functional groups on the biochar surfaces and microplastic's hydrophobic surfaces. ...
... Fig. 1 shows the overall biochar interactions with microplastics based on different functional groups on the biochar surfaces and microplastic's hydrophobic surfaces. The adsorption of particles onto the biochar surface can be possible via electrostatic attraction due to electro-kinetic potentials, physical attachment, surface complex formation due to presence of carboxyl groups, precipitation due to availability of hydroxyl and iron ions (Beckingham and Ghosh, 2017;Ye et al., 2020;Li et al., 2021;Wang et al., 2021a). Besides, various interaction mechanisms between microplastics and biochar with respect to batch and column experiments are investigated as per the data presented in Table 2. ...
The abundance of micro(nano)plastics in natural ecosystems is a crucial global challenge, as these small-sized plastic particles originate from land-based and marine-based activities and are widely present in marine, freshwater, and terrestrial ecosystems. Micro(nano)plastics can significantly be reduced through various methods, such as biological, chemical, and physical techniques. Biochar is a low-cost adsorbent and is considered an efficient material and its application is ecologically effective carbon-negative for remediation of organic and inorganic pollutants. Therefore, this review critically discusses the fate and transport of micro(nano)plastics and their interactions with different biochar in aqueous and column porous media. This review outlines the implications of biochar with the co-existence of micro(nano)plastics in efforts to understand their coupled effects on soil physicochemical properties, microbial communities, and plant growth, along with the removal of heavy metals and other toxic contaminants. In batch experiments, biochar synthesized from various biomasses such as corn straw, hardwood, pine and spruce bark, corncob, and Prosopis juliflora had shown high level of removal efficiency (>90 %) for microplastic adsorption under varying environmental conditions viz., pH, temperature, ionic strength, particle size, and dose due to chemical bonding and electrostatic attractions. Increased temperature of the aqueous solutions encouraged higher adsorption, while higher pH and dissolved organic matter and nutrients may show decreased adsorption capacities for micro(nano)plastics using biochar. Compared to other available physical, chemical, and biological methods, biochar-amended sand filters in column experiments have been very efficient in removing micro(nano)plastics. In saturated column porous media, various microplastics could be inhibited using biochar due to decreased electrostatic repulsion, steric hindrance, and competitive sorption due to humic acid, ionic strength, and cations. Finally, this review provides in-depth insights on further investigations and recommendations for overall micro(nano)plastics removal using biochar-based materials.
... show that exposure to POPs and additives via the ingestion of microplastics in the environment contributes only negligibly to the toxification of fish (Koelmans et al. 2014). The reason is that the average microplastic concentration in fish is too low relative to the high concentrations of these pollutants in the surrounding water (Herzke et al. 2016;Beckingham & Ghosh 2017;Koelmans et al. 2016). ...
... Despite an assumption of long retention time (7 days) for MP particles in the GI tract, the contribution was found to be negligible, compared to other sources. Other studies have supported these results for hydrophobic organic contaminants and even suggested that MP particles in the stomach can act as passive samplers for toxic chemicals (Beckingham & Ghosh 2017;Herzke et al. 2016;Koelmans et al. 2016). ...
Pollution of the environment with plastic waste has long been an ignored issue, but is now considered a major global threat to aquatic systems and their inhabitants. Microplastics, comprising plastic fragments, beads, and fibers smaller than 5 mm, are detected in rivers, lakes and oceans all over the world. Due to their small size, they can be ingested by a wide range of aquatic organisms, including teleost fish. To date, little is known about how severely native freshwater fish species are affected by microplastics. There is also limited knowledge about how the differing gastrointestinal morphologies and foraging strategies of fish affect the uptake mechanisms and the retention time of microplastics. The aim of the thesis was to tackle some of these knowledge gaps in order to better understand the interaction of fish with microplastics in freshwater systems.
First, a new method for the detection of microplastics in fish was developed, which allowed efficient and rapid (<1 h) digestion of the entire fish gastrointestinal tract, and included an optional density separation step to reduce mineral components. (Manuscript I). This novel method made it possible to reliably and rapidly examine a large number of samples, allowing a large-scale analysis of microplastic burden in fish. This method was then used to investigate the microplastic burden of native fish species across the German state of Baden-Württemberg (Manuscript II). The overall burden of microplastics was found to be low, with an average prevalence of ~19 % and an intensity of between one and four particles per individual. Several relevant biotic and abiotic factors, such as sampling site and trophic state, were shown to have only a minor influence on microplastic burden. The results also revealed a major limitation with currently available microplastic detection methods: particles <40 μm could not be reliably detected in the gastrointestinal tract of the examined fish. However, by using the dataset acquired in this thesis it was possible to calculate the theoretical total microplastic burden in local fish with a size distribution analysis. It was found that as particle size decreases, particle concentration increases – with a power law growth fit likely indicating that over 95 % of all microplastic particles in fish are currently being excluded from collected data. This means that only a fraction of the potential size spectrum of microplastics can currently be considered in research data.
It is still not fully understood how microplastics are taken up by fish. To gain a more holistic understanding of microplastic uptake pathways, pre-existing and recently developed theories were explored through a number of practical and theoretical approaches (Manuscript III). Four fish species (rainbow trout(Oncorhynchus mykiss), grayling (Thymallus thymallus), common carp (Cyprinus carpio), crucian carp (Carassius carassius)), representing different foraging styles and domestic status, were exposed to a range of particles (varying by type and colour) with or without the provision of food; the abundance of microplastics was subsequently determined in their gastrointestinal tract. These experiments revealed that visually-orientated fish ingest microplastics actively and/or accidentally with their food much more frequently than fish that are chemosensory-orientated. In addition to the microplastic concentration in the water and fish size, the colour of the plastic particles played an important role in uptake: particles were taken up significantly more often if they resembled the colour of the food. By contrast, chemosensory foraging fish were able to discriminate larger plastic particles, and only ingested microplastics on occasion, by chance. At smaller particle sizes, uptake pathways other than feeding become more relevant; statistical models showed that in large marine fish species, notable amounts of microplastics were ingested simply through drinking. Finally, these experiments showed for the first time that domestication plays an important role in the uptake of microplastics. Relative to wild fish, farmed fish discriminated less between differently coloured plastic particles, and were more likely to actively ingest microplastics when no food source was available.
The next step was to investigate the duration that microplastic particles remained in the gastrointestinal tract of fish (Manuscript IV). A special diet was developed that contained differently sized microplastic particles. The number of retained particles in the gastrointestinal tract was determined up to 72 h after administration in two fish species (rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio)) that have distinct gastrointestinal morphologies. The laboratory experiments showed size-dependent differences in the T50 value (time at which 50 % of the particles are excreted) of plastic particles in fish with a true stomach; particles with a size of ~1000 μm were excreted approximately three times faster than particles with a size of ~40 μm. In fish without a stomach, the differences were substantially smaller, suggesting purely passive excretion with the chyme. It was thus concluded that the morphology of the gastrointestinal tract plays a vital role in the retention of microplastics, and that large plastic particles must be actively excreted in fish with a true stomach.
Finally, controlled laboratory experiments were conducted to investigate whether realistic microplastic concentrations have detrimental short- and long-term effects on fish (Manuscript V). In addition to an analysis of established performance and health parameters, the entire rainbow trout (Oncorhynchus mykiss) liver proteome was examined and the results confirmed with the help of gene expression analysis. Two groups of fish were exposed to a realistic current environmental concentration of microplastics, and a slightly elevated microplastic concentration that reflects expected microplastic exposure levels in the near future. These two groups were then compared with a control group (no exposure to microplastics) after 120 days of continuous exposure. Microplastic exposure was shown to have a significant dose-dependent effect on growth and other performance parameters (i.e. specific growth rate, feed conversion rate). There were no significant differences in blood glucose, hematocrit levels and oxidative stress levels between the groups. The proteomic analysis identified over 6000 proteins, but no clear difference in their regulation or correlation with gene expression was found between treatments. However, a number of single proteins and their respective transcripts were identified as potential biomarkers for future studies. The results therefore conclusively showed that even low microplastic concentrations have a notable impact on fish with long-term exposure. Importantly, they provide the basis for future investigations of microplastic effects on health, and demonstrates the potential of novel state-of-the-art methods that are now emerging in the field.
... Compared to surrounding sediments of Chesapeake Bay (USA), the uptake degree of PCBs combined with PP in worms was less than 76% (Beckingham and Ghosh, 2017). The bioavailability and transfer of hydrophobic OPs adsorbed on MPs in sediment were reduced. ...
... The bioavailability and transfer of hydrophobic OPs adsorbed on MPs in sediment were reduced. Although there has been no sufficient evidence that MPs to adsorb hydrophobic OPs caused significant adverse effects (Beckingham and Ghosh, 2017;Burns and Boxall, 2018), OP desorption from MPs in organisms is quite an obvious concern. Desorption rate of 14 C-DDTs on MPs under gut surfactant (38°C at pH 4) was high up to 30 times than that in seawater (18°C at pH 7.5-8.4) ...
Wetlands are a key hub for the accumulation of microplastics (MPs) and have great load capacity to organic pollutants (OPs), thus, have been a hot research topic. It has shown that OPs adsorbed on MPs could be transported to anywhere and MP-associated biofilms also affects the co-occurrence of MPs and OPs. This would induce the desorption of MP-carrying OPs into environment again, increasing latent migration and convergence of MPs and OPs in wetlands. Considering MPs vector effect and MP-associated biofilms, it is necessary to integrate MPs information on its occurrence characteristics and migration behavior for an improved assessment of ecological risk brought by MPs and MP-carrying OPs to whole wetland ecosystems. In this review, we studied papers published from 2010 to 2020, focused on the interaction of MPs with OPs and the role of their co-occurrence and migration on ecological risk to wetlands. Results suggested the interaction between MPs and OPs dominated by adsorption altered their toxicity and environmental behavior, and the corresponding ecological risk induced by their co-occurrence to wetlands is various and complicated. Especially, constructed wetlands as the special hub for the migration of MPs and MP-carrying OPs might facilitate their convergence between natural and constructed wetlands, posing a potential enlarging ecological risk to whole wetlands. Since the study of MPs in wetlands has still been in a primary stage, we hope to provide a new sight to set forth the potential harm of MPs and MP-carrying OPs to wetlands and useful information for follow-up study.
... Natural fibres, spherical soot black carbon particles and film-like flake graphite exist, so these shape categories are not unique to microplastic. The sorption affinity of hydrophobic organic contaminants for microplastic is similar to that of organic matter but orders of magnitude lower than that of black carbon 80,85,98,99 . It is often said that chemical leaching from microplastic particles distinguishes them from natural particles. ...
... It is often said that chemical leaching from microplastic particles distinguishes them from natural particles. However, black carbon and soot particles are highly contaminated and therefore also leach chemicals [99][100][101] . The same applies to aquatic sediments contaminated with legacy compounds that leach chemicals into a cleaner overlying water column 102 . ...
Microplastic particles are ubiquitous in the environment, from the air we breathe to the food we eat. The key question with respect to these particles is to what extent they cause risks for the environment and human health. There is no risk assessment framework that takes into account the multidimensionality of microplastic particles against the background of numerous natural particles, which together encompass an infinite combination of sizes, shapes, densities and chemical signatures. We review the current tenets in defining microplastic characteristics and effects, emphasizing advances in the analysis of the diversity of microplastic particles. We summarize the unique characteristics of microplastic compared with those of other environmental particles, the main mechanisms of microplastic particle effects and the relevant dose metrics for these effects. To characterize risks consistently, we propose how exposure and effect thresholds can be aligned and quantified using probability density functions describing microplastic particle diversity. Microplastic is a complex contaminant causing great concern in society. This Review examines the properties of microplastic particles compared with natural particles in the environment and discusses methods of assessing the risks to humans and the environment.
... Finally, the sorption of AS on plastic debris could lead to a Trojan effect when the plastic debris is ingested (Beckingham and Ghosh, 2017). Most available studies have focused on aquatic organisms (Kühn and van Franeker, 2020;Sun et al., 2022). ...
Intensive agriculture relies on external inputs to reach high productivity and profitability. Plastic mulch, mainly in the form of Low-Density Polyethylene (LDPE), is widely used in agriculture to decrease evaporation, increase soil temperature and prevent weeds. The incomplete removal of LDPE mulch after use causes plastic contamination in agricultural soils. In conventional agriculture, the use of pesticides also leaves residues accumulating in soils. Thus, the objective of this study was to measure plastic and pesticide residues in agricultural soils and their effects on the soil microbiome. For this, we sampled soil (0-10 cm and 10-30 cm) from 18 parcels from 6 vegetable farms in SE Spain. The farms were under either organic or conventional management, where plastic mulch had been used for >25 years. We measured the macro- and micro-light density plastic debris contents, the pesticide residue levels, and a range of physiochemical properties. We also carried out DNA sequencing on the soil fungal and bacterial communities. Plastic debris (>100 μm) was found in all samples with an average number of 2 × 103 particles kg-1 and area of 60 cm2 kg-1. We found 4-10 different pesticide residues in all conventional soils, for an average of 140 μg kg-1. Overall, pesticide content was ~100 times lower in organic farms. The soil microbiomes were farm-specific and related to different soil physicochemical parameters and contaminants. Regarding contaminants, bacterial communities responded to the total pesticide residues, the fungicide Azoxystrobin and the insecticide Chlorantraniliprole as well as the plastic area. The fungicide Boscalid was the only contaminant to influence the fungal community. The wide spread of plastic and pesticide residues in agricultural soil and their effects on soil microbial communities may impact crop production and other environmental services. More studies are required to evaluate the total costs of intensive agriculture.
... The interactions between biochar and MPs are influenced by the functional groups present on the surfaces of both materials, as well as the hydrophobicity of the MPs (Fig. 3). Particles can be adsorbed onto the surface of biochar through electrostatic attraction resulting from physical attachment, electrokinetic potentials, and formation of surface complex facilitated by the attention of carboxyl groups, the accessibility of hydroxyl ( OH) and metal ions such as iron (Beckingham and Ghosh, 2017;Kumar et al., 2023;Nguyen et al., 2022b). Additionally, the significant porous structure and SSA of biochar are advantageous qualities that promote an aeration environment and microbial activity within the composting matrix. ...
Plastic pollution is a widespread issue that poses a threat to agroecosystems. Recent data on microplastic (MP) pollution from compost and its application to soil have highlighted the potential impact of micropollutants that may be transferred from compost. Thus, we aim with this review to elucidate the distribution-occurrence, characterization, fate/transport, and potential risk of MPs from organic compost to gain comprehensive knowledge and mitigate the adverse impacts of compost application. The concentration of MPs in compost was up to thousands of items/kg. Among micropollutants, fibers, fragments, and films are the most common, with small MPs having a higher potential to absorb other pollutants and cause harm to organisms. Various synthetic polymers, including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), polyester (PES), and acrylic polymers (AP), have been widely used of plastic items. MPs are emerging pollutants that can have diverse effects on soil ecosystems, as they can transfer potential pollutants from MPs to compost and then to the soil. Following the microbial degradation scheme, the transfer chain from plastics to compost to soil can be broken down into main stages, i.e., colonization — (bio)fragmentation — assimilation — and mineralization. Microorganisms and adding biochar play an essential role during composting, which can be an effective solution to enhance MP degradation. Findings have shown that stimulating free radical generation could promote the biodegradation efficacy of MPs and possibly remove their occurrence in compost, thereby reducing their contribution to ecosystem pollution. Furthermore, future recommendations were discussed to reduce ecosystem risks and health challenges.
... Furthermore, our observations suggest that the blackworms' collecting-gathering behavior is not limited to organic matter, as we have also observed them excreting microplastics. Although we did not observe them actively feeding on these particles, this implies that worms consumed microplastics, which is corroborated by other literature that studies their physiological effects on blackworms (Beckingham and Ghosh 2017;Scherer et al. 2017;Klein et al. 2021;Silva et al. 2021). ...
Many organisms exhibit collecting and gathering behaviors as a foraging and survival method. Certain benthic macroinvertebrates are classified as collector-gatherers due to their collection of particulate matter as a food source, such as the aquatic oligochaete Lumbriculus variegatus (California blackworms). Blackworms demonstrate the ability to ingest organic and inorganic materials, including microplastics, but previous work has only qualitatively described their possible collecting behaviors for such materials. The mechanism through which blackworms consolidate discrete particles into a larger clumps remains unexplored quantitatively. By analyzing a group of blackworms in a large arena with an aqueous algae solution, we discover that their relative collecting efficiency is proportional to population size. Examining individual blackworms under a microscope reveals that both algae and microplastics physically adhere to the worm's body due to external mucus secretions, which cause the materials to clump around the worm. We observe that this clumping reduces the worm's exploration of its environment, potentially due to thigmotaxis. To validate the observed biophysical mechanisms, we create an active polymer model of a worm moving in a field of particulate debris with a short-range attractive force on its body to simulate its adhesive nature. We find that the attractive force increases gathering efficiency. This study offers insights into the mechanisms of collecting-gathering behavior, informing the design of robotic systems, as well as advancing our understanding the ecological impacts of microplastics on benthic invertebrates.
... In China, Greece, and Portugal, polychlorinated biphenyl (PCB) congeners, polycyclic aromatic hydrocarbon isomers, hexachlorocyclohexane isomers, and dichloro-diphenyl-trichloroethane metabolites were discovered in plastic pellets. Chemical PCB congeners are more concentrated on black or aged MPs than on colored or white MPs (Beckingham and Ghosh, 2017). It has been reported that MPs can travel long distances in the water flow because of their small size and their ability to remain in the environment for long periods of time due to their resistance to degradation. ...
The prevalence of microplastics (MPs) in the environment has had a significant impact on ecosystems and posed a major threat to human health. This study investigated the distribution and characteristics of MPs in the Nhue - Day River basin in Vietnam, which is a critical source of biodiversity and used to support the economic growth of about 12 million people. The effect of seasonal variation and anthropogenic activities on the MP abundance was assessed. The findings revealed that the MPs abundance was significant in this study area. The average abundance of MPs in the dry season (754 items/m3) was insignificantly higher than that in the rainy season (706 items/m3) with n=9. The range in the abundance of MPs in the dry and rainy seasons was 49-2,827 and 400-1,133 items/m3, respectively. Microplastics in fiber forms were dominant in both seasons. The majority of the collected MPs were in the 0.5-2.0 mm size range, varying from 71% to 100% of the total MPs depend on sampling point. The total percentage of MPs size 0.3-0.5 mm in the dry season was 56.97% compared to 119.85% in the rainy season, indicating that the MPs were broken into smaller pieces due to UV exposure and weather conditions. Colored items occupied the majority of the MPs. This study can be used to gain a better knowledge of MP pollution in Vietnam’s river water.
... g/L [18,25,51]. The concentration of PCBs adsorbed to MPs ranges from 10.5 to 307 ng per gram pellet [25,37,52], and the presence of MPs in sediments reduces the bioavailability of hydrophobic organic pollutants [5]. Furthermore, the biotransformation of PCBs adsorbed to MPs is quicker than that of PCBs adsorbed into sediment [46]. ...
Polychlorinated biphenyls (PCBs) and microplastics (MPs) commonly co-exist in various environments. MPs inevitably start aging once they enter environment. In this study, the effect of photo-aged polystyrene MPs on microbial PCB dechlorination was investigated. After a UV aging treatment, the proportion of oxygen-containing groups in MPs increased. Photo-aging promoted the inhibitory effect of MPs on microbial reductive dechlorination of PCBs, mainly attributed to the inhibition of meta-chlorine removal. The inhibitory effects on hydrogenase and adenosine triphosphatase activity by MPs increased with increasing aging degree, which may be attributed to electron transfer chain inhibition. PERMANOVA showed significant differences in microbial community structure between culturing systems with and without MPs (p < 0.05). Co-occurrence network showed a simpler structure and higher proportion of negative correlation in the presence of MPs, especially for biofilms, resulting in increased potential for competition among bacteria. MP addition altered microbial community diversity, structure, interactions, and assembly processes, which was more deterministic in biofilms than in suspension cultures, especially regarding the bins of Dehalococcoides. This study sheds light on the microbial reductive dechlorination metabolisms and mechanisms where PCBs and MPs co-exist and provides theoretical guidance for in situ application of PCB bioremediation technology.
... MPs have been shown to absorb obstinate biological acquisitive and poisonous molecules from the environment, and they may function as transporters or vectors for these toxins to reach biota (Bakir et al., 2012(Bakir et al., , 2014Brennecke et al., 2016;Holmes et al., 2014). Nonetheless, previous studies (Beckingham and Ghosh, 2017;Gouin et al., 2011;Koelmans et al., 2013) contradictorily concluded that MPs is not a significant chemical transport vector. According to Chen et al. (Chen et al., 2018), plastic may have a role in chemical transmission to some marine creatures if a plastic-to-predator gradient exists. ...
The world has witnessed massive and preeminent microplastics (MPs) pollution in water bodies due to the inevitable continuous production of plastics for various advantageous chemical and mechanical features. Plastic pollution, particularly contamination by MPs (plastic particles having a diameter lesser than 5 mm), has been a rising environmental concern in recent years due to the inappropriate disposal of plastic trash. This study presents the recent advancements in different technologies for MPs removal in order to gain proper insight into their strengths and weaknesses, thereby orchestrating the preparation for innovation in the field. The production, origin, and global complexity of MPs were discussed. This study also reveals MPs' mode of transportation, its feedstock polymers, toxicities, detection techniques, and the conventional removal strategies of MPs from contaminated systems. Modification of conventional methods vis-à-vis new materials/techniques and other emerging technologies, such as magnetic extraction and sol-gel technique with detailed mechanistic information for the removal of MPs are presented in this study. Conclusively, some future research outlooks for advancing the MPs removal technologies/materials for practical realization are highlighted.
... It would have been advantageous to analyse smaller particles <50 µm, as these small sized particles have been found to be taken up by freshwater macroinvertebrates (e.g. [60][61][62]). However, this is also associated with additional analytical challenges which are imposed by methods and instruments for accurately and reliably detecting microplastic concentrations. ...
Unlabelled:
Microplastic is now ubiquitous in freshwater, sediment and biota, globally. This is as a consequence of inputs from, for example, waste mismanagement, effluents from wastewater treatment plants and surface runoff from agricultural areas. In this study, we investigated point source pollution of plastic to an upland stream, originating from a recycling plant that recycles polyethylene film in a remote area of Norway. Sediment (~2 kg) and macroinvertebrates (549 individuals in total) were sampled at one site upstream and two sites downstream of the recycling plant to study microplastic deposition and food web uptake. In total, 340 microplastic films were identified through a combination of visual and µFTIR analysis in the sediment samples. This corresponded to a concentration of 0.23 (± 0.057) items per g sediment upstream of the plastic recycling plant and 0.45 (± 0.017) and 0.58 (± 0.34) items per g downstream. The dominant plastic polymer was polyethylene, which increased significantly downstream of the plastic recycling plant. This indicates the role of the plastic recycling plant as a point source for microplastic in this catchment. Among the three sites investigated, a fairly constant concentration of polypropylene was found, indicating a diffuse source of polypropylene films across the catchment possibly relating to low-intensity agricultural land-use. Low levels of polyethylene were also observed upstream, which may be linked to either local or longer-distance atmospheric transport. Despite the considerable presence of microplastic in sediments, concentrations in macroinvertebrates were extremely low with only a single microplastic particle identified in the total of 549 macroinvertebrates-belonging to three different feeding groups-investigated. Our study suggests that: 1) microplastic pollution can be transferred to remote areas as unintended losses from recycling facilities, 2) remote areas with limited land-use pressure still have detectable levels of microplastic and 3) microplastic is only taken up by stream macroinvertebrates to a limited degree despite relatively high sediment concentrations, and thus there are no strong indications for ecological risks posed by microplastic to this ecological group at this location.
Supplementary information:
The online version contains supplementary material available at 10.1186/s43591-022-00045-z.
... The studies that compared the MP-mediated uptake of PCBs to natural bioaccumulation pathways agreed that MP would be a minor contribution to total bioaccumulation comparatively to natural environmental uptake pathways (Devriese et al., 2017;Grigorakis and Drouillard, 2018;Besseling et al., 2013Besseling et al., , 2017. Overall, there seems to be a growing consensus among various research groups that microplastics in the environment would have minor effects on bioaccumulation of associated chemicals in organisms (Koelmans et al., 2016(Koelmans et al., , 2022Besseling et al., 2013Besseling et al., , 2017Bakir et al., 2016;Beckingham and Ghosh, 2017;Devriese et al., 2017;Grigorakis and Drouillard, 2018). In contrast, it has been recently suggested that the current estimates of marine total plastic load could have been greatly underestimated (Lindeque et al., 2020), making the abundance of plastic debris and their relative importance compared to natural particles still unknown. ...
The present study reports the first experimental microplastic-mediated transfer of a key PCB congener into adult specimens of the sea urchin Paracentrotus lividus. Three experiments were conducted to assess whether 14C-PCB- 153 adsorbed onto negatively buoyant microplastics (MPs) (500–600 μm) is bioavailable to the sea urchin: (1) exposure to a low concentration of 14C-PCB-153 sorbed onto a high number of virgin MPs (“lowPCB highMP” experiment), (2) exposure to a high concentration of 14C-PCB-153 sorbed onto a relatively low number of virgin MPs (“highPCB lowMP” experiment), and (3) exposure to a low concentration of 14C-PCB-153 sorbed onto a relatively low number of aged MP (“lowPCB lowMP” experiment). Results showed that the transfer of 14C-PCB- 153 from MPs to sea urchin tissues occurred in each of the three 15-day experiments, suggesting that MPs located on the seafloor may act as vectors of PCB-153 to sea urchins even during short-term exposure events.
... Moreover, MPs can absorb halogenated organic compounds (HOCs) in marine environments (Rochman et al., 2013), thereby serving as potential carriers of xenobiotics into biota (Rodrigues et al., 2019;Wang et al., 2021). This exacerbates the ecological risks of MPs and influences the bioavailability and environmental fate of HOCs (Beckingham and Ghosh, 2017;Chi et al., 2021;Rodrigues et al., 2019;Zhang et al., 2020b). ...
Microplastics (MPs) can absorb halogenated organic compounds and transport them into marine anaerobic zones. Microbial reductive dehalogenation is a major process that naturally attenuates organohalide pollutants in anaerobic environments. Here, we aimed to determine the mechanisms through which MPs affect the microbe-mediated marine halogen cycle by incubating 2,4,6-trichlorophenol (TCP) dechlorinating cultures with various types of MPs. We found that TCP was dechlorinated to 4-chlorophenol in biotic control and polypropylene (PP) cultures, but essentially terminated at 2,4-dichlorophenol in polyethylene (PE) and polyethylene terephthalate (PET) cultures after incubation for 20 days. Oxygen-containing functional groups such as peroxide and aldehyde were enriched on PE and PET after incubation and corresponded to elevated levels of intracellular reactive oxygen species (ROS) in the microorganisms. Adding PE or PET to the cultures exerted limited effects on hydrogenase and ATPase activities, but delayed the expression of the gene encoding reductive dehalogenase (RDase). Considering the limited changes in the microbial composition of the enriched cultures, these findings suggested that microbial dechlorination is probably affected by MPs through the ROS-induced inhibition of RDase synthesis and/or activity. Overall, our findings showed that extensive MP pollution is unfavorable to environmental xenobiotic detoxification.
... Moreover, existing MPs, especially primary MPs, can also find their way into the terrestrial ecosystem directly [25]. On the other hand, MPs can absorb different organic pollutants [26] and can increase the bioavailability of heavy metals by acting as a catalyst in soil [27]. Therefore, smaller plastic materials can be transported through different elements of a terrestrial ecosystem by accumulation and uptake by soil biota [28]. ...
Pollution generated by microplastics (MPs) has become an issue of global concern because to its severe effects on the general health of the ecosystem, especially the health of the terrestrial environment. There is a scarcity of data based on MP contamination research in Bangladesh that is currently available, and no work on MP contamination has previously been done in an industrial region of Bangladesh. As a result, this research was undertaken with the aim of determining whether or not MP contamination is present in the industrial area of the Barapukuria region in Bangladesh. The method of sieving and density separation was used in the process of extracting MPs from a total of 12 soil samples that were collected from the industrial area of Barapukuria. A stereomicroscope was utilized to accomplish the visual identification of the MPs. The method of sieving and density separation was used in the process of extracting MPs from 12 soil samples that were gathered from the industrial area of Barapukuria. A stereomicroscope was utilized in order to accomplish the visual identification of the MPs. The concentration of MPs accounted for 1-15 items/100g (Mean: 6.75± 5.3) in the 12 sampled regions, mostly white in color and ranging in size from 0.5–1 mm. Fibers have been found to be the most prevalent among the detected MPs (films, fiber, foam, and fragments). 8-types of MPs (Mean: 0.32± 0.69) were detected in 5 rural farmland locations, 11 MPs (Mean: 1.1± 1.73) in 2 sub-urban farmland sites, 11 MPs (Mean: 2.2± 3.19) in 1 urban farmland site, 24 MPs (Mean: 2.4± 1.89) in 2 industrial locations, and 27 MPs (Mean: 2.7± 3.05) in 2 near metropolitan areas. Based on the land use land cover analysis, higher contamination of MPs have been detected in the industrial and coal mine region of Barapukuria whereas relatively lower amount of MPs have been found in the rural and urban regions.
... Micelle-mediated solubilization has been demonstrated for bisphenol A 26 and polychlorinated biphenyls (PCBs) 41 and is also likely responsible for the These results are consistent with previous studies that showed greater solubilization of hydrophobic contaminants, such as PAHs and PCBs, from sediment in gut fluids compared to water, both in vitro and in vivo 57,58 and also from various types of microplastics. 59,60 Micelle-mediated processes along with the hydrophobic nature of the gut fluids were also pointed out in these prior studies as drivers of the solubilization. In contrast, solubilization of only one (butyl benzyl phthalate) of 12 estrogenic compounds was enhanced under simulated fish gut conditions compared to water, 39,61 indicating that the mechanisms facilitating solubilization of organic chemicals in digestive fluids might be compound-specific. ...
Tire and road wear particles (TRWP) account for an important part of the polymer particles released into the environment. There are scientific knowledge gaps as to the potential bioaccessibility of chemicals associated with TRWP to aquatic organisms. This study investigated the solubilization and bioaccessibility of seven of the most widely used tire-associated organic chemicals and four of their degradation products from cryogenically milled tire tread (CMTT) into fish digestive fluids using an in vitro digestion model based on Oncorhynchus mykiss. Our results showed that 0.06-44.1% of the selected compounds were rapidly solubilized into simulated gastric and intestinal fluids within a typical gut transit time for fish (3 h in gastric and 24 h in intestinal fluids). The environmentally realistic scenario of coingestion of CMTT and fish prey was explored using ground Gammarus pulex. Coingestion caused compound-specific changes in solubilization, either increasing or decreasing the compounds' bioaccessibility in simulated gut fluids compared to CMTT alone. Our results emphasize that tire-associated compounds become accessible in a digestive milieu and should be studied further with respect to their bioaccumulation and toxicological effects upon passage of intestinal epithelial cells.
... The contamination protocol was adapted from Beckingham and Ghosh (2017); synthetic marine water (1.5 L) was spiked with 0.6 mL of Aroclor 1254 stock solution (20,000 mg/L in acetone) under shaking (acetone:water 0.04%), 400 g of MPs were added immediately after and incubated under shaking (180 rpm) for 10 days. MPs were recovered by sieving and dried at room temperature under sterile conditions. ...
Plastic debris dispersed into the environment provide a substrate for microbial colonization, constituting a new human-made ecosystem called "plastisphere", and altering the microbial species distribution in aquatic, coastal and benthic ecosystems. The study aims at exploring the interaction among microplastics (MPs) made of different polymers, a persistent organic contaminant (polychlorinated biphenyls, PCBs), and the environmental microbial communities, in an anoxic marine sediment. Plastic pellets were incubated in the field in a salt marsh anoxic sediment, to observe the stages of plastisphere formation, by quantitative PCR and 16S rRNA gene sequencing, and PCB dechlorination activity on the MPs surface. Microbes from the sediment rapidly colonized the different microplastics types, with PVC recruiting a peculiar community enriched in sulfate-reducing bacteria. The composition of the plastisphere varied along the 1-year incubation possibly in response either to warmer temperatures in spring-summer or to microhabitat's changes due to the progressive plastic surface weathering. Even if PCB contaminated MPs were able to recruit potentially dehalogenating taxa, actual dechlorination was not detectable after 1 year. This suggests that the concentration of potentially dehalorespiring bacteria in the natural environment could be too low for the onset of the dechlorination process on MP-sorbed contaminants. Our study, which is among very few available longitudinally exploring the plastisphere composition in an anoxic sediment context, is the first exploring the fate and possible biodegradation of persistent organic pollutants sorbed on MPs reaching the seafloor.
... For example, negatively charged MPs readily adsorb positive heavy metals . Concurrently, due to the hydrophobic nature, it is easy for MPs to combine with organic pollutants (e.g., polychlorinated biphenyls) and transfer the pollutants to marine organisms, thus negatively affecting the food web (Beckingham and Ghosh, 2017). In addition, on account of the small particle size of MPs, and it is difficult for marine organisms to distinguish MPs from food, especially for those marine organisms (e.g., crabs) that breathe using gill openings, which can easily lead to the accumulation of MPs in their gill compartments (Green, 2016). ...
Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.
... Recently polystyrene microplastics (36 ng m − 3 ) in the atmosphere upper an agricultural region have been measured (Peñalver et al., 2021). Improved measurement and understanding are still necessary, as there is a significant probability of additional contaminants such as pesticides adsorbed on MPs from agricultural soils (Abbasi et al., 2020;Beckingham and Ghosh, 2017). These particles are small and readily inhaled, presenting a serious hazard to human health chemically based on their content and each individual's vulnerability (Prata, 2018). ...
Microplastics (MPs) have been a significant worldwide issue, becoming persistent and emerging contaminants in the environment. While MPs have been the subject of extensive scrutiny in the aquatic environment, their presence, mobility, and potential for pollution control, notably in African, Latin American, Oceanian, and some Asian agro-ecosystems, remain unknown. Most MPs in croplands come from composite pesticides and fertilizers, organic waste and compost, mulch films, wastewater irrigation, and atmospheric deposition. MPs' ultimate mobility and fate in the soil ecosystem are driven mostly by MPs' physicochemical properties, soil properties, farming techniques, and soil biota heterogeneity. In different global agro-ecosystems, this review explores the MPs' origins, mobility, fate, and pollution control in the soil agro-ecosystems and explores MPs' contaminant-transport capacity and toxicity impact on soil organisms. Future studies should focus on deleterious implications on animals and humans, irregular mobility and behaviour in the soil agro-ecosystems, optimum management techniques, and worldwide agricultural policies to promote sustainable development.
... This could be due to adsorbtion of contaminants to black carbon or other refractory particles such as microplastics or engineered nanotubules (Parks et al. 2014). In fact, these types of materials have been shown to significantly reduce bioaccumulation of PCBs in marine polychaetes (Janssen et al. 2010;Beckingham and Ghosh 2017) and are thus useful for remediation of contaminated marine sediments. With PBDEs, bio-dilution (ratio <1) occurred at extreme sediment PBDE concentrations (>10,000 pg/g dry wt) in urban harbours. ...
We examined uptake of polychlorinated biphenyls (PCBs) into various marine sediment feeders relative to physical and geochemical factors and transfer to higher trophic levels. PCBs exceeding Canadian Council Ministers of the Environment Guidelines by 6–55× were found in industrialized harbours and some near-outfall sediments, indicating ongoing land input. Sediment PCBs were correlated with organic flux and content. Tissue PCBs were >10× sediment PCBs in all samples and highest in Victoria Harbour infauna, suggesting considerable uptake from these extremely contaminated, organically enriched, chronically disturbed sediments. Sediment PCBs were the primary predictor of tissue lipid PCBs followed by %fines. This results in generally higher tissue PCBs in more depositional regions. The lipid/sediment PCBs (uptake rate) declined with increasing sediment PCBs, acid volatile sulfides and benthos biomass turnover. PCB homologue composition did not change with uptake from sediments or at higher trophic levels, suggesting minimal metabolization in tissues. Trophic bio-magnification occurs since lipid PCBs were 2–100× higher in seal blubber than sediment feeders. PCBs were compared with polybrominated diphenyl ethers (PBDEs) for the same samples. PCBs were highest in industrialized harbours, whereas PBDEs were elevated in harbours but highest near wastewater discharges. This reflects differences in usage history, sediment dynamics, and affinities. PCBs appear to be more bio-accumulative and persistent at higher trophic levels than PBDEs.
... Liquid chromatography-mass spectrophotometry (LC-MS) and acute toxicity tests have also been used to measure bioavailable nonylphenol in contaminated MPs . Accumulated polychlorinated biphenyls (PCBs) were estimated along with the solid-water distribution coefficient (Beckingham and Ghosh, 2017). Similarly, bioaccumulated co-contaminants were estimated in different body parts to measure their bioavailable concentrations (Chua et al., 2014;Oliveira et al., 2018). ...
The high prevalence and persistence of microplastics (MPs) in pristine habitats along with their accumulation across environmental compartments globally, has become a matter of grave concern. The resilience conferred to MPs using the material engineering approaches for outperforming other materials has become key to the challenge that they now represent. The characteristics that make MPs hazardous are their micro to nano scale dimensions, surface varied wettability and often hydrophobicity leading to non-biodegradability. In addition, MPs exhibit a strong tendency to bind to other contaminants along with the ability to sustain extreme chemical conditions thus increasing their residence time in the environment. Adsorption of these co-contaminants leads to modification in toxicity varying from additive, synergistic, and sometimes antagonistic, having consequences on flora, fauna, and ultimately the end of the food chain, human health. The resulting environmental fate and associated risks of MPs, therefore greatly depend upon their complex interactions with the co-contaminants and the nature of the environment in which they reside. Net outcomes of such complex interactions vary with core characteristics of MPs, the properties of co-contaminants and the abiotic factors, and are required to be better understood to minimize the inherent risks. Toxicity assays addressing these concerns should be ecologically relevant, assessing the impacts at different levels of biological organization to develop an environmental perspective. This review analyzed and evaluated 171 studies to present research status on MP toxicity. This analysis supported the identification and development of research gaps and recommended priority areas of research, accounting for disproportionate risks faced by different countries. An ecological perspective is also developed on the environmental toxicity of contaminated MPs in the light of multi-variant stressors and directions are provided to conduct an ecologically relevant risk assessment. The presented analyses will also serve as a foundation for developing environmentally appropriate remediation methods and evaluation frameworks.
... Consequently, microplastics can be a source of pollutants for aquatic environments. However, under environmental conditions, the levels of exogenous POPs associated with MPs are similar to those measured in natural organic matrices (wood, sedimentary organic matter, charcoal; Beckingham & Ghosh, 2017). Thus, the limited amounts of MPs in the environment do not constitute a significant source of contamination (Mai, Bao, Shi, Liu, & Zeng, 2018). ...
Over the past decade, the number of studies examining the presence and effects of microplastics in the environment has drastically increased. Works seeking to identify these particles have proven beyond doubt that microplastics constitute a generalized pollution affecting all environmental compartments, from inside air to arctic snows. Studies on their potential ecotoxicological impacts were more nuanced but many have shown deleterious effects when these microplastics were associated with persistent organic pollutants. This primer mainly focuses on POP sorption and transport by microplastics in the aquatic environment and the possible toxic effects that result from it. Indeed, the associations between microplastics and persistent organic pollutants are very common in the environment. If the mechanisms of interactions are well known, they depend on many factors and their significance in the environment can be very variable in time and space. Indeed, these interactions depend on both the plastic particle (polymer type, crystallinity, particle size, shape, specific area, and functional groups/polarity) and the pollutant (hydrophobicity, functional groups) but also environmental factors (microorganism population, salinity/ionic strength, pH, dissolved organic matter concentration, and temperature). Changes in the interactions between pollutants and microplastics can result in pollutant release in the aquatic environment and potential toxic effects. However, apart from specific situations, the role of microplastics as local source of exogenous molecules (PAHs, PCBs, etc.) is rarely significant because the limited amounts of involved pollutants. It is much less negligible for endogenous chemicals that enter into the initial composition of the plastic (phthalates, biocides, etc.).
This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems
Science of Water > Water Quality
... Using batch equilibrium studies, Bakir et al. (2014) also reported that DDT has a strong affinity for PVC and PE. Microplastics have hydrophobic properties, and hence DDT and other hydrophobic chemicals with relatively large octanolwater partition coefficients have a large affinity for microplastics (Moyo et al. 2014;Wu et al. 2016;Beckingham and Ghosh 2017;Li et al. 2018;Llorca et al. 2018;Zuo et al. 2019). Partitioning interaction and pore filling are the predominant mechanisms controlling the sorption of DDT to microplastics (Bakir et al. 2012;Endo and Koelmans 2016;Wang et al. 2020). ...
Purpose
In addition to sediments, pesticides can be sorbed to other constituents present in rivers including ash, charcoal, and microplastics. Pesticide sorption by microplastics has been studied for hydrophobic compounds such as the legacy insecticide DDT (dichlorodiphenyltrichloroethane) but not for current-use herbicides. The purpose of this study was to investigate to what extent 2,4-dichlorophenoxyacetic acid (2,4-D) (weak acid), atrazine (weak base), and glyphosate (zwitterion) are sorbed by microplastics (i.e., fiber, polyethylene beads, polyvinyl chloride (PVC), and tire fragments) and other river constituents (i.e., ash, charcoal, suspended and bottom sediments). DDT was included in the study to provide reference data that could be compared to known literature values.
Methods
Batch equilibrium experiments were conducted following Guidelines 106 of the Organisation for Economic Co-operation and Development. Experiments utilized either a 1:100 solid/solution ratio with 0.1 g of a river constituent as the sorbent or a 1:5 solid/solution ratio with the sorbents consisted of 1.9 g bottom sediments mixed with 0.1 g of a river constituent. Background solutions included 0.01 M CaCl 2 or 0.01 M KCl, deionized water, and river water.
Result
Individual microplastics always sorbed >50% of DDT. Current-use herbicides had a weak affinity for microplastics (< 6%) except that a substantial amount of glyphosate was sorbed by PVC (32–36%) in 0.01M KCl and DI water. When river water was used as a background solution, rather than 0.01M KCl or deionized water, there was much less glyphosate sorption by PVC, ash, charcoal, and both sediments. This suggested that ions present in river water competed for sorption sites with glyphosate molecules. Across background solutions, sorption by sediments decreased in the order of DDT (91–95%) > glyphosate (36–88%) >atrazine (5–13%) >2,4-D (2–5%). Sorption of 2,4-D, atrazine, and DDT by ash and charcoal was always > 90% but < 35% for glyphosate. Relative to bottom sediments alone, the presence of ash or charcoal (5% by weight) with sediments significantly increased the sorption of 2,4-D, atrazine, and DDT. Microplastic additions (5% by weight) had no impact on all four pesticides’ sorption by sediments.
Conclusion
Microplastics are not a strong sorbent for current-use herbicides, although there are exceptions such as glyphosate by PVC. Ions present in river water competed with glyphosate for sorption sites of river constituents. Hence, the types and concentrations of ions present in rivers might have some influence on the partitioning of glyphosate between the water column and solid phase, including glyphosate fate processes in rivers.
... Micro-fragments of plant residues, clay aggregates, and tiny MPs potentially aggregate with plastic particles through adhesion and cohesion resulting from biofilm formation. Simultaneously, organic and inorganic pollutants can bind with the adhered natural organic matter and/or biopolymers in biofilms through surface complexation reactions based on the abundance of functional groups, which provide active sites that serve as ligands (Beckingham and Ghosh, 2017;Wang et al., 2020). Previous studies have noted that metal sorption is not influenced by the polymer types of plastics, whereas the organic substance availability in, and thickness of, biofilms are controlling factors for metal binding (Leiser et al., 2020, Rochman et al., 2014. ...
Microplastic (MP) surfaces are common sites for microbial colonization and promote biofilm formation in aquatic environments, resulting in changes to the surface properties of MPs and their interaction with pollutants. Although the diversity of microbial communities adhering to MPs has been well documented in aquatic environments, surface changes in MPs due to microbial colonization are still poorly understood. In this study, we aimed to evaluate the variations in the chemical structure and components of biofilms on the surface of polystyrene microplastics (PS-MPs) collected from the shore of the Tuul River in Mongolia, using micro-Fourier transform infrared (micro-FTIR) spectroscopy. We applied a spectral subtraction approach, and the differences in spectra between peroxide-treated and untreated PS-MP particles enabled us to obtain the structural features of biofilms that developed on the plastic surface. In addition, the surface photooxidation status of the sampled PS-MPs was calculated from the subtracted spectra of peroxide-treated and pristine PS-MPs. Various functional groups of N-containing organic substances from bacterial and fungal communities were detected in the obtained biofilm spectra. Based on the spectral characteristics, biofilm spectra were classified into four groups by applying principal component analysis (PCA). A wide range of carbonyl indices (CIs: 0.00–1.40) was found in the subtracted spectra between peroxide-treated and pristine PS-MPs, revealing that different levels of surface oxidation progressed by physical influences such as solar radiation and freeze-thaw cycles. Furthermore, lignocellulose and silicate were found on PS-MP surface as allochthonous attachments. Considering the variation in residence time of PS-MPs, they attract plant residues and mineral particles through the development of biofilms and travel together in the river environment. Given that the dynamic behavior of MPs can be greatly affected by changes in their surfaces, further studies are needed to emphasize their link to organic matter dynamics.
... The results showed that despite the similarities of the initial amounts of phenanthrene among different treatments, the free bioaccessible concentrations of phenanthrene in soil decreased significantly with the influence of FPs addition, due to the competitive sorption of phenanthrene between soil and the plastic particles as well as the possible irreversible sorption of phenanthrene on NPs (Fig. 1) (Liu et al., 2018). This effect on decreasing bioavailability of hydrophobic organic contaminants by MPs were reported widely as the dilution effects, which subsequently decreases their bioaccumulation (Chua et al., 2014;Koelmans et al., 2016;Beckingham and Ghosh, 2017;Rehse et al., 2018;Wang et al., 2019). At the same time, the bioaccumulation of phenanthrene in earthworm M. guillelmi depended on the sizes of the plastics added to the soils and varied in different pathways that phenanthrene entering the soil systems (Figs. 2 & 3). ...
Microplastics (MPs) and nanoplastics (NPs), are collectively referred to as fine plastic particles (FPs), have been reported for both the “vector” effect and “dilution” effect which alters the bioaccumulation of organic contaminants. However, which effect plays a dominant role, especially in terrestrial ecosystems, remains unknown. In the present study, we used ¹⁴C-radioactive labeling tracing technique to assess the sorption of a typical polycyclic aromatic hydrocarbon, phenanthrene on soil particles and FPs, as well as the contribution of vector effects of FPs on the bioaccumulation and distribution of phenanthrene by the geophagous earthworm Metaphire guillelmi. The results showed that the presence of FPs in soil decreased the bioaccumulation of ¹⁴C-Phenanthrene in M. guillelmi by decreasing the bioavailable fraction of phenanthrene in soil, and the decreasing effect was more dramatic for NPs treatments. In all cases, bioaccumulation of ¹⁴C-Phenanthrene in M. guillelmi was still determined by the free concentration of ¹⁴C-Phenanthrene in soil and limited vector effects was observed. Moreover, the different correlation coefficients between the free concentration of ¹⁴C-Phe in two soils and bioaccumulated ¹⁴C-Phenanthrene in earthworms indicated that soil properties remained a dominant factor that determines the bioaccumulation efficiency of ¹⁴C-Phenanthrene in the FPs-soil system. Although the total ¹⁴C-Phenanthrene bioaccumulation in earthworms did not increase, vector effects may be responsible for the increased relative distribution of ¹⁴C-phenanthrene in the organ region, compared with skin and gut regions, leading to unknown risks to organs that are sensitive to these contaminants.
... Nevertheless, there is controversy regarding this potential consequence, as some researchers object to MPs (or NPs) as pollutant carriers. According to Gouin et al. (2011) and Beckingham and Ghosh (2017), the transfer of organic contaminants into biological organisms by dietary MPs may be a small or limited contribution compared to other natural routes of exposure in most cases. It was reported that contaminated PE microplastics displayed a negligible vector role in terms of mercury bioaccumulation in the clams (Sıkdokur et al. 2020). ...
As emerging pollutants, direct and indirect adverse impacts of micro(nano)plastics (MPs/NPs) are raising an increasing environmental concern in recent years due to their poor biodegradability and difficulty in recycling. MPs/NPs can act as carriers of bacteria, viruses, or pollutants (such as heavy metals and toxic organic compounds), and may potentially change the toxicity and bioavailability of pollutants. Ingested or attached MPs/NPs can also be transferred from low-trophic level organisms to high-nutrient organisms or even the human body through the food chain transfer process. This article reviews the emerging field of micro- and nanoplastics on organisms, including the separate toxicity and toxicity of compound after the adsorption of organic pollutants or heavy metals, as well as possible mechanism of toxicological effects and evaluate the nano- and microplastics potential adverse effects on human health. The inherent toxic effects MPs/NPs mainly include the following: physical injury, growth performance decrease and behavioral alteration, lipid metabolic disorder, induced gut microbiota dysbiosis and disruption of the gut’s epithelial permeability, neurotoxicity, damage of reproductive system and offspring, oxidative stress, immunotoxicity, etc. Additionally, MPs/NPs may release harmful plastic additives and toxic monomers such as bisphenol A, phthalates, and toluene diisocyanate. The vectors’ effect also points out the potential interaction of MPs/NPs with pollutants such as heavy metals, polycyclic aromatic hydrocarbons, organochlorine pesticides, polychlorinated biphenyls, perfluorinated compounds, pharmaceuticals, and polybrominated diphenyl ethers. Nevertheless, these potential consequences of MPs/NPs being vectors for contaminants are controversial.
... exposure pathways of harmful substances are well established, it is less well-known how much the chemical pollution from plastics contributes to the overall chemical pollution that marine life experiences. A number of studies have suggested that the contribution of ingested plastics to the body burden of chemical pollutants is likely to be small in relation to direct uptake via sediment, water or contaminated preyBeckingham and Ghosh, 2017;Besseling et al., 2017;Devriese et al., 2017; Gouin et al., 2011; Herzke et al., 2016;Holmes et al., 2012;Koelmans et al., 2016;Koelmans et al., 2014;Paul-Pont et al., 2016;Ziccardi et al., 2016).The relative contributions of the various pathways, however, differ widely for different individuals, populations and species. While the contribution of ingested microplastics to the overall chemical burden of the lugworm Arenicola marina seemed negligible (Section 5.4.7) ...
A new report commissioned by WWF provides the most comprehensive account to date of the extent to which plastic pollution is affecting the global ocean, the impacts it’s having on marine species and ecosystems, and how these trends are likely to develop in future. The report by researchers from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) reveals a serious and rapidly worsening situation that demands immediate and concerted international action:
● Today almost every species group in the ocean has encountered plastic pollution, with scientists observing negative effects in almost 90% of assessed species.
● Not only has plastic pollution entered the marine food web, it is significantly affecting the productivity of some of the world’s most important marine ecosystems like coral reefs and mangroves.
● Several key global regions – including areas in the Mediterranean, the East China and Yellow Seas and Arctic sea ice – have already exceeded plastic pollution thresholds beyond which significant ecological risks can occur, and several more regions are expected to follow suit in the coming years.
● If all plastic pollution inputs stopped today, marine microplastic levels would still more than double by 2050 – and some scenarios project a 50-fold increase by 2100.
... In the environment, larger plastic debris undergo successive degradation and produce MPs; and artificially, tiny plastic granules are manufactured to be used for several purposes in many industries (Sruthy and Ramasamy, 2017). A large number of hydrophobic organic pollutants, which are also toxic, often adsorb to the surface of MPs, exposing the aquatic biota to the risk of chemical contamination (Beckingham and Ghosh, 2017). The increase in the surface area of MPs caused by their environmental weathering intensifies these twin phenomena of adsorption and exposure (Teuten et al., 2009). ...
Abstract
This study investigated the spatial and vertical distribution of microplastics (MPs) in the water and sediment samples collected from different locations in Kodaikanal Lake, a very popular tourist location. The lake provides water to placesdownstream. MPs are found in the surface water, surface sediment and core sediment, with their respective values of abundance being 24.42 ± 3.22 items/ L, 28.31 ± 5.29 items/ kg, and 25.91 ± 7.11 items/ kg. Spatially, abundance, colour, type and size of MPs vary in the samples of surface water and sediment. The highest levels of MPs are found in the lakes' outlet region. MPs detected are primarily fibres and fragments 3-5 mm in size with PE and PP being the predominant polymers. Seven sampling points were selected to investigate the vertical distribution of MPs. In the core sediment, the abundance and size of MPs decrease with depth. This probably indicates the presence of more MPs in the recent sediment. The core sediment is dominated by sand silt clay fractions, which facilitates potential downward infiltration of fine MPs. SEM images of MPs reveal that the degree of weathering increases with depth, and EDAX shows that smooth MP surface displays a lesser adhesion ability than the rough surface. Plastic wastes generated by tourism are the important source of MPs in the lake. The lake has high PHI values (>1000) due to MPs with high hazard score polymers (PS and PEU), whereas the PLI values (1.33) indicate low level of MP pollution representing a minor ecological risk. The MP level in Kodaikanal Lake is influenced by the lake's hydrology and the sources of pollution. Although the impacts of MP pollution on the health and functioning of the environment is uncertain, observing, understanding and halting of further MP contamination in the Kodaikanal Lakes is important.
... It is well understood that the combustion of coal causes the release of heavy metals and trace minerals (Sanchez, 2014). However, coal does not undergo the same degree of degradation when spilt into seawater and hence is considered chemically inert because the bioavailability of the compounds within coal is very low in typical open sea conditions (Beckingham & Ghosh, 2017). ...
For over 50 years, ITOPF has attended on-site at marine spills worldwide on behalf of the shipping industry. ITOPF staff have provided objective technical advice at over 800 incidents in 100 countries, gaining unparalleled insight into changing trends in ship-source pollution. Spills of oil were originally the focus of ITOPF's activities, initially from tankers and later from a wide range of ships. Over time, there has been a dramatic and sustained reduction in both the number of oil spills and the quantity of oil spilt from tankers, as ITOPF's statistics demonstrate. Though spills of oil cargoes and bunker fuel remain at the core of ITOPF's work, its activities have expanded in recent years to include other pollutants, such as vegetable oils, hazardous and non-hazardous chemicals, coal, foodstuffs, plastics and the myriad of other products transported in container ships. Almost two thirds of the incidents ITOPF attends now involve non-tankers and in the past 20 years, 14% of all attended incident involved products or substances other than, or in addition to, oil.
Oil spill events can cause environmental damage and typically attract considerable media attention. However, other marine pollutants also have the potential to cause environmental damage and pose significant challenges for responders. This paper draws on ITOPF's first-hand experience to examine some of the recent trends in spill response, using case histories to highlight key issues involved with the response of spills of assorted oils and cargoes at sea.
Plastic pollution has become a global and emergency concern. Degradation processes of plastic macrowaste, either at the millimetre- and micrometre-size scales (microplastics, MP) or a nanometre one (nanoplastic, NP), is now well documented in all environmental compartments. It is hence necessary to study the environmental dynamic of MNP (micro(nano)plastic) on aquatic macrofauna considering their dispersion in different compartments. In this context, worms, having a large habitat in natural environments (soil, sediment, water) represent a relevant model organism for MNP investigations. In aquatic systems, worms could be used to compare MNP contamination between freshwater and seawater. The aim of this review was to discuss the relevance of using worms as model species for investigating MNP pollution in freshwater, estuarine, and marine systems. In this context, studies conducted in the field and in laboratory, using diverse classes of aquatic worms (polychaete and clitellate, i.e. oligochaete and hirudinea) to assess plastic contamination, were analysed. In addition, the reliability between laboratory exposure conditions and the investigation in the field was discussed. Finally, in a context of plastic use regulation, based on the literature, some recommendations about model species, environmental relevance, and experimental needs related to MNP are given for future studies.
Graphical Abstract
Nanoplastics (NPs) and microplastics (MPs) could act as potential carriers for pharmaceuticals and personal care products (PPCPs) and alter the bioavailability in the aquatic environment. The effects of NPs and MPs of polystyrene (PS) and polyethylene (PE) on the availability of five PPCPs including carbamazepine, bisphenol A, estrone, triclocarban and 4-tert-octylphenol were investigated by negligible depletion solid- phase microextraction (nd-SPME). The freely dissolved concentrations of PPCPs decreased with the increasing concentrations of NPs/MPs. The overall order of the sorption coefficients (logKNP / logKMP) of PPCPs was as follows: 100 nm PS > 50 nm PS > 1 µm PS > 100 µm PS > 100 µm PE. Sorption of PPCPs by NPs was generally 1-2 orders of magnitude stronger than to MPs. The log KNP / log KMP values (3.16-5.21) increased with the log KOW (2.45-5.28) of PPCPs, however, linear correlation was only observed between log KMP and log KOW. The particle size, specific surface area, aggregation state as well as hydrophobicity played an important role in the sorption. Coexistence of fulic acid (FA) with NPs inhibited the sorption due to the fouling of FA on NPs. This study suggests that sorption of PPCPs to MPs/NPs could reduce bioavailability of PPCPs in the aquatic environment.
Microplastics are less than 5mm in diameter that enters the ecosystem through the breakdown of large plastic particles or climate and human activity. This study examined the geographical and seasonal distribution of microplastics in the surface water of Kumaraswamy Lake, Coimbatore. During seasons, including summer, pre-monsoon, monsoon, and post-monsoon, samples were collected from the lake's inlet, centre, and outlet. All sampling points contained linear low-density polyethylene, high-density polyethylene, polyethylene terephthalate, and polypropylene microplastics. Water samples contained fibre, thin, fragment, and film microplastics in black, pink, blue, white, transparent, and yellow colours. Lake's microplastic pollution load index was under 10, indicating risk I. Over four seasons, microplastic content was 8.77±0.27 particles per litre. The monsoon season had the highest microplastic concentration, followed by pre-monsoon, post-monsoon, and summer. These findings imply that the spatial and seasonal distribution of microplastics may be harmful to the fauna and flora of the lake.
Synopsis
Many organisms exhibit collecting and gathering behaviors as a foraging and survival method. Benthic macroinvertebrates are classified as collector–gatherers due to their collection of particulate matter. Among these, the aquatic oligochaete Lumbriculus variegatus (California blackworms) demonstrates the ability to ingest both organic and inorganic materials, including microplastics. However, earlier studies have only qualitatively described their collecting behaviors for such materials. The mechanism by which blackworms consolidate discrete particles into a larger clump remains unexplored quantitatively. In this study, we analyze a group of blackworms in a large arena with an aqueous algae solution (organic particles) and find that their relative collecting efficiency is proportional to population size. We found that doubling the population size (N = 25–N = 50) results in a decrease in time to reach consolidation by more than half. Microscopic examination of individual blackworms reveals that both algae and microplastics physically adhere to the worm’s body and form clumps due to external mucus secretions by the worms. Our observations also indicate that this clumping behavior reduces the worm’s exploration of its environment, possibly due to thigmotaxis. To validate these observed biophysical mechanisms, we create an active polymer model of a worm moving in a field of particulate debris. We simulate its adhesive nature by implementing a short-range attraction between the worm and the nearest surrounding particles. Our findings indicate an increase in gathering efficiency when we add an attractive force between particles, simulating the worm’s mucosal secretions. Our work provides a detailed understanding of the complex mechanisms underlying the collecting–gathering behavior in L. variegatus, informing the design of bioinspired synthetic collector systems, and advances our understanding of the ecological impacts of microplastics on benthic invertebrates.
Mass production, consumption, and disposal of plastics pollute the freshwater environment. Microplastics are small plastic particles less than 5mm in diameter that enter the ecosystem as a result of the breakdown of large plastic particles or the direct release of small plastic particles by climate and human activities. This study focused on investigating the spatial, and seasonal dispersal of microplastics in the surface water of Kumaraswamy Lake, Coimbatore which is located at the Latitude of 110’00.52'' N, Longitude of 76056’42” E. In different seasons, such as summer, pre-monsoon, monsoon, and post-monsoon samples were taken from the inlet, centre, and outlet. Microplastics made of linear low-density polyethylene, high-density polyethylene, and polypropylene were found in all sampling points. From the water samples, fibre, thin, fragments, and film shapes of microplastics were identified and most of them were black, pink, blue, white, transparent, and yellow in colour. The lake's microplastic pollution load index values were less than 10, which implies the risk I category. Microplastic concentration over four seasons was 8.77 ± 0.27 particles per liter and a high distribution was observed in the outlet area (10.70 ± 0.25 particles/L). Seasonally, the highest microplastic concentration was found in the monsoon season followed by pre-monsoon, post-monsoon, and the lowest in the summer season. These results emphasize that the distribution of microplastics spatially and seasonally wise may cause harmful effects on the fauna and flora that live in lake habitats.
The role of the biopolymer polyhydroxybutyrate (PHB, <250µm) as a vehicle of a synthetic musks mixture (celestolide, galaxolide, tonalide, musk xylene, musk moskene and musk ketone) to Mytilus galloprovincialis was investigated. For 30 days, virgin PHB, virgin PHB+musks (6.82 µg g-1) and weathered PHB+musks, were daily spiked into tanks containing mussels, followed by a 10-day depuration period. Water and tissues samples were collected to measure exposure concentrations and accumulation in tissues. Mussels were able to actively filter microplastics in suspension but the concentration of the musks found in tissues (celestolide, galaxolide, tonalide) were markedly lower than the spiked concentration. Estimated Trophic Transfer Factors suggest that PHB will only play a minor role on musks accumulation in marine mussels, even if our results suggest a slightly extended persistence in tissues of musks loaded to weathered PHB.
The widespread presence of microplastics (MPs) in receiving water at high levels has raised new concerns about potential toxicity. Algae, as the essential primary producers, play vital roles in substance recycling and energy flow in aquatic ecosystems. However, to date, no efforts have been made on either systematic summarization or critical thinking of the influence of MPs on algae in receiving waters. In this work, we comprehensively review the impact of MPs on algae growth and populations, discuss key factors affecting toxicity and unveil the underlying mechanisms, and analyze the combined effects of MPs with gathered or released contaminants towards algae. Based on these, the knowledge gaps and future efforts are proposed. The findings highlighted in this work could deepen the understanding of interactions between MPs and algae, draw attention to the toxicity of MPs, and call for people to strengthen MPs treatment.
Tire and road wear particles (TRWP) account for an important part of the polymer particles released into the environment. There are scientific knowledge gaps as to the potential bioaccessibility of chemicals associated with TRWP to aquatic organisms. This study investigated the solubilization and bioaccessibility of seven of the most widely used tire-associated organic chemicals and four of their degradation products from cryogenically milled tire tread (CMTT) into fish digestive fluids using an in vitro digestion model based on Oncorhynchus mykiss. Our results showed that 0.06% to 44.1% of the selected compounds were rapidly solubilized into simulated gastric and intestinal fluids within a typical gut transit time for fish (3 h in gastric and 24 h in intestinal fluids). The environmentally realistic scenario of coingestion of CMTT and fish prey was explored using ground Gammarus pulex. Coingestion caused compound-specific changes in solubilization, either increasing or decreasing the compounds’ bioaccessibility in simulated gut fluids compared to CMTT alone. Our results emphasize that tire-associated compounds become accessible in a digestive milieu and should be studied further with respect to their bioaccumulation and toxicological effects upon passage of intestinal epithelial cells.
The majority of microplastics originating mainly from the utilization of different products: toothpaste, foodstuff, skincare products, vehicle tyres, synthetic fabrics, etc., end up in sewage wastewater. Microplastics in wastewaters (e.g., polyethylene, polystyrene, polyethylene terephthalate and polypropylene) appear in different forms and shapes (e.g., fibres, pellets, films, fragments, etc.). These recalcitrant microplastics in wastewater pose some challenges during sludge stabilization—anaerobic digestion. Due to their adsorptive potential, microplastics also harbour toxic substances (e.g., antibiotic residues, heavy metals, some resilient organic pollutants) as well as antibiotic-resistant-gene-bearing pathogenic organisms. This scenario complicates the anaerobic stabilization of pollutants found in wastewater and often reduces biogas yield. Therefore, poor management of wastewater could lead to the introduction of microplastics and their co-pollutants into water bodies, thereby causing serious public health issues. The present chapter will summarize the impacts of microplastics on anaerobic stabilization and the techniques currently developed to mitigate these concerns. Also, efforts aimed at reducing the continuous influx of these pollutants into the wastewater through global regulations and policies, as well as future research prospects will be presented herein.
KeywordsAnaerobic digestion (AD)MicroplasticsWastewaterBiogas yieldAntibiotics residueHeavy metals
Globally, the problem of microplastics (MPs) pose to water resources is current concern to scientists. Sources of MPs to water resources include wastewater, atmospheric deposition, surface runoff and leaching. Many marine animals suffer from ingesting high amounts of MPs accumulating in the gut and cause obstruction and inflammation in their organs. Humans are equally exposed from the use of surface water and drinking water or ground water. In view of these problems and in a bid to mitigate potential risks from the release of MPs to receiving waters, stringent water quality requirements for effluents are required and scientists are now developing methods or techniques to remove MPs from water resources. We reviewed techniques developed or modified for MPs removal in water and wastewater such as Dynamic Membranes Technology (DM), membrane bioreactors (MBR), reverse osmosis (RO), dissolved air flotation (DAF), rapid sand filtration (RSF), disc filter (DF), inorganic–organic hybrid silica gels, metal based-coagulation and electrocoagulation. The principles of these techniques were discussed as well as the advantages and disadvantages. Conclusions were drawn and future areas of research were recommended.
Microplastics (MPs) and polychlorinated biphenyls (PCBs) generally coexist in the environment, posing risks to public health and the environment. This study investigated the effect of different MPs on the microbial anaerobic reductive dechlorination of Aroclor 1260, a commercial PCB mixture. MP exposure inhibited microbial reductive dechlorination of PCBs, with inhibition rates of 39.43%, 23.97%, and 17.53% by polyethylene (PE), polypropylene (PP), and polystyrene (PS), respectively. The dechlorination rate decreased from 1.63 μM Cl⁻ d⁻¹ to 0.99–1.34 μM Cl⁻ d⁻¹ after MP amendment. Chlorine removal in the meta-position of PCBs was primarily inhibited by MPs, with no changes in the final PCB dechlorination metabolites. The microbial community compositions in MP biofilms were not significantly different (P > 0.05) from those in suspension culture, although possessing greater Dehalococcoides abundance (0.52–0.81% in MP biofilms; 0.03–0.12% in suspension culture). The co-occurrence network analysis revealed that the presence of MPs attenuated microbial synergistic interactions in the dechlorinating culture systems, which may contribute to the inhibitory effect on microbial PCB dechlorination. These findings are important for comprehensively understanding microbial dechlorination behavior and the environmental fate of PCBs in environments with co-existing PCBs and MPs and for guiding the application of in situ PCB bioremediation.
The widespread microplastics (MPs) pollution has become a concerning environmental issue. The interactions between MPs and typical pollutants may change the bioaccumulation, and toxicity of pollutants, leading to high uncertainty in risk assessment. Still, significant gaps remain in the knowledge available to integrate these interactions in the perspectives of toxicokinetics (TK) and toxicodynamics (TD), which is also an essential part of quantitative toxicological research. This review systematically summarizes the interaction between MPs and typical pollutants in TK and TD processes. MPs can be acted as the vector or sink of pollutants to increase or decrease their bioaccumulation, and also may not affect their bioaccumulation due to no interaction. The adverse outcome pathway (AOP) framework enables novel approaches for determining the interaction between MPs and pollutants in the TD process. MPs can directly or indirectly enhance, reduce and not affect the toxicity of pollutants. A series of factors influencing the interaction in TK and TD processes are summarized, including MPs characteristics and exposure scenarios. TK-TD approach can quantitatively understand the interaction between MPs and pollutants based on the mechanism. Given the current knowledge gap in TK and TD processes, future perspectives on combined exposure research are proposed.
This paper explores different interactions and processes involved in the transport of microplastics from agricultural systems to surrounding environments. We conducted an exhaustive review of the most recent scientific papers on microplastic transport in terrestrial systems, with an emphasis on agricultural systems. In the following sections, several aspects of this problem are discussed, namely (i) direct and indirect sources of microplastics, (ii) biotic and abiotic transportation of microplastics in and from the terrestrial environment, (iii) modelling of microplastics in the terrestrial environment and (iv) facilitated chemicals and pathogens in combination with plastic particles. There is very little information available concerning microplastic transport in the terrestrial environment; therefore, more research is needed to gain a better understanding of how these processes take place. The novelty of this review lies in assessing how microplastic transport occurs from the plastisphere (cellular) to the landscape level and from agricultural systems to the surrounding areas.
Graphical Abstract
Nanoplastics (NPs, <1000 nm) may adsorb organic pollutants in the aquatic environment, thereby, influencing their bioavailability to organisms. This study aims to investigate the individual and combined toxicity of perfluorooctane sulfonate (PFOS) and virgin yellow-green fluorescent polystyrene NPs (200 nm) at sub-lethal doses on the marine mussel Perna viridis. Our results demonstrated that both PFOS single and PFOS-NP co-exposure at 1000 μg/L significantly increased PFOS distribution in the gills, gonads, and visceral mass (p < 0.05), compared to the control. Further, PFOS single and PFOS-NP co-exposures at 100 and 1000 μg/L significantly increased the reactive oxygen species (ROS) levels in mussel tissues that consequently altered the responses of antioxidant entities including MDA, CAT, SOD, GR, and GST. The transcriptional profiling of oxidative stress-related genes (cyp4, hsp22, hsp60, gst-omega, and gst-pi), showed significantly downregulated expressions at the lowest level of co-exposure (PFOS 10 μg/L) in all tissues, especially in gills, compared to the control group. Overall, the enhanced integrated biomarker response (EIBR) revealed PFOS-NP co-exposure at 1000 μg/L, as the most stressful circumstance to induce mixture toxicity, at which more structural damage to the gills and gonads were observed than single PFOS/NPs exposure. In summary, the co-exposure significantly enhanced the PFOS bioaccumulation and ROS levels in mussel tissues, resulting in altered antioxidant and genetic responses, suggesting that NPs could affect the distribution of PFOS between P. viridis and seawater. Hence, further studies should be conducted to unveil the interactive toxic effects of NPs and PFOS on marine mussels.
The hypothesis that 'microplastic will transfer hazardous hydrophobic organic chemicals (HOC) to marine animals' has been central to the perceived hazard and risk of plastic in the marine environment. The hypothesis is often cited and has gained momentum, turning it into paradigm status. We provide a critical evaluation of the scientific literature regarding this hypothesis. Using new calculations based on published studies, we explain the sometimes contrasting views and unify them in one interpretive framework. One explanation for the contrasting views among studies is that they test different hypotheses. When reframed in the context of the above hypothesis, the available data become consistent. We show that HOC microplastic-water partitioning can be assumed to be at equilibrium for most microplastic residing in the oceans. We calculate the fraction of total HOC sorbed by plastics to be small compared to that sorbed by other media in the ocean. We further demonstrate consistency among (a) measured HOC transfer from microplastic to organisms in the laboratory, (b) measured HOC desorption rates for polymers in artificial gut fluids (c) simulations by plastic-inclusive bioaccumulation models and (d) HOC desorption rates for polymers inferred from first principles. We conclude that overall the flux of HOCs bioaccumulated from natural prey overwhelms the flux from ingested microplastic for most habitats, which implies that microplastic ingestion is not likely to increase the exposure to and thus risks of HOCs in the marine environment.
Plastic litter is an environmental problem of great concern. Despite the magnitude of the plastic pollution in our water bodies there is still limited scientific understanding about the risk for the environment, particularly for microplastics. The apparent magnitude of the problem calls for quickly developing sound scientific guidance on the ecological risks of microplastics. We suggest future research into MP risks should be guided by lessons learned from the more advanced and better understood areas of (eco)toxicology of engineered nanoparticles and mixture toxicity. Relevant examples of advances in these two fields are provided to help accelerate the scientific learning curve within the relatively unexplored area of MP risk assessment. Finally, we advocate an expansion of the "vector effect" hypothesis in regards to microplastics risk to help focus research of MP environmental risk at different levels of biological and environmental organization. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of Arenicola marina (lugworm) and Gadus morhua (North Sea cod). We use a biodynamic model that allows calculations of the relative contribution of plastic ingestion to total exposure of aquatic species to chemicals residing in the ingested plastic. Uncertainty in the most crucial parameters is accounted for by probabilistic modeling. Our conservative analysis shows that plastic ingestion by the lugworm yields NP and BPA concentrations that stay below the lower ends of global NP and BPA concentration ranges, and therefore are not likely to constitute a relevant exposure pathway. For cod, plastic ingestion appears to be a negligible pathway for exposure to NP and BPA.
In situ amendment of activated carbon (AC) to sediments can effectively reduce the bioavailability of hydrophobic organic contaminants. While biochars have been suggested as low-cost and sustainable alternatives to ACs, there are few comparative sorption data especially for mercury (Hg) and methylmercury (MeHg) at low porewater concentrations in sediments. Here we compare the ability of a wide range of commercially available and laboratory synthesized ACs and biochars to sorb PAHs, PCBs, DDTs, inorganic Hg, and MeHg at environmentally relevant concentrations. Compared to natural organic matter, sorption capacity for most organic compounds was at least 1-2 orders of magnitude higher for unactivated biochars and 3-4 orders of magnitude higher for ACs which translated to sediment porewater PCB concentration reductions of 18-80% for unactivated biochars, and >99% for ACs with 5% by weight amendment to sediment. Steam activated carbons were more effective than biochars in Hg sorption and translated to modeled porewater Hg reduction in the range of 94-98% for sediments with low native Kd and 31-73% for sediments with high native Kd values for Hg. Unactivated biochars were as effective as the steam activated carbons for MeHg sorption. Predicted reductions of porewater MeHg were 73-92% for sediments with low native Kd and 57-86% for sediment with high native Kd. ACs with high surface areas therefore are likely to be effective in reducing porewater concentrations of organics, Hg, and MeHg in impacted sediments. Unactivated biochars had limited effectiveness for organics and Hg but can be considered when MeHg exposure is the primary concern.
Bioavailability and accumulation of sediment-bound polycyclic aromatic hydrocarbons (PAHs) by benthic biota are closely related to their extractability by water or mild aqueous solvents. Nevertheless, PAH accumulation by benthic organisms is sometimes considerably different from predictions based on an equilibrium partition coefficient KOC between water and bulk sedimentary organic carbon (OC). We present evidence that PAH extractability is strongly affected by the type of OC acting as a sorbent. We compared extractability of spiked [14C]fluoranthene from a variety of natural and man-made OC matrices, including bulk sediment organic carbon, peat moss, power plant fly ash, diesel soot, petroleum/natural gas soot, coal dust and carbon black. Artificial sediments were prepared from glass beads amended with equal weight percentages (2%) of nine different types of OC. Amended sediments were spiked with [14C]fluoranthene and batch-extracted with seawater and 0.5 % sodium dodecyl sulfate (SDS) after 65 h and 12 h of equilibration, respectively. Fluoranthene extractability by seawater ranged between 0.03 - 0.9%, corresponding to a 50-fold variation of apparent KOC, and 0.03-18% for SDS. Correlation between seawater and SDS extraction efficiencies was weak, suggesting differences in the mechanism of solubilization. These results demonstrate that use of a single value of KOC to predict bioavailability of fluoranthene should be avoided, and that attempts to extrapolate PAH extractability from water-only extraction experiments to aqueous solutions containing surface-active dissolved organic carbon, such as the gut fluids of deposit feeding macrofauna, is very likely to lead to erroneous predictions.
It has been hypothesised that persistent organic pollutants (POPs) in microplastic may pose a risk to aquatic organisms. Here, we develop and analyse a conceptual model that simulates the effects of plastic on bioaccumulation of POPs. The model accounts for dilution of exposure concentration by sorption of POPs to plastic (POP 'dilution'), increased bioaccumulation by ingestion of plastic containing POPs ('carrier'), and decreased bioaccumulation by ingestion of clean plastic ('cleaning'). The model is parameterised for the lugworm Arenicola marina and evaluated against recently published bioaccumulation data for this species from laboratory bioassays with polystyrene microplastic. Further scenarios include polyethylene microplastic, nano-sized plastic and open marine systems. Model analysis shows that plastic with low affinity for POPs, like polystyrene will have a marginal decreasing effect on bioaccumulation, governed by dilution. For stronger sorbents like polyethylene, the dilution, carrier and cleaning mechanism are more substantial. In closed laboratory bioassay systems, dilution and cleaning dominate, leading to decreased bioaccumulation. Also in open marine systems a decrease is predicted due to a cleaning mechanism that counteracts biomagnification. However, the differences are considered too small to be relevant from a risk assessment perspective.
Contaminants in sediments are less available than their concentrations might imply, but measures of this availability have been generally lacking. Sediments ingested by benthic animals can be expected to undergo a unique chemical environment controlled by the digestive chemistry of the organism. We measured solubilization of sedimentary contaminantsCu, Pb, and polycyclic aromatic hydrocarbons (PAH)by digestive fluids extracted from marine invertebrates. Bioavailability of these contaminants, thus measured, is a small fraction of total contaminant loadingtypically 1−10%. The amounts of metals solubilized by digestive fluids were orders of magnitude greater than would be predicted from water−solid partitioning with clean seawater, although they correlated well with solubilization by seawater. Digestive fluids from two different animal species solubilized different amounts of metals, indicating that bioavailability varies among species even under constant mode of uptake. High concentrations of solubilizing agents, such as amino acids for metals and surfactants for PAH, in the digestive fluids can explain the enhanced solubilization. This biomimetic approach to contaminant measurement provides the basis for more accurate mechanistic and routine assessments of environmental impact.
Since the mass production of plastics began in the 1940s, microplastic contamination of the marine environment has been a growing problem. Here, a review of the literature has been conducted with the following objectives: (1) to summarise the properties, nomenclature and sources of microplastics; (2) to discuss the routes by which microplastics enter the marine environment; (3) to evaluate the methods by which microplastics are detected in the marine environment; (4) to assess spatial and temporal trends of microplastic abundance; and (5) to discuss the environmental impact of microplastics. Microplastics are both abundant and widespread within the marine environment, found in their highest concentrations along coastlines and within mid-ocean gyres. Ingestion of microplastics has been demonstrated in a range of marine organisms, a process which may facilitate the transfer of chemical additives or hydrophobic waterborne pollutants to biota. We conclude by highlighting key future research areas for scientists and policymakers.
The bioavailability of particle-associated contaminants was measured by a new approach that employs the digestive fluid of deposit feeders to solubilize contaminants in vitro. The proportion of contaminant solubilized by digestive fluid of the polychaete Arenicola brasiliensis was considered a measure of bioavailability and was contrasted with other, more traditional measures (i.e., uptake clearance, bioaccumulation factor, and absorption efficiency). There was generally good agreement among the four methods on the relative bioavailability of benzo[a]pyrene from six sandy sediments. Measures of phenanthrene bioavailability did not show strong correlations due io both a more limited data set and perhaps greater importance of uptake from the dissolved phase. The bioavailability of spiked polycyclic aromatic hydrocarbons (PAHs) differed from that of equivalent in situ-contaminated PAH but not in a predictable and consistent manner. By direct measurement of PAH content of recently ingested sediments collected from the foregut, we were able to quantify the importance of particle-selective feeding in increasing PAH content of ingested material relative to the bulk, ambient sediments. In most instances, the effect of selective feeding by A. brasiliensis was minimal. increasing PAI content of ingested material <20% above the ambient sediments. Absorption efficiencies of PAH during gut passage were determined by direct measurement of PAH concentration in sediments at various points along the digestive tract. Overall digestive absorption efficiencies were similar to the extent of in vitro solubilization by digestive fluids from the same sediments. These data suggest that extent of solubilization of sediment-bound contaminants during gut passage is a critical constraint on uptake and that absorption efficiency, with respect to the solubilized fraction, approaches 100%.
In vitro extraction of contaminated sediments using the digestive fluid of a deposit-feeding polychaete has recently been proposed to study contaminant bioaccumulation mechanisms and perhaps to better quantify the bioavailable contaminant fraction. This approach was evaluated using digestive fluid from the polychaete Arenicola brasiliensis and six marine sediments containing both spiked radiolabeled polycyclic aromatic hydrocarbons (PAHs) anti in situ-contaminated unlabeled PAHs. The proportion of total contaminant extracted by digestive fluid from each sediment varied from 22 to 71% and 13 to 52% for phenanthrene and benzo[a]pyrene, respectively. The proportions of contaminant solubilized were inversely correlated with the sediments' organic carbon content. The extent of PAH solubilization among sediments by A. brasiliensis digestive Fluid was highly correlated with that of digestive fluid from the echiuran Urechis caupo and appears to be a consequence of surfactant properties of the fluids rather than of their enzymatic activity. The proportion of PAHs solubilized in vitro was similar to in vivo measurements of solubilization for contaminant exposures lasting about 24 h. However, with continued exposure, in vivo PAH concentrations in the digestive fluid increased fivefold, suggesting that digestive fluid is retained in the gut longer than sediment and thus accumulates PAHs through sequential digestion of many gut volumes. This phenomenon may enhance contaminant fugacity in the gut and increase the potential for bioaccumulation or toxicity.
Significance
Plastics are a contaminant of emerging concern accumulating in marine ecosystems. Plastics tend to break down into small particles, called microplastics, which also enter the marine environment directly as fragments from a variety of sources, including cosmetics, clothing, and industrial processes. Given their ubiquitous nature and small dimensions, the ingestion and impact of microplastics on marine life are a cause for concern, notably for filter feeders. Oysters were exposed to polystyrene microparticles, which were shown to interfere with energy uptake and allocation, reproduction, and offspring performance. A drop in energy allocation played a major role in this reproductive impairment. This study provides ground-breaking data on microplastic impacts in an invertebrate model, helping to predict ecological impact in marine ecosystems.
The northern fulmar (Fulmarus glacialis) is defined as an indicator species of plastic pollution by the Oslo-Paris Convention (OSPAR) for the North-East Atlantic, but few data exist for fulmars from Norway. Moreover, the relationship between uptake of plastic and pollutants in seabirds is poorly understood. We analysed samples of fulmars from Norwegian waters and compared the POP concentrations in their liver and muscle tissue with the corresponding concentrations in the loads of ingested plastic in their stomachs, grouped as 'no', 'medium' (0.01 - 0.21 g; 1 - 14 pieces of plastic) or 'high' (0.11 - 0.59 g; 15 - 106 pieces of plastic). POP concentrations in the plastic did not differ significantly between the high and medium plastic ingestion group for sumPCBs, sumDDTs and sumPBDEs. By combining correlations among POP concentrations, differences in tissue concentrations of POPs between plastic ingestion subgroups, fugacity calculations and bioaccumulation modeling, we showed that plastic is more likely to act as a passive sampler than as a vector of POPs, thus reflecting the POP profiles of simultaneously ingested prey.
Marine filter feeders are exposed to microplastic because of their selection of small particles as food source. Baleen whales feed by filtering small particles from large water volumes. Macroplastic was found in baleen whales before. This study is the first to show the presence of microplastic in intestines of a baleen whale (Megaptera novaeangliae). Contents of its gastrointestinal tract were sieved, dissolved in 10% potassium hydroxide and washed. From the remaining dried material, potential synthetic polymer particles were selected based on density and appearance, and analysed by Fourier transform infrared (FTIR) spectroscopy. Several polymer types (polyethylene, polypropylene, polyvinylchloride, polyethylene terephthalate, nylon) were found, in varying particle shapes: sheets, fragments and threads with a size of 1mm to 17cm. This diversity in polymer types and particle shapes, can be interpreted as a representation of the varying characteristics of marine plastic and the unselective way of ingestion by M. novaeangliae.
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Plastic contamination is an increasing environmental problem in marine systems where it has spread globally to even the most remote habitats. Plastic pieces in smaller size scales, microplastics (particles <5mm), have reached high densities (e.g., 100 000 items per m3) in waters and sediments, and are interacting with organisms and the environment in a variety of ways. Early investigations of freshwater systems suggest microplastic presence and interactions are equally as far reaching as are being observed in marine systems. Microplastics are being detected in freshwaters of Europe, North America, and Asia, and the first organismal studies are finding that freshwater fauna across a range of feeding guilds ingest microplastics.
The presence of microplastic and carbon-based nanoparticles in the environment may have implications for the fate and effects of traditional hydrophobic chemicals. Here we present parameters for the sorption of 17 CB congeners to 10-180 µm sized polyethylene (micro-PE), 70 nm polystyrene (nano-PS), multiwalled carbon nanotubes (MWCNT), fullerene (C60) and a natural sediment, in the environmentally relevant 10-5 to 10-1 μg L-1 concentration range. Effects of salinity and sediment organic matter fouling were assessed by measuring the isotherms in fresh- and seawater, with and without sediment present. Sorption to the 'bulk' sorbents sediment organic matter (OM) and micro-PE occurred through linear hydrophobic partitioning with OM and micro-PE having similar sorption affinity. Sorption to MWCNT and nano-PS was non-linear. PCB sorption to MWCNT and C60 was 3 to 4 orders of magnitude stronger than to OM and micro-PE. Sorption to nano-PS was 1 to 2 orders of magnitude stronger than to micro-PE, which was attributed to the higher aromaticity and surface-volume ratio of nano-PS. Organic matter effects varied among sorbents, with the largest OM fouling effect observed for the high surface sorbents MWCNT and nano-PS. Salinity decreased sorption for sediment and MWCNT, but increased sorption for the polymers nano-PS and micro-PE. The exceptionally strong sorption of (planar) PCBs to C60, MWCNT and nano-PS may imply increased hazards upon membrane transfer of these particles.
There is increasing concern about the impacts of microplastics (< 1mm) on marine biota. Microplastics may be mistaken for food items and ingested by a wide variety of organisms. While the effects of ingesting microplastic have been explored for some adult organisms, there is poor understanding of the effects of microplastic ingestion on marine larvae. Here, we investigated the ingestion of polyethylene microspheres by larvae of the sea urchin Tripneustes gratilla. Ingestion rates scaled with the concentration of microspheres. Ingestion rates were, however, reduced by biological fouling of microplastic and in the presence of phytoplankton food. T. gratilla larvae were able to egest microspheres from their stomach within hours of ingestion. A microsphere concentration far exceeding those recorded in the marine environment had a small non-dose dependent effect on larval growth, but there was no significant effect on survival. In contrast, environmentally realistic concentrations appeared to have little effect. Overall, these results suggest that current levels of microplastic pollution in the oceans only pose a limited threat to T. gratilla and other marine invertebrate larvae, but further research is required on a broad range of species, trophic levels and polymer types.
Inadequate products, waste management, and policy are struggling to prevent plastic waste from infiltrating ecosystems [1, 2]. Disintegration into smaller pieces means that the abundance of micrometer-sized plastic (microplastic) in habitats has increased [3] and outnumbers larger debris [2, 4]. When ingested by animals, plastic provides a feasible pathway to transfer attached pollutants and additive chemicals into their tissues [5-15]. Despite positive correlations between concentrations of ingested plastic and pollutants in tissues of animals, few, if any, controlled experiments have examined whether ingested plastic transfers pollutants and additives to animals. We exposed lugworms (Arenicola marina) to sand with 5% microplastic that was presorbed with pollutants (nonylphenol and phenanthrene) and additive chemicals (Triclosan and PBDE-47). Microplastic transferred pollutants and additive chemicals into gut tissues of lugworms, causing some biological effects, although clean sand transferred larger concentrations of pollutants into their tissues. Uptake of nonylphenol from PVC or sand reduced the ability of coelomocytes to remove pathogenic bacteria by >60%. Uptake of Triclosan from PVC diminished the ability of worms to engineer sediments and caused mortality, each by >55%, while PVC alone made worms >30% more susceptible to oxidative stress. As global microplastic contamination accelerates, our findings indicate that large concentrations of microplastic and additives can harm ecophysiological functions performed by organisms.
Recently, research examining the occurrence of microplastics in the marine environment has substantially increased. Field and laboratory work regularly provide new evidence on the fate of microplastic debris. This debris has been observed within every marine habitat. In this study, at least 101 peer-reviewed papers investigating microplastic pollution were critically analysed (Supplementary material). Microplastics are commonly studied in relation to (1) plankton samples, (2) sandy and muddy sediments, (3) vertebrate and invertebrate ingestion, and (4) chemical pollutant interactions. All of the marine organism groups are at an eminent risk of interacting with microplastics according to the available literature. Dozens of works on other relevant issues (i.e., polymer decay at sea, new sampling and laboratory methods, emerging sources, externalities) were also analysed and discussed. This paper provides the first in-depth exploration of the effects of microplastics on the marine environment and biota. The number of scientific publications will increase in response to present and projected plastic uses and discard patterns. Therefore, new themes and important approaches for future work are proposed.
The occurrence of microplastics (MPs) in the ocean is an emerging world-wide concern. Due to high sorption capacity of plastics for hydrophobic organic chemicals (HOCs), sorption may play an important role in the transport processes of HOCs. However, sorption capacity of various plastic materials is rarely documented except in the case of those used for environmental sampling purposes. In this study, we measured partition coefficients between MPs and seawater (KMPsw) for 8 polycyclic aromatic hydrocarbons (PAHs), 4 hexachlorocyclohexanes (HCHs) and 2 chlorinated benzenes (CBs). Three surrogate polymers - polyethylene, polypropylene, and polystyrene - were used as model plastic debris because they are the major components of microplastic debris found. Due to the limited solubility of HOCs in seawater and their long equilibration time, a third-phase partitioning method was used for the determination of KMPsw. First, partition coefficients between polydimethylsiloxane (PDMS) and seawater (KPDMSsw) were measured. For the determination of KMPsw, the distribution of HOCs between PDMS or plastics and solvent mixture (methanol:water=8:2 (v/v)) was determined after apparent equilibrium up to 12weeks. Plastic debris was prepared in a laboratory by physical crushing; the median longest dimension was 320-440μm. Partition coefficients between polyethylene and seawater obtained using the third-phase equilibrium method agreed well with experimental partition coefficients between low-density polyethylene and water in the literature. The values of KMPsw were generally in the order of polystyrene, polyethylene, and polypropylene for most of the chemicals tested. The ranges of log KMPsw were 2.04-7.87, 2.18-7.00, and 2.63-7.52 for polyethylene, polypropylene, and polystyrene, respectively. The partition coefficients of plastic debris can be as high as other frequently used partition coefficients, such as 1-octanol-water partition coefficients (Kow) and log KMPsw showed good linear correlations with log Kow. High sorption capacity of microplastics implies the importance of MP-associated transport of HOCs in the marine environment.
Sorbent amendment with activated carbon (AC) is a novel in situ management strategy for addressing human and ecological health risks posed by hydrophobic organic chemicals (HOCs) in sediments and soils. A large body of literature shows that AC amendments can reduce bioavailability of sediment-associated HOCs by more than 60% to 90%. Empirically derived biodynamic models can predict bioaccumulation in benthic invertebrates within a factor of two, allowing for future scenarios under AC amendment to be estimated. Higher AC dose and smaller AC particle size further reduce bioaccumulation of HOCs but may induce stress in some organisms. Adverse ecotoxicity response to AC exposure was observed in one fifth of 82 tests, including changes in growth, lipid content, behavior, and survival. Negative effects on individual species and benthic communities appear to depend on the characteristics of the sedimentary environment and the AC amendment strategy (e.g. dose and particle size). More research is needed to evaluate reproductive endpoints, bacterial communities, and plants, and to link species- and community-level responses to amendment. In general, the ability of AC to effectively limit the mobility of HOCs in aquatic environments may outshine potential negative secondary effects, and these outcomes must be held in comparison to traditional remediation approaches.
It has been speculated that marine microplastics may cause negative effects on benthic marine organisms and increase bioaccumulation of persistent organic pollutants (POPs). Here, we provide the first controlled study of plastic effects on benthic organisms including transfer of POPs. The effects of polystyrene (PS) microplastic on survival, activity, and bodyweight as well as the transfer of 19 polychlorinated biphenyls (PCBs), were assessed in bioassays with Arenicola marina (L.). PS was pre-equilibrated in natively contaminated sediment. A positive relation was observed between microplastic concentration in the sediment and both uptake of plastic particles and weight loss by A. marina. Furthermore, a reduction in feeding activity was observed at a PS dose of 7.4% dry weight (DW). A low PS dose of 0.074% increased bioaccumulation of PCBs by a factor 1.1 - 3.6, an effect that was significant for ΣPCBs and several individual congeners. At higher doses, bioaccumulation decreased compared to the low dose, which however, was only significant for PCB105. PS has statistically significant effects on the organisms' fitness and bioaccumulation, but the magnitude of the effects was not high. This may be different for sites with different plastic concentrations, or plastics with a higher affinity for POPs.