Plastic in the Pacific Garbage Patch, toxic substances contaminate fish
Photo: Mario Aguilera / Scripps Institution of Oceanography
Ever wonder where that bottle cap or cheap dime store action figure went when you casually tossed it away years ago? Well, there’s a good chance it ended up somewhere in the Pacific Garbage Patch, a soupy mixture of plastic and other debris swirling in the north Pacific Ocean.
Trapped there, the plastic becomes food for fish, clams, krill and even some sharks. In the process, they absorb PCBs, flame retardants, detergents and pesticides contained within the plastic particles.
Nearly one in every 10 small fish contain plastic, according to researchers at the Scripps Institution of Oceanography at UC San Diego, who released a report last week about the Garbage Patch. The authors estimate that small, inch-long fish in the intermediate ocean depths of the north Pacific are ingesting up to 24,000 tons of plastic per year.
The Patch, a vast expanse of plastics and other trash, is located in an area of ocean roughly twice the size of Texas, with slack winds and currents. Debris stagnates there for years before jettisoning off to one of the other four major oceanic gyres or washing up on our shores.
Fish and other forms of ocean life consume tiny plastic pieces known as microplastics, which break off from larger bits when exposed to waves and sunlight. These microplastics are usually an unidentifiable confetti of brightly colored plastic pieces.
Why does this matter to you? Well, plastics act as sponges for waterborne contaminants. Further raising alarms are the unknown effects of the toxins that plastic absorbs as the toxins work their way up the food chain into the larger fish species we eat. The majority of fish sampled by Scripps researchers include lantern fish, which play a key role in the food chain by connecting plankton at the base of the chain with species at higher levels. Although there is evidence of toxic accumulation in larger fish species, Scripps researchers reiterated the need to decipher the potentially damaging impact these toxins can have on humans.
All is not lost, though. Los Angeles has used the protections of the Clean Water Act to institute Total Maximum Daily Loads (TMDLs) for trash in the Los Angeles River, establishing limits on the amount of trash that can be discharged into the river. The TMDL, effective since 2008, mandates a 10 percent reduction in trash each year with a goal of zero trash by 2015. So far, the city has been successful in meeting its goals by using a combination of street sweeping, catch basins, cleaning, enforcement and installing trash control devices in the storm drain system. The Los Angeles River Trash TMDL can serve as a model for municipalities across the country to prevent plastic from entering oceans and other waterways.
While more research is conducted on the effects of toxins leached from plastics into our food source, you can start or join a beach cleanup group, avoid using single-use plastics, and re-use what you can. Every piece of plastic properly discarded is one that doesn’t end up on our plates.