Background
Microplastics, loosely defined as any fragment of plastic between one nanometer and five millimeters in diameter, have managed to permeate almost every corner of the globe [2]. They most commonly originate from one of two sources: the breakdown of larger plastic pieces into smaller fragments or products manufactured with microplastics in their original form.
Microplastics have been found in oceans, freshwater ways, soils, and various air samples. They have even found their way into plants, marine organisms, and human anatomical structures [3]. The average person consumes between 39,000 and 52,000 microplastics annually, increasing to 74,000 to 121,000 annually when accounting for inhalation [4].
Microplastic ingestion is shown to have negative effects on zooplankton, marine species and humans, though more research is necessary to better understand the nuanced effects on each. Preliminary research regarding microplastic consumption in humans has indicated that it increases intestinal blockage, inflammatory responses, and shifts in gut microbe composition and metabolism [5].
Mismanagement of plastic waste – waste that is not recycled, incinerated, or effectively sealed in landfills – results in one to two million tons of plastic entering oceans each year [6].
Reducing the Spread of Microplastics
With the spread of microplastics showing no signs of slowing, what can be done?
Reducing consumption appears to be the most obvious step towards solving the pervasive problem, as decreased demand would lower overall production and drive a collective shift toward alternatives.
Replacing single-use plastics with biodegradable plastics (plastics derived from starch or plant-based polyester products) would dramatically decrease the scale and quantity of microplastics in the natural environment [7]. There is also research and development into other materials such as seaweed and silicone that could be used instead of plastic [8].
Further, improving waste management by mainstreaming recycling and sealing landfills to withstand shifting environments can decrease the risk of microplastic particles leaking into the environment. Improving membrane filtration in wastewater and stormwater systems can also reduce the concentration of microplastics entering oceans and freshwater ways, thereby limiting exposure among humans and other organisms [7].
Opportunities for Remediation
Removing microplastic contaminants from the environment is called remediation. Microalgae, fungi, and bacteria are all capable of breaking down existing microplastics through various biochemical processes. Though still in their preliminary stages, studies have demonstrated the potential of genetic engineering to optimise microbes for breaking down plastic [5]. Though this research is promising, there are still limitations to bioremediation. The reality is that these processes are time-consuming and only applicable to biodegradable compounds [5].
Electrocagulation is another emerging strategy. It is a technology that provides a cost-efficient, three-stage wastewater treatment process to remove microplastics from wastewater systems [9]. During the processes, metal electrodes produce positively charged metal ions, commonly referred to as cations, and release them into the wastewater. This triggers biochemical reactions that remove microplastics from the wastewater system [9]. While the technology is still in its infancy, early studies have shown promising results [9].
Conclusion
Microplastic pollution is pervasive, with almost every ocean, river and continent affected. In order to reduce the harmful effects of future microplastic exposure and consumption, collective global efforts are needed. Mitigation strategies need to be prioritised, accompanied by remediative strategies that reduce the concentration of already existing microplastics.
