Laboratory Test Methods to Determine the Degradation of Plastics in Marine Environmental Conditions

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = −66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

The test method of composting in vermiculite is unaffected by the priming effect

Glucose, starch, and cellulose can increase the biodegradation of the compost used as a solid matrix in the biodegradation test under composting conditions (priming effect). The enhanced evolution of carbon dioxide determines an overestimation of the biodegradation of the starch- and cellulose-based materials and, in some cases, values higher than 100% can be reached. The work has verified that using activated vermiculite, an inorganic matrix, the priming effect can be reduced, improving the reliability of the test method. Glucose, the most effective primer, causes the attainment of biodegradation values significantly higher than 100% in mature compost while this does not happen in activated vermiculite. Since all the initial carbon present in the activated vermiculite is converted into CO2 within the test period, we conclude that a substantial priming effect cannot occur for the lack of organic carbon. Furthermore, by measuring in parallel both the consumption of glucose and the CO2 evolution, the yield of CO2 production ( ) was determined. In no case a value higher than 1, a clear indication of priming effect, was found

Degradability of plastics. Standard methods developed in Italy

Degradability of plastics. Standard methods developed in Ital

Activated Vermiculite, a Solid Bed for Testing Biodegradability under Composting Conditions

Vermiculite, a clay mineral, can be activated and used as a solid matrix in place of mature compost in the controlled composting test, a respirometric essay widely applied to assess biodegradability of plastics. The results obtained with two materials (cellulose and a starch-based blend) indicate that activated vermiculite affects neither the biodegradation rate nor the final biodegradation level. On the other hand, possible metabolic intermediates and polymeric residues left after biodegradation can be recovered more easily from activated vermiculite than from mature compost, a very complex organic matter. Therefore, at test termination it was possible to determine the carbon balance taking into account both the evolved CO2 and a polymeric residue extracted from vermiculite, totalling 101% of the carbon present originally in the test material. This work was partly financed by the European Commission (DGXII) with the SMT “Labelling biodegradable products” project SMT4-CT97-2187

Detection of toxicity released by a biodegradable plastic after composting in activated vermiculite

The composting test method based on activated vermiculite is a comprehensive system for the assessment of the environmental impact of biodegradable plastics. It allows, in a single test, (i) the measurement of the mineralization of the polymer under study; (ii) the retrieval of the final polymeric residues and (iii) determination of the biomass (to make a final mass balance); (iv) detection of breakdown products of the original polymer. In this study it is shown that the vermiculite test method is also suitable to perform ecotoxicological studies. The Flash test is a method based on kinetic measurement of bioluminescence by Vibrio fischeri, and was applied to evaluate the toxicity of compost samples and vermiculite samples after the biodegradation of a polyurethane (PU) based plastic material. Toxicity was detected in vermiculite samples contaminated by 4,4′ diamino diphenyl methane (MDA), a toxic breakdown product released by the PU moiety, as shown by HPLC. On the other hand, neither toxicity nor the presence of MDA was detected in mature compost. A recovery experiment previously performed had shown a 10% MDA recovery yield from mature compost. The possibility of testing the ecotoxicity of extracts obtained from mineral matrix after biodegradation makes the vermiculite test system particularly interesting for the overall assessment of the environmental impact of biodegradable plastics

Isolation and characterisation of thermophilic micro-organisms able to grow on cellulose acetate

Cellulose acetate (CA) can be successfully used for producing compostable plastics. It is biodegradable under composting conditions, but neither the mechanism of degradation nor the involved microorganisms are known. We isolated five thermophilic strains from compost which were identified by molecular characterisation as belonging to the family Thermomonosporaceae, probably to the genus Actinomadura. The strains are able to grow at 50 °C on minimal plates supplemented with CA (DS=2) or microcrystalline cellulose in powder. The degradation of CA is visible by the clarification of the area surrounding the mycelium. The strains grow at 37 °C on cellulose but not on CA. At 20 and 58 °C no growth is detected on both substrates. The strains are viable after a 2-week incubation period at 65 °C. Neutral and basic pHs are the best for CA degradation, while poor results are obtained under acidic conditions. The best degradation of CA is obtained using nitrate as nitrogen source. Solid-state respiration tests, performed using sterile vermiculite as a matrix, confirmed that the strains are able to mineralise the CA. The strains failed to grow in CA under liquid conditions

Opening bio-based markets via standards, labelling and procurement : Validated biogasification test

Public summaryWork package 6Managed end-of-life optionsDeliverable N° 6.8:<br/