Hazard profiling of compostable shopping bags. Towards an ecological risk assessment of littering

Comparative toxicity of conventional versus compostable plastic consumer products: An in-vitro assessment

This study investigates the toxicity of methanolic extracts obtained from compostable plastics (BPs) and conventional plastics (both virgin and recycled). Additionally, it explores the potential influence of plastic photodegradation and composting on toxic responses using a battery of in vitro assays conducted in PLHC-1 cells. The extracts of BPs, but not those of conventional plastics, induced a significant decrease in cell viability (<70%) in PLHC-1 cells after 24 h of exposure. Toxicity was enhanced by either photodegradation or composting of BPs. Extracts of conventional plastics, and particularly those of recycled plastics, induced 7-ethoxyresorufin-O-deethylase (EROD) activity and micronucleus formation in exposed cells, indicating the presence of significant amounts of CYP1A inducers and genotoxic compounds in the extracts, which was enhanced by photodegradation. These findings highlight the importance of investigating the effects of degradation mechanisms such as sunlight and composting on the toxicity of BPs. It is also crucial to investigate the composition of newly developed formulations for BPs, as they may be more harmful than conventional ones.

A systematic review on bioplastic-soil interaction: Exploring the effects of residual bioplastics on the soil geoenvironment

Growing demand for plastic and increasing plastic waste pollution have led to significant environmental challenges and concerns in today's world. Bioplastics offer exciting new opportunities and possibilities where biodegradable and bio-based plastics are expected to be more eco-friendly and rely on renewable resources. With all its promises, evaluating its real impact and fate on the geoenvironment is paramount for promoting bioplastic use. This paper presents a systematic literature review to understand current bioplastic-soil research and the effects of its residues on the geoenvironment. 632 studies related to bioplastic research in soil since 1973 were identified and categorized into different relevant topics. Publication trend showed bioplastic-soil research grew exponentially after 2010 wherein field studies accounted to 33.1 % of the total studies and only about 9.7 % studied the effects of bioplastic residues on the geoenvironment. Majority of the lab studies were on development and subsequent stability of bioplastics in soil. Short-term studies (in months) dominated the longer-term studies and studies over 4 years were almost non-existent. Lab and field experiments often gave inconsistent results with seasonal, climatic and bio-geographical factors strongly influencing the field results and bioplastic stability in soil. Most existing studies reported significant effects for microbioplastic concentrations at or above 1 % w/w. Bioplastic residues were found to substantially affect soil C/N ratio, impact soil microbial diversity by favouring certain microbial taxa and alter soil physical structure by influencing soil aggregates formation. At higher concentrations, plant health and germination success were also negatively affected. Conclusively, the review found it important to focus more on long-term field experiments to better understand the degree and extent of bioplastic residue impact on soil physico-chemical properties, mechanical properties, soil biology, soil-bioplastic-plant response, nutrients and toxicity. There are also very few studies investigating contaminant transport and migration of micro or nano-bioplastics in soil.

The impact of thermomechanical and chemical treatment of waste Brewers' spent grain and soil biodegradation of sustainable Mater-Bi-Based biocomposites

Due to the massive plastic pollution, development of sustainable and biodegradable polymer materials is crucial to reduce environmental burdens and support climate neutrality. Application of lignocellulosic wastes as fillers for polymer composites was broadly reported, but analysis of biodegradation behavior of resulting biocomposites was rarely examined. Herein, sustainable Mater-Bi-based biocomposites filled with thermomechanically- and chemically-modified brewers' spent grain (BSG) were prepared and subjected to 12-week soil burial test simulating their biodegradation in natural environment. BSG stabilizing effect on polymer matrix affected by the content of melanoidins and antioxidant phytochemicals, along with the impact of diisocyanate applied to strengthen the interfacial adhesion. Biocomposites showed 25-35 wt% mass loss over 12 weeks resulting from swelling of BSG filler and sample microcracking, which increased surface roughness by 247-448 %. The degree of decomposition was partially reduced by BSG modifications pointing to the stabilizing effect of melanoidins and phytochemicals, and enhanced interfacial adhesion. Soil burial-induced structural changes enhanced biocomposites' thermal stability determined by thermogravimetric analysis shifting decomposition onset by 14.4-32.0 °C due to the biodegradation of lower molecular weight starch macromolecules confirmed by differential scanning calorimetry. For unfilled Mater-Bi, it caused an average 32 % reduction in complex viscosity and storage modulus captured by oscillatory rheological measurements. Nonetheless, the inverse effect was noted for biocomposites where modulus increased even by one order of magnitude due to the swelling of BSG particles and amorphous phase decomposition. Presented results indicate that BSG promotes soil degradation of Mater-Bi and its rate can be engineered by biofiller treatment elaboration.

The role of waste management in reducing bioplastics' leakage into the environment: A review

Bioplastics are becoming more and more widespread as substitutes for petroleum-derived plastics due to their biodegradability. Bioplastics degradation under different environments has been described and reported to depend mainly on bioplastics' compositions and the environmental conditions. Incomplete degradation during waste management processes and leakage of bioplastics into the environment are becoming major concerns that need to be further investigated. In this context, the present paper aimed to review recent literature dealing with biodegradation of bioplastics under industrial (e.g. anaerobic digestion and composting) and natural (e.g. soil and water) environments, and to link it to the potential bioplastics' leakage into the environment. Reviewed data were used to estimate the potential role of waste management processes in decreasing the potential leakage of bioplastics. Depending on bioplastics' type and processing conditions, waste management can effectively reduce bioplastics' potential leakage, decreasing the concentration of these materials that can reach the natural environments.