What Are Microplastics?
Microplastics are categorized into two main types: primary and secondary microplastics.
Primary Microplastics
Primary microplastics are manufactured to be small for specific uses. They are often found in personal care products like exfoliating scrubs and toothpaste, where they are used as microbeads. Additionally, they are used in industrial applications such as sandblasting and in the production of some medicines.
Secondary Microplastics
Secondary microplastics are the result of larger plastic items breaking down over time due to environmental exposure. This degradation process can be caused by sunlight (photodegradation), mechanical forces (such as wave action in oceans), and biological degradation. Common sources of secondary microplastics include plastic bags, bottles, fishing nets, and other discarded plastic items that fragment into smaller pieces as they degrade.
How Do Microplastics Enter the Environment?
Microplastics enter the environment through various pathways. Here are some of the primary ways they spread:
Wastewater Treatment Plants
Many microplastics originate from personal care products that are washed down the drain. Wastewater treatment plants are not fully equipped to filter out these tiny particles, allowing them to pass through and enter rivers, lakes, and oceans.
Breakdown of Larger Plastics
As mentioned earlier, larger plastic items break down into smaller pieces over time. This process is exacerbated by improper disposal and the accumulation of plastic waste in the environment. For example, plastic litter left on beaches or in urban areas can be carried by wind and rain into water bodies, where it fragments into microplastics.
Synthetic Clothing
Washing synthetic fabrics like polyester and nylon releases microfibers, a type of microplastic, into the wastewater system. These microfibers are shed from clothes during washing and can easily pass through wastewater treatment plants, ending up in aquatic environments.
Industrial Processes
Industrial activities, such as plastic production and recycling, can release microplastics into the air and water. Additionally, plastic pellets (nurdles) used as raw material in the manufacturing of plastic products are often spilled during transport and handling, contributing to microplastic pollution.
The Impact of Microplastics on the Environment
Microplastics pose a significant threat to various ecosystems, particularly aquatic environments. Here are some of the key impacts:
Marine Life
Microplastics are ingested by a wide range of marine organisms, from tiny plankton to large fish and marine mammals. Ingestion can lead to physical harm, such as blockages in the digestive system, and can also expose organisms to toxic chemicals that adhere to the surface of microplastics. These chemicals can accumulate in the food chain, ultimately affecting human consumers.
Habitat Disruption
Microplastics can accumulate in sediments, altering the physical and chemical properties of habitats. This can affect the organisms that live in these environments, disrupting food webs and ecological processes.
Chemical Pollution
Microplastics can act as carriers for harmful pollutants, such as pesticides and heavy metals. These pollutants can be released into the environment when microplastics degrade or are ingested by organisms, leading to further contamination of ecosystems.
Human Health Concerns
The presence of microplastics in the environment also raises concerns for human health. While research is ongoing, here are some potential risks associated with microplastics:
Ingestion
Microplastics have been found in various food items, including seafood, salt, and even drinking water. Ingesting microplastics can expose humans to harmful chemicals and additives used in plastic production, some of which are known to be endocrine disruptors and carcinogens.
Inhalation
Microplastics can become airborne and be inhaled by humans. Inhalation of microplastics may cause respiratory issues and introduce toxic substances into the body.
Chemical Exposure
The chemicals associated with microplastics, such as phthalates, bisphenol A (BPA), and persistent organic pollutants (POPs), can pose significant health risks. These substances have been linked to various health problems, including hormonal imbalances, reproductive issues, and an increased risk of certain cancers.