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Americans dispose of millions of tons of plastic trash each year, including a few billion plastic bags. Some of that plastic invariably ends up in rivers, bays, and oceans either carried away by the wind, washed out to sea, or dumped directly in the ocean. Plastic bags and other bits of plastic post a substantial risk to birds, turtles, marine mammals, and fish. In fact, accidental ingestion of plastic trash is a common source of health problems and fatalities among sea birds, sea turtles, marine mammals, and fish. Boaters are also at some risk from encounters with plastic bags and other plastic trash.  Finally, the chemicals in plastics pose an additional hazard to fish, sea birds, turtles, marine mammals, and people. This post describes the nature of the problem in more detail.

The Nature of the Problem:

According to statistics from environmental advocacy organization EcoWatch, each year about 500 billion plastic bags are used worldwide. Most of those bags will float if they reach oceans or other bodies of water and can take 500 to 1,000 years to completely degrade. The average American produces 185 pounds of plastic trash per year. This vast amount of durable plastic trash collects in garbage gyres located at several Atlantic and Pacific locations where currents bring together streams of water and plastic trash.  According to Ocean Conservancy, plastic bags and utensils are the second worst form of ocean trash, after fishing gear, in terms of the threat posed to birds, turtles, and marine mammals.


Plastic bags can look like jellyfish,  a common food source for sea turtles like the endangered loggerhead. According to the Sea Turtle Conservancy, plastics kill about 100 million marine animals, including many turtles. All species of sea turtle are at risk. Turtles are at risk from floating plastic bags and other debris for two reasons. First, turtles also have downward-facing spines in their digestive tracts so they cannot regurgitate inedible items like plastic bags. Sometimes these trapped plastic bags decompose in the turtle creating gas bubbles that make it difficult for the turtle to swim. Turtles in this situation become easy pray for predators. Second, choking on plastic is a hazard. In addition to ingestion being a risk, turtles are also in some danger of becoming entangled in bags, which makes it harder for them to hunt and flee from predators, though entanglement with old fishing line is much more common.

Loss of Fish and Marine Mammals:

Fish and turtles eat bits of plastic, and develop health problems both directly from having bits of plastic accumulate in their digestive systems and from chemicals in the plastic leaching into their bodies. To a lesser extent, this is also a problem that sea birds face. Fish can also be caught and killed by abandoned nets. Accidentally ingesting bits of plastic can be just as harmful to fish as to turtles and sea birds. Even sharks, whales, and dolphins are accidentally eating plastic bags and other debris, often with fatal results.  Plastic straps, fishing lines, and bags can entangle sea creates and choke them or keep them from hunting effectively.

Sea Birds:

Sea birds like gulls and pelicans encounter plastic bags and other debris in several ways. Birds can die from eating plastic bags and other debris.  How often this is a cause of death is not known. Birds can also become entangled and drown or choke on plastic trash.  The plastic bits can choke birds, accumulate in their digestive tracts and starve them, or leach toxic chemicals into their bodies. In rare cases, birds exposed to decaying plastic and the chemicals that result would not be able to reproduce.

Plastic trash now turns up in almost every seabird checked, from Hawai’i to the Mediterranean Sea and elsewhere. The plastic debris has taken many forms: bottle caps, bits of plastic bags, fishing line, tiny bits of unidentifiable debris.  Because plastic debris turns up in so many dead sea birds around the world it is reasonable to call the threat a serious one.

Toxic Compounds:

Many marine animals are killed by being tangled in plastic trash or because of ingesting plastic but the chemicals in the bags also pose a hazard. [Research]((https:/phys.org/news/2009-08-plastics-oceans-decompose-hazardous-chemicals.html) has raised awareness of the hazards posed by these chemicals when they get into the water. As bags, soda rings, and bottles decompose they release toxic chemicals into the water. Some chemical components in plastic bags can have negative effects on hormones in both humans and animals. The hormonal changes, in turn, endanger the animals’ reproductive health. Two chemicals associated with plastics are connected with cancer. A chemical created when certain plastics decompose called styrene trimer (ST) is also suspected of causing cancer.  BPA is a known endocrine disruptor. These compounds disrupt the reproductive cycles of marine mammals and fish and may end up being consumed by seafood lovers.

Damage to Boats:

Floating plastic bags might not seem like much of a threat to boaters, but they are. Bags, rings from six-packs of cans, and other plastic can foul propellers or jam jet intakes. Impacts with heavier plastic trash can also damage a boat’s hull. This is an uncommon problem but an inconvenient and expensive one. The great plastic garbage patches in the oceans also pose a threat to smaller craft. Boats are more a source of plastic bag trash than a victim of it though.

What’s Being Done:

The risks to so many marine animals have led governments and nonprofits to implement many programs aimed at cleaning up plastic trash or keeping out of the ocean. Scientists and conservationists have been working on cleaning up plastic debris. Other environmental activists are taking steps to keep plastic bags and other trash out of the sea. Everyone has heard or read ads encouraging them to buy reusable cloth or plastic grocery bags. Scientists have also developed biodegradable plastics that may be beneficial in plastic bag production. The easiest way to combat plastic pollution is to avoid buying plastic bags and other disposable plastic containers. Whenever possible, make sure your’re using reusable plastic that won’t end up in a landfill or the ocean.