Biodegradation In Seawater Research Articles

Plasticized cellulose bioplastics with beeswax for the fabrication of multifunctional, biodegradable active food packaging

Plasticized cellulose bioplastics with antioxidant and antimicrobial properties were prepared by blending cellulose and glycerol in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, adding a solution of beeswax in chloroform, and subsequent drop-casting. Optical, chemical, structural, mechanical, thermal, and hydrodynamic properties were fully characterized. In addition, the biodegradability in seawater was investigated by determination of the biological oxygen demand. The incorporation of beeswax ruled out the transparency and UV blocking, modified the main mechanical parameters, and improved the thermal stability and the antioxidant capacity, as well as the hydrodynamic and barrier properties. In general, these features were comparable to those of common petroleum-based food packaging plastics. Such changes were explained by the incorporation of beeswax into the polymer matrix, as determined by infrared spectroscopy and X-ray diffraction. These cellulose-beeswax bioplastics were evaluated as viable food packaging materials by determination of the overall migration by using Tenax® as a dry food simulant, oxygen permeability at different relative humidities, measurement of antimicrobial activity against Escherichia coli and Bacillus cereus, and through preservation of fresh-cut pear slices, showing results similar to those obtained by using low-density polyethylene.

Biodegradable thermoplastic elastomers synthesized from C7–C10 aliphatic dicarboxylic acids, 2-methyl-1,3-propanediol, and L-lactide

Elastic materials with high biodegradability should replace those with low biodegradability in some applications. We previously reported biodegradable thermoplastic elastomers (TPEs) composed of poly(l-lactide) (PLLA) as a hard segment and aliphatic polyesters from 2-methyl-1,3-propanediol (MP) and short aliphatic dicarboxylic acids as soft segments. In this study, we synthesized the biodegradable thermoplastic elastomers using longer aliphatic dicarboxylic acids to develop the TPEs with lower glass-transition temperature (Tg) and high biodegradability. A series of aliphatic polyesters were prepared by polycondensation of MP and aliphatic dicarboxylic acids bearing 7–10 carbons. Among them, poly(2-methyl-1,3-propylene azelate) (PMP9) was found to have lower Tg, amorphous nature, and high biodegradability in seawater. The ring-opening polymerization of l-lactide (LLA) using PMP9 as a macroinitiator afforded triblock copolymers, PLLA-b-PMP9-b-PLLA (TPE9). The successive addition of LLA to in-situ generated PMP9 resulted in the successful one-pot synthesis of high molecular weight TPE9. The TPE9s showed both low Tg of the PMP9 segment and high melting temperature of the PLLA segment. The TPE9s exhibited elastic behavior showing elongation at break of up to 2500 % in tensile tests and also high biodegradability in seawater. Thus, we developed potentially practical TPE with tunable physical properties and high biodegradability obtainable from easily available and renewable starting materials.

Biodegradability of oxidized films of polyhydroxyalkanoate copolymers containing 2-hydroxy-4-methylthiobutyrate unit in seawater

Polyhydroxyalkanoate (PHA) copolymers consisting of 3-hydroxybutyrate, 2-hydroxy-4-methylthiobutyrate (2H4MTB), and 2-hydroxy-4-methylvalerate were biosynthesized by recombinant Escherichia coli using L-methionine as the 2H4MTB precursor. The 2H4MTB unit contains a sulfide group in its side chain that can be oxidized to sulfoxide and sulfone groups by oxidants, thereby increasing the hydrophilicity of the polymer. The PHAs were biosynthesized at 3.9, 9.2, and 13.9 mol% 2H4MTB, and their polymer films were oxidized with hydrogen peroxide. The surface of the oxidized film was characterized using Fourier-transform infrared spectroscopy, Raman spectroscopy, and contact angle analysis. The oxidized films with 13.9 mol% 2H4MTB showed a 30° lower water contact angle than the non-oxidized films. To assess their marine biodegradability, the PHA films were immersed for 114 days in seawater continuously pumped from two depths (24 and 397 m) in Suruga Bay, Shizuoka, Japan. The weight loss of the films immersed in deep seawater was higher than that of those immersed in surface seawater. Additionally, there was a tendency for higher degradation of the oxidized films than that of the non-oxidized films, which was also confirmed by the biochemical oxygen demand test. In the surface morphology analysis by scanning electron microscopy, irregularities were observed in the degraded films, but their morphologies differed between the oxidized and non-oxidized films. Based on these observations, the biodegradation of the PHA films in seawater is discussed.

Biobased and biodegradable imine vitrimers from epoxidized soybean oil as packaging

AbstractA flexible and stretchable vitrimer was synthesized using exclusively biobased building blocks and following green chemistry principles. Epoxidized soybean oil (ESO), vanillin, the biobased diamine, Priamine®, and oleic acid were used to create a material that can replace fossil‐derived, non‐biodegradable packaging. Vanillin and Priamine® were used to develop a crosslinker that could react with the epoxide groups of ESO without the need for solvents, with a catalyst‐free synthesis that does not generate any waste or byproducts. Oleic acid was incorporated, to tune the properties of the final material, since it can react with ESO and control the crosslink density. The vitrimers produced in this work showed excellent reprocessability and recyclability. They possess the ability to be molded, and they can also strongly adhere on surfaces. Moreover, they exhibited oxygen and water vapor barrier comparable to low density polyethylene, while showing very low migration into food simulant, which position them as a promising material for flexible food and general packaging market. The vitrimers showed also the capability of biodegradation in seawater, providing a safe end of life in case of mismanagement.

Study on the onset mechanism of bio-blister degradation of polyolefin by diatom attachment in seawater

It is essential to develop a mechanism for lowering the molecular weight of polyolefins to achieve biodegradation in seawater. In this study, a polypropylene/polylactic acid blend sample was first subjected to photodegradation pretreatment, and it was confirmed that in pure water, the acid generated promotes the polypropylene degradation (autoxidation), while in alkaline seawater, the promotion was inhibited by a neutralization reaction. In the autoxidation of polyolefins in alkaline seawater, aqueous Cl− was also the inhibitor. However, we found that autoxidation could be initiated even in seawater by lowering the pH and using dissociation of ClOH (called blister degradation). The blister degradation mechanism enabled autoxidation, even in seawater, by taking advantage of the ability of diatoms to secrete transparent exopolymer particles (TEP) to prevent direct contact between the surface layer of polyolefins and alkaline seawater. We named blister degradation in seawater with diatoms as bio-blister degradation and confirmed its manifestation using linear low-density polyethylene (LLDPE)/starch samples by SEM, IR, DSC and GPC analysis.

Hydrolytic degradation and biodegradation of polylactic acid electrospun fibers

Increased use of bioplastics, such as polylactic acid (PLA), helps in reducing greenhouse gas emissions, decreases energy consumption and lowers pollution, but its degradation efficiency has much room for improvement. The degradation rate of electrospun PLA fibers of varying diameters ranging from 0.15 to 1.33 μm is measured during hydrolytic degradation under different pH from 5.5 to 10, and during aerobic biodegradation in seawater supplemented with activated sewage sludge. In hydrolytic conditions, varying PLA fiber diameter had significant influence over percentage weight loss (W%L), where faster degradation was achieved for PLA fibers with smaller diameter. W%L was greatest for PLA-5 > PLA-12 > PLA-16 > PLA-20, with average W%L at 30.7%, 27.8%, 17.2% and 14.3% respectively. While different pH environment does not have a significant influence on PLA degradation, with W%L only slightly higher for basic environments. Similarly biodegradation displayed faster degradation for small diameter fibers with PLA-5 attaining the highest degree of biodegradation at 22.8% after 90 days. Hydrolytic degradation resulted in no significant structural change, while biodegradation resulted in significant hydroxyl end capping products on the PLA surface. Scanning electron microscopy (SEM) imaging of degraded PLA fibers showed a deteriorated morphology of PLA-5 and PLA-12 fibers with increased adhesion structures and irregularly shaped fibers, while a largely unmodified morphology for PLA-16 and PLA-20.

Incorporation of bioactive compounds from avocado by-products to ethyl cellulose-reinforced paper for food packaging applications.

Reinforced films were fabricated by impregnating paper in ethyl cellulose solutions. After solvent evaporation, the infused ethyl cellulose acted as binder of the paper microfibres and occupied the pores and cavities, thus improving the mechanical and barrier properties. To prepare active films, avocado by-products from guacamole industrial production were extracted in ethyl acetate. Then, the extract (optimized to be rich in phenolic compounds and flavonoids and mainly composed by lipids) was incorporated to the paper reinforced with the highest content of ethyl cellulose. In general, the addition of the avocado by-products extract decreased the water uptake and permeability, improved the wettability, and increased the biodegradability in seawater and the antioxidant capacity. In addition, these films acted as barriers and retainers for Escherichia coli and Bacillus cereus. The potentiality of these materials for food packaging was demonstrated by low overall migrations and a similar food preservation to common low-density polyethylene.

Metatranscriptomic responses and microbial degradation of background polycyclic aromatic hydrocarbons in the coastal Mediterranean and Antarctica

Although microbial degradation is a key sink of polycyclic aromatic hydrocarbons (PAH) in surface seawaters, there is a dearth of field-based evidences of regional divergences in biodegradation and the effects of PAHs on site-specific microbial communities. We compared the magnitude of PAH degradation and its impacts in short-term incubations of coastal Mediterranean and the Maritime Antarctica microbiomes with environmentally relevant concentrations of PAHs. Mediterranean bacteria readily degraded the less hydrophobic PAHs, with rates averaging 4.72 ± 0.5 ng L h−1. Metatranscriptomic responses showed significant enrichments of genes associated to horizontal gene transfer, stress response, and PAH degradation, mainly harbored by Alphaproteobacteria. Community composition changed and increased relative abundances of Bacteroidota and Flavobacteriales. In Antarctic waters, there was no degradation of PAH, and minimal metatranscriptome responses were observed. These results provide evidence for factors such as geographic region, community composition, and pre-exposure history to predict PAH biodegradation in seawater.

Isolation and characterization of polyhydroxyalkanoate-degrading bacteria in seawater at two different depths from Suruga Bay.

Polyhydroxyalkanoate (PHA) is a highly biodegradable microbial polyester, even in marine environments. In this study, we incorporated an enrichment culture-like approach in the process of isolating marine PHA-degrading bacteria. The resulting 91 isolates were suggested to fall into five genera (Alloalcanivorax, Alteromonas, Arenicella, Microbacterium, and Pseudoalteromonas) based on 16S rRNA analysis, including two novel genera (Arenicella and Microbacterium) as marine PHA-degrading bacteria. Microbacterium schleiferi (DSM 20489) and Alteromonas macleodii (NBRC 102226), the type strains closest to the several isolates, have an extracellular poly(3-hydroxybutyrate) [P(3HB)] depolymerase homolog that does not fit a marine-type domain composition. However, A. macleodii exhibited no PHA degradation ability, unlike M. schleiferi. This result demonstrates that the isolated Alteromonas spp. are different species from A. macleodii. P(3HB) depolymerase homologs in the genus Alteromonas should be scrutinized in the future, particularly about which ones work as the depolymerase.

Ultimate and primary biodegradation of a range of non-polymeric and polymeric surfactants in seawater.

Surfactants are a major class of chemicals commonly used in a wide range of domestic and industrial products. In this study, ultimate biodegradation of 18 surfactants representing different classes (including several polymeric alcohol ethoxylates), was determined in seawater (SW) at 20°C by the OECD306 Closed Bottle test method. After 28 days of incubation, 12 surfactants reached 60% biodegradation and were considered to be readily biodegradable in SW. The results for the 6 additional surfactants indicated that the 60% threshold level may be reached by extended incubation time, or that reduced biodegradation could be associated with toxicity of the chemicals. All these 6 surfactants were biodegraded >20% after 28 days, indicative of primary biodegradation in SW. Polymeric ethoxylates with high numbers of ethylene oxide (EO) groups (40-50 EO groups) were more slowly biodegraded than polyethoxylates with 4 to 23 EO groups. A primary biodegradation experiments of the alcohol ethoxylate (AE) C12-EO9 (3 to 18 EO groups) in a carousel system at 20°C with natural SW and a surfactant concentration of 500 µg/L, showed rapid primary biodegradation by targeted analyses of the AE, with >99% primary biodegradation after 2 days of incubation. The surfactant depletion coincided with temporary formation of polyethylene glycols, suggesting that central fission is an important degradation step in SW. A primary biodegradation experiment in the carousel system with C12-EO9 was conducted in the presence of suspended particulate materials (SPMs; marine phytoplankton and clay particles), showing that the presence of SPMs did not hamper the primary biodegradation of the surfactant. Separation of fractions in 20 µm steel filters indicated some particle association of the surfactant. This article is protected by copyright. All rights reserved. Environ Toxicol Chem 2023;00:0-0. © 2023 SETAC.

Surface oxidation of polyhydroxyalkanoate films with different molecular structure via photo-activated chlorine dioxide radical and comparison of the influence on the properties

Polyhydroxyalkanoates (PHAs) are novel candidates for biodegradable plastics, and hydrophobic surfaces have been modified to improve their dyeability and adhesion to other materials. In this study, surface oxidation by photoactivated chlorine dioxide radicals was carried out on four types of PHA films with different molecular structures to investigate whether the number of introduced functional groups changes. Whether the mechanical properties, crystallinity, enzymatic degradability, and biodegradability in seawater were changed by oxidation was also investigated. It was found that the number of functional groups decreased in the polymer having monomer units without side chains, indicating that the reactivity of the oxidation is affected by the presence of the side chain. No significant changes in mechanical properties and crystallinity were observed. The enzymatic degradability of some of the oxidized PHA films was significantly reduced because it did not match the substrate specificity of the catalytic domain of a PHA depolymerase due to changes in the molecular structure caused by oxidation. In a biodegradation test using seawater, the initial biodegradation rate of the oxidized films was slightly reduced, suggesting that the oxidation may affect the biodegradation of microorganisms in the environment.

Synthesis, Properties, and Biodegradability of Novel Sequence-Controlled Copolyesters Composed of Glycolic Acid, Dicarboxylic Acids, and C3 or C4 Diols

We have previously reported that sequence-controlled copolyesters such as poly((ethylene diglycolate) terephthalate) (poly(GEGT)) showed higher melting temperatures than those of the corresponding random copolymers and high biodegradability in seawater. In this study, to elucidate the effect of the diol component on their properties, a series of new sequence-controlled copolyesters composed of glycolic acid, 1,4-butanediol or 1,3-propanediol, and dicarboxylic acid units was studied. 1,4-Butylene diglycolate (GBG) and 1,3-trimethylene diglycolate (GPG) were prepared by the reactions of 1,4-dibromobutane or 1,3-dibromopropane with potassium glycolate, respectively. Polycondensation of GBG or GPG with various dicarboxylic acid chlorides produced a series of copolyesters. Terephthalic acid, 2,5-furandicarboxylic acid, and adipic acid were used as the dicarboxylic acid units. Among the copolyesters bearing terephthalate or 2,5-furandicarboxylate units, the melting temperatures (Tm) of the copolyesters containing 1,4-butanediol or 1,2-ethanediol units were substantially higher than those of the copolyester containing the 1,3-propanediol unit. Poly((1,4-butylene diglycolate) 2,5-furandicarboxylate) (poly(GBGF)) showed a Tm at 90 °C, while the corresponding random copolymer was reported to be amorphous. The glass-transition temperatures of the copolyesters decreased as the carbon number of the diol component increased. Poly(GBGF) was found to show higher biodegradability in seawater than that of poly(butylene 2,5-furandicarboxylate) (PBF). On the other hand, the hydrolysis of poly(GBGF) was suppressed in comparison with that of poly(glycolic acid). Thus, these sequence-controlled copolyesters have both improved biodegradability compared to PBF and lower hydrolyzability than PGA.

A Biodegradable, Bio-Based Polymer for the Production of Tools for Aquaculture: Processing, Properties and Biodegradation in Sea Water.

Bio-based, biodegradable polymers can dramatically reduce the carbon dioxide released into the environment by substituting fossil-derived polymers in some applications. In this work, prototypes of trays for aquaculture applications were produced via injection molding by using a biodegradable polymer, Mater-Bi®. A characterization carried out via calorimetric, rheological and mechanical tests revealed that the polymer employed shows properties suitable for the production of tools to be used in aquaculture applications. Moreover, the samples were subjected to a biodegradation test in conditions that simulate the marine environment. The as-treated samples were characterized from gravimetrical, morphological and calorimetric point of views. The obtained data showed a relatively low biodegradation rate of the thick molded samples. This behavior is of crucial importance since it implies a long life in marine water for these manufacts before their disappearing.

A starch-based, crosslinked blend film with seawater-specific dissolution characteristics

Existing biodegradable plastics may not be ideal replacements of petroleum-based single-use plastics owing to their slow biodegradation in seawater. To address this issue, a starch-based blend film with different disintegration/dissolution speeds in freshwater and seawater was prepared. Poly(acrylic acid) segments were grafted onto starch; a clear and homogenous film was prepared by blending the grafted starch with poly(vinyl pyrrolidone) (PVP) by solution casting. After drying, the grafted starch was crosslinked with PVP by hydrogen bonds, owing to which the water stability of the film is higher than that of unmodified starch films in fresh water. In seawater, the film dissolves quickly as a result of disruption of the hydrogen bond crosslinks. This technique balances degradability in marine environment and water resistance in everyday environment, provides an alternative route to mitigate marine plastic pollution and could be potentially useful for single-use applications in different fields such as packaging, healthcare, and agriculture.

Biodegradation of crude oil in seawater by using a consortium of symbiotic bacteria

This work presents the enhancement of oil biodegradation in seawater using a mixture of oil and microorganisms. Retardation of crude oil biodegradation in seawater is hypothetically due to the inhibiting of metabolites produced by the oil bacterium which inhibit its enzymes. For this purpose, the bacteria consortium consisting of an active oil-oxidizing bacterium (AR3-Pseudomonas pseudoalcaligenes) and two oil-resistant and active heterotrophic bacteria (OG1 and OG2-Erythrobacter citreus) were formed. The heterotrophic bacteria, OG1 and OG2 were able to remove metabolites produced during oil degradation. It was found that AR3 was retarded by metabolites, while OG1 and OG2 were able to grow in the metabolites. OG1 and OG2 were applied together to enhance growth and removal of the metabolites. About 59.9% of crude oil degradation was degraded by AR3 pure culture, while 68.6% was degraded by the bacteria consortium. About 31.4% of the crude oil was found to remain in seawater due to the presence of asphaltenes and resin hydrocarbons. The bacteria consortium was able to degrade 84.1% of total hydrocarbons while 67.0% was degraded by AR3. A total of 99.8% of the aliphatic content and 38.4% of the total aromatic hydrocarbons were degraded by the bacteria consortium, while a lower 79.4% of total aliphatic and 31.0% of total aromatic were degraded by AR3 under the same experimental conditions. The results which were obtained from this study support the hypothesis that the retardation of oil degradation by AR3 is due to the inhibition of metabolites on the growth.

Environmental risk assessment of inter-well partitioning tracer compounds shortlisted for the offshore oil and gas industry

Quantifying residual oil saturation (SOR) in the inter-well region of oil and gas reservoirs is key for successfully implementing EOR solutions. Partitioning inter-well tracer tests (PITTs) has become a common method for quantifying SOR. A new group of seven chemicals – pyridine, 2,3-dimethyl pyrazine, 2,6-dimethyl pyrazine, 4-methoxybenzyl alcohol, 3,4-dimethoxybenzyl alcohol, 4-chlorobenzyl alcohol, and 2,6-dichlorobenzyl alcohol – have been proposed as potential partitioning tracers for quantifying SOR. Using these tracers can lead to their environmental release in the marine environment through produced water discharges, with currently limited knowledge on impacts in the marine ecosystem. The primary objective of the present study is to assess the environmental risk of discharging the tracer compounds in the marine environment. We investigated the fate and effect of these tracers in the marine environment. Biodegradability in seawater was measured to understand the fate of tracers in the marine environment. The acute toxicity of tracers was measured in terms of the percent cell viability of a rainbow trout gill cell line (RTgill-W1) and growth inhibition of the algae Skeletonema costatum. The ecotoxicological information obtained from these experiments was used in the dynamic risk and effects assessment model (DREAM) to calculate the tracers’ contribution to the environmental impact factor (EIF). The results from the DREAM simulations suggest no contribution towards EIF values from any of the tracers at the expected back-produced concentrations. Results from simulations at higher concentrations suggest that both pyrazines have the lowest environmental risk, followed by 3,4-dimethoxybenzyl alcohol, 4-methoxybenzyl alcohol, and pyridine; while both chlorobenzyl alcohols show the highest environmental risk.

The degradation and environmental risk of camptothecin, a promising marine antifoulant

Given the adverse environmental impacts of the antifoulants currently used in marine antifouling paints, such as copper and booster biocides, it is urgent to identify potential substitutes that are environmentally benign. Here, we examined the degradation of camptothecin (a natural product previously identified as an efficient antifoulant in the laboratory and in the field) under various conditions and evaluated the environmental risks associated with its use as a marine antifoulant. We found that camptothecin was rapidly photolyzed in seawater: the half-life of camptothecin was less than 1 d under a light intensity of 1000–20,000 lx and was approximately 0.17 d under sunlight irradiation. At pH 4 and pH 7, camptothecin had half-lives of 30.13 and 16.90 d, respectively; at 4 °C, 25 °C, and 35 °C, the half-lives of camptothecin were 23.90, 21.66, and 26.65 d, respectively. Camptothecin biodegradation in seawater was negligible. The predicted no-effect concentration (PNEC) of camptothecin was 2.19 × 10−1 μg L−1, while the average predicted environmental concentrations (PECs) in open seas, shipping lanes, commercial harbors, and marinas were 6.14 × 10−7, 9.39 × 10−7, 6.80 × 10−3, and 5.03 × 10−2 μg L−1, respectively. The PEC/PNEC ratio of camptothecin was much lower than 1 (i.e., 2.80 × 10−6, 4.29 × 10−6, 3.11 × 10−2, and 2.30 × 10−1 for open seas, shipping lanes, commercial harbors, and marinas, respectively), indicating that the use of camptothecin as a marine antifoulant posed little environmental risk.

Effects of Marine Sand on the Microbial Degradation of Biodegradable Plastics in Seawater and Biofilm Communities that Formed on Plastic Surfaces.

Four types of biodegradable plastics were evaluated for their biodegradability in seawater collected at Ajigaura coast, Japan, in the presence or absence of marine sand. One of the plastics, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), showed a degree of biodegradation in a seawater sample, and the addition of marine sand markedly accelerated its biodegradation. The addition of marine sand did not affect the bacterial composition of the biofilm that formed on PHBH, and the family Rhodobacteraceae, which was predicted to contribute to the degradation of PHBH, was dominant in biofilm communities regardless of the addition of marine sand. Marine sand may serve as a bacterial source, resulting in the accelerated degradation of PHBH.

Design of Polyhydroxyalkanoate (PHA) Microbeads with Tunable Functional Properties and High Biodegradability in Seawater

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) were used to prepare microbeads, with diameter ranging from 50 to 100 µm, by an emulsion-evaporation process. The emulsification-evaporation process enables the formation of spherical polyhydroxyalcanoate beads, with crystalline rates similar to the ones of the former polymer and with important surface roughness as compared to amorphous polylactic acid smooth beads. The mechanical properties of the different PHA beads are also found to be intimately linked with their crystalline content, with modulus varying between 1 and 7 GPa. The degradation behavior of these PHA microbeads was tested under marine environment and revealed a rapid degradation, similar to cellulose, and a degradation rate correlated with the crystalline content. These results emphasize the possibility and interest in developing PHA materials with tunable functions and degradation properties.

Assessment of Toxicity and Biodegradability of Poly(vinyl alcohol)-Based Materials in Marine Water.

Due to the continuous rise in conventional plastic production and the deficient management of plastic waste, industry is developing alternative plastic products made of biodegradable or biobased polymers. The challenge nowadays is to create a new product that combines the advantages of conventional plastics with environmentally friendly properties. This study focuses on the assessment of the potential impact that polyvinyl alcohol (PVA)-based polymers may have once they are released into the marine environment, in terms of biodegradation in seawater (assessed by the percentage of the Theoretical Oxygen Demand, or % ThOD, of each compound) and aquatic toxicity, according to the standard toxicity test using Paracentrotus lividus larvae. We have tested three different materials: two glycerol-containing PVA based ones, and another made from pure PVA. Biodegradation of PVA under marine conditions without an acclimated inoculum seems to be negligible, and it slightly improves when the polymer is combined with glycerol, with a 5.3 and 8.4% ThOD achieved after a period of 28 days. Toxicity of pure PVA was also negligible (<1 toxic units, TU), but slightly increases when the material included glycerol (2.2 and 2.3 TU). These results may contribute to a better assessment of the behavior of PVA-based polymers in marine environments. Given the low biodegradation rates obtained for the tested compounds, PVA polymers still require further study in order to develop materials that are truly degradable in real marine scenarios.