Variability in Toxicity of Plastic Leachates as a Function of Weathering and Polymer Type: A Screening Study with the Copepod <i>Nitocra spinipes</i>

Gewert, Berit; MacLeod, Matthew; Breitholtz, Magnus

doi:10.1086/714506

Cited by 29 publications

(21 citation statements)

References 47 publications

(63 reference statements)

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“…Although data are scarce and our knowledge is based exclusively on pure polymers, the impacts of photochemical weathering appear to be mixed. A couple of studies reported that exposure of plastic to sunlight increased toxicity, 68,69 one reported no major impact, 70 and another reported decreased toxicity. 71 Our collective findings indicate that a comprehensive and accurate understanding of the fate and impacts of marine plastic pollutiona critical step toward establishing evidence-based policies and developing next-generation materialsrequires the research community to embrace the diverse formulations and sunlight-driven transformations of plastics in the environment.…”

Section: Characterization Of Plastic Opticalmentioning

confidence: 99%

Plastic Formulation is an Emerging Control of Its Photochemical Fate in the Ocean

Walsh

Reddy

Niles

et al. 2021

Environ. Sci. Technol.

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Sunlight exposure is a control of long-term plastic fate in the environment that converts plastic into oxygenated products spanning the polymer, dissolved, and gas phases. However, our understanding of how plastic formulation influences the amount and composition of these photoproducts remains incomplete. Here, we characterized the initial formulations and resulting dissolved photoproducts of four single-use consumer polyethylene (PE) bags from major retailers and one pure PE film. Consumer PE bags contained 15–36% inorganic additives, primarily calcium carbonate (13–34%) and titanium dioxide (TiO2; 1–2%). Sunlight exposure consistently increased production of dissolved organic carbon (DOC) relative to leaching in the dark (3- to 80-fold). All consumer PE bags produced more DOC during sunlight exposure than the pure PE (1.2- to 2.0-fold). The DOC leached after sunlight exposure increasingly reflected the 13C and 14C isotopic composition of the plastic. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry revealed that sunlight exposure substantially increased the number of DOC formulas detected (1.1- to 50-fold). TiO2-containing bags photochemically degraded into the most compositionally similar DOC, with 68–94% of photoproduced formulas in common with at least one other TiO2-containing bag. Conversely, only 28% of photoproduced formulas from the pure PE were detected in photoproduced DOC from the consumer PE. Overall, these findings suggest that plastic formulation, especially TiO2, plays a determining role in the amount and composition of DOC generated by sunlight. Consequently, studies on pure, unweathered polymers may not accurately represent the fates and impacts of the plastics entering the ocean.

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Section: Characterization Of Plastic Opticalmentioning

confidence: 99%

Plastic Formulation is an Emerging Control of Its Photochemical Fate in the Ocean

Walsh

Reddy

Niles

et al. 2021

Environ. Sci. Technol.

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“…Moreover, decreased swimming activities were observed in the positive control with NaCl, whereas the chemicals leaching from the tested microplastics (SB foil and LDPE-R) did not result in adverse effects. In general, the exposure of the shrimps to the leachates from (un)weathered LDPE-R and SB microplastics resulted in varied swimming activities, which is in accordance with the results by Qiu et al (2022) but in contrast to what has been reported by Gewert et al (2021). Finally, performed a metaanalysis on locomotor behaviors for aquatic organisms that were exposed to plastic particles and their chemicals.…”

Section: Uv-induced Changes Of the Leachate Toxicitysupporting

confidence: 86%

Ecotoxicological assessment of microplastics in limnic systems with emphasis on chemicals released by weathering

Klein¹

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Plastic pollution is a pervasive problem. In the environment, both the physical and chemical aspects of the material contribute to pollution. For instance, discarded plastic is useless waste that is fragmented upon degradation and so-called microplastics <5 mm are formed. Besides, the chemicals added into plastics are usually customized for specific functions, but these can easily transfer from the polymer into an ambient medium. This work examined both of these aspects. Moreover, the question of whether ecotoxicological effects are more likely to appear because of the microparticle properties or the chemicals transferring from the microplastics was addressed. A special focus was laid on the UV-weathering-induced chemical release. First, conventional and biodegradable plastics made from fossil and bio-based resources were chosen. The different materials (pre-production and recycled pellets as well as final products)were weathered and their leachates evaluated in vitro. The leachates were analyzed with nontarget screening in order to measure the number of transferred chemicals. Plastics identified as toxic were subjected to further investigations in vivo. A biodegradable shampoo bottle was processed to microplastics and the particles’ physical and chemical properties were assessed with the freshwater worm Lumbriculus variegatus. Here, commonly used endpoints such as mortality, reproduction and weight were tested via different exposure routes. Moreover, the freshwater shrimp Neocaridina palmata was exposed to microplastic beads and fragments to clarify if the shape of the particles affects the ingestion and egestion, respectively. Thereafter, two materials that displayed the strongest toxic responses in vitro within the first study were weathered and leached. Finally, the shrimps were exposed to the leachates and the locomotor behavior was used as an ecologically relevant but less frequently studied endpoint. The results of the studies highlight that plastics are chemically complex mixtures, containing a wide range of chemicals in terms of the number and functionality. These chemicals induced oxidative stress, baseline toxicity and endocrine activities. This shows that pellets represent a processing state that comprises chemically heterogenous materials. Moreover, it was shown that a degradation initiator is not necessarily relevant to trigger inherent substances to leach out from plastics. Despite this, the UV-weathering resulted in increasingly released chemicals and exacerbated the in vitro toxicities. Even plastics assessed as toxicologically harmless prior to weathering released toxic chemical mixtures once they were weathered. One recycled and all of the biodegradable plastics were toxicologically most concerning. This means that such materials are currently not better than conventional, virgin plastics in terms of their toxicity. To clarify the source of the microplastic toxicity, L. variegatus was exposed to biodegradable microplastics. The particles were ingested by the worms and adversely affected the examined endpoints. In comparison, microplastics that were depleted from their chemicals via a solvent treatment were less toxic. Kaolin as a natural particle control was evaluated alongside and positively affected the weight of the worms. This emphasizes the ecological relevance of fine-sized matter for the test species. The chemicals extracted from the microplastics induced a 100% mortality. A chemical analysis of the material revealed two ecotoxicologically relevant biocides. The physically-mediated effects of the microplastics seemed to be less of a concern for the worms, which is probably linked to their adaptation to high concentrations of naturally occurring particles in the environment. However, the effects related to the chemicals of plastic cannot be ignored, especially for materials that are claimed to be environmentally friendly. In the third study, the role of the particle shape in the gut passaging of N. palmata was studied. While the particle size was a determinant factor for the ingestion, the ingestion and egestion of the beads and fragments did not differ, respectively. The shrimps ingested less fragments when food was provided than in the absence of food. As for the worms, the shrimps are known to ingest many naturally occurring particles. Their unselective feeding behavior towards the particle shape could indicate that microplastics as a physical pollutant are negligible for the shrimps. That is why the chemicals of the two most toxic in vitro materials were tested with N. palmata. However, no trend towards elevated or reduced movements of the shrimps was observed, even though the leachates contained baseline toxicants. This shows that the in vitro toxicities of plastics are not necessarily indicative for effects to occur at the in vivo level...

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“…8,10 This leaching into the environment is concerning as many functional organic plastic additives have been associated with health effects such as different cancers, endocrine disruption, adverse effects to reproduction and development, as well as general toxicity in a variety of organisms. 1,2,12,13 Given their potential toxicity and detection in the environment, some plastic additives have been identied as potential contaminants of concern or even as persistent organic pollutants (POPs). 13 Nevertheless, many hazardous plastic additives are not restricted.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Persistent, mobile, and toxic plastic additives in Canada: properties and prioritization

Fries

Grewal

Suehring

2022

Environ. Sci.: Processes Impacts

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Variability in Toxicity of Plastic Leachates as a Function of Weathering and Polymer Type: A Screening Study with the Copepod Nitocra spinipes

Cited by 29 publications

References 47 publications

Plastic Formulation is an Emerging Control of Its Photochemical Fate in the Ocean

Plastic Formulation is an Emerging Control of Its Photochemical Fate in the Ocean

Ecotoxicological assessment of microplastics in limnic systems with emphasis on chemicals released by weathering

Persistent, mobile, and toxic plastic additives in Canada: properties and prioritization

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