ABSTRACT

Solid waste collection, handling, and processing systems are chang­ ing worldwide as concerns increase regarding the environmental impact of solid waste. Recycling, waste to energy, and composting options are all expected to increase significantly as available landfill capacity de­ creases. As composting becomes an important method of managing solid waste, information about the biodegradability of polymeric materials and products is required in order to understand the fate of polymers in the environment. This paper describes the development of a tiered testing strategy for assessing the aerobic biodegradability and compostability of synthetic polymers. This testing strategy is demonstrated with polycaprolactone (PCL), a polymeric material that is generally regarded as biode­ gradable and compostable. PCL biodegradation was assessed in screen­ ing-level tests using the OECD 301B and ASTM D5338 test methods. In addition, 14C-PCL was synthesized and used in confirmatory-level biodegradation tests that were conducted under realistic composting con­ ditions. These studies show that screening-level biodegradation tests can provide knowledge of the inherent biodegradability of polymers, but the rate of biodegradation and the ultimate fate of polymeric materials in environmental matrices must be determined under realistic test condi­ tions.