Degradation of bio-based and biodegradable plastics in a salt marsh habitat: Another potential source of microplastics in coastal waters

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

Biodegradable plastics can be made from biomass-based or oil-based polymers and are engineered to decompose faster than conventional plastics mainly through microbial enzymatic action.

“Another type of eco-friendly plastic are the biodegradable plastics, which can be composed of either biomass-based or oil-based polymers, and are engineered to decompose more quickly than conventional plastics primarily through the enzymatic action of microorganisms (Song et al., 2009).”

• cites Song et al., 2009 sourceSupported

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

In a study exposing several carrier bag types to open-air, soil, and seawater for up to 3 years, none could be relied upon to deteriorate substantially more than conventional HDPE bags in all three environments; however, a compostable bag disappeared in seawater after 3 months.

“They found that none of the bags could be relied upon to substantially deteriorate more than conventional HDPE plastic bags in all three environments; however, it is of interest that the compostable bag completely disappeared in seawater after only 3 months (Napper and Thompson, 2019).”

• cites Napper and Thompson, 2019 sourceSupported

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

Ingested microplastic particles can increase gut residency time among invertebrates, causing fatal injuries from gut blockage and becoming caught in respiratory structures.

“Ingested microplastic particles can increase gut residency time among invertebrates, producing fatal injuries associated with gut blockage, as well as getting caught in respiratory structures (Watts et al., 2014; Gray and Weinstein, 2017; Leads et al., 2019).”

• cites Watts et al., 2014 sourceNot checked — no full text of the source
• cites Gray and Weinstein, 2017 sourcePartly supported

  The Introduction reports longer gut residence times in lugworms, and the Acute toxicity results report shrimp deaths with particles present in the gut, gills, or both. The Discussion describes fatal gut blockage as a possible mechanism, not a demonstrated cause of those deaths. The paper also documents particles in gills, supporting the respiratory-structure part of the claim. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites Leads et al., 2019 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

In coastal waters, degradation of plastic litter is believed to be a major source of microplastics.

“In coastal waters, the degradation of plastic litter is believed to be a major source of microplastics (Gray et al., 2018), and their presence has received much attention due to their potential to adversely impact a variety of organisms (reviewed by Avio et al., 2017).”

• cites Gray et al., 2018 sourcePartly supported

  The Introduction (page unavailable) says microplastics can result from the degradation of large plastic debris. The Discussion (page unavailable) suggests that fragmentation of macroplastic litter produced microplastics found in Charleston Harbor. It does not establish that degradation is a major source across coastal waters generally. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

Tosin et al. (2012) found that Mater-Bi® degraded 68.9% after 236 days in laboratory seawater, but achieved total degradation within 9 months when buried in wet sand in aquaria.

“Tosin et al. (2012) found that Mater-Bi® degraded 68.9% following 236 days when exposed to seawater in the laboratory, but when buried in wet sand in aquaria, total degradation was achieved within 9 months.”

• cites Tosin et al. (2012) sourcePartly supported

  Test Method C reports 68.9% biodegradation after 236 days, but the material was at a sediment–seawater interface, not exposed to seawater alone. The Abstract reports total disintegration in less than nine months when Mater-Bi was buried in wet sand; the Discussion clarifies that this was visual disintegration, not a demonstration of complete biodegradation. The indexed passages provide section labels but no page numbers. (LLM, conf=0.91)

  Experimental — accuracy not yet measured

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

PLA has previously degraded slowly in home compost, with negligible degradation after 180 days and less than 5% mass loss.

“The relatively slow degradation of PLA has previously been observed in both home compost, where negligible degradation was observed after 180 days (<5% mass loss) (Song et al., 2009)”

• cites Song et al., 2009 sourceSupported

May combine two claims.

Ioakeimidis et al. (2016) found that PET remains structurally intact in the submarine environment for about fifteen years, with decreases in native functional groups occurring afterward.

“For example, Ioakeimidis et al. (2016) found PET remains structurally intact in the submarine environment for approximately fifteen years with decreases in native functional groups occurring thereafter.”

• cites Ioakeimidis et al. (2016) sourceSupported

May combine two claims.

Marsh periwinkles grazed on strips of all plastic types, and this continued throughout the study.

“Following one week of deployment, biofilm was observed covering the upper side of all strips, and marsh periwinkles (Littoraria irrorata) were observed grazing on strips of all plastic types.”

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

Periwinkle trails were observed on 41.7% of collected strips, ranging from 0 to 100% depending on plastic type and collection time.

“Periwinkle trails were observed on 41.7% of the collected strips throughout the study, although this ranged from 0 to 100% depending on the plastic type and collection time (Fig. 2 ).”

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

Biofilm was observed covering the upper side of all plastic strips after one week of deployment.

“Following one week of deployment, biofilm was observed covering the upper side of all strips, and marsh periwinkles (Littoraria irrorata) were observed grazing on strips of all plastic types.”

May combine two claims.

The peak area increased by about 1500% for bioPS and by only about 200% for PS.

“Of note, a ~ 1500% increase in peak area was observed for bioPS, while this peak increased by only ~200% for PS.”

May combine two claims.

HDPE strips increasingly shriveled and became more brittle over time, and by 32 weeks most had visibly fragmented.

“Similar to the MB strips, the HDPE strips increasingly shriveled over time becoming more brittle, and by 32 weeks, most had visibly fragmented.”

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

A large C-O peak at 1037 cm−1 emerged in the MB spectra.

“Additionally, similar to other samples, a large C—O peak (1037 cm−1) emerged in the spectra.”

May combine two claims.

The decreases in weight between 16 and 32 weeks were 69.7% for HDPE and 41.1% for bioHDPE.

“The decreases in weight between these two exposure periods were 69.7% and 41.1% for HDPE and bioHDPE, respectively.”

May combine two claims.

HDPE surface area decreased 34.1% at 16 weeks and 66.5% at 32 weeks.

“For HDPE, surface area decreased 34.1% and 66.5% at 16 and 32 weeks, respectively.”

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

Control bioPS strips had a sponge-like surface with numerous cavities and pores.

“The only exception was the control bioPS strips which exhibited a sponge-like surface with numerous cavities and pores (Fig. 7D).”

May combine two claims.

The 32-week rPET strips showed extensive pitting and surface delamination, but no microcracks or large holes.

“The surface of the 32-week rPET strips exhibited areas where extensive pitting and surface delamination were evident; however, unlike the HDPE and PS strips, there were no microcracks or large holes on the surface”

May combine two claims.

Microplastic particle production from field-collected strips in the laboratory fragmentation test was first evident following 4 weeks of exposure for all plastic types and increased throughout the experiment.

“The production of microplastic particles from field-collected strips in the laboratory fragmentation test was first evident following 4 weeks of exposure for all plastic types and increased throughout the experiment (Fig. 4C).”

May combine two claims.

MB bag strips began disintegrating by 16 weeks, and none remained attached to the apparatus at 32 weeks.

“which began disintegrating by 16 weeks and none remained attached to the experimental apparatus at 32 weeks.”

May combine two claims.

MB bags were more than 60% thicker than other single-use bags but had similar UV transmittance.

“Relative to the other single use bags, the MB bags were >60% thicker, but had similar levels of UV transmittance.”

May combine two claims.

A repeated measures ANOVA for surface area was significant for exposure time (p < 0.0001) but not for plastic type (p = 0.44).

“A repeated measures ANOVA comparing surface area produced a significant model for exposure time (p < 0.0001) but not for plastic type (p = 0.44).”

The quote only partly states this claim.

In MB samples, strong C-H peaks present initially decreased in intensity by 16 weeks.

“While strong C—H peaks (2913, 2845, 1460 cm−1) were present initially in the control sample, the intensity of these peaks decreased by 16 weeks.”

May combine two claims.

Relative to controls, MB strips decreased 52.6% at 8 weeks and 56.3% at 16 weeks.

“Relative to control strips, MB strips at 8 and 16 weeks had decreased 52.6% and 56.3%.”

May combine two claims.

PS and bioPS showed the expected aromatic infrared peaks at about 3000 and 1450 cm−1, which remained mostly unchanged except for a slight intensity decrease over 32 weeks.

“For PS and bioPS samples, the expected IR peaks for aromatic groups (~3000 and 1450 cm−1) were observed and remained mostly unchanged, except for a slight decrease in intensity throughout the 32-week exposure period.”

May combine two claims.

The 32-week PLA and 16-week MB strips showed limited minor degradation, with no evidence of microcracks, pitting, or surface delamination.

“The surface of the 32-week PLA and the 16-week MB strips exhibited limited areas of minor degradation, and there was no evidence of microcracks, pitting, or surface delamination”

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

Control strips of the plastics generally had largely featureless and smooth surfaces.

“SEM examination of the surface of the control strips revealed that, in general, the plastics chosen for this study had a largely featureless and smooth surface (Fig. 7A–G).”

May combine two claims.

The rPET sample showed no new infrared peaks after environmental exposure, but its transmittance decreased across all peaks, which indicates degradation.

“For the rPET sample, no new peaks appeared in the IR spectra over the course of environmental exposure, but transmittance across all peaks decreased, indicating degradation.”

May combine two claims.

PLA cup strips showed the least degradation in this study, with only limited surface degradation and almost no FT-IR spectral changes after 32 weeks.

“The least amount of degradation in this study was exhibited by the strips from the PLA cups, which following 32 weeks of exposure, only exhibited limited surface degradation and almost no changes to spectra produced by FT-IR.”

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

These oxidative reactions decrease polymer molecular weight and increase oxygen-rich functional groups.

“Collectively, these reactions result in a decrease in the molecular weight of the polymers and an increase in the presence of oxygen-rich functional groups.”

• cites Andrady, 2011 sourceNot checked — no full text of the source

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

Polyethylene films and thermoplastic materials degraded more slowly when submerged in seawater than in air, probably because of lower sunlight, temperature, and oxygen.

“For example, polyethylene films and thermoplastic materials were found to degrade at slower rates while submerged in seawater compared to those in the air, probably as a result of lower sunlight exposure, lower temperatures, and lower oxygen levels (Pegram and Andrady, 1989; Andrady et al., 1993).”

• cites Pegram and Andrady, 1989 sourceNot checked — no full text of the source
• cites Andrady et al., 1993 sourceNot checked — no full text of the source

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

Most eco-friendly plastics have physical and chemical properties that either enhance biodegradation or, for PLA, facilitate degradation under commercial composting conditions.

“By contrast, most eco-friendly plastics have physical and chemical properties to either enhance biodegradation or, as in the case of PLA, facilitate degradation under commercial composting conditions.”

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

Hydrolysis and biodegradation occur several orders of magnitude slower than oxidative mechanisms for oil-based plastics.

“Other degradative mechanisms for oil-based plastics, such as hydrolysis and biodegradation, occur at rates several orders of magnitude slower than oxidative mechanisms (Andrady, 2011).”

• cites Andrady, 2011 sourceNot checked — no full text of the source

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

For most oil-based plastics, degradation results from oxidative reactions initiated by UV photooxidation and followed by temperature-dependent thermooxidative reactions.

“For most oil-based plastics, degradation is the result of oxidative reactions, beginning with photooxidation from UV radiation exposure followed by temperature-dependent thermooxidative reactions (Andrady, 2011).”

• cites Andrady, 2011 sourceNot checked — no full text of the source

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

Surface biofouling may reduce plastic degradation rate by reducing UV reaching the plastic surface and may increase density, causing the object to sink.

“Surface biofouling, such as that associated with biofilm, may reduce the rate of plastic degradation by reducing the amount of UV radiation reaching the surface of the plastic, while simultaneously increasing the density of the object causing it to sink (Kershaw et al., 2011).”

• cites Kershaw et al., 2011Not matched

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

May combine two claims.

Only a limited number of studies have examined degradation of bio-based and biodegradable plastics, and their results have been mixed.

“Although it is generally assumed that bio-based and biodegradable plastics will degrade faster than oil-based plastics, only a limited number of studies have been conducted, and their results have been mixed.”

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

A compostable bag had 100% surface area loss after 24 weeks of exposure in seawater.

“These results corroborate those of O'Brine and Thompson (2010), who found that a compostable bag had 100% surface area loss following 24 weeks of exposure in seawater.”

• cites O'Brine and Thompson, 2010 sourceNot checked — no full text of the source

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

Mechanical forces such as turbulence and abrasion could increase the susceptibility of plastics to fragmentation.

“Mechanical forces, such as those associated with turbulence and abrasion could increase the susceptibility of plastics to fragmentation (Pegram and Andrady, 1989; Browne et al., 2010).”

• cites Pegram and Andrady, 1989 sourceNot checked — no full text of the source
• cites Browne et al., 2010 sourceNot checked — no full text of the source

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

Degradation of all plastics results from chemical changes that reduce molecular weight and weaken structural integrity.

“Degradation for all types of plastics, whether considered eco-friendly or not, is ultimately the result of chemical changes in the structure of the material reducing its molecular weight, invariably weakening its structural integrity (reviewed by Singh and Sharma, 2008).”

• cites Singh and Sharma, 2008 sourceNot checked — no full text of the source

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

The rate at which any plastic degrades depends largely on environmental conditions such as UV radiation, oxygen, and temperature.

“Because plastic degradation is dependent upon factors such as UV radiation, oxygen, and temperature, the rate at which any plastic degrades will largely be dependent upon environmental conditions.”

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

Microplastic ingestion could reduce energetics, adversely affecting growth and fitness.

“In addition, microplastic ingestion could lead to reduced energetics, adversely impacting both growth and fitness (reviewed by Auta et al., 2017).”

• cites Auta et al., 2017 sourceNot checked — no full text of the source

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

Salt marshes and their tidal creeks serve as the hydrographic link between upland watershed activities and the adjacent estuary.

“Salt marshes and their associated tidal creeks serve as the hydrographic link between anthropogenic activities in the upland portion of the watershed and the adjacent estuary (Holland et al., 2004), and as such, higher levels of plastic debris have been associated with salt marshes occurring near population centers (Viehman et al., 2011).”

• cites Holland et al., 2004 sourceNot checked — no full text of the source

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

Adding grapefruit seed extract to a composite plastic film increased its moisture content from 16.43% to 35.75%.

“For example, the addition of grapefruit seed extract into a composite plastic film increased the moisture content from 16.43 to 35.75% (Kanmani and Rhim, 2014).”

• cites Kanmani and Rhim, 2014 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Increased consumer demand for bio-based and biodegradable plastics is predicated in part on the assumption that they pose less environmental threat because of faster degradation.

“Increased consumer demand for bio-based and biodegradable plastics is predicated, in part, upon the assumption that they pose less of a threat to the environment because of their faster degradation rates.”

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

Embrittlement from random chain scission in linear polymers, causing a ductile-to-brittle transition, has been described previously for polyethylene films at temperatures up to 90 °C.

“Degradation-induced embrittlement as a result of linear polymers undergoing random chain scission resulting in a transition of the material from a ductile to a brittle state has been previously described for polyethylene films at temperatures up to 90 °C (Fayolle et al., 2007).”

• cites Fayolle et al., 2007 sourceNot checked — no full text of the source

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

The authors of that study attributed the moisture increase to the extract's hydrophilic character, which may have increased hydroxyl group availability for binding water.

“The authors attribute the increase in moisture content to the hydrophilic character of the extract which may have increased the availability of hydroxyl groups within the plastic polymer to bind to water molecules.”

• cites Kanmani and Rhim, 2014 sourceNot checked — no full text of the source

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

Embrittlement of extensively eroded plastics, especially polyethylene, has been documented on beaches in Kauai, Hawaii.

“Embrittlement of extensively eroded plastics, especially those made from polyethylene, has been documented on the beaches in Kauai (Hawaii) (Cooper and Corcoran, 2010).”

• cites Cooper and Corcoran, 2010 sourceNot checked — no full text of the source

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

MB bags were made from Mater-Bi®, a bio-based plastic manufactured entirely from renewable agricultural raw materials and non-genetically modified starch.

“MB bags were produced from a bio-based plastic called Mater-Bi®, which is manufactured completely from renewable raw materials of agricultural origin and from non-genetically modified starch (Novamont, 2019).”

• cites Novamont, 2019Not matched

  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).

Higher levels of plastic debris have been associated with salt marshes near population centers.

“Salt marshes and their associated tidal creeks serve as the hydrographic link between anthropogenic activities in the upland portion of the watershed and the adjacent estuary (Holland et al., 2004), and as such, higher levels of plastic debris have been associated with salt marshes occurring near population centers (Viehman et al., 2011).”

• cites Viehman et al., 2011 sourceNot checked — no full text of the source

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

Previous studies have shown that adding plant material to synthetic plastics during manufacturing can dramatically change the physical properties of the plastic.

“Previous studies have shown that the addition of plant material to synthetic plastics during the manufacturing process can dramatically alter the physical properties of a plastic (reviewed by Mir et al., 2018).”

• cites Mir et al., 2018 sourceNot checked — no full text of the source

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

In subtidal conditions in the Clyde Sea, rope made from polyethylene, polypropylene, and nylon lost weight averaging between 0.39% and 1.02% per month, presumably as microplastics.

“In subtidal conditions (10 m depth) in the Clyde Sea (Scotland), rope made from polyethylene, polypropylene, and nylon exhibited a reduction of weight averaging between 0.39% and 1.02% per month, presumably due to the loss of material in the form of microplastics (Welden and Cowie, 2017).”

• cites Welden and Cowie, 2017 sourceNot checked — no full text of the source

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

Andrady (2011) suggested that embrittlement is a common pathway by which extensively degraded plastics release microplastic particles.

“Andrady (2011) has also suggested that embrittlement is a common pathway by which extensively degraded plastics emit microplastic particles.”

• cites Andrady (2011) sourceNot checked — no full text of the source

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

At 32 weeks, the number of available strips was HDPE n = 6, PS n = 4, rPET n = 7, bioPS n = 6, bioHDPE n = 6, PLA n = 7, and MB n = 0.

“The number of strips available for each plastic type at 32 weeks was as follows: HDPE n = 6, PS n = 4, rPET n = 7, bioPS n = 6, bioHDPE n = 6, PLA n = 7, MB n = 0.”

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

Measures were taken to reduce microplastic contamination during the laboratory fragmentation test, including stainless steel sieves, glass jars, white cotton laboratory coats, and nitrile gloves.

“A number of measures were taken to reduce microplastic contamination for the laboratory fragmentation test. For example, stainless steel sieves and glass jars were used throughout the procedure. In addition, white cotton laboratory coats and nitrile gloves were worn in the laboratory when processing samples.”

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

In Charleston Harbor, SC, an estimated 6.9 metric tonnes of plastic debris were present in surrounding salt marshes.

“In Charleston Harbor, SC (USA), Wertz (2015) estimated that there were 6.9 metric tonnes of plastic debris in the salt marshes surrounding the harbor.”

• cites Wertz, 2015Not checked — no full text of the source

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

Procedural blanks (n = 16) contained an average of 2.1 ± 2.4 microplastic particles per blank, and reported data were not blank-corrected.

“Laboratory procedural blanks (n = 16) contained an average of 2.1 ± 2.4 microplastic particles/blank. Reported data were not blank-corrected.”

May combine two claims.

Müller et al. (2012) found negligible degradation of Mater-Bi® bags in seawater after 49 days and only 50% degradation after 389 days.

“For example, Müller et al. (2012) found negligible degradation (4.5% mass loss) of Mater-Bi® bags in seawater following 49 days, and only 50% degradation following 389 days.”

• cites Müller et al. (2012) sourceNot checked — no full text of the source

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

Percent UV/visible transmission data were arcsine square root transformed, surface area was log10 transformed, and weight and particle abundance were log10 (x + 1) transformed to meet assumptions of normality and homogeneity of variance.

“Percent UV/Visible light transmission data were arcsine square root transformed, surface area was log10 transformed, and weight and particle abundance were log10 (x + 1) transformed to meet the assumptions of normality and homogeneity of variance.”

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

Although plastic debris occurs in all estuarine habitats, the highest abundances are found in tidal wrack in salt marshes.

“Although plastic debris can be found in all habitats associated with estuaries, the highest abundances can be found in areas associated with natural debris in salt marshes known as tidal wrack (Viehman et al., 2011).”

• cites Viehman et al., 2011 sourceNot checked — no full text of the source

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

Salt marshes are physically dynamic intertidal habitats with cyclical fluctuations in dissolved oxygen, UV radiation, temperature, and salinity largely driven by diurnal tides with a 1.5-3.0 m range.

“Salt marshes are physically dynamic intertidal habitats, characterized by cyclical fluctuations in dissolved oxygen, UV radiation, temperature, and salinity largely driven by diurnal tides having a 1.5–3.0 m range (Wenner et al., 1998).”

• cites Wenner et al., 1998Not matched

  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.

Of 203 plastic strips initially deployed, 183 were successfully collected, with 20 strips lost.

“Of the 203 plastic strips initially deployed, 183 were successfully collected. The loss of 20 strips resulted in a reduction in the number of strips available for collection at 32 weeks.”

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

Torres et al. (2000) found recycled PET was more brittle than virgin PET and attributed this to contaminants and residual moisture from the recycling melt process.

“Likewise, Torres et al. (2000) found that recycled PET was more brittle than virgin PET and attributed it to the presence of contaminants and residual moisture associated with the recycling melt process.”

• cites Torres et al. (2000) sourceNot checked — no full text of the source

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

Wertz (2015) estimated that intertidal areas of Charleston Harbor contained nearly 22,000 single-use grocery bags weighing close to 1.1 metric tonnes, representing 15.7% of total plastic debris.

“In the intertidal areas of Charleston Harbor, Wertz (2015) estimated that there were nearly 22,000 single use grocery bags weighing close to 1.1 metric tonnes, representing 15.7% of the total plastic debris.”

• cites Wertz (2015)Not checked — no full text of the source

May combine two claims.

The algal additive in the bioHDPE bags may have increased the plastic's moisture content, preventing shrinkage without necessarily enhancing degradability over the 32-week study.

“the evidence provided here suggests that this additive may have increased the moisture content of the plastic thereby preventing shrinkage, while concurrently not necessarily imparting any enhanced degradability to the material over the course of this 32-week study.”

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

The darker wheat color of bioPS strips compared with white PS strips may have contributed to higher degradation by producing higher surface temperatures.

“Also contributing to the higher rate of degradation of the bioPS strips in this study was their darker color (wheat) relative to that of the PS strips (white), which may have produced higher temperatures at their surface.”

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

A challenge in making PS more eco-friendly is that virgin PS responds poorly to UV-mediated degradation because of phenyl rings in its repeating units.

“The challenge in making PS eco-friendlier has been the decreased responsiveness that virgin PS has to degradation mediated by UV radiation due to the presence of phenyl rings in its repeating units (Bandyopadhyay and Basak, 2007).”

• cites Bandyopadhyay and Basak, 2007 sourceNot checked — no full text of the source

May combine two claims.

Biber et al. (2019) found that polyethylene, PET, PS, and Biothene® deteriorated faster in direct sunlight than in shade, and in air than in water.

“The role of photo-oxidation in the degradation of plastics has been previously noted in a study by Biber et al. (2019), who found that the deterioration of polyethylene, PET, PS, and Biothene® was faster in direct sunlight compared to shade, and in air compared to water.”

• cites Biber et al. (2019) sourceNot checked — no full text of the source

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

The study did not confirm that the microplastic particles generated in the fragmentation test matched the plastic composition of the strips.

“It should also be noted that although we did not confirm that the microplastic particles generated in the fragmentation test matched the plastic composition of the strips in this study”

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

Plastic bags make up a large proportion of plastic debris in coastal regions.

“Plastic bags account for a large proportion of plastic debris in coastal regions.”

• cites Ocean Conservancy, 2019Not matched

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

• cites Wertz (2015)Not checked — no full text of the source

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

In soil burial tests, no PLA degradation was observed after 6 weeks.

“and in soil burial tests, where no degradation was observed after 6 weeks (Ohkita and Lee, 2006).”

• cites Ohkita and Lee, 2006 sourceNot checked — no full text of the source

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

Laboratory studies showed that adding ZnO to PS under UV radiation caused 16% net weight loss in only 2 hours, and adding Eosin Y further increased weight loss by 18%.

“For example, laboratory studies have demonstrated that the addition of ZnO to PS under UV radiation exposure resulted in a net weight loss of 16% in only 2 h, and with the addition of the photoreactive dye, Eosin Y, further increased weight loss by 18% (Bandyopadhyay and Basak, 2007).”

• cites Bandyopadhyay and Basak, 2007 sourceNot checked — no full text of the source

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

According to the manufacturer, bioPS plates are made using green2technologyTM, produced with CO2 rather than pentane, and contain an active organic catalyst added to accelerate degradation.

“According to the manufacturer for the bioPS plates, these single use plates are manufactured using green2technology™ to ensure maximum recycled content, are produced with CO2 rather than pentane, and have an active organic catalyst added to the polymer during manufacturing to accelerate the degradation rate (D&W Fine Pack, 2016).”

• cites D&W Fine Pack, 2016Not matched

  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).

Evidence from the literature suggests that recycled PET may degrade faster than virgin PET.

“evidence from the literature suggests that recycled PET may degrade faster than virgin PET.”

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

Increased moisture content of plastic films has also been observed after adding betel leaf extract.

“Increased moisture content of plastic films has also been noted following the addition of betel leaf extract (Nouri and Nafchi, 2014).”

• cites Nouri and Nafchi, 2014 sourceNot checked — no full text of the source

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

PLA can degrade relatively quickly in an industrial composter, where it is hydrolyzed into smaller molecules after 45-60 days at 50-60 °C.

“However, PLA can be degraded relatively quickly in an industrial composter where it is hydrolyzed into smaller molecules after 45–60 days at 50–60 °C (Tokiwa and Calabia, 2006).”

• cites Tokiwa and Calabia, 2006 sourceNot checked — no full text of the source

May combine two claims.

The first few weeks of exposure had the least biofilm and therefore the greatest UV transmittance, which would have facilitated photo-oxidation reactions.

“These first few weeks of exposure were marked by the least amount of biofilm, and consequently, the greatest amount of UV transmittance, which would have facilitated photo-oxidation reactions.”

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

The relative weight increase of bioPS strips may have resulted from increased water content associated with the added organic catalyst, as occurs with plant-derived additives.

“The relative weight increase of the bioPS strips may have been the result of an increased water content associated with the addition of this organic catalyst, as happens with additives derived from plants (as described above).”

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

Adding compounds that act as photo-catalysts by transferring absorbed UV energy to different bonds in the PS polymer matrix has been found effective in enhancing degradation.

“The addition of compounds that act as photo-catalysts by transferring absorbed energy from UV radiation to different bonds in the PS polymer matrix have been found to be effective in enhancing degradation (Bandyopadhyay and Basak, 2007).”

• cites Bandyopadhyay and Basak, 2007 sourceNot checked — no full text of the source

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

The present study did not directly compare recycled and virgin PET strips.

“Although one of the limitations of the present study is that we did not directly compare recycled and virgin PET strips”

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

Pegram and Andrady (1989) found little evidence of weathering of polyethylene samples floating in seawater over 8 weeks, whereas samples exposed to air nearly embrittled over the same period.

“These results corroborate those of an earlier study by Pegram and Andrady (1989), who found little evidence of weathering of polyethylene samples floating in seawater over an 8-week period, whereas those exposed to air nearly embrittled over the same period.”

• cites Pegram and Andrady (1989) sourceNot checked — no full text of the source

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

Moisture can influence polymer degradation by supplying water for microbial growth and multiplication, thereby accelerating degradation through microbial action.

“Functionally, moisture can also influence polymer degradation by providing water for the growth and multiplication of microbes, thus accelerating polymer degradation through microbial action (Ho et al., 1999).”

• cites Ho et al., 1999Not matched

  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).

The Ocean Conservancy reported that single-use bags were the seventh most common debris type collected during its 2018 International Coastal Cleanup.

“The Ocean Conservancy reported that single use bags were the seventh most common type of debris collected during their annual International Coastal Cleanup in 2018 (Ocean Conservancy, 2019).”

• cites Ocean Conservancy, 2019Not matched

  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).

Acid catalysts have also been found to lower the apparent activation reaction for decomposition reactions.

“They have also been found to lower the apparent activation reaction for decomposition reactions (Garforth et al., 1997).”

• cites Garforth et al., 1997 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Oromiehie and Mamizadeh (2004) reported that PET recycling decreases average molecular weight and mechanical properties because of hydrolytic chain excision and thermomechanical degradation during processing.

“Oromiehie and Mamizadeh (2004) reported that the recycling process for PET results in a decrease in average molecular weight and mechanical properties of the end-product due to the hydrolytic chain excision and thermomechanical degradation that occurs during processing.”

• cites Oromiehie and Mamizadeh (2004) sourceNot checked — no full text of the source

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

Acid catalysts such as zeolites have been reported to transform polymers into hydrocarbons by favoring hydrogen transfer reactions.

“The addition of acid catalysts, such as zeolites, has also been reported in the literature for use in transforming polymers into hydrocarbons by favoring hydrogen transfer reactions (Singh and Sharma, 2008).”

• cites Singh and Sharma, 2008 sourceNot checked — no full text of the source

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

Considerable research has been conducted on enhancing PS degradation by adding catalysts.

“Considerable research has been performed on enhancing the degradation of PS through the addition of catalysts (reviewed by Singh and Sharma, 2008).”

• cites Singh and Sharma, 2008 sourceNot checked — no full text of the source