Plastic and microplastic pollution has caused a great deal of ecological problems because of its persistence and potential adverse effects on human health. The degradation of plastics through biological processes is of great significance for ecological health, therefore, the feasibility of plastic degradation by microorganisms has attracted a lot of attention. This study comprises a preliminary discussion on the biodegradation mechanism and the advantages and roles of different bacterial enzymes, such as PET hydrolase and PCL-cutinase, in the degradation of different polymers, such as PET and PCL, respectively. With a particular focus on their modes of action and potential enzymatic mechanisms, this review sums up studies on the biological degradation of plastics and microplastics related to mechanisms and influencing factors, along with their enzymes in enhancing the degradation of synthetic plastics in the process. In addition, biodegradation of plastic is also affected by plastic additives and plasticizers. Plasticizers and additives in the composition of plastics can cause harmful impacts. To further improve the degradation efficiency of polymers, various pretreatments to improve the efficiency of biodegradation, which can cause a significant reduction in toxic plastic pollution, were also preliminarily discussed here. The existing research and data show a large number of microorganisms involved in plastic biodegradation, though their specific mechanisms have not been thoroughly explored yet. Therefore, there is a significant potential for employing various bacterial strains for efficient degradation of plastics to improve human health and safety.

Antibiotic pollution has become an increasingly serious issue due to the extensive application of antibiotics, their resistance to removal, and the harmful effects on aquatic environments and humans. Breeding wastewater is one of the most important sources of antibiotics in the aquatic environment because of the undeveloped treatment systems in breeding farms. It is imperative to establish an effective antibiotic removal process for breeding wastewater. This paper reviews the treatment methods used to remove antibiotics from breeding wastewater. The mechanisms and removal efficiency of constructed wetlands, biological treatments, advanced oxidation processes (AOPs), membrane technology, and combined treatments are explained in detail, and the advantages and disadvantages of the various treatment methods are compared and analyzed. Constructed wetlands have high removal rates for sulfonamide (SM), tetracycline (TC), and quinolone (QN). The antibiotic removal efficiency of biological treatment methods is affected by various processes and environmental factors, whereas AOPs and combined treatment methods have better antibiotic removal effects. Although it has broad application prospects, the application of membrane technology for the treatment of antibiotics in breeding wastewater needs further research.

Microplastic is an emerging global pollutant that have attracted a great deal of attention from researchers and the public. Guangdong Province has a large population and a relatively well-developed economy, but lacks a modern pollution control system. Guangdong has a long coastline with varying levels of pollution, and little research has been conducted on microplastics. Therefore, we investigated the level of microplastic pollution in coastal areas of Guangdong Province, and the abundance of microplastics in surface waters and sediments at 13 sampling sites. The abundance of microplastics in surface water and sediment samples ranged from 850 to 3500 items/L and 433.3 to 4166.3 items/kg, respectively. Fiber is the main type of microplastics in both surface water and sediment. The sampled microplastics were typically transparent. Raman results show that the surface water sample mainly includes rayon (38.2%), polyethylene terephthalate (16.4%), and ethylene/vinyl acetate copolymer (12.7%). This study used the pollution load index method to evaluate the pollution risk of microplastics along the coast of Guangdong, and provided the basis for the formulation of environmental policy.