Marine Biology

Toxins that don’t Flush out

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The oceans of the earth are contaminated with many things. The main toxins that are currently alarming for the orcas are the persistent organic pollutants (POPS). Contaminants that fall under this umbrella are PCB’s (polychlorinated biphenyls), PBDE’s (polybrominated diphenyl ethers), dioxins and furans. Each of these comes from a unique source.

Dioxins and furans are produced when organic material is burned in the presence of chlorine. Some instances where this may happen are metal smelting, coal-fired generators, and paper and pulp mills.

Polychlorinated biphenyls were used in adhesives, paints, sealants, coolants, hydraulic fluids and transformer insulating fluids. PCB’s were banned in Canada and the United States in the 1970s. They are still produced in other areas on the planet and are still present in the environment.

Polybrominated diphenyl ethers (PBDE’s) are used as a flame retardant in a wide variety of products such as electronics, polyurethane foam, TVs, computers and sleeping mattresses.

What makes these toxins more deadly than others? It is all about the way the bodies of the mammals respond to exposure to the toxins and the food chain. The killer whales are most affected because they are at the top of food chain and they consume a lot of food.

The persistent organic pollutants do not quickly flush out of the body of the exposed creature. Instead, a great portion of the persistent organic pollutants is stored in the body and the fat cells. It begins at the very bottom with the mud and the water that is exposed. Then it moves up to the microscopic plants and algae.  The small vertebrates eat the algae and plants. The fish eat the small vertebrates. The salmon eat the small fish and the orcas eat the salmon.

Of course, it doesn’t always go in that order, and each of these food items is not necessarily one that every orca gets to eat every day. However, almost everything an orca eats is likely contaminated. That means very high concentrates of  POP are entering the orcas on a daily basis and in turn stored in their bodies at very high concentrations. So high that some are dying.

Another prominent and alarming factor is what happens as the females give birth. The calves are born with very high levels of POPS and the fatty rich milk is like infusing the calf with even more toxins. While the first calf tends to get the most, the milk is still contaminated through all the future births. The adult males have lower POP levels because the females release some during gestation and feeding.

Whales eat their prey whole or in large chunks by ripping and tearing them apart if they are attacking a large whale. They hunt in packs and alone. They have been known to “chum” the water with blood to gather larger prey.  An adult killer whale eats about 500 pounds of food a day to survive.

As the whales migrate and travel from region to region, their diets change. Scientists believe that part of the reason is that they won’t be competing for the same food source.

Is there really anything you can do to help? Be aware of the products you use and what happens to the environment. Be active in encouraging companies and countries to take care and use products and chemicals that are not harmful. Awareness often helps people make better decisions.

More about this author: Trenna Sue Hiler

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