If we are what we eat, there’s growing evidence to help explain how nanoplastics and microplastics are in our blood, in our intestines and in some of our organs.

Two new studies published this week shed further, and alarming, light on all the tiny plastic particles that people are consuming every day.

A liter of bottled water may contain nearly a quarter million pieces of the smallest particles of plastic. These nanoplastic particles are so small, scientists have found, that some pass through intestines and lungs or make their way into human blood and placental fluid. The bottled water study, done by researchers at Columbia and Rutgers Universities, was published Monday in the Proceedings of the National Academy of Sciences.

Also published Monday, in the journal Environmental Pollution, was a paper from scientists at the University of Toronto and the Ocean Conservancy, which found that nearly 90 percent of 16 different kinds of protein commonly eaten by people, including seafood, chicken and beef—and even plant-based meat alternatives such as tofu and veggie burgers—contain microplastics.

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The scientists estimated that Americans are consuming up to 3.8 million particles of microplastics per year from protein alone.

“Our message is that you can’t hide,” said George Leonard, co-author of the Environmental Pollution paper and chief scientist at the Ocean Conservancy, an environmental nonprofit. “We need to know more about this, clearly,” and the health implications, he said. “There is zero chance that exposure to plastics is good for you. The question is, what is the magnitude of the risk and how do you minimize that?”

The two studies add to a global body of scientific research that has documented micro- and nanoplastics’ ubiquity in the world and increasingly in human bodies.

Researchers are still trying to understand the health implications, but many like Leonard have come to believe they’re not good.

Last year, the United Nations Environment Program counted 13,000 chemicals in plastic, many of them toxic. Chemical additives are used to give different kinds of plastic their own properties, such as flexibility, clarity and stretch.

The UNEP report, “Chemicals in Plastic,” noted that only half of the 13,000 chemicals in plastic have been screened for properties to know whether they are hazardous to people or the environment. But at least 3,200 of the 7,000 screened chemicals have been identified as potentially of concern, it concludes.