evidence: Your Soothing Cup of Tea May Contain Billions of Microplastics [...] She and her colleagues, led by McGill graduate student Laura Hernandez, decided to test the theory. They purchased four types of commercial loose leaf teas that are packaged in plastic bags, cut the bags open and removed the tea—so as to make sure that if any microplastics were found, they were coming from the bags and not the tea itself. Then the researchers dunked the tea bags in glass vials containing water heated to 95 degrees Celsius (203 degrees Fahrenheit), an average brewing temperature. Using electron microscopy, the team analyzed samples of the water and estimated that a single plastic tea bag steeped in hot water releases around 11.6 billion microplastics (which the study authors define as pieces that range from 100 nanometers to 5 millimeters in size) and 3.1 billion nanoplastics (pieces that are less than or equal to 100 nanometers in size). [...] As part of their study, the McGill team exposed water fleas, small aquatic organisms formally known as Daphnia magna, to various doses of microplastics and nanoplastics leached from tea bags. The little critters didn’t die, but they began to exhibit anatomical and behavioral abnormalities. They swam "crazily," Tufenkji tells Chung, and their carapaces—or defensive shells—did not develop properly.