Potential pollution by biodegradable waste: Assessing the degradability of oxo-degradable, compostable, and biodegradable products under laboratory conditions

Abstract

Biodegradable products are promoted as environmentally friendly alternatives due to their claimed ability to decompose into CO₂, water, and biomass under natural conditions. This study evaluated the degradability of three products, an oxo low density polyethylene (oxo-LDPE) garbage bag (GB), a compostable lunch sheet (LS), and a biodegradable salad plate (SP) under four controlled laboratory simulations representing natural environmental scenarios of a freshwater body (FW), river bank (RS), landfill (COM), and direct ultraviolet (UV) light exposure. Degradation was assessed over time by monitoring changes in weight, mechanical strength, and chemical composition. Among the tested products, SP exhibited the highest mean percentage weight loss (43.76-100%) under RS. Instead of weakening, GB exhibited increased Mean Tensile Strength at Break and Mean Elongation at Break under RS (7.25 ± 0.29 and 317.776 ± 9.15, respectively) and COM (4.35 ± 0.88 and 46.158 ± 28.11, respectively), suggesting possible crosslinking or physical ageing rather than degradation. No loss of characteristic peaks indicating biodegradation of the polymer was observed in SP under FW and UV exposures, in LS under UV exposure, and in GB under FW, RS, or COM exposures. The findings highlight the potential contribution of certain biodegradable products, particularly oxo-LDPE, to long-term plastic pollution.