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Cited by 355Microplastics and Plastic PollutionEnvironmental Toxicology and EcotoxicologyPharmaceutical and Antibiotic Environmental Impacts

Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates

Open access
Redondo-Hasselerharm, Paula E., Falahudin, Dede, Peeters, Edwin T. H. M., Koelmans, Albert A.·2018·Environmental Science & Technology
DOI 10.1021/acs.est.7b05367PMC PMC5822217
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Abstract

Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20–500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species.

AI snapshot

Written from the paper’s full text.

TL;DR

This study measured microplastic effect thresholds in six freshwater benthic macroinvertebrates using 28-day sediment bioassays with polystyrene particles (20–500 μm) at 0–40% sediment dry weight. Most species showed no effects, but *Gammarus pulex* had reduced growth with an EC10 of 1.07% sediment dw and EC50 of 3.57% sediment dw.

Key findings

  • No significant mortality occurred in *G. pulex*, *Hyalella azteca*, *Asellus aquaticus*, *Sphaerium corneum*, or *Tubifex* spp. up to 40% sediment dw, and no significant reproduction effects were found for *Lumbriculus variegatus*.
  • Growth was unaffected in *H. azteca*, *A. aquaticus*, *S. corneum*, *L. variegatus*, and *Tubifex* spp., but *G. pulex* showed significant growth reduction at 10–40% sediment dw, with EC10 = 1.07% sediment dw and EC50 = 3.57% sediment dw (±3.22).
  • Microplastic uptake by *G. pulex* was proportional to sediment concentration, with trophic transfer factors of (4.47 ± 0.35) × 10⁻¹¹ by number and (10.5 ± 1.3) × 10⁻³ by mass; no microplastics were found in *H. azteca* bodies or faecal pellets.
  • Feeding rate of *G. pulex* and *H. azteca* and egestion rate of *L. variegatus* and *Tubifex* spp. showed no negative effects from microplastic exposure.

Methods

  • Standardized 28-day single-species bioassays were run with six species in 750 mL glass beakers containing 211 g wet sediment and 300 mL copper-free Dutch Standard Water, using eight polystyrene microplastic concentrations: 0, 0.1, 1, 5, 10, 20, 30, and 40% plastic weight in total sediment mixture.
  • Four replicates were used per concentration, except *H. azteca* had three replicates and the 5% concentration was excluded; endpoints included mortality, growth, feeding/egestion rates, and microplastic ingestion, retention, and egestion.
  • Data were analyzed with generalized linear models with binomial/probit models for survival, one-way ANOVA and regression for growth and feeding/egestion, repeated-measures ANOVA for egestion over time, and four-parameter log-logistic dose–response models when significant effects were found.

Limitations

  • The paper states that the EC50 for *G. pulex* had high uncertainty due to variability among replicates, that field-measured freshwater microplastic concentrations are often provisional due to methodological limitations, and that the particle-volume approximation is not accurate for individual particles but becomes robust for larger numbers of irregular particles.
  • The paper also states that *L. variegatus* mortality could not be determined because of reproduction by fragmentation, that *G. pulex* control survival was 66%, and that the observed trophic transfer factors may change over time.
  • Evident from the text: the study did not aim to assess chemical effects, so conclusions are limited to physical effects of the tested polystyrene particles under these laboratory conditions.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1021/acs.est.7b05367

Cites

48 of 48 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

22 of 71 cited sources checked · 11 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Nonstandardized laboratory bioassays and unrealistic exposure scenarios impede understanding of microplastic risks.

    “The use of nonstandardized laboratory bioassays and unrealistic exposure scenarios hinders the understanding of the risks associated with microplastics.9,22,23”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [9] Koelmans, 2017, Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief, Environ. Sci. Technol. source
    • cites [22] Connors, 2017, Advancing the quality of environmental microplastic research, Environ. Toxicol. Chem. source
    • cites [23] Karami, 2017, Gaps in aquatic toxicological studies of microplastics, Chemosphere source
  • Premisecitation

    Chronic exposure of G. fossarum to PMMA and PHB microplastics in water reduced growth at 100,000 particles per individual.

    “However, chronic exposure of a closely related freshwater shrimp, G. fossarum, to poly(methyl methacrylate) (PMMA) and polyhydroxybutyrate (PHB) microplastics in water caused a decrease in growth at a concentration of 100 000 microplastics particles per individual with a similar size range.12”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [12] Straub, 2017, Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum, Int. J. Environ. Res. Public Health source
  • Interpretationcitation

    Based on excretion studies with other freshwater amphipods, G. pulex is expected to completely depurate if given enough time and if ingestion stops.

    “Based on microplastic excretion studies performed with other freshwater amphipods exposed to different microplastic types,11,12G. pulex is expected to be able to completely depurate if enough time is given and if the ingestion of particles concludes.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [11] Au, 2015, Responses of Hyalella azteca to acute and chronic microplastic exposures, Environ. Toxicol. Chem. source
    • cites [12] Straub, 2017, Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum, Int. J. Environ. Res. Public Health source

      Methods §2.5.1 describes transferring G. fossarum to microplastic-free beakers, and Results §3.1 reports substantial excretion over 64 hours. The study did not test G. pulex or establish complete depuration: some particles remained in G. fossarum guts at 64 hours. Page numbers are unavailable in our copy. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
  • Premisecitation

    Field-measured microplastic concentrations in freshwater sediments are far below the calculated EC10 or EC50 effect thresholds for G. pulex.

    “Field measured concentrations in freshwater sediments2−4,7,8 although often provisional due to methodological limitations, are far below the calculated EC10 or EC50 effect threshold values for G. pulex.”
    Quote in the paperSubstantial claim2 of 5 sources checked
    • cites [2] Horton, 2017, Microplastics in freshwater and terrestrial environments: Evaluating the current understanding to identify the knowledge gaps and future research priorities, Sci. Total Environ. source
    • cites [3] Wagner, 2014, Microplastics in freshwater ecosystems: what we know and what we need to know, Environ. Sci. Eur. source
    • cites [4] Eerkes-Medrano, 2015, Microplastics in freshwater systems: A review of the emerging threats, identification of knowledge gaps and prioritisation of research needs, Water Res. source
    • cites [7] Klein, 2015, Occurrence and Spatial Distribution of Microplastics in River Shore Sediments of the Rhine-Main Area in Germany, Environ. Sci. Technol. source
    • cites [8] Leslie, 2017, Microplastics en route: Field measurements in the Dutch river delta and Amsterdam canals, wastewater treatment plants, North Sea sediments and biota, Environ. Int. source
  • Findingown data

    No significant growth differences were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp.

    “No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 27
  • May combine two claims. 52
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    No mortality was reported for the marine isopod Idotea emarginata exposed to PE, PS, and PA microplastics, or for the marine lugworm Arenicola marina exposed to PE microplastics.

    “Furthermore, no mortality was reported for the marine isopod Idotea emarginata exposed to PE, PS, and PA (polyamide) microplastics and the marine lugworm A. marina exposed to PE microplastics.19”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [19] Besseling, 2017, The Effect of Microplastic on the Uptake of Chemicals by the Lugworm Arenicola marina (L.) under Environmentally Relevant Exposure Conditions, Environ. Sci. Technol. source

      The Results and discussion section (“Lugworm Survival, Feeding Activity, Weight, and Lipid Content”) reports 81% overall lugworm survival, meaning mortality did occur. It found no significant difference in survival between PE treatments, which is not the same as no mortality. The cited paper does not examine Idotea emarginata. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Premisecitation

    Understanding how microplastics interact with freshwater biota is a high-priority research need, and there is general agreement that exposure risk should be assessed.

    “Understanding the interaction between microplastics and biota in freshwater systems has been identified as a high priority research need4 and there is a general agreement on the idea that an effect assessment should be performed to evaluate the risk of exposure to microplastics.9”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [4] Eerkes-Medrano, 2015, Microplastics in freshwater systems: A review of the emerging threats, identification of knowledge gaps and prioritisation of research needs, Water Res. source
    • cites [9] Koelmans, 2017, Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief, Environ. Sci. Technol. source

  • May combine two claims.

    Premisecitation

    The selected species are common freshwater community members, frequently used in laboratory experiments, and differ in living and feeding strategies and in sensitivity to environmental pollutants.

    “These species are common members of freshwater communities, are often used in laboratory experiments and differ in their living and feeding strategies, as well as in their sensitivity to environmental pollutants.26−28”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [26] Maltby, 1995, Sensitivity of the crustaceans Gammarus pulex (L.) and Asellus aquaticus (L.) to short-term exposure to hypoxia and unionized ammonia: observations and possible mechanisms, Water Res. source
    • cites [27] Kupryianchyk, 2011, Ecotoxicological Effects of Activated Carbon Amendments on Macroinvertebrates in Nonpolluted and Polluted Sediments, Environ. Sci. Technol. source
    • cites [28] Diepens, 2016, Prospective environmental risk assessment for sediment-bound organic chemicals: A proposal for tiered effect assessment source

      No passage from our copy matched the claim. Searches for freshwater species, laboratory use, feeding strategies, and pollutant sensitivity returned no passages, so the copy does not establish these characteristics of the selected species. (LLM, conf=0.68)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    It is still unclear whether microplastic adverse effects arise from physical particle impact, chemical toxicity, or both.

    “Furthermore, it remains unclear if adverse effects are caused by a physical impact of the particles themselves, by chemical toxicity or by a combination of both.2”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [2] Horton, 2017, Microplastics in freshwater and terrestrial environments: Evaluating the current understanding to identify the knowledge gaps and future research priorities, Sci. Total Environ. source

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Premisecitation

    Effect assessments for microplastics should target traditional ecotoxicological thresholds such as LC50 or EC50, and fitting dose-response models requires sufficient doses and replication.

    “Moreover, an effect assessment for microplastics should aim at detecting the effect thresholds for traditional end points in ecotoxicology (i.e., LC50 or EC50),22 and for this, sufficient doses and replication are needed in order to fit dose–response models, which are commonly used in chemical risk assessment.9”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [22] Connors, 2017, Advancing the quality of environmental microplastic research, Environ. Toxicol. Chem. source
    • cites [9] Koelmans, 2017, Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief, Environ. Sci. Technol. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Microplastic uptake had no effect on the marine isopod Idotea emarginata, but it caused weight loss and lower feeding activity in the marine lugworm Arenicola marina.

    “Microplastic uptake did not cause any effects on the marine isopod Idotea emarginata(16) but did cause weight loss and a reduced feeding activity for the marine lugworm Arenicola marina.17−19”
    Quote in the paperNot a substantial claim2 of 4 sources checked
    • cites [16] Hämer, 2014, Fate of microplastics in the marine isopod Idotea emarginata, Environ. Sci. Technol. source

      The Discussion (p. 4) reports no distinct adverse effects on the isopods’ survival, intermolt duration, or growth. But the Discussion (p. 6) also reports reduced uptake of food supplemented with microplastics, so “did not cause any effects” is too absolute. The lugworm finding is attached to citations 17–19, not this source. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [17] Wright, 2013, Microplastic ingestion decreases energy reserves in marine worms, Curr. Biol. source
    • cites [18] Besseling, 2013, Effects of microplastic on fitness and PCB bioaccumulation by the lugworm Arenicola marina (L.), Environ. Sci. Technol. source
    • cites [19] Besseling, 2017, The Effect of Microplastic on the Uptake of Chemicals by the Lugworm Arenicola marina (L.) under Environmentally Relevant Exposure Conditions, Environ. Sci. Technol. source

      The Results and discussion section, “Lugworm Survival, Feeding Activity, Weight, and Lipid Content” (page not supplied), reports significantly lower faeces-heap mass in polyethylene treatments, supporting reduced feeding activity in Arenicola marina. Lugworms also lost weight, but weight loss did not significantly differ among treatments, so this paper does not support attributing the weight loss to microplastic. The isopod finding is attached to a different citation in the citing sentence. (LLM, conf=0.91)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In Gammarus fossarum, microplastic uptake was linked to reduced growth after exposure to PMMA and PHB particles.

    “Moreover, this uptake was related to a decrease in the growth of Gammarus fossarum exposed to poly(methyl methacrylate) (PMMA) and polyhydroxybutyrate (PHB) microplastics.12”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [12] Straub, 2017, Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum, Int. J. Environ. Res. Public Health source

  • May combine two claims.

    Premisecitation

    Freshwater species take up microplastics from sediments, and the ingestion capacity of freshwater invertebrates varies with feeding type.

    “Previous studies have indeed demonstrated that microplastics are taken up from sediments by freshwater species10−15 and that the capacity of freshwater invertebrates to ingest microplastics depends on their feeding type.15”
    Quote in the paperNot a substantial claim2 of 6 sources checked
    • cites [10] Imhof, 2013, Contamination of beach sediments of a subalpine lake with microplastic particles, Curr. Biol. source
    • cites [11] Au, 2015, Responses of Hyalella azteca to acute and chronic microplastic exposures, Environ. Toxicol. Chem. source
    • cites [12] Straub, 2017, Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum, Int. J. Environ. Res. Public Health source

      The Methods (section 2.4) describe microplastics sinking to the bottom of experimental beakers, where Gammarus fossarum ingested them; the study does not demonstrate uptake from natural sediments. The Discussion (sections 4.1 and 4.4) identifies the amphipods as shredders that readily ingest certain particle sizes, but it does not compare invertebrates with different feeding types or establish that ingestion capacity depends on feeding type. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [13] Hurley, 2017, Ingestion of Microplastics by Freshwater Tubifex Worms, Environ. Sci. Technol. source
    • cites [14] Weber, 2018, PET microplastics do not negatively affect the survival, development, metabolism and feeding activity of the freshwater invertebrate Gammarus pulex, Environ. Pollut. source
    • cites [15] Scherer, 2017, Feeding type and development drive the ingestion of microplastics by freshwater invertebrates, Sci. Rep. source

      The Abstract and Results and Discussion (Species; pages not provided) show that freshwater invertebrates ingested microplastics at rates that varied with feeding type. The paper also reports ingestion by benthic feeders and observes that larger beads settled, but it does not directly demonstrate uptake of microplastics from sediments; it describes ingestion of settling particles at the sediment surface as likely. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Growth of G. fossarum was reduced after 28-day exposure to PMMA and PHB particles, while its feeding rate was unaffected.

    “Similarly, while the growth of G. fossarum was reduced after a 28 day exposure to PMMA and PHB particles, the feeding rate was also unaffected.12”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [12] Straub, 2017, Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum, Int. J. Environ. Res. Public Health source

  • May combine two claims.

    Interpretationcitation

    Differences between study outcomes may be due to exposure medium and greater bioavailability of suspended particles compared with sediment-mixed particles.

    “Such differences between study outcomes may relate to (a) differences in the exposure medium, as the presence of natural particles seems to reduce the ingestion of microplastics in freshwater invertebrates,15 and (b) to a higher bioavailability of particles in suspension as compared to particles mixed in the sediment as in the present bioassays.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Scherer, 2017, Feeding type and development drive the ingestion of microplastics by freshwater invertebrates, Sci. Rep. source

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    Microplastic concentrations spanned environmentally relevant levels (0-1% plastic weight in sediment dry weight) to very high levels, in order to evaluate dose-response relationships and maximize detection of the effect threshold.

    “Concentrations ranged from environmentally relevant (0–1% plastic weight in sediment dw) to very high concentrations, to evaluate dose–response relations and to maximize the chance of accurately detecting the effect threshold.9”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [9] Koelmans, 2017, Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief, Environ. Sci. Technol. source

      In “Measure Effect Thresholds” (page not provided), Koelmans recommends testing a range of concentrations to detect effect thresholds and fit dose–effect models. The paper does not give the claimed 0–1% sediment-dry-weight range or report that such concentrations were used in an experiment; it makes a recommendation rather than describing a completed test. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    No growth effects were found for the marine isopod I. emarginata exposed to PE, PS, and PA microplastics in water.

    “No effects were found on growth for the marine isopod I. emarginata exposed to PE, PS, and PA microplastics in water,16”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [16] Hämer, 2014, Fate of microplastics in the marine isopod Idotea emarginata, Environ. Sci. Technol. source

      The Discussion (p. 4) reports no distinct adverse effect on growth, and the Materials and Methods (p. 2) describe food containing PE fragments; the Introduction (p. 2) identifies PS particles and polyacrylic fibers. But the isopods ingested microplastics embedded in artificial food, rather than being exposed to microplastics dispersed in water. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Growth reduction of G. pulex was a sublethal effect caused by reduced food assimilation due to PS microplastic ingestion and by gut blockage from longer excretion time.

    “our results indicate that growth reduction of G. pulex was a sublethal effect caused by a lower ability of these organisms to assimilate food due to the ingestion of PS microplastics,11,12 as well as by the gut blockage by these particles due to a longer excretion time needed to depurate their gut.11”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [11] Au, 2015, Responses of Hyalella azteca to acute and chronic microplastic exposures, Environ. Toxicol. Chem. source
    • cites [12] Straub, 2017, Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum, Int. J. Environ. Res. Public Health source

      The Results (§3.2) report reduced assimilation efficiency and wet-weight gain, and the Discussion (§§4.2, 4.6) proposes prolonged gut retention and possible obstruction as explanations. But this paper studied G. fossarum exposed to PMMA and PHB, not G. pulex exposed to PS; it also presents gut obstruction as a possibility rather than an established cause. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    The high mobility of G. pulex could have increased its microplastic uptake compared with other epibenthic species, highlighting species-specific traits in microplastic effects.

    “Moreover, the high mobility of G. pulex(46) could have increased microplastic uptake in comparison to the other epibenthic species, revealing the importance of species specific traits in the effects of microplastics on benthic invertebrates.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [46] Vadher, 2015, Fine sediment reduces vertical migrations of Gammarus pulex (Crustacea: Amphipoda) in response to surface water loss, Hydrobiologia source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Previous studies show that microplastic uptake by freshwater invertebrates is size-specific and feeding-type dependent, and irregularly shaped microplastics need longer clearance time than spherical ones.

    “This is in accordance with previous studies showing that microplastic uptake by freshwater invertebrates is size- specific and feeding type dependent and that irregularly shaped microplastics need a significant longer clearance time in comparison to spherical microplastics.11,15”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [11] Au, 2015, Responses of Hyalella azteca to acute and chronic microplastic exposures, Environ. Toxicol. Chem. source
    • cites [15] Scherer, 2017, Feeding type and development drive the ingestion of microplastics by freshwater invertebrates, Sci. Rep. source

      The Abstract and Results and Discussion (Species) show that uptake varies with particle size and feeding strategy. Results and Discussion (Size) says the study tested only spheres and suggests that depuration of irregular particles may differ; it does not establish that irregular particles take significantly longer to clear. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    The polystyrene particles had a unimodal size distribution from 20 to 500 μm, with a volume mode at 229 μm and a number mode at 36 μm.

    “Particle size distribution (PSD), measured with a Mastersizer 3000 (Malvern Instruments), revealed an unimodal distribution spanning from 20 to 500 μm, with a modus centered at 229 μm in volume and 36 μm in number (SI Figure S1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    In controls, the average number of surviving L. variegatus worms per replicate increased by at least 1.8-fold, and reproduction factor was calculated as final worm number divided by initial worm number.

    “As the average number of surviving worms per replicate in controls was increased by a factor of at least 1.8, the reproduction factor could be calculated as the number of worms at the end of the experiment divided by the number of worms at the beginning of the experiment.31”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] OECD., 2007, OECD Guidelines for the testing of chemicals source

  • May combine two claims.

    Findingown data

    All L. variegatus and Tubifex spp. survived the experiment, and no reproduction was observed in the additional 15-day period.

    “At the end of the experiment, all L. variegatus and Tubifex spp. survived and no reproduction was observed in the additional 15 day period experiment.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    Microplastic uptake increased proportionally with microplastic concentrations in sediment.

    “However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The sediment total organic matter content was 31.6% ± 3.5 (n = 4).

    “Four representative subsamples were taken to determine the % TOM through loss on ignition (3 h, 550 °C), which was 31.6% ± 3.5 (n = 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    L. variegatus egestion rate increased in the first week then decreased until the end, whereas Tubifex spp. egestion rate increased over time until the end.

    “The egestion rate of L. variegatus increased during the first week of exposure and then decreased until the end of experiment, whereas the egestion rate for Tubifex spp. increased over time until the end of experiment (SI Figure S5).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Average egestion rates were 0.43 mg dry faeces per mg dry organism per h for L. variegatus and 0.32 for Tubifex spp.

    “The average egestion rates of L. variegatus and Tubifex spp. were 0.43 and 0.32 mg dry faeces per mg dry organism per h, respectively”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    G. pulex showed a significant growth reduction, with an EC10 of 1.07% sediment dry weight.

    “However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Microplastics in G. pulex bodies (n = 191) ranged from 22 to 165 μm, with an average of 61 μm.

    “Size frequency distribution of the microplastics found in the body of all organisms (n = 191) ranged from 22 to 165 μm, with an average size of 61 μm (SI Figure S6A).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Chronic exposure to PS microplastic concentrations up to 40% sediment dry weight caused no significant mortality in G. pulex, A. aquaticus, S. corneum, H. azteca, and Tubifex spp., and no significant effects on L. variegatus reproduction.

    “Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus.”
    • Also stated in: § Mortality · plain
      “Chronic exposure to PS microplastic concentrations up to 40% in sediment dw caused no significant mortality in G. pulex, A. aquaticus, S. corneum, H. azteca, and Tubifex spp. (Figure 1A–E), and no significant effects were found on the reproduction of L. variegatus (Figure 1F).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The Rhine river has the highest microplastic concentrations recorded among freshwater bodies studied, with up to 4000 particles per kg or 1 g per kg dry weight in German shore sediments, and the smallest fraction (63-630 μm) is most abundant by number.

    “Recent data shows that the Rhine river contains the highest microplastic concentrations detected in all freshwater bodies studied. Concentrations up to 4000 particles kg–1 or 1 g kg–1 (dw) were recorded in the German Rhine river shore sediments, with the smallest microplastic fraction (63–630 μm) being the most abundant in numbers.7”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [7] Klein, 2015, Occurrence and Spatial Distribution of Microplastics in River Shore Sediments of the Rhine-Main Area in Germany, Environ. Sci. Technol. source

  • May combine two claims.

    Premisecitation

    Polystyrene density matches that of the average environmental microplastic, and polymer density has little influence on physical effects.

    “After all, polystyrene density matches that of the average environmental microplastic5,25 (see calculation in Supporting Information (SI) Table S1) and polymer density has limited impact on physical effects.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [5] Besseling, 2017, Fate of nano- and microplastic in freshwater systems: A modeling study, Environ. Pollut. source
    • cites [25] Andrady, 2011, Microplastics in the marine environment, Mar. Pollut. Bull. source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Among the selected species, G. pulex, H. azteca, and A. aquaticus are mainly shredders; S. corneum is a facultative suspension feeder; and L. variegatus and Tubifex spp. are endobenthic deposit feeders, with L. variegatus a bulk feeder and Tubifex spp. selective.

    “G. pulex, H. azteca, and A. aquaticus are regarded as being mainly shredders, whereas S. corneum is classified as a facultative suspension feeder.”
    • Also stated in: § Test Organisms · plain
      “L. variegatus and Tubifex spp. are both endobenthic deposit feeders, with L. variegatus regarded as a bulk feeder while Tubifex spp. exhibits selectivity in its feeding behavior.29”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [29] Rodriguez, 2001, Selective feeding by the aquatic oligochaete Tubifex tubifex (Tubificidae, Clitellata), Hydrobiologia source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    After taking up PET microplastics, Gammarus pulex showed no effects on survival, molting, metabolism, or feeding activity.

    “However, no effects were reported on the survival, molting, metabolism and feeding activity of Gammarus pulex after the uptake of polyethylene terephtalate (PET) microplastics.14”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Weber, 2018, PET microplastics do not negatively affect the survival, development, metabolism and feeding activity of the freshwater invertebrate Gammarus pulex, Environ. Pollut. source

  • May combine two claims.

    Study design and conductreasoning

    For every endpoint, the study simulated environmentally relevant exposure by using natural sediments and including the highest concentration reported in freshwater sediment.

    “For all end points, environmentally relevant exposure conditions were simulated by using natural sediments and by including the highest concentration found in a freshwater sediment.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The evidence suggests that benthic macroinvertebrates are affected by microplastics, but susceptibility may differ among species.

    “This suggests that benthic macroinvertebrates are affected by the presence of microplastics but also that the susceptibility could be species specific.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Sediments can serve as a sink for microplastics, as indicated by the strong influence of particle size on river-sediment microplastic hotspots.

    “In fact, particle size has been found to strongly affect the presence of microplastic hotspots along river sediments, indicating that sediments can act as a sink for microplastics.5”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] Besseling, 2017, Fate of nano- and microplastic in freshwater systems: A modeling study, Environ. Pollut. source

  • May combine two claims.

    Study design and conductown data

    FTIR spectrometry confirmed polymer identity and purity, and stereomicroscopy confirmed particle shape.

    “Polymer identity and purity were confirmed with FTIR spectrometry (Nicolet iN10, ThermoFisher) and particle shape was confirmed with an Olympus SZX10 stereomicroscope (Figure S2, SI).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductcitation

    Sediments came from a noncontaminated ditch, with ∑PAH and ∑PCBs more than 8 and 70 times below toxicity thresholds, respectively, and heavy metals below negligible risk levels under Dutch sediment quality criteria.

    “Freshwater sediments were collected from a noncontaminated ditch in Veenkampen (Wageningen, The Netherlands) using a standard dip net. Background concentrations of ∑PAH and ∑PCBs were factors of >8 and >70 below toxicity thresholds,27 whereas heavy metals were below negligible risk levels according to Dutch sediment quality criteria (SI Table S2).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [27] Kupryianchyk, 2011, Ecotoxicological Effects of Activated Carbon Amendments on Macroinvertebrates in Nonpolluted and Polluted Sediments, Environ. Sci. Technol. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Other marine invertebrates have shown no or limited effects from microplastics.

    “No or limited effects have also been found for other marine invertebrates.20,21”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [20] Kaposi, 2014, Ingestion of Microplastic Has Limited Impact on a Marine Larva, Environ. Sci. Technol. source
    • cites [21] Lo, 2018, Negative effects of microplastic exposure on growth and development of Crepidula onyx, Environ. Pollut. source

  • May combine two claims.

    Premisecitation

    Exposure to polyethylene microplastics reduced both growth and reproduction in Hyalella azteca.

    “Also, a reduction in the growth and reproduction of Hyalella azteca was found after the exposure to polyethylene (PE) microplastics.11”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Au, 2015, Responses of Hyalella azteca to acute and chronic microplastic exposures, Environ. Toxicol. Chem. source

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Potential additives in the microplastics were removed so that the cause of any particle effect would not be ambiguous.

    “Any potential additives present were removed from the microplastics to eliminate any ambiguity concerning what caused the effect of the particles.”
    • Also stated in: § Microplastics · plain
      “To remove additives present, if any, the microplastics were washed with methanol three times, shaken, filtered with a 20 μm metal sieve and dried for at least 2 days in a fume hood at room temperature.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Un-ionized ammonia decreased over the experiment, reaching an average of 0.002 ± 0.001 mg NH3/L at the end, and remained below available LC50 values for the species.

    “Un-ionised levels of ammonia decreased along the experiment for all species, reaching an average of 0.002 ± 0.001 mg NH3/l at the end of the experiment. All un-ionized ammonia levels were always below the LC50 values available for these species.26,32−34”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [26] Maltby, 1995, Sensitivity of the crustaceans Gammarus pulex (L.) and Asellus aquaticus (L.) to short-term exposure to hypoxia and unionized ammonia: observations and possible mechanisms, Water Res. source
    • cites [32] Ankley, 1995, Influence of pH and hardness on toxicity of ammonia to the amphipod Hyalella azteca, Can. J. Fish. Aquat. Sci. source
    • cites [33] Schubaur-Berigan, 1995, Influence of pH on the toxicity of ammonia to Chironomus tentans and Lumbriculus variegatus, Environ. Toxicol. Chem. source
    • cites [34] Arrate, 2014, Tubifex tubifex chronic toxicity test using artificial sediment: methodological issues, Limnetica

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    Organisms and faecal pellets from the 1% treatment and one replicate of the 30% treatment were used to optimize microplastic extraction, and their data were excluded from further analysis.

    “Organisms and faecal pellets from the 1% treatment, as well as one replica of the 30% treatment, were used to optimize the extraction of microplastics and, therefore, their data were omitted from further analysis.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    Water quality variables stayed constant in all beakers except in Tubifex spp. and L. variegatus treatments, where pH approached below recommended limits at days 14 and 24; this was corrected by replacing surface water with fresh DSW.

    “Water quality variables remained constant in all beakers along the experiment (Table S3, SI), except for the treatments with Tubifex spp. and L. variegatus where pH approached values below the recommended limits (6–9) at day 14 and 24, respectively.31”
    • Also stated in: § Experimental Design · plain
      “This was solved by replacing 100 mL from the surface water layer in the bioassay by fresh DSW.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] OECD., 2007, OECD Guidelines for the testing of chemicals source

  • May combine two claims.

    Interpretationown data

    Up to 40% concentration, PS microplastic uptake by G. pulex is proportional to sediment concentration, whether expressed as number or mass.

    “These data show that up to a concentration of 40%, uptake by G. pulex (Figure 3) is proportional to the concentration in the sediment, either expressed as number or as mass.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    No mortality occurred during the 15-day egestion experiment.

    “No mortality occurred during the 15 day experiment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Weight loss of G. pulex was probably not caused by reduced consumption of Populus sp. leaves, and sediment microplastics did not alter feeding rate of these amphipods.

    “These findings indicate that weight loss of G. pulex was probably not caused by a reduction in the consumption of Populus sp. leaves during the experiment and that the presence of microplastics in the sediment did not alter the feeding rate of these benthic amphipods.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    After correction for the 165-500 μm biounavailable fraction, net transfer TTF estimates are (5.16 ± 0.40) × 10−11 for number and 0.028 ± 0.0036 for mass.

    “When corrected for the 165–500 μm biounavailable fraction, pure estimates of net transfer are obtained, being TTF = (5.16 ± 0.40) × 10–11 (number) and 0.028 ± 0.0036 (mass).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The results suggest that risks from environmentally realistic microplastic concentrations may be low, but such concentrations may still affect aquatic community biodiversity and functioning because these depend on sensitive species.

    “These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    For the five species whose growth was unaffected up to 40% plastic in sediment dw, EC10 values exceed 40% plastic in sediment dw.

    “Hence, the EC10 values for these species are higher than 40% plastic in sediment dw.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Control blanks contained 0.10 retained and 0.6 egested particles per organism, and these values were subtracted from treatment replicates.

    “The numbers of particles found in controls for the retained and egested particles were subtracted from the numbers of particles found in each replica of each PS treatment, and were 0.10 and 0.6 particles per organism, respectively.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The observed constancy and magnitude of TTF may still change over time.

    “Therefore, the observed constancy and magnitude of TTF may still change over time.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Weight loss of the marine lugworm A. marina was reported at 7.4% PS microplastics and >5% uPVC microplastics in sediment dw.

    “while weight loss of the marine lugworm A. marina was reported at concentrations of 7.4% PS microplastics18 and >5% uPVC microplastics in sediment dw.17”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [18] Besseling, 2013, Effects of microplastic on fitness and PCB bioaccumulation by the lugworm Arenicola marina (L.), Environ. Sci. Technol. source
    • cites [17] Wright, 2013, Microplastic ingestion decreases energy reserves in marine worms, Curr. Biol. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Average measured exposure conditions were 16 ± 0.3 °C, pH 7.3 ± 0.5, oxygen 8.9 ± 0.2 mg/L, and conductivity 477 ± 45 μS/cm.

    “On average, the measured temperature was 16 ± 0.3 °C, pH was 7.3 ± 0.5, oxygen concentration was 8.9 ± 0.2 mg/L and conductivity was 477 ± 45 μS/cm.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Control survival exceeded 80% for all species except G. pulex, which averaged 66%.

    “Survival for the other species was higher than 80% in controls, except for G. pulex, for which the average survival was 66%.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    One concentration was identified as an outlier by Iglewics and Hoaglin's robust test and excluded from regression parameter determination.

    “One of the concentrations was designated as an outlier (Iglewics and Hoaglin’s robust test) which was not taken into account in the subsequent determination of the regression parameters.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The slope of the exposure-uptake relation can be interpreted as trophic transfer factors, with TTFnumber = (4.47 ± 0.35) × 10−11 and TTFmass = (10.5 ± 1.3) × 10−3.

    “Given the demonstrated proportionality between exposure and uptake, the slope of the line in Figure 3A and B can be interpreted as trophic transfer factors (TTF) with a value of (4.47 ± 0.35) × 10–11 (TTFnumber; Figure 3A) and (10.5 ± 1.3) × 10–3 (TTFmass; Figure 3B).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Survival of G. pulex and H. azteca was unaffected by PET and PE microplastics, respectively.

    “For instance, survival of the freshwater amphipods G. pulex and H. azteca were not affected by the exposure to PET and PE microplastics, respectively.11,14”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [11] Au, 2015, Responses of Hyalella azteca to acute and chronic microplastic exposures, Environ. Toxicol. Chem. source
    • cites [14] Weber, 2018, PET microplastics do not negatively affect the survival, development, metabolism and feeding activity of the freshwater invertebrate Gammarus pulex, Environ. Pollut. source

  • May combine two claims.

    Study design and conductown data

    Microplastics larger than 165 μm accounted for <0.01% of the total and were treated as external contamination and excluded from analysis.

    “Microplastics with a size >165 μm accounted for only <0.01% of the total amount (in number) and were considered to originate from an external source of microplastics (i.e., particles attached to the external body of the organisms), and were removed from the analysis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The low TTF values can be explained by only a limited part of the sediment size range being taken up, so TTFs reflect transfer and size selection.

    “These TTF values are low, which can be explained by the fact that only a limited part of the size range in the sediment is actually taken up, that is, the TTFs mechanistically reflect transfer and size selection.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Residual normality and variance homogeneity were tested using Shapiro-Wilk and Levene's tests, respectively.

    “Normality of the residuals and homogeneity of variances were tested with a Shapiro-Wilk Normality test and Levene’s test, respectively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Only G. pulex showed significant growth reduction, likely explained by size-selective PS uptake and slow excretion leading to energy reserve depletion.

    “Only for one of the species, G. pulex, a significant reduction in growth was found, which is likely to be explained by the demonstrated size-selective uptake of PS microplastics and their slow excretion, leading to a depletion of energy reserves as found earlier for marine worms as a result of microplastic ingestion.17”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [17] Wright, 2013, Microplastic ingestion decreases energy reserves in marine worms, Curr. Biol. source

  • May combine two claims.

    Interpretationreasoning

    Extrapolating these results to the environment implies small chances of such physical effects and consequently low current risk for the freshwater benthic community.

    “This means that extrapolating these results to the environment leads to small chances of such physical effects, and consequently low current risk for the benthic community of freshwater systems.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The range of PS particle sizes and shapes used is a fair approximation of environmental microplastics for physical effects.
    • Rests on an assumption: The test conditions are environmentally relevant.

  • May combine two claims.

    Premisecitation

    G. pulex plays a key role in processing coarse particulate organic matter in streams, is important prey for fish, and its feeding inhibition can alter the benthic macroinvertebrate community.

    “In fact, G. pulex plays a key role in the processing of coarse particulate organic matter in streams,48 is an important prey for fish,49 and its feeding inhibition has shown to alter the benthic macroinvertebrate community,36”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [48] Kelly, 2002, The functional role of Gammarus (Crustacea, Amphipoda): shredders, predators, or both?, Hydrobiologia source
    • cites [49] Macneil, 1997, The Thropic Ecology of Freshwater Gammarus spp. (Crustacea: Amphipoda): Problems and Perspectives Concerning the Functional Feeding Group Concept, Biol. Rev. Cambridge Philos. Soc. source
    • cites [36] Maltby, 2002, Evaluation of the Gammarus pulex in situ feeding assay as a biomonitor of water quality: Robustness, responsiveness, and relevance, Environ. Toxicol. Chem. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    Microplastic concentrations are expected to increase in the environment, implying that effects are not unthinkable in the future.

    “However, microplastic concentrations are expected to increase in the environment,47 which implies that effects are not unthinkable in the future.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [47] Rochman, 2013, Policy: Classify plastic waste as hazardous, Nature source

  • May combine two claims.

    Interpretationcitation

    Microplastic uptake is size-dependent, and particle shape might affect the ability of organisms to excrete them.

    “These findings indicate that microplastic uptake is size-dependent and that shape might affect the ability of organisms to excrete them.”
    Quote in the paperSubstantial claim
62 of 62

  • The paper relies on this without support.

    No earlier studies systematically assessed microplastic effect thresholds for a range of organisms.

    “We are not aware of earlier studies systematically assessing microplastic effect thresholds for a range of organisms.”

  • The paper relies on this without support.

    This is the first study to determine effect thresholds for six freshwater benthic macroinvertebrates across a wide range of microplastic concentrations.

    “This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations.”

  • The authors state this as an assumption.

    The unknown third dimension of the polystyrene particles is the smallest and can be approximated as half of the second dimension.

    “This unknown third dimension was assumed to be the smallest and was thus approximated as half of the second dimension.”

  • The authors state this as an assumption.

    The polystyrene particles prefer a flat position on the filter, so their length and width are directly measurable and larger than their depth.

    “First it was assumed that the particles would prefer a flat position on the filter, such that their length and width dimensions directly measurable from the 2D map top view, each are larger than the third (depth) dimension, which is not observable from the 2D maps.”

  • The authors state this as an assumption.

    For larger numbers of irregular particles, the distribution of the third (depth) dimension is symmetrical.

    “where the distribution of the third (depth) dimension can be assumed to be symmetrical.”

  • The authors state this as an assumption.

    The weight of faecal pellets represents the feeding rate of worms.

    “assuming that the weight of the faecal pellets represents the feeding rate of worms.38”

  • The paper relies on this without support.

    Growth inhibition of G. pulex by chronic PS microplastics exposure from sediment had not been reported before this study.

    “Growth inhibition of G. pulex by a chronic PS microplastics exposure from sediment has not been reported before.”

  • The paper relies on this without support.

    The range of PS particle sizes and shapes used is a fair approximation of environmental microplastics for physical effects.

    “our wide range of PS particle sizes and shapes can be considered as a fair approximation of environmental microplastics when it concerns their physical effects.”

  • The paper relies on this without support.

    The test conditions are environmentally relevant.

    “under the same environmentally relevant conditions”

  • The paper relies on this without support.

    The six species tested represent a range of freshwater species with different traits sufficient to generalise about benthic macroinvertebrates.

    “for a range of freshwater species with different traits exposed to PS microplastics in sediment under the same environmentally relevant conditions”
10 of 10

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Mintenig, S.; Bauerlein, P.; Koelmans, A. A.; Dekker, S.; van Wezel, A. Closing the Gap between Small and Smaller: Towards an Analytical Protocol for the Detection of Micro- And Nanoplastic in Freshwater Systems., MICRO 2016 Conference; Lanzarote, Spain, May 25–27, 2016.

Cited by

Sorted by citations

Related

Authors
Redondo-Hasselerharm, P. E., Falahudin, D., Peeters, E. T. H. M., & Koelmans, A. A.
Affiliations
  • Wageningen University & Research , , P.O. Box 47 , ,
  • Wageningen University & Research (NL)
  • Wageningen Marine Research (NL)
ORCID
Venue
Environmental Science & Technology
Publisher
American Chemical Society (ACS)
Published
2018-01-16
Volume
52
Issue
4
Pages
2278-2286
ISSN
  • 0013-936X (ISSN-L)
  • 1520-5851
DOI
10.1021/acs.est.7b05367
PMC
PMC5822217
OpenAlex
W2783751248
Cited by
355
References
48
Citations by year
2026: 25 · 2025: 42 · 2024: 37 · 2023: 45 · 2022: 64 · 2021: 51 · 2020: 47 · 2019: 29 · 2018: 15
FWCI
12.30
Type
journal article
Language
en
Open access
Licence
Locations
  • Environmental Science & Technology (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • Socio-Environmental Systems Modeling (acceptedVersion, cc-by-nc-nd)
  • Europe PMC (PubMed Central) (submittedVersion)
  • PubMed Central (submittedVersion)
  • Data Archiving and Networked Services (DANS) (submittedVersion, cc-by-nc-nd)
Funders
  • Wageningen University and Research Centre (NA)
  • Ministerie van Volksgezondheid, Welzijn en Sport (NA)
  • Stichting voor de Technische Wetenschappen (13940)
  • Ministerie van Infrastructuur en Milieu (NA)
  • KWR Water Cycle Research Institute (NA)
  • Nederlandse Voedsel- en Warenautoritet, Ministerie Landbouw, Natuur en Voedselkwaliteit (NA)
  • RIWA-Meuse (NA)
  • Stichting Toegepast Onderzoek Waterbeheer (NA)
  • Waterschappen en Hoogheemraadschappen (NA)
Topics
  • Physical Sciences › Environmental Science › Pollution › Microplastics and Plastic Pollution
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Environmental Toxicology and Ecotoxicology
  • Physical Sciences › Environmental Science › Pollution › Pharmaceutical and Antibiotic Environmental Impacts
Keywords
microplastics, freshwater benthic macroinvertebrates, effect thresholds, polystyrene microplastics, sediment contamination, Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, Tubifex, Lumbriculus variegatus, microplastic ingestion, growth inhibition, survival, reproduction, ecotoxicology
MeSH terms
Animals, Fresh Water, Plastics, Water Pollutants, Chemical, Amphipoda, Rivers

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

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