Thanks to a new technology, microplastic and nanoplastic particles can now be detected in human organs.
Microplastics have polluted the entire planet, from arctic snow and alpine soils to the deepest oceans. They are also known to be consumed and inhaled by humans through food and water, but the potential effects on human health are not yet known.
The researchers expect to find the particles in human organs and have identified chemical traces of plastic in the tissue. However, such tiny fragments are difficult to isolate and characterize, and airborne plastic contamination is also a challenge.
questions and answers
What are microplastics?
Microplastics, defined as pieces of plastic less than 5mm in size, are repelled by washing synthetic clothing, vehicle tires, and spilling plastic pellets used by manufacturers. The physical breakdown of plastic waste creates them too. Rain washes them into rivers and the sea, but they can also be wind-blown, spread by flying insects, and land in fields when treated wastewater is used as fertilizer.
Studies have found microplastics in marine animals living on the ground and in sediments from the North Sea. Once ingested by small creatures, the microplastics move through the food chain. One study found that microplastic was present in each of the 50 marine mammals washed up on UK shores, and the pollution also occurs in humans.
In 2018, the World Health Organization announced a review of the potential risks of plastic in drinking water after an analysis found that more than 90% of the world’s most popular bottled water brands contained tiny pieces of plastic. The UK banned plastic microspheres in cosmetics and personal care products in January 2019, and the EU proposed new measures to curb their use.
To test their technique, they added 47 samples of lung, liver, spleen, and kidney tissue to particles obtained from a tissue bank set up to study neurodegenerative diseases. Their results showed that the microplastic could be detected in every sample.
The scientists, whose work will be unveiled at a meeting of the American Chemical Society Monday, said their technique would allow other researchers to determine the level of contamination in human organs around the world.
“It would be naive to believe that there is plastic everywhere but not in us,” said Rolf Halden of Arizona State University. “We now offer a research platform with which we and others can search for the invisible – these particles that are too small for the naked eye. The risk [to health] really lies in the small particles. “
The analytical method developed enables researchers to identify dozens of types of plastic, including the polyethylene terephthalate (PET) used in plastic drinking bottles and the polyethylene used in plastic bags.
They found bisphenol A (BPA), a chemical used in the manufacture of plastics, in all 47 samples. The US Environmental Protection Agency is concerned about BPA because “it is a reproductive, developmental and systemic toxin when tested on animals.” The researchers examined lung, liver, spleen and kidney tissues as these organs are likely to be exposed to or collect microplastics.
“We never want to be alarming, but the point is that these non-biodegradable materials are ubiquitous [may] enter and accumulate in human tissue and we don’t know the potential health effects, ”said Varun Kelkar of Arizona State University, part of the research team.
“Once we have a better idea of what’s in tissues, we can conduct epidemiological studies to evaluate human health outcomes,” he said. “That way, we can begin to understand the potential health risks, if any.”
Charles Rolsky, another member of the team, said, “In a few decades we have seen plastic no longer as a wonderful asset, but as a threat.”
Microplastics are less than 5 mm in diameter and nanoplastics are less than 0.001 mm in diameter. Both are largely caused by the abrasion of larger pieces of plastic that get into the environment. Research in wildlife and laboratory animals has linked exposure to tiny plastics to infertility, inflammation, and cancer.
The researchers are now testing tissue to find microplastics that have accumulated over the life of the donors. Tissue bank donors often provide information about their lifestyle, diet and occupation. It can therefore be helpful in future work to determine the main ways people are exposed to microplastics.
The new method the team has developed to extract plastics from the tissues and analyze them will be published online so other researchers can report their results in a standardized way. “This shared resource will help build a plastic exposure database so we can compare exposures in organs and groups of people over time and geographic area,” Halden said.
Previous studies have shown that people eat and breathe at least 50,000 microplastic particles a year and that microplastic pollution rains down city dwellers, with London, UK having the highest level of four cities analyzed last year. The particles can contain toxic chemicals and harmful microbes and are known to harm some marine animals.
Other work has shown that various types of nanoparticles from air pollution are present in human hearts and brains and have been linked to brain cancer.
This article was updated on August 17, 2020 after the researchers provided the Guardian with additional information to reflect the fact that the plastic particles had been introduced into the samples of human tissue.