Assessing Biodegradation Rates of Biodegradable Plastics Under Diverse Environmental Conditions

This study investigated the biodegradation rates of various biodegradable plastics in soil and aqueous environments, demonstrating that these materials do not always degrade as efficiently as expected due to their strong dependence on environmental conditions. Biodegradation was examined under controlled variations of temperature, pH, salinity, and microbial activity to simulate real-world disposal scenarios, with conditions adjusted weekly to accelerate breakdown and allow for measurable results. Degradation rates were monitored through weekly mass measurements. The results showed significant variation among plastics, with degradation strongly influenced by temperature, pH, microbial activity, and polymer chemical structure. Alkaline conditions (pH 9) combined with higher temperatures were the most effective in accelerating degradation. Polylactic acid (PLA) degraded the fastest, particularly in water-based environments under high heat and alkaline conditions, fragmenting at 70 °C, while Polyhydroxyalkanoates (PHA) exhibited gradual mass loss and required longer exposure to heat to degrade. Polycaprolactones (PCL) showed the least degradation across all conditions. These findings suggest that higher ester bond density within polymer structures may correlate with faster degradation under high heat and alkaline environments. Overall, the study highlights that biodegradable plastics require specific conditions to degrade efficiently and may persist otherwise, contributing to microplastic pollution or methane emissions in landfills, emphasizing the need for improved waste management strategies to maximize their environmental benefits.