A critical review on the interactions of microplastics with heavy metals: Mechanism and their combined effect on organisms and humans.

A comparative review of microplastics and nanoplastics: Toxicity hazards on digestive, reproductive and nervous system

Microplastics contamination is becoming a major concern worldwide. More than 1 million seabirds and 100,000 sea animals have died due to plastic contamination. In addition, plastic particles have been found in juvenile turtles. Statistical data on plastic pollution indicate that this is a serious issue. Due to their small size, microplastics have a large surface area and have more ability to absorb into biological cells. The hydrophobic surface of microplastics attracts co-contaminants such as heavy metals, pharmaceutical toxicants, flame retardants, and other plasticizers, which can then enter biological organisms. Microplastics are usually recalcitrant in the environment, causing microplastics to be transported along the food chain, with humans as the final consumer. Research has been conducted to evaluate the best way to treat and remediate microplastic pollution. Research on microplastic degradation is focused on biological and non-biological approaches. To date, microorganisms such as algae, fungi, and bacteria have attracted the attention of scientists as a tool for microplastic treatment. The degradation of microplastics is closely related to the enzymatic reactions produced by the microorganisms. Here we review microplastics degradation through enzymes from the microorganism’s perspective. We present the enzymes that have been isolated from microorganisms for specific microplastics; the mechanisms of microplastics degradation by various enzymes; and the types of microplastics for which degradation mechanisms remain unclear.

Microbial degradation of microplastics by enzymatic processes: a review

Plastic particles of less than 5 mm size, referred as microplastics, have recently become a major environmental issue. While microplastics are well known in marine and lake systems, there have been less investigations in soils and groundwater. Here we review the origin, shape, impact, and mitigation strategies of soil and groundwater microplastics. We found that littering is the main origin of microplastics in global topsoils, while greenhouses are the main source of microplastics in South Korea. Fibers and pellets are dominant microplastic shapes in soil and groundwater. Microplastic contamination of soil and groundwater is detrimental to human health, plants, nematodes, earthworms, and soil properties. Remediation methods include pyrolysis, replacing plastics by biodegradable plastics, plastic filtration, and subsequent chemical or biological degradation.

Microplastic pollution in soil and groundwater: a review

Gut microbiota protects honey bees (Apis mellifera L.) against polystyrene microplastics exposure risks.

Barrier function of zebrafish embryonic chorions against microplastics and nanoplastics and its impact on embryo development.

Toxicities of microplastic fibers and granules on the development of zebrafish embryos and their combined effects with cadmium.

Microplastics in Yellow River Delta wetland: Occurrence, characteristics, human influences, and marker

Diet preference of zebrafish (Danio rerio) for bio-based polylactic acid microplastics and induced intestinal damage and microbiota dysbiosis.

Objective Three ciprofloxacin derivatives (CPDs) were synthesized. Also, their sonodynamic antibacterial activities and possible mechanism under ultrasound (US) irradiation were preliminarily investigated. Methods Staphylococcus aureus and Escherichia coli were selected as the research objects. The sonodynamic antibacterial effects of three CPDs and their structure-effective relationship were explored by the inhibition rate. The reactive oxygen species (ROS) produced under US irradiation were detected by oxidative extraction spectrophotometry and used to analyze the sonodynamic antibacterial mechanism of three CPDs. Results Research indicated that three CPDs, named compound 1 (C1), compound 2 (C2) and compound 3 (C3), separately all had strong sonodynamic antibacterial activities. In addition, C3 had the strongest effect relative to the other CPDs. The study also found that CPDs’ concentration, US irradiation time, US solution temperature and US medium could disturb their sonodynamic antimicrobial effects. Moreover, 1O2 and ·OH were the main types of ROS produced by C1 and C3; the ROS produced by C2 included 1O2, among other types. Conclusion Results showed that all three CPDs could be activated to produce ROS after US irradiation. Among them, C3 displayed the highest ROS production and the utmost activity, which may be related to the introduction of the electron-giving group at the C-3 position of the quinoline backbone. Three ciprofloxacin derivatives (CPDs) were synthesized. Also, their sonodynamic antibacterial activities and possible mechanism under ultrasound (US) irradiation were preliminarily investigated. Staphylococcus aureus and Escherichia coli were selected as the research objects. The sonodynamic antibacterial effects of three CPDs and their structure-effective relationship were explored by the inhibition rate. The reactive oxygen species (ROS) produced under US irradiation were detected by oxidative extraction spectrophotometry and used to analyze the sonodynamic antibacterial mechanism of three CPDs. Research indicated that three CPDs, named compound 1 (C1), compound 2 (C2) and compound 3 (C3), separately all had strong sonodynamic antibacterial activities. In addition, C3 had the strongest effect relative to the other CPDs. The study also found that CPDs’ concentration, US irradiation time, US solution temperature and US medium could disturb their sonodynamic antimicrobial effects. Moreover, 1O2 and ·OH were the main types of ROS produced by C1 and C3; the ROS produced by C2 included 1O2, among other types. Results showed that all three CPDs could be activated to produce ROS after US irradiation. Among them, C3 displayed the highest ROS production and the utmost activity, which may be related to the introduction of the electron-giving group at the C-3 position of the quinoline backbone. 

Xinyue Duan

Papers

Barrier function of zebrafish embryonic chorions against microplastics and nanoplastics and its impact on embryo development.

Toxicities of microplastic fibers and granules on the development of zebrafish embryos and their combined effects with cadmium.

Microplastics in Yellow River Delta wetland: Occurrence, characteristics, human influences, and marker

Diet preference of zebrafish (Danio rerio) for bio-based polylactic acid microplastics and induced intestinal damage and microbiota dysbiosis.

Synthesis and Sonodynamic Antibacterial Activity Evaluation of Three Novel Fluoroquinolone Compounds.