One Hundred Billion
Last August marked the fiftieth anniversary of plastic pollution landing the cover of Science.
The August 1974 issue pictured a petri dish teaming with plastic particles netted from the Caribbean and the waters off the eastern United States. Depending on the location, sometimes half, sometimes two-thirds of the researchers' plankton samples contained plastic particles, ranging from preproduction pellets to smaller slips of foam, film, and even fragments of (what the researchers surmised were) former tableware, food containers, and other disposable items. The feral plastics had been collected during the summer of 1972, as worldwide production of plastics approached 100 billion pounds per year* and atmospheric levels of carbon dioxide (CO2) climbed to 327 parts per million (ppm).
One Hundred Ninety Billion
A decade later, in 1984, 150 marine scientists gathered in Hawaii to discuss the proliferation of plastic debris. The conference caught the attention of the New York Times, which on Christmas Day ran the headline: "Deadly Tide of Plastic Waste Threatens Worlds' Oceans." The plastics industry produced 190 billion pounds of plastics that year. Carbon dioxide topped 334 ppm.
Soon Ronald Reagan's White House convened an Interagency Task Force on Marine Debris. The marine biologist Kathryn O'Hara founded the International Coastal Cleanup and published A Citizen's Guide to Plastics in the Ocean. Beach cleanups became popular, even regular events.
Three Hundred Billion
Richard Thompson organized one such cleanup in the early 1990s as global production rates exceeded 300 billion pounds per annum. Thompson was a graduate student at the University of Liverpool. He busied himself carting plastics off UK shorelines where he'd meant to be studying algae and limpets. As Thompson cataloged the gleanings – some 20,000 items – he assigned them to categories: "bottles, bags, rope, netting." But much more of what he'd found wasn't identifiable. He couldn't parse their former function or what product they once contained, he wrote in The Conversation last year. Absent a category, he worried, a predominant kind of plastic pollution was going un- or underreported.
Eventually, he wondered: as plastics fragment into smaller pieces, how small do the pieces get? At the University of Plymouth, he challenged his graduate students to investigate. They placed sand and other shoreline sediment under the microscope; they looked in the guts of marine life and in plankton samples from the 1960s and 1970s. Everywhere the researchers found tiny fibers and trace fragments, their levels increasing as time passed.
Five Hundred Sixty-Four Billion
In 2004, Thompson, joined by seven others, published their findings (also in Science), naming the category: microplastics. That year, the global industry produced more than 564 billion pounds of plastics. CO2 levels approached 378 ppm.
Microplastics research bloomed. In just two decades, seven thousand research publications have documented the planetary spread of microplastics into the deep sea, the atmosphere, or mixed into soil. Research showed microplastics weren't just the result of pellet releases or the environmental weathering of larger items, but also intentionally added to products and generated during use, shedding from tires and painted surfaces, from wearing and not just washing synthetic fabrics, and from the mundane acts of twisting open plastic-capped bottles or ripping into plastic-bagged foods. Now researchers are developing even more sensitive methods to detect particles as small as viruses in bodies, in organs, and even cells. (See Thompson and colleagues' twenty-year retrospective in Science and Dr. Ted Schettler's piece in this issue).
