Microplastics Not Fantastic

Microplastics! They’re everywhere! Didn’t you know? Surely, you knew! Microplastics have been found everywhere from the equator all the way to the poles. Over the course of the last four decades there has been an increasingly accumulation of microplastics. Global microplastic contamination pose hazardous impacts for marine environments, including risk ingestion by invertebrates and toxicological effects for biota. Before delving into micro-plastic contamination if you’re interested in differing definitions of micro-plastics, I highly recommend my former blog post or literature discussions about intuitive defining values.

Sources of microplastics:

Micro-plastics within our marine environments are derived from two core tenets: direct runoff carrying microplastics into our oceans via waste water and poor sewage treatment and fragmentation of meso and macro-plastic fragments.

1.      Direct runoff: The consumer manufacturing of micro-plastics and nanoparticles has become prevalent within cosmetic products, including our own facemasks with microbeads and exfoliants. These consumer products are introduced into waste water and evidence suggests unlikely to be removed by sewage treatment.   In addition, industry abrasives, such as acrylic plastics, can often be introduced easily into runoff. Microplastics are increasingly accumulating within our oceans, with Gouin et al., (2011) suggesting 100 tonnes of microplastic might be entering marine environments annually.

2.      Fragmentation: The fragmentation of macro-plastics and meso-plastics can occur through the mechanism of in situ weathering. Weathering through wind and wave processes can help fragment macro-plastics, such as commonly found beach litter, to micro-plastic sizes and then introduce them to the oceans.  Moreover, fragmentation has recently been indicated to occur from quotidian practices, such as the simple act of using a washing machine. Research from Napper and Thompson (2016) suggests washing a simple fluffy jumper can help release microplastic fibres into our waste water runoff.

Figure 1: Microplastics. Source: National Geographic. 

Distribution:

The understanding behind the spatial distribution of microplastics currently remains in its infancy. Most research studies implicate that microplastics are commonly found within a range of locations, including surface water, sediments and even inside some marine organisms. Moreover, research studies have indicated that the abundance of microplastics will vary according to time and space, with limited factors suggesting distribution. Our ability therefore, to assess potential sources of microplastics, either from potential poor sewage treatment or industrial spillages, contributing towards the spatial distribution of microplastics requires more comprehensive research prior to the arrival at a conclusion.

Figure 2: Microplastics within our environment. Source: Youtube.

Impacts on the marine environment:

Now to challenge all your preconceived, positive perceptions of those mighty fine microbeads within your facial cleanser. Recent research regarding microplastics has indicated severe and negative implications for the marine environment. The major negative implications of microplastics within marine environments involve the risk of ingestion by marine species. A plethora of empirical literature exists referencing accounts whereby marine species have accidentally ingested microplastics after mistaking particles as a food source. Notably, the North Pacific krill has been found to ingest microplastic particles, after lacking non-discrimination abilities and mistaking particles as an algae food source.

The ingestion of microplastics might also induce potential toxicological effects for marine species. The ingestion of contaminated plastics can sensu lato provide chemical transference from plastics to organisms, following mistaken ingestion. Sea birds following microplastic ingestion were found to have chemical additives transferred from plastics. Additive chemicals, found within microplastics could potentially provide pain and harm to marine species. Nevertheless, the ability to examine levels of harm from microplastics are still at preliminary stages, with limited empirical evidence postulated to support pain claims. Moreover, Lusher (2015) claims ‘a majority of birds examined did not die as a direct result of microplastic uptake’ and suggests macro-plastics, prior to fragmentation, had greater negative implications for marine environments.  

Figure 3: Distribution of micro plastics, with each dot representing total accumulation. Source: National Geographic.

A final caveat from the contamination of microplastics within  our marine environments is habitat change. If you want to know more about the habitat changes of species from plastics, check out this incredible blog post!

Solutions:

One proposed solution for tackling the negative marine implications of microplastics is the introduction and improvement of beach cleaning efforts. The removal of plastics prior to their fragmentation and introduction to oceans is a mitigation strategy towards limiting ingestion by marine species.

Figure 4: Beach cleaning efforts. Source: CNN.