Plastic Debris in Aquatic Habitats

The problem is global as plastic is in salt and fresh water, on land and in rain, snow, ice and dust. 
plastic bottle - plastic waste washed up on shore

Plastic Debris in Aquatic Habitats

By Marge Sidney (BCLSS Director)

It seems nearly impossible to escape plastic in our everyday lives, doesn’t it?  And we can’t escape plastic pollution either.  Plastic is at our fingertips all day long.  Where does it all go?  We ship some of it overseas to be recycled.  Quite a bit ends up in landfills.  And more than you can imagine ends up on the loose as plastic pollution, eventually making its way into our water ways.

Plastic was discovered to be a problem in the oceans in 1996.  Here are some interesting facts:

1996 Now
90% of floating litter is plastic. 90% of debris in seabirds is plastic.
80% of marine litter comes from land. The rest is from ships. 88% of surface water collected contains plastic.
46,000 pieces of plastic litter are floating on every square kilometre of the oceans.  ~70% will eventually sink. 80% of plastic debris comes from land.  8 million metric tonnes enters each year from diverse sources.
1 million seabirds choke or get entangled in plastic each year. On average there are ~364,800 pieces of floating plastic per square kilometre. It is unknown how much sinks.
It’s projected that there will be a 10 fold increase in marine plastic debris every decade. No apparent increase or decrease in trends.
In North America, per capita usage will  increase to 148 kg/yr by 2010. Per capita usage of plastic in 2015 was 139 kg/yr in North America

Contamination

The problem is global as plastic is in salt and fresh water, on land and in rain, snow, ice and dust.  There are 5 gyres or collection points in the world’s oceans where ocean currents, particularly those involved with large wind movement, concentrate garbage. It has been found that more than 800 species have become entangled or have ingested plastic in the oceans.  Every level of the food chain is impacted.  Plastics can act as a source and/or a sink for various contaminants.  Plastic is derived from organic substances including crude oil, salt, cellulose, coal and natural gas and can leach these compounds into the environment.  Different plastic types (recycling numbers 1 through 7) absorb different contaminants from the environment such as PAH’s (Polycyclic Aromatic Hydrocarbons, PCB’s (Polychlorinated Biphenyls) and metals.  Chemicals from the plastic can be absorbed into the tissues of organisms that consume the particles.

Impact of Plastic

There are direct effects to wildlife both physically and chemically.  Entanglement is a serious issue as is a blocked or perforated gut.  Chemically, ingestion of plastic can cause liver toxicity resulting in tumors. In addition, much research is being done to determine the relationship between plastics and endocrine disruption. Indirect effects are seen when the food chain is taken into account as chemical compounds accumulate at the top.

Plastic Impacts to Human Health

Wastewater and runoff carry plastics into waterways and plastic objects are broken down into smaller pieces by sunlight and wave action.  These small pieces of plastic are often mistaken for food by organisims that are then harvested commercially and sold to grocery distributors.

Disturbing Facts about Plastic Pollution

  • In the Los Angeles area alone, 10 metric tonnes of plastic fragments—like grocery bags, straws and soda bottles—are carried into the Pacific Ocean every day.
  • Over the last ten years we have produced more plastic than during the whole of the last century.
  • 50 percent of the plastic we use, we use just once and throw away.
  • We currently recover only five percent of the plastics we produce.
  • The average North American throws away approximately 84 kgs of plastic per year.
  • Plastic accounts for around 10 percent of the total waste we generate.
  • The production of plastic uses around 8% of the world’s oil production (bioplastics are not a good solution as they require food source crops).
  • Annually approximately 500 billion plastic bags are used worldwide. More than one million bags are used every minute.
  • 46 percent of plastics float and it can drift for years before eventually concentrating in the ocean gyres.
  • It takes 500-1,000 years for plastic to break down.
  • The Great Pacific Garbage Patch is located in the North Pacific Gyre off the coast of California and is the largest ocean garbage site in the world. This floating mass of plastic is about the size of British Columbia, with plastic pieces outnumbering sea life 6 to 1.
  • Plastic constitutes approximately 90 percent of all trash floating on the ocean’s surface, with 17,700 pieces of plastic per 1 square km.
  • One million sea birds and 100,000 marine mammals are killed annually from plastic in our oceans.
  • 44 percent of all seabird species, 22 percent of cetaceans, all sea turtle species and a growing list of fish species have been documented with plastic in or around their bodies.
  • In samples collected in Lake Erie, 85 percent of the plastic particles were smaller than 0.5 cm, and much of that was microscopic. Researchers found 1.5 million of these particles per km2. Much of it was micro beads from personal care products and micro strands from fleece clothing.
  • Virtually every piece of plastic that was ever made still exists in some shape or form (with the exception of the small amount that has been incinerated).

What’s Next for Research

  1. Collect the detailed sources of contribution.
  2. What is the fate of plastics (missing sink?) and associated chemicals?
  3. What are the ecologically relevant impacts?
  4. What are the impacts to food safety?

This complex problem requires complex solutions.  If we are to continue manufacturing plastic then we need to ban harmful chemicals in the manufacturing process and in addition make plastic that degrades. Fortunately micro beads have been banned in Canada but we will need to decide if making fleece clothing from recycled plastic is the lesser of 2 evils.

Literature Cited

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