We now know where microbeads are found and how they came to be such a common ingredient in our everyday cosmetics. But microbeads aren’t just be all end all for microplastic pollution – secondary plastics also contribute greatly to the plastic soup that is our oceans. And they’re just as harmful, if not more so, than their primary counterparts.
Secondary microplastics are derived from the degradation of bigger plastic products, many of which are single-use plastics. The gradual breakdown of these bigger plastics (also known as macroplastics) mainly is caused by natural environmental influences, including radiation from the sun and abrasion from ocean waves (National Geography, n.a.). Unlike microbeads, secondary microplastics are not manufactured to be used as they are. Instead, they are a long-term consequence of littering and other inconsiderate behaviours that humans engage in without a care for the environment.
The main sources of secondary microplastics are not limited to littering from beachgoers or those who are out on the waters for recreational purposes. The fishing industry is another major contributor of plastics, as well as domestic sewage from other factories and industries that release their waste directly into seas and oceans. Currently, we release a whopping 8 million metric tons, or 8 billion kilograms of plastic into the oceans. Out of this number, almost 10% of it is attributed to fishing equipment at approximately 640,000 tonnes (Laville, 2019).
Fishing equipment can often get lost, or are abandoned when they become non-functional. This equipment includes fishing nets and hooks that can pose as a strangulation or choking hazards to turtles, fish and even sea birds. The durable and long-lasting nature of these equipment also continues to have an enduring impact on marine wildlife. Not to mention the microplastics that come from the gradual degradation of plastic equipment which may be ingested by all sorts of marine creatures, it is clear that the fishing industry needs to change the way it approaches the issue of discarding its damaged, lost or otherwise discarded gear.
Domestic sewage is a less obvious, yet surprising source of secondary microplastic pollution. Treated sewage contributes greatly to microplastics in water bodies, with much of it being fibres, fragments and flakes, as a study done in 2018 found (Kay, Hiscoe, Moberly, Bajic & McKenna, 2018). Although the study was conducted in England and data was limited to river catchments, there has also been evidence suggesting that a large amount of these microplastics flow from rivers into various oceans in the world. As mentioned before, microbeads are also able to bypass water treatment systems due to their small size, and can enter water bodies easily.
There is much to unlearn about the prevalence of plastics and much to dissect about the impacts that it has on both humans and marine wildlife. On an individual level, we have critical roles to play in reducing our microplastic pollution. If everyone were able to reduce their usage by even just 20%, the plastic soups of our oceans would be greatly reduced.
If you are interested in reading up on river plastics entering the ocean, a study has been done studying its impacts. Read about it here: https://www.nature.com/articles/ncomms15611
Bibliography:
Kay, P., Hiscoe, R., Moberley, I., Bajic, L., & McKenna, N. (2018). Wastewater treatment plants as a source of microplastics in river catchments. Environmental Science And Pollution Research, 25(20), 20264-20267. DOI: 10.1007/s11356-018-2070-7
Laville, S. (2019). Dumped fishing gear is biggest plastic polluter in ocean, finds report. Retrieved 7 September 2020, from https://www.theguardian.com/environment/2019/nov/06/dumped-fishing-gear-is-biggest-plastic-polluter-in-ocean-finds-report
National Geography. n.d. Microplastics. Retrieved 7 September 2020, from https://www.nationalgeographic.org/encyclopedia/microplastics/
