Degradable plastic of high-density polyethylene (HDPE)-CaCO3 reduced the abundance of antibiotic resistance genes in soil.

A large number of degradable plastics have entered the market because traditional plastics are not easy to degrade. However, degradable plastics have problems such as inability to be completely degraded in time. Therefore, evaluating whether degradable plastics pose environmental harm is both urgent and crucial. High-density polyethylene (HDPE) disposable degradable plastic bags which were filled with CaCO₃ have been widely circulated in the market. But there has been no reported research on whether HDPE/CaCO₃ degradable plastics are harmful to the environment. Therefore, in this study, HDPE-CaCO₃ degradable plastics circulated in the market were taken as the research objects, and the antibiotic resistance genes (ARG), a new type of environmental pollution indicator, were used as the evaluation indicators. The HDPE/CaCO₃ degradable plastics were made into plastic pieces less than 10 mm in size and then evenly mixed with soil. After 30 days, metagenomic sequencing was performed on the soil microorganisms, and the soil microbial community structure and the abundance of ARGs in the soil were analyzed to evaluate the potential environmental risks of HDPE/CaCO₃ degradable plastics. The results showed that comparing with HDPE, the HDPE/CaCO₃ degradable plastics could reduce the abundance of soil ARGs and change the soil microbial community structure. Our results indicated that HDPE/CaCO₃ degradable plastics imposed a reduced environmental impact compared to conventional HDPE plastics.