Fish and Paint Chips Part I: The Science of Trash

Recent research has the National Oceanic and Atmospheric Administration (NOAA) concerned that the huge quantities of metal, plastic, paint chips and other man-made debris floating at sea, hundreds and even thousands of miles from land, may be working their way into the American diet. NOAA, a part of the Commerce Department, largely exists to track weather patterns and hurricanes, and its entry into the public health sphere serves as an indication of how severe the problem has become. It is not too much to suggest that millions of seafood lovers might be ingesting the very chemicals that land-based health and safety regulations are designed to keep out of reach.

The world’s increasingly famous mountains of waterborne garbage are out of sight, but for the international community of ocean-watchers they’re hardly out of mind. The five so-called pollution gyres ─ massive fields of waste collected by wind and ocean currents in the North Atlantic, South Atlantic, North Pacific, South Pacific and Indian oceans ─ are already known to kill birds and sea life on a frightening scale. In 2002, a minke whale shocked the scientific world by washing up on a British beach, unable to eat because of plastic bags found in its stomach. Kenneth Weiss won a Pulitzer Prize in 2007 for his multi-part series in the Los Angeles Times explaining, among other things, how bottle caps, toy soldiers, toothbrushes and spray nozzles are choking hundreds of thousands of albatrosses to death on Midway Atoll, about 1,000 miles from the nearest city.

In-depth research on the scale and composition of these gyres is still in its infancy. What is known, however, is already troubling. The best understood of the five, the North Pacific gyre ─ sometimes referred to as the Great Pacific Garbage Patch ─ is itself divided into eastern and western halves, connected by a 6,000-mile-long current called the Subtropical Convergence Zone. The eastern half, although largely invisible from the ocean surface, is thought to be twice the size of Texas, a mostly submerged continent of solid waste, old fishing lines and suspended plastic bits off the coast of California that is known to kill jellyfish, sea turtles, birds, sea lions, fish and other animals by choking them or snaring them in rope. The western patch, off the eastern coast of Japan, is a prime source of Hawaiian beach litter, much of it decades old.

Although there is precious little hard information on the gyres’ sizes or exact composition, the risks to underwater and airborne wildlife are fairly well understood. Holly Bamford, the director of NOAA’s marine debris program, said that her staff has focused for more than a decade on removing derelict fishing nets from monk seal habitats around the northwest Hawaiian Islands. Three or four already large nets can clump together after being cast adrift and can move “like tumbleweeds” through the water, she said, necessitating massive removal efforts ─ over 600 metric tons’ worth near Hawaii alone since 1996.

What has received less attention, until now, is the potential for the gyres not only to kill ocean-dwellers but to send the chemicals in much of that garbage back up the food chain, ending in your stomach. Set against the vivid and obvious risks from nets and other sorts of visible dangers, Bamford said, it’s difficult to convince government agencies to spend time or money on such research. (Her program was only allotted about $4 million this fiscal year, despite being authorized $10 million a year in the 2006 Marine Debris Research, Prevention, and Reduction Act.) While NOAA predicted the existence of pollution gyres as far back as 1988 based on scattered data, there has been little concerted effort to measure their impacts on human health, she said.

Bamford admitted, however, that the potential dangers are very real, not least because plastic is proliferating at an astounding pace. According to a recent issue of the Philosophical Transactions of the Royal Society, the volume of plastic produced in the first decade of the 21st century approaches all plastic production during the previous hundred years. Floating plastic not only contains its own chemicals but readily absorbs others, such as from paints, coolants and metals, known to be harmful to humans. Small plastic bits, including pellets often referred to as nurdles, which form the raw materials of many plastic products of all types worldwide, are essentially toxic sponges, and they exist in the oceans (and on beaches) in uncountable numbers thanks to shipping spills, accidental releases at factories and a variety of other hazards. By the time small animals consume them, according to Bamford and other experts, they may have accumulated any number of toxic hitchhikers. Earlier this decade, research by Hideshige Takada and a team of Japanese experts found that plastic pellets can contain toxin levels up to a million times higher than that in the surrounding water.

What are these chemicals? To take just one example, exposure to polychlorinated biphenyls (PCBs), a common class of ingredient in old paints, has been linked to cognitive impairment in young children, severe rashes, liver damage and lowered immune response, depending on the dose and length of exposure. A 1968 overdose in northern Japan of PCBs in rice bran oil used as chicken feed led to an outbreak of what became known as Yusho Disease, sickening more than 14,000 people. Although the relative presence of PCBs in the gyres is unknown, according to Bamford, “we find paint chips and metal, not just plastics,” when trawling the gyres to study their pollution content.

A map of the worlds five major Gyres. The Garbage Patch is created in North Pacific Gyre. Photo by the National Oceanic and Atmospheric Administration

This is sobering when considered alongside recent research by Richard Thompson, a biologist at the United Kingdom’s University of Plymouth, who showed that zooplankton and other creatures at the bottom of the ocean’s food chain are definitely consuming nurdles and other small plastic pieces from the gyres. The fact that fish then eat those small creatures is well known. The last link in the chain, Bamford said, is whether the chemicals in the plastic enter the fishes’ systems, what researchers call “bioavailability.” If that is shown to be the case, then fish living in the vicinity of the gyres ─ which together cover vast swathes of the world’s oceans ─ are likely a conduit for toxic substances to humans.

Not everyone who follows the issue is convinced. Bill Cooper, who heads the Urban Water Research Center at the University of California, Irvine, is one of the academic community’s biggest advocates of further ocean cleanup, and is part of a team that set sail Sept. 7 from Hawaii to try to measure the scope and severity of the North Pacific gyre. Joining him on the trip, among other people, was Charles Moore, the founder of the California-based non-profit Algalita Foundation famous for discovering the gyre after a 1997 boat race. Working through his foundation, which promotes ocean research and education rather than political advocacy, Moore found in 1999 that there was six times more plastic in that polluted area of the ocean than zooplankton to feed the ecosystem, and in 2002 showed that off the California coast the ratio was only somewhat better at 2.5 to one. Altogether, the research team comprises some of the world’s most eminent gyrologists, people who have been at the forefront of bringing the issue to the world’s attention.

Yet Cooper doubts the human connection. “I’m not convinced there’s a human health problem here, but there is an ecosystem problem,” he said. Although some researchers have laid out the scenario already described, by which plastic collects toxins that move from smaller creatures through bigger ones to humans, “I have a hard time believing that’s related to human health.” In his view, the threats to wildlife are serious enough by themselves. “We know about a million sea birds die a year from [pollution] ingestion, and about a hundred thousand sea animals die a year from plastics. I don’t think [plastic] changes the ocean chemistry much, but derelict nets scour the oceans” killing marine life ─ a major danger, with or without any added human health concerns.

Given this note of skepticism, Bamford and her colleagues are hardly leaping to conclusions; indeed, NOAA has received some criticism for moving too slowly on the issue. A planned three-year research approach she described, complete with new standardized data collection protocols to replace the information she receives now, “not all of it from scientists,” was derided by Marcus Eriksen, Algalita’s director of research and education, as an unnecessary delay. “I think we’re already finding what we’re looking for,” he said of current data collection methods, which involve using simple net-dragging techniques often used to find plankton now being adapted to find plastic bits. More importantly, he said, the risks are already apparent and call for a swifter response. During a gyre research trip last year, he said, his team collected 671 small fish known as myctophids, no more than three inches long, “and 35 percent of them had plastic chips in their guts. They’re the base of the food chain for the fish people eat” ─ tuna and swordfish, for instance. “But we haven’t found plastics transfer pollutants to the fish. That’s on the horizon.”

For Eriksen and others who agree with him, that horizon shouldn’t be three years away. “This time next year, we should have surface sample data from all five gyres,” he said, describing a new coordinated effort by Algalita and allied experts around the world to gather and share information. Those samples will consist of fish from the gyres and fish known to be plastic-free, which will be sent to independent labs to compare their relative levels of toxicity. “We know albatross, snails and worms uptake pollutants they eat, but we don’t know if the fish do it,” he said. “We’ll know next year.”

Bamford is more cautious. “A good study takes two years to get results at the other end,” she said. “It will take two or three years for a full understanding, but we’re not sitting back in the meantime.” One reason for the longer time frame is that NOAA is not just sampling fish tissue, she said. “The increased measurements of this material in the oceans is interesting, and we’re trying to measure the density of the total debris.” Discovering the sources and movement patterns of all those loose nets in Hawaii and elsewhere is another large challenge, one with a potentially large payoff: if they can find where the nets damaging monk seal habitats come from, “we can get them with ships before they reach an island. We’ve gone out and done a few test runs based on ocean current models, but it’s hit and miss. It’s in its infancy, like trying to find a needle in a haystack at this point.” Predicting any kind of definitive breakthrough on any of these complicated problems within a year is to her mind premature.

The remains of an Laysan Albatross chick illustrates how much plastic is consumed by wildlife and its deadly consequences. Photo by Duncan Wright

But some experts are already warning of the danger to today’s consumers. Theo Colborn, a pioneering researcher on the ecosystem impacts of endocrine-disrupting chemicals and a de facto scientific leader of the movement to make products less environmentally harmful, said the risks from seafood “definitely need more attention, but it’s difficult for people to understand. How do you prioritize it versus terrorism and other problems people can feel?” While Greenpeace was once instrumental in pointing out the risks of chemicals to whales, she said, lately “it’s just been left behind,” not only as a scientific issue but as a political one.