National parks like Joshua Tree, Rocky Mountain and the Grand Canyon — places that people generally think of as pristine —are plagued by microplastics, researchers have found. In a recent study published in Science, they showed just how many of these tiny plastic particles (ranging between four and 188 microns) are landing in protected areas. They determined more than 1,000 tons of these plastics are accumulating in national parks in the West each year, which equals about 123 million to 300 million plastic water bottles. The plastics, which come off of artificial clothing fibers or consumer products, can be consumed by different wildlife, from worms to seabirds to birds of prey. They can block their digestive systems, and plastics can also carry mutagenic, carcinogenic and endocrine disrupting chemicals, researchers said.