What are Microplastics?
Microplastics are plastic components that are around a millimetre to a nanometre in size. These are usually the broken down components of larger plastic items. In some cases, they are so small that they cannot be seen with the naked eye. Microplastics are the sad result of the use of plastics that has taken the world since their invention. While there hasn’t been much scientific literature on them as of yet, the studies that have been carried out so far give serious indication they pose a large threat to marine life. The problem is that plastics do not decompose and their continued use is because of their versatile and cheap nature.
To make matters worse, so many things are made out of plastic, and not a great number of those items made are meant to be used long term. Such items are plastic bags and bottles. Besides, the problem is compounded by the lack of recycling drives in many countries outside Europe and the West where waste is usually just dumped out. The result is that these plastic materials end up in the terrestrial environment, and most detrimentally, the seas and oceans.
Sources of Microplastics (Formation)
1. Environmental Action
As previously established, plastics do not decompose, but they are broken down. It is predominantly the case in aquatic environments where the microplastics are created and also have the deepest impacts. As the plastic waste and debris floats around the ocean, they are exposed to the elements of harsh solar radiation and constant abrasion from the action of wind and water waves.
Over time, these elements break down the plastics into smaller chunks of debris and the cycle continues on and on until the remaining debris become microscopic. On the terrestrial environment, microplastics are created by human and animal action as the trudge on the plastics makes it easier to break them apart.
2. Human cosmetics
While environmental action is the most common way that microplastics are formed, the other relevant means comes from intentional human production of small beaded plastics. These have found use in the skin care and hygiene industry where small, plastic, microbeads are added to products such as shower gels and facial scrubs to increase their abrasive qualities and ensure that they provide proper exfoliation and cleaning.
These microbeads then slowly find their way into the water systems where they fail to be filtered out before being pumped back into natural waterways due to their microscopic size.
The other source of microplastics come in the shape of microfibres. Microfibres are essentially microscopic strands of plastics that unlike beads, are longer. They are a product of human clothing and when one washes plastic clothing, it sheds microscopic fibres into the water. These are arguably worse than the relatively spherical microplastics because they have a larger surface area.
Effect of Microplastics on the Environment
The challenges that microplastics pose on the environment are great in terms of three aspects;
- They are sources of chemical poisons,
- They are indigestible,
- They are choking hazards and an avenue for the spread of microorganisms.
Among aquatic life, microplastics are highly present. Researches from around the world have found the occurrence of microplastics in all oceans both the Arctic and the Antarctic. The challenge is that the size of these microplastics and the vast amount of human production of plastics coupled with the dumping of these materials in the ocean has intensified plastic pollution.
Nowhere else is this more evident than in the Pacific Gyre where ocean current pull the floating waste and plastics into a large region estimated to be the size of the state of Texas – also known as the Pacific Garbage Patch.
Effects on Animals
1. Choking Hazard
As the action of environmental elements continues to breakdown the plastics, they breakdown the plastics into smaller and smaller bits that are then inhaled by the various microbes and fish in the seas and oceans. These go ahead to clog up the insides of the animals and create a choking hazard. They end up in the gills of fish where they clog their breathing system.
2. Sediment in Blood
There are also challenges that are faced by molluscs and other bottom feeders. The individual organisms in these situations are particularly bad in that they draw water to feed and breathe, but the plastics cross the barriers that naturally occur among the animals’ membranes, making their way into the bloodstreams of the molluscs. Zooplankton also end up feeding on these microscopic plastics as they attempt to collect algae from the water.
Effects on Both Humans and Animals
3. Trophic level accumulation
What happens next is that these plastics are passed along the food chain towards the animals that feed on these molluscs and plankton such as bigger fish like whales and finally, human beings. This issue is compounded by the fact that unlike other indigestible materials that human beings feed on, microplastics end up within the bodies of the organisms rather than passing along the digestive system and being evacuated in urine or faeces.
4. Chemical poisoning
The biggest challenge is that plastics are both the source and sponge for many hazardous chemicals. For one, plastics contain within themselves various chemicals such bisphenol A (BPA), a chemical that is used to harden plastics such as water bottles and food dishes. The chemical has caused concern over the effects it has on the brain and possible effects on foetuses and their development as well.
Another example is triclosan, which is an antimicrobial chemical that is used on plastics but then ends up killing worms and fish that feed on the plastics for those very same antibacterial chemicals.
5. Attachment to body fats
Another danger is based on the manner the chemicals used in making plastics are made. Notably, the majority of the chemicals are fat loving and water hating. In other words, they attach strongly to the fatty acids and lipid layers within fish and not the water that surrounds them, which means that once the microplastics find their way to the body, it is very difficult to be eliminated. As a result, it poses even more dangers to the survival of aquatic fish.
6. Chemical Collection
Plastics have been known to soak up chemicals within their environs to very high concentrations. This is of particular concern owing to the fact that the sea has been the dumping ground for a lot of industrial waste for a very long time.
The toxic chemicals include DDT, PCB, and heavy metals such as copper, cadmium, and lead. All these are absorbed into the plastics, forming very high concentrations, which are then transferred to the animals that ingest these plastics.
7. Compounded effects with Microfibres
The other avenue for concern when it comes to the environment presents itself in the other kind of microplastics that cause a huge problem in the ocean – microfibres. Microfibres are a challenge because of their high density occurrence and the fact that they offer a wider surface area for organisms and chemicals to attach to. Hence, it makes them a greater source of the above mentioned challenges as compared to microbeads.
8. Introduction of invasive species
Another threat that microfibers pose is that they provide avenues for the transfer of biota across the world. Microbial organisms from various sea and fresh water regions attach themselves to the microfibres and enter the sea or vice versa in situations such as when ships carrying seawater as ballast end up dumping the water in fresh water lakes in order to rise above the water level in canals.
This practice also transfers the microplastics and their relevant microbes into regions that they are not indigenous. With the introduction of different microbes in the system, it can lead to the creation of alien species crisis in the ecologies of the affected regions. Therefore, it could lead to imbalances where organisms end up in a region where there is no predator and in turn, becomes overgrown and takes over the ecosystem. Ultimately, it leads to the destruction of the ecosystem.
Image credit: oregonstateuniversity , 5gyres
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