If you happened to read the Vancouver, British Columbia Sun newspaper last month, you might have noticed an article stating that the waters off the British Columbia coast are awash in minute plastic particles, each about the size of a coffee ground. Research conducted by Peter Ross, a former research scientist with the federal Institute of Ocean Sciences, and his team found a record high of 9,200 particles per cubic meter of ocean (1 cu. meter = 3 cu. feet). That density can increase or decrease, depending on geography and currents.
So where do these plastics come from, and are they a threat to ocean organisms and the ocean food web?
For answers to these questions, read the article below. Reprinted with permission from WSU Snohomish County Extension, by J Styrna.
Humans are the source of all plastic debris in Puget Sound; the majority of it originates from land-based sources. Plastic products and pieces are produced in many shapes and forms and are used in myriad ways every day. Think about the plastic you may have used today - water bottles, computers, phones, packaging and DVD cases – and you’ll know how pervasive plastic has become in our lives. With more than four million people living in this region, our daily choices and consumer patterns impact the health and legacy of Puget Sound in many ways.
Products that eventually enter Puget Sound include things like fishing line, rope, wrappers, bags, netting, six-pack beverage rings, hollow fish floats, bottles, coolers, and small particles like nurdle pellets (plastic pellets that are the starting material for many plastic products).
In the North Pacific Central Gyre (pronounced jire) – one of seven gyres on the planet – the currents circle around due to wind patterns and objects are pushed into the center where it’s calm. Plastic pieces gather on an average of 334,271 pieces per square mile. Worldwide marine debris harms more than 267 species, including 86 percent of all sea turtle species, 44 percent of all sea bird species, and 43 percent of marine mammal species. |
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The Lifecycle of Plastic
Plastic Degradation
Plastic does not fully degrade; it continually breaks into smaller and smaller and smaller pieces. In fact, most of the plastic in the North Pacific Gyre is so small it’s almost invisible to the human eye; and many of the larger items are heavy enough to sit below the ocean’s surface. The degradation process is determined by the density and type of plastic, the temperature of the water and the types of additives embedded in the plastic during production.
Most plastics photo-degrade on land due to exposure to solar ultraviolet radiation and break down into smaller and smaller pieces. When in water, plastic may not get direct sunlight exposure; therefore breakdown happens much more slowly. Compostable plastics do not biodegrade in the ocean.
Plastics and Toxins
There have been a number of studies on persistent organic pollutants (POPs) binding to
plastic debris in the oceans. Recent studies have focused on the potential of organic contaminants from the marine environment to attach or adhere to plastic debris. It is shown that plastic debris can transport organic contaminants in the oceans. They have the potential to adsorb organic contaminants from the marine environment. It is possible, though not proven, that plastics could also release these contaminants to animals that eat these plastic particles.
Organic toxins that don’t dissolve well in water, such as PCBs (polychlorinated biphenyls), may bind to and accumulate on plastic debris at a rate of up to 100,000-1,000,000 times what is found in normal seawater concentrations. Research on invertebrates that feed on the bottom of the ocean suggests that toxins may be transferred from plastics to sediment to invertebrate. Further research is needed, taking into consideration the range of contaminant types, types of plastic, and environmental exposure effects.
Why Animals Eat Plastic
Degraded plastic can resemble natural food sources for fish and wildlife. There are three zones where marine life eats; surface, open water and bottom zones. Different food types live in the different ocean levels, and some food is found on the beach. Many birds are surface feeders and skim bugs or small bits of fish. Gulls, for example, eat fish, intertidal organisms, and beach debris on the ocean’s surface and on shore.
Fish are usually pelagic feeders, finding food in the open water column. Given the rich variety of food at this level, many whales, turtles, seals, and diving birds come here to dine on krill, anchovies, herring and other foods. Dolphins are also pelagic feeders, eating surfperch with their teeth. Orcas eat here, too.
Benthic, or bottom, feeders include sea otters, some whales, turtles, and schools of fish. Sea otters, for example, eat urchins and shellfish by diving down to the bottom and bringing them to the surface to eat.
Animals that feed in different areas of the ocean encounter different forms of plastic. Gulls, for example, accidentally eat up bits of floating plastic pellets thinking it is a food source, but wouldn’t scoop up a large, floating, angular object such as a pieces of a Styrofoam ice chest, or a hollow plastic bottle.
Plastics harm aquatic animals in a variety of ways, based on the buoyancy of the object. Some plastics float, while other plastics sink. Animals can be harmed through entanglement, laceration, suffocation, and ingestion because marine organisms don’t recognize it as non-food or know how to respond to it. Many encounters result in injury or starvation (with a full belly of plastic) and death.
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The albatross has become the poster child for ingesting plastics. Locally, the Port Townsend Marine Science Center studied the stomach contacts of gulls on Protection Island to determine how much plastic the birds residing on this preserve just off Port Townsend were eating.
How to Prevent Plastics Pollution
We, as humans, are connected to the ocean, and the health of the ocean depends on us. Common land-based sources of plastic pollution are littering, dumping and improper waste management practices, storms that clean our landscape of litter (where storm drains flow into nearby streams that flow into rivers that flow into the ocean), and extreme natural events.
#1. The best thing that each of us can do is to use fewer plastic products. Each year, Americans throw away approximately 100 billion plastic bags. Simply by reducing the number of plastic bags we use, each of us will help reduce the amount of plastic that winds up in Puget Sound and eventually the Pacific Ocean. Many stores now will sell you reusable cloth bags. Why buy new plastic bottles of water when you can refill a glass jar or aluminum canister?
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#2. Secondly, don’t litter. Elementary school children today know that littering is not good for
Puget Sound. Most adults do as well. If you drive vehicles with open air compartments, like trucks, keep the debris from leaving your vehicle with traps and ropes. A car litter bag is always helpful to have in your vehicle.
#3. Pick up litter when you see it. Whether you are walking on a city street or a pristine beach in Puget Sound, pick up at least one thing you find. If you have a favorite spot you enjoy, bring a bag and clean it up! You’ll be amazed at how much you’ll find if you start looking. If you want to pick up beach litter on a regular basis, find out if there is a litter pick-up program for that area.
#4. Reuse and Recycle items as much as possible. When given the choice, purchase reusable items over single use items. Consider shopping for food items in “bulk food” sections where you can get larger quantities with less packaging – and often more cheaply. Recycling options keep expanding. Today, you can recycle items as diverse as printer cartridges, bottles, some plastic food containers, plant pots and even Styrofoam at special locations…it varies by community (and who your recycling hauler is) so check your local guidelines.
#5. Lastly, consider letting your neighbors, friends and any groups you participate in know about plastics and their impact. Organize a school poster contest on the problems with plastics, set up a recycling program at your community club – let your creativity guide you. Many organizations hold public land clean ups, so consider inviting others to join you in these events.