Influence of weather conditions and soil properties on degradation of biodegradable plastics in soil

Abstract Climatic and soil factors responsible for the degradation of biodegradable plastics in soil were analyzed by placing poly-(3-hydroxy-butylate-valerate) (PHB/V), poly-(ɛ:-caprolactone) (PCL), poly-(butylene succinate) (PBS), poly-butylene succinate and adipate) (PBSA), and poly-lactide (PLA) in soil at 19sites in Honshu Island, Japan for 12 months. Degradation was determined every 3 months by collecting sample specimens for the measurement of weight loss. All the polymers were found to be degradable in soil. The degradation was faster, with the following order: PBSA=PHB/V=PCL > PBS> PLA. The sum of effective temperatures (over 10°C) was correlated with the degradation of PHB/V, PCL, PBS, and PBSA. Among the soil factors, the amount of total nitrogen in soil showed a correlation with the degradation of the polymers at various sampling times. On the contrary, the amount of total carbon, the pH, and the soil texture did not show a good correlation with the degradation of the tested biodegradable plastics. Key Words: biodegradable plasticsclimatesoil nitrogensoil propertytemperature