Special Issue "Prevalence, Fate and Effects of Plastic in Freshwater Environments"

A special issue of Toxics (ISSN 2305-6304). This special issue belongs to the section "Environmental Chemistry".

Deadline for manuscript submissions: closed (29 February 2020).

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A printed edition of this Special Issue is available here.

Special Issue Editor

Assoc. Prof. Farhan Khan
E-Mail Website
Guest Editor
Department of Science and Environment, Roskilde University, Universitetsvej 1, PO Box 260, DK-4000 Roskilde, Denmark
Interests: plastics and microplastic pollution; microplastic vector effects; nanoparticles and nanoplastics; ecotoxicology and ecophysiology; ecotoxicology in the Anthropocene
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Special Issue Information

Dear Colleagues,

Plastic (and microplastic) pollution has been described as one of the greatest environmental challenges of our time, and a hallmark of the Anthropocene. It has grabbed the attention of the general public, governments, and environmental scientists worldwide. Up until recently, the main focus has been on plastics in the marine environment, but interest into the presence and effects of plastics in freshwaters has increased in the last few years. The occurrence of plastics within inland lakes and rivers, as well as their biota, has been demonstrated in a handful of studies. Experiments with freshwater organisms have started to explore the direct and indirect effects resulting from plastic exposure. There is a clear need for further research, and a dedicated space for its dissemination. 

This Special Issue is devoted to highlighting current research from around the world into the prevalence, fate, and effects of plastic in freshwater environments. Authors are invited to submit original research papers, reviews, and short communications. Topics may include, but are not limited to, the following:

  • Plastic debris of all size ranges (macro-, meso-, micro-, and nano-plastics) in freshwaters
  • Sources, fate, and transport in the freshwater environment
  • Sampling and monitoring, and the associated challenges, from different freshwater compartments (e.g., water, sediments, and biota)
  • Degradation, characterization, and analysis of environmental plastic samples
  • Plastic ingestion and retention by freshwater organisms
  • Toxicity and biological impacts
  • Plastics as chemical and biological vectors
  • Citizen science and stakeholder involvement
  • Regulation and management
  • Knowledge gaps and future research needs
  • Mitigation and solutions

Assoc. Prof. Farhan Khan
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Macro-, meso-, micro-, and nano-plastics
  • Freshwaters and inland waters
  • Polymers
  • Characterization and analysis
  • Sources, presence, and fate
  • Sampling and monitoring studies
  • Plastic ingestion and retention
  • Vector effects
  • Toxicity and biological impacts
  • Regulation and management.

Published Papers (7 papers)

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Editorial

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Editorial
Prevalence, Fate and Effects of Plastic in Freshwater Environments: New Findings and Next Steps
Toxics 2020, 8(3), 72; https://doi.org/10.3390/toxics8030072 - 17 Sep 2020
Viewed by 746
Abstract
At a time when a global pandemic rightly holds our collective attention, environmental issues have taken a backseat to the ongoing battle against Covid-19 [...] Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)

Research

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Article
Effects of MP Polyethylene Microparticles on Microbiome and Inflammatory Response of Larval Zebrafish
Toxics 2020, 8(3), 55; https://doi.org/10.3390/toxics8030055 - 11 Aug 2020
Cited by 5 | Viewed by 1686
Abstract
Plastic polymers have quickly become one of the most abundant materials on Earth due to their low production cost and high versatility. Unfortunately, some of the discarded plastic can make its way into the environment and become fragmented into smaller microscopic particles, termed [...] Read more.
Plastic polymers have quickly become one of the most abundant materials on Earth due to their low production cost and high versatility. Unfortunately, some of the discarded plastic can make its way into the environment and become fragmented into smaller microscopic particles, termed secondary microplastics (MP). In addition, primary MP, purposely manufactured microscopic plastic particles, can also make their way into our environment via various routes. Owing to their size and resilience, these MP can then be easily ingested by living organisms. The effect of MP particles on living organisms is suspected to have negative implications, especially during early development. In this study, we examined the effects of polyethylene MP ingestion for four and ten days of exposure starting at 5 days post-fertilization (dpf). In particular, we examined the effects of polyethylene MP exposure on resting metabolic rate, on gene expression of several inflammatory and oxidative stress linked genes, and on microbiome composition between treatments. Overall, we found no evidence of broad metabolic disturbances or inflammatory markers in MP-exposed fish for either period of time. However, there was a significant increase in the oxidative stress mediator L-FABP that occurred at 15 dpf. Furthermore, the microbiome was disrupted by MP exposure, with evidence of an increased abundance of Bacteroidetes in MP fish, a combination frequently found in intestinal pathologies. Thus, it appears that acute polyethylene MP exposure can increase oxidative stress and dysbiosis, which may render the animal more susceptible to diseases. Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)
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Article
Occurrence of Microplastic Pollution at Oyster Reefs and Other Coastal Sites in the Mississippi Sound, USA: Impacts of Freshwater Inflows from Flooding
Toxics 2020, 8(2), 35; https://doi.org/10.3390/toxics8020035 - 15 May 2020
Cited by 10 | Viewed by 1979
Abstract
Much of the seafood that humans consume comes from estuaries and coastal areas where microplastics (MPs) accumulate, due in part to continual input and degradation of plastic litter from rivers and runoff. As filter feeders, oysters (Crassostrea virginica) are especially vulnerable [...] Read more.
Much of the seafood that humans consume comes from estuaries and coastal areas where microplastics (MPs) accumulate, due in part to continual input and degradation of plastic litter from rivers and runoff. As filter feeders, oysters (Crassostrea virginica) are especially vulnerable to MP pollution. In this study, we assessed MP pollution in water at oyster reefs along the Mississippi Gulf Coast when: (1) historic flooding of the Mississippi River caused the Bonnet Carré Spillway to remain open for a record period of time causing major freshwater intrusion to the area and deleterious impacts on the species and (2) the spillway was closed, and normal salinity conditions resumed. Microplastics (~25 µm–5 mm) were isolated using a single-pot method, preparing samples in the same vessel (Mason jars) used for their collection right up until the MPs were transferred onto filters for analyses. The MPs were quantified using Nile Red fluorescence detection and identified using laser direct infrared (LDIR) analysis. Concentrations ranged from ~12 to 381 particles/L and tended to decrease at sites impacted by major freshwater intrusion. With the spillway open, average MP concentrations were positively correlated with salinity (r = 0.87, p = 0.05) for sites with three or more samples examined. However, the dilution effect on MP abundances was temporary, and oyster yields suffered from the extended periods of lower salinity. There were no significant changes in the relative distribution of MPs during freshwater intrusions; most of the MPs (>50%) were in the lower size fraction (~25–90 µm) and consisted mostly of fragments (~84%), followed by fibers (~11%) and beads (~5%). The most prevalent plastic was polyester, followed by acrylates/polyurethanes, polyamide, polypropylene, polyethylene, and polyacetal. Overall, this work provides much-needed empirical data on the abundances, morphologies, and types of MPs that oysters are exposed to in the Mississippi Sound, although how much of these MPs are ingested and their impacts on the organisms deserves further scrutiny. This paper is believed to be the first major application of LDIR to the analysis of MPs in natural waters. Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)
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Article
‘The Plastic Nile’: First Evidence of Microplastic Contamination in Fish from the Nile River (Cairo, Egypt)
Toxics 2020, 8(2), 22; https://doi.org/10.3390/toxics8020022 - 25 Mar 2020
Cited by 13 | Viewed by 3481
Abstract
The presence of microplastics (MPs) in the world’s longest river, the Nile River, has yet to be reported. This small-scale study aimed to provide the first information about MPs in the Nile River by sampling the digestive tracts of two fish species, the [...] Read more.
The presence of microplastics (MPs) in the world’s longest river, the Nile River, has yet to be reported. This small-scale study aimed to provide the first information about MPs in the Nile River by sampling the digestive tracts of two fish species, the Nile tilapia (Oreochromis niloticus, n = 29) and catfish (Bagrus bayad, n = 14). Fish were purchased from local sellers in Cairo, and then their gastrointestinal tracts were dissected and examined for MPs. Over 75% of the fish sampled contained MPs in their digestive tract (MP prevalence of 75.9% and 78.6% for Nile tilapia and catfish, respectively). The most abundant MP type was fibers (65%), the next most abundant type was films (26.5%), and the remaining MPs were fragments. Polyethylene (PE), polyethylene terephthalate (PET) and polypropylene (PP) were all non-destructively identified by attenuated total reflectance Fourier transform infrared spectroscopy. A comparison with similar studies from marine and freshwater environments shows that this high level of MP ingestion is rarely found and that fish sampled from the Nile River in Cairo are potentially among the most in danger of consuming MPs worldwide. Further research needs to be conducted, but, in order to mitigate microplastic pollution in the Nile River, we must act now. Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)
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Communication
Microplastics Exposure Causes Negligible Effects on the Oxidative Response Enzymes Glutathione Reductase and Peroxidase in the Oligochaete Tubifex tubifex
Toxics 2020, 8(1), 14; https://doi.org/10.3390/toxics8010014 - 15 Feb 2020
Cited by 4 | Viewed by 983
Abstract
Microplastics (MPs) are emerging pollutants, which are considered ubiquitous in aquatic ecosystems. The effects of MPs on aquatic biota are still poorly understood, and consequently, there is a need to understand the impacts that MPs may pose to organisms. In the present study, [...] Read more.
Microplastics (MPs) are emerging pollutants, which are considered ubiquitous in aquatic ecosystems. The effects of MPs on aquatic biota are still poorly understood, and consequently, there is a need to understand the impacts that MPs may pose to organisms. In the present study, Tubifex tubifex, a freshwater oligochaete commonly used as a bioindicator of the aquatic environment, was exposed to fluorescent polyethylene microspheres (up to 10 µm in size) to test whether the oxidative stress status was affected. The mortality rate of T. tubifex, as well as the activities of the oxidative stress status biomarker enzymes glutathione reductase and peroxidase, were assessed. In terms of oxidative stress, no significant differences between the exposure organisms and the corresponding controls were detected. Even though the data suggest that polyethylene MPs and the selected concentrations did not pose a critical risk to T. tubifex, the previously reported tolerance of T. tubifex to environmental pollution should be taken into account and thus MPs as aquatic pollutants could still represent a threat to more sensitive oligochetes. Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)
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Article
Enchytraeus crypticus Avoid Soil Spiked with Microplastic
Toxics 2020, 8(1), 10; https://doi.org/10.3390/toxics8010010 - 10 Feb 2020
Cited by 6 | Viewed by 1217
Abstract
Microplastics (MPs) of varying sizes are widespread pollutants in our environment. The general opinion is that the smaller the size, the more dangerous the MPs are due to enhanced uptake possibilities. It would be of considerably ecological significance to understand the response of [...] Read more.
Microplastics (MPs) of varying sizes are widespread pollutants in our environment. The general opinion is that the smaller the size, the more dangerous the MPs are due to enhanced uptake possibilities. It would be of considerably ecological significance to understand the response of biota to microplastic contamination both physically and physiologically. Here, we report on an area choice experiment (avoidance test) using Enchytraeus crypticus, in which we mixed different amounts of high-density polyethylene microplastic particles into the soil. In all experimental scenarios, more Enchytraeids moved to the unspiked sections or chose a lower MP-concentration. Worms in contact with MP exhibited an enhanced oxidative stress status, measured as the induced activity of the antioxidative enzymes catalase and glutathione S-transferase. As plastic polymers per se are nontoxic, the exposure time employed was too short for chemicals to leach from the microplastic, and as the microplastic particles used in these experiments were too large (4 mm) to be consumed by the Enchytraeids, the likely cause for the avoidance and oxidative stress could be linked to altered soil properties. Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)
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Article
Collection of Anthropogenic Litter from the Shores of Lake Malawi: Characterization of Plastic Debris and the Implications of Public Involvement in the African Great Lakes
Toxics 2019, 7(4), 64; https://doi.org/10.3390/toxics7040064 - 13 Dec 2019
Cited by 3 | Viewed by 1320
Abstract
Anthropogenic debris is an environmental problem that affects beaches and coastlines worldwide. The abundance of beach debris is often documented with the use of public volunteers. To date, such community participations have been largely confined to the marine environment, but the presence and [...] Read more.
Anthropogenic debris is an environmental problem that affects beaches and coastlines worldwide. The abundance of beach debris is often documented with the use of public volunteers. To date, such community participations have been largely confined to the marine environment, but the presence and impact of anthropogenic debris on freshwater shorelines has been increasingly recognized. Our study presents the first such information from the African Great Lakes, specifically Lake Malawi. A total of 490,064 items of anthropogenic litter were collected by over 2000 volunteers in a clean-up campaign that took place annually between 2015 and 2018. Approximately 80% of the anthropogenic debris was comprised of plastic litter, with plastic carrier bags being the most common item. The dominance of plastic litter, and in particular the presence of plastic bags, which have subjected to bans in some African countries, is discussed. The broader implications of citizen science in the African Great Lakes area is also discussed. Full article
(This article belongs to the Special Issue Prevalence, Fate and Effects of Plastic in Freshwater Environments)
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