Microplastics: Understanding The Sources Of Pollution

Microplastics are plastic particles smaller than 5mm in size. They are found in marine and terrestrial life, having invaded the food chain, and have been detected in soil, surface waters, coastal sediments, beach sands, freshwater sediments, deep environments, and even rain and snow. They are caused by larger plastic pieces that break apart, resin pellets used for plastic manufacturing, or microbeads, which are small manufactured plastic beads used in health and beauty products. They can also be caused by synthetic textiles, city dust, tires, road markings, marine coatings, and personal care products. The increase in plastic production and poor waste management have led to a massive accumulation of plastic waste in the environment, which has resulted in microplastic pollution.

Poor waste management

In addition, even nations with well-established waste management systems still contribute significantly to the problem. For example, the United States and the United Kingdom produce the most plastic waste per person of any large country. Inadequate waste management practices in these countries can lead to the release of microplastics into the environment, particularly through wastewater treatment plants and landfills.

The improper handling of plastics in metropolitan areas can also lead to clogged drains, flooding, and health issues such as cholera and diarrhea outbreaks. Furthermore, the illegal trade of plastic waste, often due to limited plastic waste processing facilities in importing countries, poses an additional threat to the environment and rural communities.

The current waste management systems in many countries are not equipped to handle the growing problem of plastic waste. This is further exacerbated by the fact that plastics are used in nearly every industry, from packaging and vehicle manufacturing to aquaculture and personal care items. As a result, plastic waste ends up in landfills, where it can break down into microplastics and be released into the environment through wind or water erosion.

To address the issue of microplastic pollution, it is essential to improve waste management practices and reduce plastic consumption. This includes promoting recycling, proper disposal of plastic waste, and the use of reusable items instead of single-use plastics. Bioremediation, which uses microorganisms to break down microplastics via hydrolysis, has also been proposed as a potential solution to reduce microplastic-contaminated environments, particularly in soil.

Plastic products and packaging

One of the major sources of microplastic pollution from plastic products is synthetic textiles. Synthetic fibres such as polyester, nylon, and acrylic are forms of plastic and make up a significant portion of the fabric content in our clothes. These microplastics can be released during washing, with laundry detergents and fabric softeners also containing microplastics. Synthetic textiles account for 35% of engineered microplastics in the ocean.

Another source of microplastic pollution is plastic packaging. Single-use plastic products such as bottles and bags are often not disposed of properly and end up in the environment. Over time, light, oxygen, and mechanical abrasion cause the plastic to weaken and crumble into microplastics. Marine animals are at risk of ingesting these microplastics, mistaking them for food, which can lead to toxic chemicals dispersing into their bloodstream and tissue.

Microplastics can also come from larger plastic pieces that break apart. This can include plastic pellets used in manufacturing or plastic debris that degrades into smaller pieces. Marine coatings, such as polyurethane and epoxy, also contribute to microplastic pollution through weathering and spills during application, maintenance, and disposal.

To reduce microplastic pollution from plastic products and packaging, individuals can adopt reusable alternatives, such as water bottles, shopping bags, and food containers. Choosing natural fibres over synthetic fibres in clothing can also help reduce the presence of microplastics in the environment.

Synthetic textiles

The production and consumption of synthetic textiles are increasing due to population growth and the fast-fashion trend. The fibres released from these textiles during washing, drying, and wearing are a new source of environmental pollution and pose a risk to human health. These microfibres can pass through wastewater treatment plants and enter the oceans, where they are ingested by marine organisms, causing adverse effects on their metabolic activities.

Studies have estimated that synthetic textiles contribute about 35% of primary microplastics released into the oceans globally, with approximately 0.2 to 0.5 million tonnes of microplastics discharged annually. The first few washes of new synthetic clothing are particularly significant, as they release the highest amounts of microplastics. This has led to concerns about the impact of fast fashion on microplastic pollution, as garments are used briefly and then replaced frequently.

The type of fibres constituting the yarns and their twist can influence the release of microfibres during washing. The mechanical and chemical stresses that synthetic fabrics undergo during the washing process lead to the detachment of microfibres from the yarns. Additionally, the use of detergent and fabric softener can impact microfibre release, with powder detergents increasing friction and causing fibre breakage.

To reduce microfibre pollution from synthetic textiles, alternative production processes and textile construction methods can be employed. Pre-washing at manufacturing plants and using non-aggressive liquid detergents can also help capture a large proportion of released microfibres. By understanding the impact of synthetic textiles on microplastic pollution, we can make informed choices to minimise our contribution to this environmental issue.

Marine coatings

The liberation of microplastics associated with marine coatings during application, throughout its service life, and during removal and disposal is believed to be a contributor to ocean plastic pollution. For example, one study predicted that about 3.7% (around 55,000 tons/year) of the 1.5 million tons/year of primary ocean microplastics come from ship and yacht coatings. The release of microplastics from coatings may be amplified by in-water cleaning operations to remove biofouling.

The main release of microplastics associated with a ship's coating is thought to be a direct result of ultraviolet (UV) radiation, heat, microbial activity, and mechanical stress from wave and wind energy, all of which are known to degrade marine coatings. The hypothesis that ships leave a kind of "skid mark" of microplastics in the water has been proposed, similar to how tire wear particles from cars are left on land.

Commercial shipping operations have also been identified as a notable source of marine plastic pollution through the release of waste, marine coatings, and grey water. For example, cruise ships' grey water can contain 2,000 to 50,000 microplastic particles per liter. Several studies have found debris collected on beaches that is likely connected directly to shipping activities.

To address this issue, the International Maritime Organization (IMO) has promulgated preventative regulations intended to improve ship waste management systems, including plastics.

Personal care products

The mass production and wide application of plastics have resulted in a vast number of discarded plastic products in the environment, which gradually break down into microplastics. These microplastics, with a size of less than 5mm, persist in the environment and attract attention due to their potential ecological threats. They have been found in various ecosystems, including aquatic environments, terrestrial soils, and even in food and drinking water.

The consumption of single-use plastics and the improper disposal of plastic waste contribute significantly to the generation of microplastics. Plastic waste can persist for centuries if not disposed of properly, polluting the air, soil, and water. This disruption of the natural environment can lead to adverse effects on human health, including the disruption of the endocrine system and potential links to cancer.

To address this issue, several countries, including the United States, the United Kingdom, the Netherlands, Canada, and New Zealand, have banned microbeads in personal care products. However, current policies are often fragmented and fail to address all synthetic polymers used in these products. There is a need for more comprehensive regulations, increased public awareness, and further scientific research to fully understand the long-term health impacts of microplastics.

While some progress has been made, the problem of microplastic pollution from personal care products persists. With plastic production projected to triple by 2060, addressing this issue requires a combined effort from policymakers, industries, and individuals to reduce plastic consumption and transition to more environmentally friendly alternatives.

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