01/06/2011 12:42 pm ET Updated May 25, 2011

Did You Just Eat a Plastic Bag? How Plastic Pollution Has Entered Our Food Chain

Many of us limit our intake of tuna and swordfish due to high mercury levels in those fish, but research is just beginning to show that we are consuming many other chemicals through our seafood, and our disposable plastic waste may be a potent source of this contamination. This article will take you on a possible journey from your plastic bag, to the ocean, and back to your dinner plate with a fish that may have fed on a plastic bag. Has our quest for convenience with throw away plastics led to contaminated fish?

What Happens to Disposable Plastic Products?

Unlike paper, glass and metals, which are well suited to recycling, plastics almost always make a one-way trip from the factory through limited use to the landfill or into the environment as pollution. The United States Environmental Protection Agency reports the following data on plastic products in the American municipal waste stream for 2008 alone:

1. Plastic Plates and Cups: 780,000 tons were produced, and all 780,000 tons were discarded.
2. Plastic Trash Bags: 930,000 tons were produced, and all 930,000 were discarded.
3. Plastic Bags, Sacks and Wraps: 3,960,000 tons were produced. 9.8% was recovered (390,000). 3,570,000 tons were discarded.
4. "Other" non-durable goods including plastic disposable diapers, footwear and clothing: amounted to 4,810,000 tons produced with all 4,810,000 tons discarded.
5. PET Bottles and Jars: 2,680,000 tons were produced, 27.2 % were recovered (730,000 tons) and 1,950,000 tons were discarded.
6. HDPE (white translucent homopolymer bottles): 750,000 tons were produced, and 29.3 % (220,000 tons) were recovered. 530,000 tons were discarded.
7. "Other Plastic Packaging" including coatings, closures, lids, caps, clamshells, egg cartons, produce baskets, trays, shapes, and loose fill: 3,720,000 tons were produced. 3% (110,000 tons) were recovered, and 3 Million 610 Thousand Tons were discarded.

From this data, you can see that your plastic bag had more than a 90% chance of becoming waste, not recovered. Recovered means kept out of the waste stream to be used again.

Why Wasn't my Plastic Bag Recycled?

Metals, glass and paper can return in the same form so that no new materials are needed. Plastic that is recovered is usually downcycled into a less pure product like fill for many reasons including the oliophillic nature of plastics (they attract oil and so are often contaminated from food or other oily contents), and different melting points for different plastics making segregation of plastics vital, while many products are hybrids of different plastics with different melting points. Many plastic products are not intended for recycling -- such as plastic trash bags, plastic personal hygeine items,and plastic razors that are hybrids of plastic and metal. Some plastics, like plastic grocery bags, are too lightweight to justify recycling for their raw material which is inexpensive. Many plastic bags are contaminated with food or other waste. Plastic bags are also infamous for jamming recycling center equipment, another reason they are not recycled even if they make it to a recycling center. Much potentially recyclable plastic is sent as waste to China where it is burned releasing toxins into the air that settle over the oceans just like mercury from coal burning.

Thus efforts to "recover" plastics doesn't stop the demand for virgin petrochemical product for new plastic goods. This means we are producing more and more disposable plastics that make a one way journey to wasteland.

Where does the discarded plastic, like my plastic bag, Go?

Into landfills and into the environment (through litter, open garbage dumps, waste burning, overflowing waste receptacles, loss in waste transport, loss from waste facilities etc...) where it washes into the oceans, now the world's great plastic dumps. Plastic bags, also known as urban tumbleweeds or plastic wind socks, travel easily with air and water currents to the ocean.

Here is a report from The State of California Action Plan for Plastic Debris :

"The quantities of plastic in ocean waters world-wide are increasing significantly. Within the Southern Atlantic Ocean, the amount of debris increased 100-fold during the early 1990s. In the coastal areas of Japan during the 1970s to 1980s, marine plastic-particle densities increased ten fold every ten years. However, in the 1990s, densities appear to have increased ten fold every two-three years. Micro plastics in the North Pacific have tripled during the last decade. Researchers at the University of Plymouth (UK) showed that particles as small as 20 micrometers in diameter are now common in marine sediments and in the water column. They also demonstrated that the abundance of this type of debris had increased significantly over the last 40 years. A range of common polymers was identified indicating that the microscopic particles probably formed by the breakdown of larger items. They concluded that their "findings demonstrate the broad spatial extent and accumulation of this type of contamination. Given the rapid increase in plastic production, the longevity of plastic, and the disposable nature of plastic items, this contamination is likely to increase. The environmental consequences of this debris are not known, but when kept in aquaria amphipods (detritivores), lugworms (deposit feeders), and barnacles (filter feeders) all ingested microscopic particles within a few days."

The data is not confined to the laboratory. Marcus Eriksen and Anna Cummins collected samples from the North Pacific Gyre during Algalita Marine Research Foundation's 2008 voyage across 4,000 miles of the North Pacific. On this voyage, Algalita MRF documented a doubling in the density of plastic particles since Moore's first published findings in 1999, as well as new evidence of plastic ingestion by lantern fish. Surfacing only at night to feed on zooplankton, these small fish are ingesting the plastic particles they find floating on the ocean surface. Of the 671 fish Algalita MRF collected in their night trawls, 35% had plastic particles in their stomachs. The record holder, a 2.5 inch long lantern fish, had consumed 84 pieces of plastic. Making up 50% of the oceans fish biomass, these lantern fish are a primary food source for Salmon, Tuna, Mahi Mahi, and other fish commonly eaten by humans, raising the obvious question: are chemicals from plastics getting into our sushi?

What does it Mean that Plastic has Become Part of the Oceanic Food Chain?

Just as Mercury from our coal-burning plants has entered our food chain through ariel deposits onto the waters, so too plastics and all the chemicals that make them and adhere to them are entering our food chain as they are consumed by ocean life. Apart from the chemicals such as BPA and Phthalates that are additives to the petroleum base of plastic, plastics are oliophillic (attract oil), absorbing oily toxins from the surrounding water (such as PCBs, partially burned hydrocarbons, like oil drops from cars, and pesticides, like DDT) and accumulating the toxins in concentrations up to one million times greater than those in the surrounding seawater. Algalita MRF has documented that our plastic waste, and presumably the toxins it concentrates, have entered our food chain. This means we are poisoning fish, an important source of protein, with our toxic waste. Using a canvas bag next time you go to the market is both good for the environment and good for keeping toxins out of your fish dinner.

For excellent visuals of how plastic pollution has entered our food chain, see the trailer for the new documentary Plastic Paradise.

Also see a recent televised news report on Plastic in Mahi Mahi.