Plastic additives alter the influence of photodegradation on biodegradation of PP/PE polymers in natural rivers

The understanding of the effects and the underlying microbial mechanisms of additives on the cascade photo- and biodegradation processes remains limited. In this study, the characteristics of morphology, functional groups, and indictive degrading bacteria of additive-free polyethylene (PE) and polypropylene (PP) films were detected to analyze the effects of three typical functional additives, the high-content Dioctyl phthalate (DOP), the low-content Bisphenol A (BPA) and Benzotriazole (BTA), on the single and cascade photo- and biodegradation processes of PP/PE films (PP/PEP, PP/PEB, PP/PEPB). The results showed that photodegradation enhanced the biodegradation of PP/PE films, by creating more smaller fractions which induced the proliferation of new PP/PE-degrading bacteria (P-bacteria) on PP/PEPB films without additives.