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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.
... Due to their large surface-to-volume ratio and charged hydrophobic surfaces, MP provide an excellent sorption site to scavenge some particle-reactive, dissolved contaminants (e.g., PBTs, PBDEs, DDT, PAHs, and pharmaceuticals), trace metals (e.g., copper, zinc, lead), and other plastic additives (Teuten et al. 2007Beckingham and Ghosh 2017;Ribeiro et al. 2019). Consequently, MP can also become a potential, albeit diffuse source for diverse co-contaminants Nakashima et al. 2016;Alimi et al. 2018). ...
... This hampers data interpretation and has led to uncertainty with respect to the applicability of the results of some studies. This especially occurs for studies that used gradient between MP sorbed with chemicals and clean water Chua et al. 2014;Beckingham and Ghosh 2017). In a recent review, re-analysed exposure in a study where Oryzias latipes were exposed to MP associated with organic contaminants sorbed from San Diego Bay and assessed that there was insufficient chemical mass on the MP to explain mass measured in fish for most chemicals, suggesting that the cod oil in the diet also was a source. ...
... Nature Several studies have mentioned non-equilibrium exposure as a limitation in the interpretation of their data (e.g.Beckingham and Ghosh 2017; Sleight et al. 2017;Rochman et al. 2017). Furthermore, it has been argued that chemical equilibrium is the most likely state for chemicals on small microplasticDiepens and Koelmans 2018;De Frond et al. 2019; Seidensticker et al. 2019). ...
This open access book examines global plastic pollution, an issue that has become a critical societal challenge with implications for environmental and public health. This volume provides a comprehensive, holistic analysis on the plastic cycle and its subsequent effects on biota, food security, and human exposure. Importantly, global environmental change and its associated, systems-level processes, including atmospheric deposition, ecosystem complexity, UV exposure, wind patterns, water stratification, ocean circulation, etc., are all important direct and indirect factors governing the fate, transport and biotic and abiotic processing of plastic particles across ecosystem types. Furthermore, the distribution of plastic in the ocean is not independent of terrestrial ecosystem dynamics, since much of the plastic in marine ecosystems originates from land and should therefore be evaluated in the context of the larger plastic cycle. Changes in species size, distribution, habitat, and food web complexity, due to global environmental change, will likely alter trophic transfer dynamics and the ecological effects of nano- and microplastics. The fate and transport dynamics of plastic particles are influenced by their size, form, shape, polymer type, additives, and overall ecosystem conditions. In addition to the risks that plastics pose to the total environment, the potential impacts on human health and exposure routes, including seafood consumption, and air and drinking water need to be assessed in a comprehensive and quantitative manner. Here I present a holistic and interdisciplinary book volume designed to advance the understanding of plastic cycling in the environment with an emphasis on sources, fate and transport, ecotoxicology, climate change effects, food security, microbiology, sustainability, human exposure and public policy.
... The shape and size of microplastics often resemble natural (organic and inorganic) particles, but their behavior, effects on organisms, and sorption properties may differ (Beckingham and Ghosh, 2017;Mueller et al., 2020b;Wang and Wang, 2018b). Microplastics fate and behavior was compared with other particles in 3% of all studies (Table S3), mostly with natural particles such as kaolin (Ateia et al., 2020b;Gorokhova et al., 2020;Ogonowski et al., 2016;Scherer et al., 2020;Schür et al., 2020;Zimmermann et al., 2020), natural aquatic sediment (Bartonitz et al., 2020;Besson et al., 2020;Harris and Carrington, 2020;Wang and Wang, 2018b), silica particles (Mueller et al., 2020b;Straub et al., 2017), cobblestones (Miao et al., 2020;Miao et al., 2019b), wood particles (Beckingham and Ghosh, 2017), coal (Beckingham and Ghosh, 2017), sandy loam (Leads et al., 2019), diatomite (Scherer et al., 2017), rock , leaves and beech sawdust (Kalčíková et al., 2020). ...
... The shape and size of microplastics often resemble natural (organic and inorganic) particles, but their behavior, effects on organisms, and sorption properties may differ (Beckingham and Ghosh, 2017;Mueller et al., 2020b;Wang and Wang, 2018b). Microplastics fate and behavior was compared with other particles in 3% of all studies (Table S3), mostly with natural particles such as kaolin (Ateia et al., 2020b;Gorokhova et al., 2020;Ogonowski et al., 2016;Scherer et al., 2020;Schür et al., 2020;Zimmermann et al., 2020), natural aquatic sediment (Bartonitz et al., 2020;Besson et al., 2020;Harris and Carrington, 2020;Wang and Wang, 2018b), silica particles (Mueller et al., 2020b;Straub et al., 2017), cobblestones (Miao et al., 2020;Miao et al., 2019b), wood particles (Beckingham and Ghosh, 2017), coal (Beckingham and Ghosh, 2017), sandy loam (Leads et al., 2019), diatomite (Scherer et al., 2017), rock , leaves and beech sawdust (Kalčíková et al., 2020). Some studies compared microplastics with other types of particles, such as glass beads (Parrish and Fahrenfeld, 2019;Schrank et al., 2019), cotton fibres (Cesa et al., 2020;Treilles et al., 2020), wool fibres (Treilles et al., 2020), biochar (Beckingham and Ghosh, 2017), and cellulose . ...
... The shape and size of microplastics often resemble natural (organic and inorganic) particles, but their behavior, effects on organisms, and sorption properties may differ (Beckingham and Ghosh, 2017;Mueller et al., 2020b;Wang and Wang, 2018b). Microplastics fate and behavior was compared with other particles in 3% of all studies (Table S3), mostly with natural particles such as kaolin (Ateia et al., 2020b;Gorokhova et al., 2020;Ogonowski et al., 2016;Scherer et al., 2020;Schür et al., 2020;Zimmermann et al., 2020), natural aquatic sediment (Bartonitz et al., 2020;Besson et al., 2020;Harris and Carrington, 2020;Wang and Wang, 2018b), silica particles (Mueller et al., 2020b;Straub et al., 2017), cobblestones (Miao et al., 2020;Miao et al., 2019b), wood particles (Beckingham and Ghosh, 2017), coal (Beckingham and Ghosh, 2017), sandy loam (Leads et al., 2019), diatomite (Scherer et al., 2017), rock , leaves and beech sawdust (Kalčíková et al., 2020). Some studies compared microplastics with other types of particles, such as glass beads (Parrish and Fahrenfeld, 2019;Schrank et al., 2019), cotton fibres (Cesa et al., 2020;Treilles et al., 2020), wool fibres (Treilles et al., 2020), biochar (Beckingham and Ghosh, 2017), and cellulose . ...
In recent decades, much attention has been paid to microplastic pollution, and research on microplastics has begun to grow exponentially. However, microplastics research still suffers from the lack of standardized protocols and methods for investigation of microplastics under laboratory conditions. Therefore, in this review, we summarize and critically discuss the results of 715 laboratory studies published on microplastics in the last five years to provide recommendations for future laboratory research. Analysis of the data revealed that the majority of microplastic particles used in laboratory studies are manufactured spheres of polystyrene ranging in size from 1 to 50 µm, that half of the studies do not characterize the particles used, and that a minority of studies use aged particles, investigate leaching of chemicals from microplastics, or use natural particles as controls. There is a large discrepancy between microplastics used in the laboratory and those found in the environment, and many laboratory studies suffer from a lack of environmental relevance and provide incomplete information on the microplastics used. We have summarized and discussed these issues and provided recommendations for future laboratory research on microplastics focusing on i) microplastic selection, ii) microplastic characterization, and iii) test design of laboratory research on microplastics.
... 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.
... Even though the literature provides insights into uptake capabilities of MPs for freshwater worms (Imhof et al., 2013;Hurley et al., 2017;Scherer et al., 2017), toxicological data is still rare in this context (Haegerbaeumer et al., 2019). For instance, the freshwater oligochaete Lumbriculus variegatus has been solely examined by Beckingham & Ghosh (2017) and Redondo-Hasselerharm et al. (2018a,b) despite its ecological role (Chapman, 2001). In its natural environment, L. variegatus is exposed to contaminants via two major routes: enteral route by ingestion of sediment particles with pore water and dermal route by uptake from pore and overlying water Leppänen & Kukkonen, 1998b). ...
... Since uptake capabilities depend mostly on particle size , this property could have contributed to adverse effects of the MP. Because the size fractions of both particulates were within an ingestible range for L. variegatus (Beckingham & Ghosh, 2017), we reject the size as a major influence and assume that MP chemicals induced adverse effects (see first section of 4.1). This was not confirmed by kaolin findings as it proved to be a biologically active control due to enhanced dry weights in Exp. ...
... Because we added hydrophobic compounds to the sediment, the observed mortality of L. variegatus might be induced by non-specific narcosis, complying with intercalation of hydrophobic pollutants into membranes (Escher & Hermens, 2002). Chemicals may desorb from ingested sediment particles during gut passage (Browne et al., 2013;Beckingham & Ghosh, 2017) or can be taken up percutaneously from pore water (Leppänen & Kukkonen, 1998b). In the present study, the ingestion of pore water and contaminated sediment particles with food are likely both operating routes for exposure. ...
Microplastics (MPs) as complex synthetic pollutants represent a growing concern for the aquatic environment. Previous studies examined the toxicity of MPs, but infrequently used a natural particle control such as kaolin. The cause of toxicity, either the physical structure of the particles or chemical components originating from the MPs, has rarely been resolved. Moreover, the ecotoxicological assessment of biodegradable plastics has received little attention.
To narrow down the main driver for toxicity of irregular biodegradable MPs, we conducted a series of 28-days sediment toxicity tests with the freshwater oligochaete Lumbriculus variegatus and recorded the number of worms and dry weight as endpoints. Therefore, MPs containing several biodegradable polymers were either mixed with the sediment or layered on the sediment surface with concentrations from 1 to 8.4% sediment dw⁻¹. Kaolin particles were evaluated in parallel as particle control. Furthermore, aqueous leachates and methanolic extracts as MP equivalents as well as solvent-treated, presumably pure MPs were investigated after mixing them into the sediment.
Our results reveal that MP mixed with the sediment induced stronger adverse effects than layered MP. Kaolin particles caused no adverse effects. In contrast, they enhanced dry weight in both applications. The impact of aqueous leachates was comparable to the control without MPs, whereas methanolic extracts affected the worm number at the highest concentration with 100% mortality. Solvent-treated, presumably pure MP resulted in mostly higher worm numbers when compared to untreated MPs mixed into the sediment.
This study demonstrates that MPs mixed into the sediment affect L. variegatus more than MPs that are layered on the sediment surface. Kaolin as a natural, fine-sized particle control created somewhat favorable conditions for the worm. The main driver for toxicity, however, proved to be chemicals associated with the plastic product and its previous content.
... Ingestion of microplastics loaded with HOPs by earthworms might influence transfer and transformation (e.g., accumulation and degradation) of the pollutants. For example, the presence of microplastics in sediments reduced the bioavailability and transfer of PCBs to Lumbriculus variegatus (Beckingham and Ghosh 2017). Microplastics decreased the accumulation of total arsenic in the gut and the transformation rate of As(V) to As(III), resulting in a lower toxicity on the earthworm (Wang et al. 2019a). ...
... The vials were shaken in a rotary shaker (150 r/min) at 25 °C under dark for 4 h and then centrifuged at 4000 r/min for 20 min. Four hours has been reported as an intermediate gut retention time for deposit feeders (Beckingham and Ghosh 2017). Two milliliters of the supernatants was taken to determine the concentration of phenanthrene by HPLC. ...
... Letters A-C and a-f indicate significant difference (p < 0.05) among different sampling days of the same treatment and among each treatment on the same sampling day, respectively change in the percent solubilization of phenanthrene from soils in simulated intestinal fluid was consistent with that in desorbing fraction of phenanthrene during the experiment (r = 0.818, n = 27, p < 0.05), suggesting that particle sorption is the key reason resulting in the reduction in phenanthrene desorption in simulated intestinal fluid. Our results are similar to what was observed by Beckingham and Ghosh (2017). Phenanthrene concentrations in Pheretima guillelmi at the end of the experiment are shown in Fig. 2. It can be seen that phenanthrene concentration in Pheretima guillelmi was small (1.17-3.52 mg/kg) and obviously reduced by particle addition (p < 0.05). ...
PurposeIn the natural environment, microplastics and biochar are normally coexistent. However, interactions between them on bioavailability and degradation of organic pollutants in soils are not clear.Materials and methodsHere, wheat straw biochar produced at 400 °C (BC) and polyethylene (PE) with particle size ranges of 840–2000 and 104–178 μm were selected and named as LBC, SBC, LPE, and SPE, respectively. Their effects on bioavailability and degradation of phenanthrene in soils with or without earthworms were investigated.Results and discussionSorption ability (lgKf) of PE-BC (1:1) mixtures for phenanthrene was higher than that of their corresponding individual PE or BC in general, which is mainly related to the change in DOC content in the equilibrium solution. Both initial desorbing fraction of phenanthrene extracted by n-butanol and degradation ratio of phenanthrene were more obviously decreased by the addition of 2% PE-BC mixtures than by the addition of 2% PE or BC in general. Correlation analysis results indicated that particle sorption played a key role in controlling phenanthrene bioavailability and then phenanthrene degradation no matter whether earthworm Pheretima guillelmi was present or not. Earthworm presence enhanced phenanthrene degradation in soils with SPE, LBC, or LPE but had no obvious effect on the degradation in soils with PE-BC mixtures due to the change in ingestion of SPE by earthworms or DOC solubilization.Conclusion
The enhanced sorption ability and the reduced SPE ingestion by earthworms by coexistence of PE and BC inhibited phenanthrene degradation, leading to higher persistence of phenanthrene.
... 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. ...
... GC-MS measurements documented up to 80 % sorption of BkF to PMMA particles. The ability to bind and transfer hazardous organic compounds such as polychlorinated biphenyls (PCBs) or PAHs strongly depends on polymer type, surface area and surrounding medium (Rochman et al., 2013b;Beckingham and Ghosh, 2017;Diepens and Koelmans, 2018;Müller et al., 2018). In this study, 0.6 -0.7 mg BkF were sorbed to 1 g PMMA particles after the incubation and washing procedure. ...
... However, in line with previous results (Tosetto et al., 2016(Tosetto et al., , 2017Rochman et al., 2017), BkF uptake from particles and bioaccumulation only occurred in chironomid larvae, and trophic transfer of microplastic-sorbed BkF could not be confirmed. It seems more likely, that in aquatic ecosystems the pollutant transfer by particle ingestion will be dominated by natural particles such as clay minerals, algae, biochar, black carbon, but not by MPs (Gouin et al., 2011;Koelmans et al., 2016;Beckingham and Ghosh, 2017;Diepens and Koelmans, 2018;Lee et al., 2019). ...
Given the continually increasing global polymer production, environmental pollution from plastic debris has been widely perceived as an ecological threat with potentially adverse (eco-)toxicological impacts on various species and ecosystems. Especially small fragments of plastic debris measuring 1 ≤ 1000 µm in size − so-called microplastics (MPs) − can pose a risk to biota by physical or chemical hazards due to ingestion, sorption and transfer of anthropogenic environmental pollutants (e.g., pesticides, polycyclic aromatic hydrocarbons, pharmaceuticals). In recent years, there has been extensive research on the impact of streams and rivers as main entry routes for MPs into the marine environment. However, the evidence of adverse effects caused by the intake of MPs and the transfer of contaminants sorbed to MPs into freshwater ecosystems is still not conclusively documented. Therefore, this thesis addressed the impact of microplastic particles in limnic ecosystems by investigating the biological fate and effects of MPs and associated anthropogenic pollutants on different life stages of zebrafish (Danio rerio). To this end, effects of two common environmental pollutants (benzo(k)fluoranthene, chlorpyrifos) and two synthetic polymers (polystyrene, polymethyl methacrylate) were investigated with regard to alterations of complementary biomarkers during acute and chronic exposure, as well as the trophic transfer of MPs and MP-sorbed contaminants from invertebrate organisms to zebrafish and acute toxic effects of MPs pre-exposed in a natural aquatic ecosystem. Overall, the sorption of both anthropogenic pollutants to MPs could be confirmed under various exposure scenarios. In contrast to recent study results, no adverse effects were observed when zebrafish were exposed to clean, pristine polystyrene and polymethyl methacrylate. The ingestion of MPs was documented in the gastrointestinal tract of zebrafish and did not induce any physiological impairment. The uptake of both pollutants was verified for all investigated species by GC-MS and fluorescence measurements. In the acute exposure scenario using the fish embryo toxicity test (FET), zebrafish embryos displayed sublethal effects and morphological deformities related to the underlying mode of action of benzo(k)fluoranthene and chlorpyrifos. Exposure to MP-associated contaminants significantly reduced malformations and attenuated biomarker responses of acetylcholine esterase activity and CYP450 induction and hence indicated a reduced bioavailability of both pollutants for zebrafish embryos. Chronic exposure of adult zebrafish to both types of MPs and pollutants was designed to assess the potential impact of long-term exposure and possible bioaccumulation of these contaminants of emerging concern. However, exposure to MP-sorbed pollutants failed to alter biomarker responses over the prolonged experimental period. In addition, a novel approach was applied to monitor the uptake of benzo(k)fluoranthene in the intestinal epithelium using confocal laser scanning microscopy. However, no significant bioaccumulation or biotransformation of benzo(k)fluoranthene and chlorpyrifos in brain and liver tissue could be demonstrated using ultra performance liquid chromatography coupled with fluorescence detection and with a high-resolution mass spectrometer (UPLC-FLD/HRMS). In order to address the possible vector effects of MPs, the transfer of benzo(k)fluoranthene and polymethyl methacrylate particles in a simplified limnic food web were investigated, consisting of zooplankton (Daphnia magna), sediment-dwelling invertebrates (Chironomus riparius larvae) and zebrafish as highlevel predator. However, the trophic transfer of benzo(k)fluoranthene via MPs could not be confirmed by a combination of highly sensitive fluorescence tracking using CLSM, hepatic CYP450 induction, and advanced chemical-analytical methods. To account for the demand for environmentally relevant exposure scenarios and to improve risk assessment of MPs, a mixture of the most commonly used synthetic polymers (polyethylene, polypropylene, polystyrene, polyvinyl chloride) was exposed in a well-monitored surface water body. To evaluate the potential transfer of hazardous pollutants under natural conditions, the toxicity of the MP mixture was assessed in terms of acute toxic effects (FET), potential neurotoxic effects (AChE activity, larval visual motor response test) and effects of dioxin-like substances (EROD assay) using zebrafish embryos. In conclusion, the exposed MP mixture did not elicit significantly different effects than the natural particles from sediment and suspended matter samples. Eventually, it could only be confirmed that MPs could act as carriers for environmental contaminants following ingestion by various organisms. However, increased deleterious effects of MP-sorbed contaminants on various sensitive life stages of zebrafish could not be corroborated by acute or prolonged exposure, trophic transfer, or natural exposure. The findings suggest that the sorption of pollutants to MPs is more likely to reduce the bioavailability as a result of slow desorption within the organism. Although, MPs offer an alternative exposure route for aquatic organisms via ingestion. Even chronic exposure at environmentally relevant concentrations did not induce bioaccumulation of both highly lipophilic substances in zebrafish tissues. Lastly, the sorption behavior of MPs under realistic environmental exposure conditions was more likely to approximate the behavior of natural particles. Consequently, MPs might pose only a limited risk to limnic communities, especially with regard to the comparatively small fraction of plastic particles in freshwater ecosystems compared to the multitude of naturally occurring (a)biotic particles.
... 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.
... Nature reviews | Materials 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.
... 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.
... The boundless quantum of plastic products expelled into the environment and has become ubiquitously in nature, present in both freshwater and marine ecosystem particularly, water surface and water column, tourist places like beaches, benthic sediments, and particularly aquatic organisms (Van Cauwenberghe et al. 2015;Wright et al. 2013). As of now, several works of literature report that, issues associated with microplastic analysis (Qiu et al. 2016;Ivleva et al. 2017), dispersal of MPs in seawater (Wagner et al. 2014), freshwater, and in sediments (Van Cauwenberghe et al. 2015;Beckingham and Ghosh 2017). For example, in day-today activities like in particular residential areas, washing machines produce around 1900 fibers (100 particles per liter) in every single wash (Browne et al. 2011). ...
Microplastics (MPs) are considered as an emerging contaminant in aquatic environments which enter through various routes. The number of studies on MPs has increased dramatically in recent years, owing to a growing awareness of the potential health hazards associated with MPs exposure. The adoption of a set of acceptable methodologies to reliably identify and measure MPs from various matrices is an underlying issue in this study field due to its complexity and impact. These approaches should then be harmonized to create quantitative, repeatable, and comparable data in the quantification of MPs. In concern to this unique problem; this focal point review aims to provide researchers with an overview of methods for collection, handling, and sampling from the aqueous environment; delineation and quantification of MPs; the advantages and limits of such processes; approaches for future studies to surmount such limitations. The review findings highlighted that the sampling needs an appropriate design, collection tool, exact sampling site, and size for accuracy. The development of extractive effectiveness by re-utilizing the chemicals recommended for accurate separation of the MPs. The subsequent validation of spectroscopic analysis in addition to visual imaging is essential for the qualitative analysis of MPs. Temporal comparison and large-scale spatial data procured from existing analytical techniques and approaches are the major issues delimiting the decision appropriate in the monitoring of MPs. Hence, it’s recommended that future research needs to focus on developing standard methodologies and highly equipped automated analytical techniques for rapid and reliable detection of MPs.
... MPs have a profound impact on the material cycle and energy flow of terrestrial ecosystems. Due to their adsorption characteristics, not only do entering MPs absorb organic pollutants (Beckingham and Ghosh, 2017), but they also act as carriers of heavy metals, increasing the bioavailability of the latter (Hodson et al., 2017) and their accumulation in the food chain through the ingestion of animals (Huerta Lwanga et al., 2016, 2017b). High MP levels may change soil chemistry by interfering with the degradation of soil organic matter (SOM) Rochman et al., 2014). ...
Microplastics (MPs) are emerging persistent contaminants in the terrestrial subsurface, and evidence has emerged for significant effects of MPs on soils’ biological and ecosystem functions. Main MPs sources include land spreading of sewage sludge and biowaste composts, plastic mulching film used in horticultural fields, wastewater irrigation, and leachate from the landfills, amongst others. This updated state-of-the-art review paper describes recent experimental and numerical research and developments in understanding the accumulation, fate and effects of MPs in soil environment (focusing on their storage, degradation, transportation, leaching to groundwater, etc.), followed by mitigation and bioremediation measures, including soil bacterial- and fungus-eating MPs, best management practices for reducing MP pollution of soil, etc. Other areas covered are the combined effects of MPs and various other environmental contaminants (heavy metals, organic pollutants and antibiotics) in soil ecosystems, and standardization of methods for detection, quantification and characterisation of MPs in soils, which is critical for MPs research. The paper concludes by identifying knowledge gaps and presents recommendations on prioritized research needs.
... It has been shown that plastic materials are capable of conveying pollutants to the body's tissues [60,92]. Although some authors give little importance to this vector function [93][94][95][96], it is known that the toxicity of plastics and their interaction with others pollutants can affect the bioavailability and toxicity of these pollutants for the biota [92]. Plastics have shown the ability to absorb various pollutants (IPA, PCB, HCH) [97]. ...
Micro- and nano-plastic (MP/NP) pollution represents a threat not only to marine organisms and ecosystems, but also a danger for humans. The effects of these small particles resulting from the fragmentation of waste of various types have been well documented in mammals, although the consequences of acute and chronic exposure are not fully known yet. In this review, we summarize the recent results related to effects of MPs/NPs in different species of fish, both saltwater and freshwater, including zebrafish, used as model organisms for the evaluation of human health risk posed by MNPs. The expectation is that discoveries made in the model will provide insight regarding the risks of plastic particle toxicity to human health, with a focus on the effect of long-term exposure at different levels of biological complexity in various tissues and organs, including the brain. The current scientific evidence shows that plastic particle toxicity depends not only on factors such as particle size, concentration, exposure time, shape, and polymer type, but also on co-factors, which make the issue extremely complex. We describe and discuss the possible entry pathways of these particles into the fish body, as well as their uptake mechanisms and bioaccumulation in different organs and the role of blood response (hematochemical and hematological parameters) as biomarkers of micro- and nano-plastic water pollution.
... The transfer of PCBs from MPs to organisms in the aquatic environment is challenging to quantify in natural conditions but laboratory studies indicate that PCBs can be transferred from plastics to tissues of various organisms Rochman et al. 2013). Nevertheless, the contribution of MPs in bioaccumulation of PCBs might be less relevant than previously thought, since other sources of pollutants like dietary intake can have a more important role (Koelmans et al. 2013;Beckingham and Ghosh 2017). Using environmental data and conceptual models that simulate the effects of plastic on the bioaccumulation of POPs, it has been estimated that under environmentally relevant concentrations, MPs might reduce the bioaccumulation of PCBs through a "cleaning" mechanism that counteracts the biomagnification derived from the food web (Koelmans et al. 2013). ...
Microplastics (MPs) have become an environmental threat due to their persistence, ubiquity, and potential harm to wildlife. Once dispersed in the ecosystem, MPs can sorb environmental pollutants such as organic compounds, metals, and emerging contaminants. This pollution has caused concern in the scientific community. A lot of research is focusing on MPs’ role as vectors for toxic chemicals in the biota. The aim of this chapter is to provide a review of studies of toxic pollutants adsorbed on MPs and present an overview of their ability to leach, bioaccumulating in the organisms. Moreover, the effects that the combination of MPs and adsorbed compounds have on the biota are explored. The importance of MPs as a vector for environmental pollutants is still mainly under discussion. The ecotoxicological consequences of the ingestion of contaminated MPs are still mostly understudied and require further research to be fully understood. Future research challenges include the risk assessment of long-term exposition to different combinations of MPs-contaminants, especially under environmentally relevant concentrations, and the determination of the relative importance of MPs-mediated input of pollutants in biota, taking into account the other exposure pathways.
... 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). ...
• The pollution of aquatic systems with microplastics (MPs) affects marine and freshwater fish species worldwide. However, little is known about the size‐dependent retention time of these inert particles. To approach this question, the retention time of MP particles was examined in two freshwater fish species with distinct differences in gastrointestinal morphology: rainbow trout (Oncorhynchus mykiss) with a true stomach, and stomachless common carp (Cyprinus carpio).
• A special diet was developed that contained environmentally relevant concentrations of MPs with sizes ranging from 20 to 1,000 µm. The two species were exposed to three different concentrations and numbers of retained particle were determined up to 72 hr after administration.
• The results revealed significant differences in retention time between large and small MP particles in rainbow trout, in which the T50 value (time for 50% of particles to be evacuated) ranged from 12.1 hr for 42.7 µm particles to 4.0 hr for 1,086 µm particles. In contrast, the differences observed between sizes in common carp were considerably smaller, with T50 ranging from 7.3 hr for 42.7 µm particles to 4.6 hr for 1,086 µm particles.
• It is therefore concluded that large particles in rainbow trout must be actively transported out of the stomach, as the evacuation times are significantly shorter than those for food. Small particles, however, are passively excreted with the chyme. In common carp, the evacuation rates of all particle sizes were in the range of that for food, suggesting a passive excretion.
• The results are particularly relevant in the contexts of particle transfer through the food chain, the release of toxic chemicals, and the translocation into tissues and organs. For this reason, it is essential that the particle size is given more consideration in future studies of microplastics in aquatic environments.
... Comparable concentrations of BPA in MPs were found in our study, indicating that the accumulation of BPA by MPs were similar to that of sediment. However, one should note that the bioavailability of MPs and sediment may be different (Beckingham and Ghosh, 2017). Considering the ubiquitous distribution of MPs and their ingestion by numerous marine biota, MPs could be one of the significant pathways for the transfer of organic pollutants along the food chain. ...
The occurrence and spatial distribution of bisphenol A (BPA) and analogues bisphenol B (BPB), bisphenol F (BPF) and bisphenol S (BPS) were investigated in microplastic on 11 beaches in Hong Kong. At 10 sites, BPA was the only detected chemical with concentrations ranged from 82.4–989 ng g⁻¹ microplastic. BPA, BPB and BPS co-occurred at only one site, where it is located close proximity to the outfall of a sewage treatment plant. There was no significant spatial difference of BPA concentrations in microplastic when all the sites were considered, indicating that some remote and presumably cleaner beaches have been contaminated. PE, PP and PS (represented >90% of total polymers) were the most dominated polymers, but there was no correlation between polymer types and BPA concentrations. No evidence was found that the BPA and its analogues accumulate on microplastic since the concentrations were comparable to those found in the sediment.
... Microplastics may also impact on WWTP performance through the fouling of filtration membranes (Enfrin et al., 2020b). In addition, MPs may act as toxicological vectors, adsorbing concentrations of contaminants commonly found in WWTPs such as pharmaceuticals (Beckingham and Ghosh, 2017;Seidensticker et al., 2017;Li et al., 2018). Through these mechanisms a wide range of MP particles are released from WWTPs, including nanoplastics which may be ingested via skin diffusion during embryogenesis of fish cells, resulting in mortality of marine organisms (Enfrin et al., 2020a). ...
The global distribution of microplastic debris on the sea floor poses an increasing risk to marine organisms and ecosystems. Here, we present a distribution analysis of microplastics collected from eight marine multicores recovered from the Iceland continental shelf and surrounding areas at water depth between 241 and 1628 m. We report a total of 306 microplastics from the size range > 250 μm −5 mm, of which all were fibers. Microplastic numbers range between 0.119 and 0.768 per gram of dry sediments. In the analysis we assess the potential role of oceanic surface and bottom water currents, organic content, and sediment type on the distribution, deposition, and burial of microplastics in marine sediments. Our results provide the first record of microplastic pollution of marine sediments from the Iceland continental shelf and identify Atlantic Cod feeding and breeding grounds as potential hot spot for the accumulation of marine debris.
... PCBs are another important class of hydrophobic pollutants with great potential to be bioaccumulated [71] which are no longer produced and used since the 1970s. However, their residues in soil, sediments and now also those found in MPs, continue to be a risk to ecosystems due to their high persistence in the environment. ...
Nowadays, one of the greatest concerns regarding environmental pollution is the presence of plastics in every environmental compartment (water, soil and air), in particular, microplastics (sizes between 1 μm and 5 mm -the most accepted definition-). Their persistence, wide distribution and constant accumulation in the environment are the main causes of their current classification as contaminants. Apart from the known effects that they may have on organisms (which clearly depend on their size) and their tendency to leach some of their components, especially additives, an important concern has also arisen in the last years as a result of their capability of retaining onto their surface organic contaminants of a wide nature. In this regard, it is worth highlighting the adsorption of persistent organic contaminants such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, or organochlorine pesticides, among others. This review article pretends to provide a critical, updated, and general vision of the current analytical methods that have been developed so far (period covered between 2001 and 2020) for the analysis of organic contaminants present in microplastics found in the environment, including their occurrence. The analysis of the published literature clearly indicates that most of the methods applied up to now are relatively complex and that their analysis is also nowadays a challenge, as a result of the wide variability in the composition, sizes, and shapes of microplastics.
... Furthermore, the ingestion of MPs with venlafaxine and O-desmethylvenlafaxine elevated their concentration in fish ten-fold . Moreover, polychlorinated biphenyls (PCBs) adsorbed onto MPs were found to have the same range of distribution coefficients as compared to those of lipids and sediment organic carbon (Beckingham and Ghosh, 2017). Another study revealed that fishes fed with microbeads spiked with polybrominated diphenyl ethers (PBDEs) presented higher concentration and accumulation than those of the control batch (Wardrop et al., 2016). ...
In the last decade, microplastics (MPs) have become an increasing cause for concerning. These particles are scattered throughout seas and oceans and have the capability of transporting adsorbed pollutants as pharmaceutical compounds, which can cause toxic effects and be transferred along the food chain.
The development, optimization and validation of a sensitive and reliable analytical procedure for the extraction and determination of ten common pharmaceuticals adsorbed on MPs is reported in this study. This method involves ultrasound-assisted extraction coupled with ultra-high-performance liquid chromatography and tandem mass spectrometry. All of the variables included in the extraction process, such as the extraction time and type and solvent volume, were studied and optimised. Under optimal conditions, good reproducibility and repeatability, with relative standard deviations lower than 15% in most cases, were obtained while limits of detection between 0.25 and 15.8 ng g⁻¹ were achieved.
Last, the method was applied to the analysis of samples collected from beaches in the Canary Islands (Spain). The results indicated the presence of several analytes adsorbed on MPs in concentrations ranging from 34.0 to 111 ng g⁻¹.
... MPs can also affect greenhouse gas emissions by changing the abundance of microbes associated with N 2 O emission and CH 4 absorption, but their contribution is limited (Cornejo-D'Ottone et al., 2020). Compared with other media, MPs contribute less to the integration of the organic compound in the environment (Koelmans et al., 2016), and their contribution to the transfer to aquatic organisms is not significant (Beckingham and Ghosh, 2017). ...
The source, distribution, migration, and fate of microplastics (MPs) in aquatic and terrestrial ecosystems have received much attention. However, the relevant reports in wetland ecosystems, the boundary area between water and land, are still rare. Where are the sources and sinks of MPs in the wetland? The latest researches have shown that the sources of MPs in wetlands include sewage discharge, surface runoff, and plastic wastes from aquaculture. Fibers and fragments are the most common shapes, and PE, PP, PS can be detected in water or sediment matrices, and biota of wetlands. The distribution is affected by hydrodynamic conditions, sediment properties, and vegetation coverage. Factors affecting the vertical migration of MPs include their own physical and chemical properties, the combination of substances that accelerate deposition (mineral adsorption and biological flocculation), and resuspension. Minerals tend to adsorb negatively charged MPs while algae aggregates have a preference for positively charged MPs. The wetlands vegetation can trap MPs and affect their migration. In water matrices, MPs are ingested by organisms and integrated into sediments, which makes them seem undetectable in the wetland ecosystem. Photodegradation and microbial degradation can further reduce the MPs in size. Although recent research has increased, we are still searching for a methodological harmonization of the detection practices and exploring the migration rules and fate patterns of MPs. Our work is the first comprehensive review of the source, distribution, migration, and fate of MPs in wetland ecosystems. It reveals the uniqueness of wetland habitat in the research of MPs and indicates the potential of wetlands acting as sources or sinks for MPs.
... The ability of plastic particles to adsorb contaminants onto their surfaces and potentially transport them into the bodies of organisms has been established (Pittura et al., 2018) and is attributed to the low polarity, high degree of surface roughness, high surface area, and varying surface chemistries of the particles (Hodson et al., 2017;Koelmans et al., 2015). Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dichlorodiphenyltrichloroethane (DDT), polybrominated diphenyl ethers (PBDEs), and metals have been shown to adsorb onto the surface of plastic fragments (Mato et al., 2001;Endo et al., 2005;Ogata et al., 2009;Law and Thompson, 2014;Fisner et al., 2013a;Fisner et al., 2013b;Van Cauwenberghe et al., 2015;Beckingham and Ghosh, 2017;Wang et al., 2020). Toxins such as bisphenol-A (BPA) could be transported by nanoplastics in this way to the brain (Chen et al., 2017a). ...
In response to the growing worldwide plastic pollution problem, the field of nanoplastics research is attempting to determine the risk of exposure to nanoparticles amidst their ever-increasing presence in the environment. Since little is known about the attributes of environmental nanoplastics (concentration, composition, morphology, and size) due to fundamental limitations in detection and quantification of smaller plastic particles, researchers often improvise by engineering nanoplastic particles with various surface modifications as models for laboratory toxicological testing. Polystyrene and other commercially available or easily synthesized polymer materials functionalized with surfactants or fluorophores are typically used for these studies. How surfactants, additives, fluorophores, the addition of surface functional groups for conjugation, or other changes to surface attributes alter toxicological profiles remains unclear. Additionally, the limited polymers used in laboratory models do not mimic the vast range of polymer types comprising environmental pollutants. Nanomaterials are tricky materials to investigate due to their high surface area, high surface energies, and their propensity to interact with molecules, proteins, and biological probes. These unique properties can often invalidate common laboratory assays. Extreme care must be taken to ensure that results are not artefactual. We have gathered zeta potential values for various polystyrene nanoparticles with different functionalization, in different solvents, from the reported literature. We also discuss the effects of surface engineering and solvent properties on interparticle interactions, agglomeration, particle-protein interactions, corona formation, nano-bio interfaces, and contemplate how these parameters might confound results. Various toxicological exemplars are critically reviewed, and the relevance and shortfalls of the most popular models used in nanoplastics toxicity studies published in the current literature are considered.
... Due to their large surface-to-volume ratio and charged hydrophobic surfaces, MP provide an excellent sorption site to scavenge some particle-reactive, dissolved contaminants (e.g., PBTs, PBDEs, DDT, PAHs, and pharmaceuticals), trace metals (e.g., copper, zinc, lead), and other plastic additives (Teuten et al. 2007(Teuten et al. , 2009Beckingham and Ghosh 2017;Ribeiro et al. 2019). Consequently, MP can also become a potential, albeit diffuse source for diverse co-contaminants (Koelmans et al. 2013(Koelmans et al. , 2016Avio et al. 2015;Brennecke et al. 2016;Nakashima et al. 2016;Alimi et al. 2018). ...
Environmental microplastic particles (MPs) represent a potential threat to many aquatic animals, and experimental exposure studies, when done well, offer a quantitative approach to assess this stress systematically and reliably. While the scientific literature on MP studies in aquatic environments is rapidly growing, there is still much to learn, and this chapter presents a brief overview of some of the successful methods and pitfalls in experimental MP exposure studies. A short overview of some experimental design types and recommendations are also presented. A proper experimental exposure study will yield useful information on MP-organism impacts and must include the following: a comprehensive MP characterization (e.g., density, buoyancy, type, nature, size, shape, concentration, color, degree of weathering/biofilm formation, an assessment of co-contaminant/surfactant toxicity and behavior, an understanding exposure modes, dose and duration, and the type and life stage of the target species). Finally, more conventional experimental considerations, such as time, costs, and access to clean water, specialized instrumentation, and use of appropriate controls, replicate, and robust statistical analyses are also vital. This short review is intended as a necessary first step towards standardization of experimental MP exposure protocols so one can more reliably assess the transport and fate of MP in the aquatic environment as well as their potential impacts on aquatic organisms.
... mg/L whereas the BPA concentration was found to be 0.70-2.72 mg/L. Due to their high absorption capacity, the microplastics may easily absorb toxic organic substances [97] and increase the heavy metal concentration in soils [98]. Soils involving these microplastics, that are carried with the leachates seeping into the soil in the vicinity of landfills, are sometimes used in agricultural practices and the toxic substances that are absorbed by the microplastics might quickly deteriorate soil health and hinder plant growth. ...
Microplastic contamination is a growing threat to marine and freshwater ecosystems, agricultural production, groundwater, plant growth and even human and animal health. Disintegration of plastic products due to mainly biochemical or physical activities leads to the formation and existence of microplastics in significant amounts, not only in marine and freshwater environments but also in soils. There are several valuable studies on microplastics in soils, which have typically focused on environmental, chemical, agricultural and health aspects. However, there is also a need for the geotechnical engineering perspective on microplastic contamination in soils. In this review paper, first, degradation, existence and persistence of microplastics in soils are assessed by considering various studies. Then, the potential role of solid waste disposal facilities as a source for microplastics is discussed by considering their geotechnical design and addressing the risk for the migration of microplastics from landfills to soils and other environments. Even though landfills are considered as one of the main geotechnical structures that contribute to the formation of considerably high amounts of microplastics and their contamination in soils, some other geotechnical engineering applications (i.e., soil improvement with tirechips, forming engineering fills with dredged sediments, soil improvement with synthetic polymer-based fibers, polystyrene based lightweight fill applications), as potential local source for microplastics, are also mentioned. Finally, the importance of geotechnical engineering as a mitigation tool for microplastics is emphasized and several important research topics involving geotechnical engineering are suggested.
... 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.
... 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 Microplastics influence the mobility and the transfer of exogenous pollutants (PAHs, PCBs, etc.) from contaminated areas to aquatic environments and they are sources of endogenous toxics to the water column, the sediment and the biota.
... 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.
... 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.
... 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.
... 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.
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.
Research on the environmental impact of plastics, especially on the effect of microplastics (MPs), has become a priority issue in recent years, mainly in terrestrial ecosystems where there is a lack of studies. This work aims to assess the impact of two types of polyethylene MPs, white microbeads (W) and fluorescent blue microbeads (FB), and their interactions with two contaminants, ibuprofen (Ib) and simazine (Sz), on different organisms. A set of bioassays for Vibrio fischeri, Caenorhabditis elegans and Lactuca sativa was carried out, which helped to establish the ecotoxicological impact of those pollutants. C. elegans showed the least sensitivity, while V. fischeri and L. sativa showed a high toxicological response to MPs alone. We found that W and FB induced an inhibition of 27 % and 5.79 %, respectively, in V. fischeri, and the growth inhibition rates were near 70 % in L. sativa for both MPs. MPs exhibited a potential role as contaminant vectors in V. fischeri since the inhibition caused by W-Ib or W-Sz complexes was near 39 %. The W-Sz complex significantly reduced leaf development in L. sativa, and a reduction of 30 % in seed germination was detected when the complex FB-Sz was tested. This study reveals the importance of designing a complete set of analyses with organisms from different trophic levels, considering the great variability in the effects of MPs and the high number of relevant factors.
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.
This chapter discusses the various dynamic aspects of environmental systems. This includes the relationship between spatial and temporal scales, especially as they relate to the formation, transport, transformation, and environmental fate of substances. The processes and mechanisms that drive and influence a system's thermodynamics and fluid dynamics are explained. The discussion also compares natural and engineered systems in terms of biogeochemical cycling and dynamic processes that affect ecosystems and human populations.
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 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 site with no known PCB contamination sources and from a contaminated site with non-paint PCB sources. Particles <0.045 mm generated concentrations in the PS over one order of magnitude higher than coarser particles. 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 and was ~50-60 and ~ 5 times higher than for the 0.25-0.3 mm and <0.045 mm fractions, respectively, of PC mixed in sediment. 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 are co-located with PCB PC.
Passive sampling to quantify net partitioning of hydrophobic organic contaminants between the porewater and solid phase has advanced risk management for contaminated sediments. Direct porewater (Cfree) measures represent the best way to predict adverse effects to biota. However, when the need arises to convert between solid-phase concentration (Ctotal) and Cfree, a wide variation in observed sediment-porewater partition coefficients (KTOC) is observed due to intractable complexities in binding phases. We propose a stochastic framework in which a given Ctotal is mapped to an estimated range of Cfree through variability in passive sampling-derived KTOC relationships. This mapping can be used to pair estimated Cfree with biological effects data or inversely to translate a measured or assumed Cfree to an estimated Ctotal. We apply the framework to both an effects threshold for polycyclic aromatic hydrocarbon (PAH) toxicity and an aggregate adverse impact on an assemblage of species. The stochastic framework is based on a "bioavailability ratio" (BR), which reflects the extent to which potency-weighted, aggregate PAH partitioning to the solid-phase is greater than that predicted by default, KOW-based KTOC values. Along a continuum of Ctotal, we use the BR to derive an estimate for the probability that Cfree will exceed a threshold. By explicitly describing the variability of KTOC and BR, estimates of risk posed by sediment-associated contaminants can be more transparent and nuanced.
As a new type of environmental pollutant, microplastics (MPs) can adsorb residual organochlorine pesticides (OCPs) in the soil and pose a severe threat to the soil ecosystems. To understand the interaction between soil MPs and OCPs, the sorption of two kinds of OCPs, including hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), on polyethylene (PE) microplastics in soil suspension was studied through sorption kinetics and isotherm models. The effects of solution/soil ratio and MPs diameter on sorption were examined. The kinetic experiment results show that the sorption equilibrium was 12 h， and the sorption process of OCPs on MPs can be well described by a pseudo-second-order model. The Freundlich model (R² = 0.942–0.997) provides a better fit to the sorption isotherm data than the Langmuir model (R² = 0.062–0.634), indicating that the sorption process takes place on the nonuniform surface of MPs. The MPs had a good sorption effect on OCPs when the solution/soil ratio was from 75:1 to 100:1. As the diameter of MPs increases, the sorption capacity decreases. These results provide support for further research on microplastic pollution in soil.
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
The concern that in nature, ingestion of microplastic (MP) increases exposure of organisms to plastic-associated chemicals (the 'MP vector effect') plays an important role in the current picture of the risks of microplastic for the environment and human health. An increasing number of studies on this topic have been conducted using a wide variety of approaches and techniques. At present, the MP vector effect is usually framed as 'complex', 'under debate' or 'controversial'. Studies that critically discuss the approaches and techniques used to study the MP vector effect, and that provide suggestions for the harmonization needed to advance this debate, are scarce. Furthermore, only a few studies have strived at interpreting study outcomes in the light of environmentally relevant conditions. This constitutes a major research gap, because these are the conditions that are most relevant when informing risk assessment and management decisions. Based on a review of 61 publications, we propose evaluation criteria and guidance for MP vector studies and discuss current study designs using these criteria. The criteria are designed such that studies, which fulfil them, will be relevant to inform risk assessment. By critically reviewing the existing literature in the light of these criteria, a weight of evidence assessment is provided. We demonstrate that several studies did not meet the standards for their conclusions on the MP vector effect to stand, whereas others provided overwhelming evidence that the vector effect is unlikely to affect chemical risks under present natural conditions.
The sorption of hydrophobic organic compounds (HOC) onto microplastics is relatively well reported in the literature, while their desorption remains poorly investigated, especially in biological fluids. The present study investigated the sorption and desorption of progesterone on polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics. The sorption experiments showed that the equilibrium was reached in a few hours for all plastics. A sorption efficiency of 357.1 μg g-1 was found for PE and PS, and 322.6 μg g-1 for PP. Sorption experiments indicated that adsorption would certainly happen via surface sorption and a potentially pore-filling mechanism. The desorption was carried out in Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF), whose formulations were more complex than similar models reported so far. It has been found that the desorption was higher in SIF as compared to SGF, due to micelle formation in SIF promoting the pollutant solubilization. The sorption of pepsin onto microplastics has also been revealed, suggesting a competition between pollutants and pepsin for sorption sites and a potent reduction in pollutant solubilization. This study indicates that the ingestion of microplastics could be considered as an additional route of exposure to pollutants and therefore emphasizes pollutant bioavailability for aquatic organisms.
Environmental microplastics are gaining interest due to their ubiquity and the threat they pose to environmental and human health. Critical studies have revealed the abundance of microplastics in nature, while others have tested the impacts of these small plastics on organismal health in the laboratory. Yet, there is often a mismatch between these two areas of research, resulting in major discrepancies and an inability to interpret certain findings. Here, we focus on several main lines of inquiry. First, even though the majority of environmental microplastics are plastic microfibers from textiles, laboratory studies still largely use spherical microbeads. There are also inconsistencies between the measurements of microplastics in the environment as compared to the concentrations that tend to be used in experimental studies. Likewise, the period of exposure occurring in experimental studies and in the environment are vastly different. Lastly, although experimental studies often focus on a particular subset of toxic chemicals present on microplastics, textile microfibers carry other dyes and chemicals that are understudied. They also cause types of physical damage not associated with microspheres. This review will analyze the literature pertaining to these mismatches, focusing on aquatic organisms and model systems, and seek to inform a path forward for this burgeoning area of research.
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.
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.
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.
Plastics are persistent synthetic polymers that accumulate as waste in the marine environment. Microplastic (MP) particles are derived from the breakdown of larger debris or can enter the environment as microscopic fragments. Because filter-feeder organisms ingest MP while feeding, they are likely to be impacted by MP pollution. To assess the impact of polystyrene microspheres (micro-PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 µm in diameter; 0.023 mg·L(-1)) for 2 mo during a reproductive cycle. Effects were investigated on ecophysiological parameters; cellular, transcriptomic, and proteomic responses; fecundity; and offspring development. Oysters preferentially ingested the 6-µm micro-PS over the 2-µm-diameter particles. Consumption of microalgae and absorption efficiency were significantly higher in exposed oysters, suggesting compensatory and physical effects on both digestive parameters. After 2 mo, exposed oysters had significant decreases in oocyte number (-38%), diameter (-5%), and sperm velocity (-23%). The D-larval yield and larval development of offspring derived from exposed parents decreased by 41% and 18%, respectively, compared with control offspring. Dynamic energy budget modeling, supported by transcriptomic profiles, suggested a significant shift of energy allocation from reproduction to structural growth, and elevated maintenance costs in exposed oysters, which is thought to be caused by interference with energy uptake. Molecular signatures of endocrine disruption were also revealed, but no endocrine disruptors were found in the biological samples. This study provides evidence that micro-PS cause feeding modifications and reproductive disruption in oysters, with significant impacts on offspring.
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.
Marine debris, especially plastic debris, is widely recognized as global environmental problem. There has been substantial research on the impacts of plastic marine debris, such as entanglement and ingestion. These impacts are largely due to the physical presence of plastic debris. In recent years there has been an increasing focus on the impacts of toxic chemicals as they relate to plastic debris. Some plastic debris acts as a source of toxic chemicals: substances that were added to the plastic during manufacturing leach from plastic debris. Plastic debris also acts as a sink for toxic chemicals. Plastic sorbs persistent, bioaccumulative, and toxic substances (PBTs), such as polychlorinated biphenyls (PCBs) and dioxins, from the water or sediment. These PBTs may desorb when the plastic is ingested by any of a variety of marine species. This broad look at the current research suggests that while there is significant uncertainty and complexity in the kinetics and thermodynamics of the interaction, plastic debris appears to act as a vector transferring PBTs from the water to the food web, increasing risk throughout the marine food web, including humans. Because of the extremely long lifetime of plastic and PBTs in the ocean, prevention strategies are vital to minimizing these risks.