Plastic is an integral material in modern society, valued for its durability, low cost, and versatility. Its presence is pervasive, found in everything from food packaging to construction materials. This widespread use has led to a significant accumulation of plastic in the environment. As plastic items break down, they create smaller particles that can infiltrate ecosystems and the human body, and research is illuminating how this material interacts with human biology.
Pathways of Plastic Exposure
The primary routes for plastics to enter the human body are ingestion, inhalation, and to a lesser extent, dermal contact. When plastic items degrade, they form smaller particles known as microplastics (less than 5 millimeters) and nanoplastics. These particles are widespread in the air, water, and soil, creating multiple opportunities for human exposure.
Ingestion is a significant route of exposure, as microplastics have been found in a wide array of foods and beverages. They contaminate seafood, as fish and shellfish can mistake the particles for food. Microplastics are also present in drinking water, both bottled and tap, and in products like sea salt. Additionally, chemicals from plastic containers and wrappers can leach into food, leading to direct consumption.
Humans are also exposed by breathing in plastic particles suspended in the air. These airborne fibers originate from sources like the shedding of synthetic textiles and vehicle tire wear on roads. Once airborne, these particles can be inhaled and travel into the respiratory system, where they may lodge in lung tissue.
Dermal contact is another potential pathway, though it is less understood than ingestion and inhalation. Many personal care products, such as exfoliants, have historically contained microbeads, which are tiny plastic particles. While the absorption of these particles through intact skin is still being researched, chemicals within these plastics may be absorbed.
Chemical Components of Concern
Plastics are complex materials containing chemical additives to provide properties like flexibility, color, or fire resistance. Many of these substances can leach out over time and enter the human body. Two of the most studied groups of these chemicals are phthalates and bisphenols.
Phthalates are chemicals used as plasticizers to make rigid plastics soft and flexible. This property makes them common in consumer goods, including vinyl flooring, food packaging, and children’s toys. Because phthalates are not chemically bound to the plastic, they can easily migrate out of products into the surrounding environment, including dust, air, and food.
Bisphenol A (BPA) is a chemical used in polycarbonate plastics for food and beverage containers and in epoxy resins that line metal food cans. Similar to phthalates, BPA can leach from packaging into the contents, leading to dietary exposure. While many products are now marketed as “BPA-free,” research suggests some replacement chemicals, like bisphenol S (BPS), may have similar biological activities.
Documented Health Impacts
The presence of plastic particles and their associated chemicals in the body can trigger a range of biological responses. Both the physical particles and the chemical additives can interfere with normal bodily functions, leading to health issues. The impacts can range from cellular stress to systemic problems, with significant concerns revolving around the endocrine system.
A primary health concern is endocrine disruption. Chemicals like BPA and certain phthalates are known as endocrine-disrupting chemicals (EDCs) because they interfere with the body’s hormonal system. They can mimic natural hormones, block hormone receptors, or alter hormone production. This interference can affect reproductive health, potentially leading to fertility problems, and may impact fetal development.
The physical presence of micro- and nanoplastics can also cause problems at a cellular level. When these particles accumulate in tissues, they can trigger an inflammatory response. Ongoing exposure can lead to chronic inflammation and oxidative stress, a condition where an imbalance between free radicals and the body’s ability to counteract them leads to cellular damage.
Research has pointed to potential effects on specific organs. Inhaled plastic fibers have been linked to respiratory irritation and may exacerbate conditions like asthma. Ingested plastics can interact with the gut, potentially altering the microbiome, and as particles enter the bloodstream, they may be transported to other organs, raising questions about long-term cardiovascular and neurological impacts.
Reducing Personal Exposure
Individuals can take practical steps to reduce their exposure to plastic particles and associated chemicals. These actions focus on conscious choices in the kitchen, household environment, and general consumption habits.
In the kitchen, shifting away from plastic for food storage and heating is an effective strategy. Using containers made of glass, stainless steel, or ceramic for storing food can prevent chemicals from leaching into meals. It is important to avoid microwaving food in plastic containers, as heat can accelerate the release of chemicals like BPA and phthalates. Filtering tap water can also help reduce the ingestion of microplastics.
Managing the home environment can lower inhalation of airborne plastics. Since synthetic textiles are a major source of microplastic fibers, frequent vacuuming with a HEPA filter can capture these particles. When possible, choosing clothing and furniture made from natural fibers like cotton or wool over synthetic alternatives can reduce the shedding of plastic fibers.
Consumer choices also play a part in limiting exposure. Reading labels on personal care products can help identify and avoid items containing phthalates. Opting for fresh, whole foods with minimal packaging can reduce exposure from food containers and wrappers, decreasing the ingestion of both leached chemicals and microplastics.