Microplastics, tiny plastic fragments less than 5 millimeters in length, are ubiquitous in the environment, found from the highest mountains to the deepest oceans. A recent scientific discovery, widely reported in 2022, involves their detection within human blood. This indicates plastic pollution has permeated our internal systems, raising significant questions for public health and environmental science.
How Microplastics Enter the Body and Bloodstream
Microplastics can enter the human body through various pathways, with ingestion and inhalation being primary routes. People unknowingly consume tens of thousands to millions of microplastic particles annually, estimated to be about 0.1 to 5 grams per week, roughly the weight of a credit card. These particles are found in drinking water, both tap and bottled, as well as in seafood, salt, sugar, tea bags, and milk. Microplastics can also transfer from plastic packaging into food, especially when exposed to high temperatures, such as during microwaving or from hot beverages.
Inhalation represents another significant pathway, as airborne microplastics are present in both indoor and outdoor environments. Sources include synthetic textiles, tire wear particles from vehicles, and general city dust. Indoor air often contains higher concentrations of microplastics, stemming from synthetic clothing, carpets, furniture, and even the unwrapping of plastic packaging. These inhaled particles can deposit in the respiratory system, with smaller particles potentially penetrating deep into the lungs.
Once inside the body, microplastics can travel into the bloodstream. For ingested microplastics, the particles can cross the intestinal barrier. From the lungs, microplastics small enough to reach the alveoli may then enter the bloodstream. Dermal absorption is also being investigated, with recent studies showing that toxic chemicals added to plastics can be absorbed through the skin into the bloodstream.
Potential Health Implications
The presence of microplastics in human blood raises concerns, though research into their long-term health effects is still early. One area of investigation is the body’s inflammatory response. Studies indicate microplastics can stimulate immune cells, particularly macrophages, leading to the release of pro-inflammatory molecules that contribute to chronic inflammation. This reaction is a general response to foreign invaders and could affect various bodily systems.
Microplastics can also cause cellular damage. In laboratory settings, smaller plastic particles induce oxidative stress, damaging proteins, lipids, and DNA within cells. This stress involves the production of harmful molecules that disrupt normal cell function. Such damage has been observed in various cell types, including intestinal, lung, and placental cells.
Harmful chemicals can also leach from microplastics once inside the body. Plastics contain various additives, such as flame retardants, plasticizers (like phthalates), and bisphenol A (BPA), which can separate from the particles. These chemicals are known endocrine disruptors, potentially interfering with hormone signaling and leading to adverse health effects, including impacts on reproductive health, metabolism, and increasing cancer risk.
Once in the bloodstream, microplastics can accumulate in various organs. Research has detected microplastics in human organs such as the liver, kidneys, and brain. Their accumulation in organs responsible for filtration and detoxification raises questions about long-term persistence and interference with organ function. The immune system’s response may also be altered, potentially leading to less efficient immune responses and a weakened ability to fight infections.
Minimizing Exposure
Reducing personal exposure to microplastics involves making conscious choices in daily life. A straightforward step is to minimize the use of single-use plastics, such as disposable water bottles, straws, and plastic bags. Opting for reusable alternatives made from glass or stainless steel for beverages and food storage can significantly reduce daily intake. Avoiding heating food in plastic containers, especially in microwaves, is also advised, as heat can accelerate the leaching of microplastics and associated chemicals into food.
Choosing natural fibers over synthetics for clothing and household textiles can help reduce microplastic shedding. Synthetic materials like polyester and nylon release microfibers during washing and wear, contributing to airborne and waterborne microplastics. Natural fibers such as cotton, wool, linen, and hemp shed fewer microplastics, and their fibers tend to biodegrade more readily in the environment. Using laundry bags designed to catch microfibers and air-drying clothes can further limit their release.
Filtering tap water is another practical measure, as both tap and bottled water can contain microplastics. Water filters with physical barriers, such as reverse osmosis or ceramic filters, are effective at removing a significant percentage of microplastics. Boiling hard water for five minutes can also help, as minerals can ensnare plastic particles, which can then be filtered out.
Improving indoor air quality by reducing dust and ensuring good ventilation can also lower exposure. Regularly vacuuming with HEPA-filtered vacuums and dusting with a damp cloth can capture airborne microplastics from synthetic textiles and other household items. Proper ventilation can help dilute indoor air pollutants, including microplastics, and prevent their accumulation within living spaces.