microplastics, macroproblem Tiny particles of this man-made substance could mean big trouble in our oceans By Filiz Satir A century after its invention, plastic surrounds us from cradle to grave. It’s hard to imagine a world without the ubiquitous consumer goods and packaging materials in our everyday lives. It’s the baby’s pacifier and bib. It’s the nylon fibers woven into our clothes. It’s the cell phone and laptop, iPod and television remote. It’s the ballpoint pen and credit card, the grocery sack and “clamshell” food container. Through the decades, affordable plastic consumer goods have played a pivotal role in raising our standard of living. Durable equipment and commodities composed of plastic—the vacuum cleaner, dishwasher and computer, for example—have enhanced our productivity. Plastic medical equipment—a syringe used for injecting vaccine or a defibrillator that restarts a heart—saves lives. In all its forms, plastic has brought us all manner of affordability, durability and convenience. However, this amazing substance made from oil, coal and natural gas has become a growing ecological threat.
Scientists began describing the problem of large pieces of plastic debris in the environment during the 1960s. By the 1970s, researchers were reporting plastic’s effects on aquatic animals: Albatrosses ingested plastic bottle tops and balloons that blocked digestion and caused them to starve. Dolphins and turtles became entangled in fishing nets and drowned. Some 40 years later, a small group of ecologists, marine biologists and other scientists are pointing out an even greater threat—the widespread accumulation of small fragments of plastic. International scientists met at UW Tacoma this past fall to exchange research on this global pollutant. At stake are the world’s oceans, which have become dumping grounds for microscopic debris known as “microplastic.” The three-day international conference, hosted by UW Tacoma and sponsored by the National Oceanic and Atmospheric Administration (NOAA), brought many of the best minds in the field of marine plastic debris together for the first time to grapple with this emerging global problem. They left agreeing that far more research needs to be done in order to quantify microplastic’s prevalence, identify sources of the debris and understand its full effects.
“The world is seeing an exponential accumulation of plastic debris, from the very large to tiny fragmented pieces,” says Dr. Joel Baker, professor and Port of Tacoma Chair of environmental science at UW Tacoma. “In the past four decades, we’ve come to understand the ecological issues of large flotsam, but we lack substantive evidence on consequences of the smallest plastic particles for marine ecosystems.” Without definitive data it is difficult to rank microplastic’s effects on the environment with other known pollutants, Baker points out. But the occurrence of tiny plastics in our oceans, and their potential for transporting other toxic compounds, may come to rival the worldwide prevalence of DDT and its adverse effects on wildlife. “Initial findings suggest that microplastics, like DDT and other persistent pollutants, do not completely break down in the environment,” Baker said. “What is more, plastic particles in the ocean appear to have the capacity to absorb and desorb organic chemicals.”
Only a handful of the world’s scientists study plastic’s effects in marine environments. Nearly 20 years ago, Dr. Richard Thompson, a marine biologist in the United Kingdom, pioneered the investigation of microplastic and its pervasiveness in marine environments. Thompson studies microplastics present in ocean water, mixed in with seabed sediments and blended into sandy beaches. “Oceans and shorelines overrun with microscopic plastics absolutely is a greater concern than ‘macro-plastic,’ ” Thompson warns. “The widespread distribution of microplastics, combined with their size (five millimeters or less), make this debris highly available to more creatures that likely will ingest them.” International surveys investigating the amount of plastic debris in the oceans have, in general, focused on large detritus. The vast size of the oceans of the world make quantifying plastic particles the size of a pencil eraser or smaller a herculean challenge. Small plastic particles, in varying quantities, have been reported in habitats from the poles to the equator. Thompson’s groundbreaking research has shown that tiny creatures such as barnacles, lugworms and mussels ingest plastic particles added to aquarium sediment. His research indicates that plastic pieces in the organisms’ guts can migrate into their circulatory systems. Microplastics may play a role in passing pollutants to marine organisms. Various studies have suggested that plastic specks in water and sediment appear to absorb highly toxic and pervasive pollutants, such as PCBs (polychlorinated biphenyls) and pesticides such as DDT. As one theory goes, if the oceans’ smallest organisms are dining on plastics dosed up with toxins, then highly concentrated chemicals could possibly accumulate up the food chain.
“The possibility of more and more creatures ingesting plastics that contain concentrated pollutants is real, and quite disturbing,” Thompson says. Researchers studying the effects of microplastic on the environment do not advocate for a world without plastic. “Clearly, plastic products have many benefits,” Thompson notes. “I am not anti-plastic, but I am convinced that society is not using plastic in the right way. Most plastic is manufactured into products or packaging that we discard in one year or less from the date of purchase. That’s not sustainable.” The pioneering scientists hope to make a robust case for living in a world where plastic, in all its forms, causes as little ecological degradation to the planet as possible. Baker is working with national and international partners to change the way we see plastic. Later this year, he hopes to establish a microplastics research unit through the Center for Urban Waters. Baker serves as science director for the center, a new collaboration between UW Tacoma, the City of Tacoma and the Puget Sound Partnership. “As microplastics go, we need to put energies into research—investigations of the kind that will allow the scientific community to draw solid conclusions,” Baker says.
|
