In the United States, Americans eat and drink between 74,000 and 121,000 microplastic particles each year depending on their sex and their age, new research says. Those who drink bottled water exclusively, rather than tap water, can add up to 90,000 plastic particles to their estimated annual total, according to the new study.
The impact of this discovery on our health is not known. Research shows that some particles are small enough to enter out tissues, where they can trigger an immune reaction or release toxic substance and pollutants absorbed from the environment, including heavy metals. How do microplastics get into our food and drinks?
Not only do animals ingest tiny plastic particles in their environments, but microplastics contaminate our food during production and during packaging, previous studies suggest. To gain a handle on the ingestion levels, the researchers reviewed 26 previous studies that analyzed microplastic particle consumption in eight categories: alcohol, air, honey, bottled water, salt, seafood, sugar and tap water. Other foods, such as vegetables and meat, were not included in their analysis owing to insufficient data.
The researchers then estimated average consumption in these eight categories based on United States Department of Agriculture reports and the 2015-2020 Dietary Guidelines for Americans. Inhalation rates of microplastic particles were estimated using data from the US Environmental Protection Agency.
There are around 81,000 particles for boys, 121,000 for men, 74,000 for girls and 98,000 for women of ingested and inhaled microplastics every year, according to the study. Whether you drink tap or bottled water is key to ingestion of microplastics, the researchers estimated the particle intake through drinking water to be around 75,000 for boys, 127,000 for men, 64,000 for girls and 93,000 for women if bottled water is the only source.
For those who consume only tap water, microplastic intake for boys is 3,000 particles, 6,000 for men, 3,000 for girls and 4,000 for women.
"Our estimates of American consumption of microplastics are likely drastic underestimates overall," the study authors concluded.
Professor Richard Lampitt, the leader of the microplastic research team at the National Oceanography Centre in the United Kingdom, told Science Media Center that "the paper is a careful assessment of the data which has to date been published" and "the conclusions are sound." Still, Lampitt, who was not involved in the research, criticized the study's lack of a definition of "microplastics."
"Particle size is only mentioned in passing ... and yet this has a massive effect on the data presented and the conclusions reached," he said: Many of the studies on which the study's database is built will have failed to detect very small particles that some consider being "nano plastics and outside of this present study."
Alastair Grant, the professor of ecology at the University of East Anglia in the UK, also criticized the study's scope. He said, "No evidence is presented that these rates of consumption are a significant danger to human health."
He also said that "the figure for inhalation... does not take into account the systems that our bodies have to remove particles from the air that we breathe."
Stephanie Wright, the research associate at King's College London's analytical and environmental sciences department said the researchers have synthesized information for existing studies of plastic particle consumption and they reiterate something that is already known.
"Some of the included studies should be interpreted with caution, especially those which only rely on visual means to identify microplastics," said Wright, who was not involved in the research. "These current estimates suggest microplastic exposure is relatively low" and more research is needed to quantify individual exposures to "smaller microplastics, for example in air."
Ultimately, the impact on our health remains "unknown," she added. "It is difficult to interpret the current findings beyond the fact that we consume microplastics."
