Tuesday, December 3, 2013

Why Should We Care?

 Everyday about 140,000 pounds of toxic chemicals enter the Puget Sound, endangering the environment that many orcas call home. According to Environment Washington: In 2008, 549 streams and rivers carried poor water quality from stormwater and toxins that were in tributaries to the Sound. By 2010, more than 521,000 pounds of toxic waste, including cancer-causing chemicals, developmental toxins and reproductive toxins, were dumped in Washington waterways. Every year, more than 9,600 pounds of plastic additives are discharged from sewage treatment plants in the Puget Sound region. More than 1 million pounds of toxic chemicals made their way into Puget Sound from surface runoff, groundwater discharge and city wastewater outfalls.

According to the Port Townsend Marine Science Center: Both transient and resident orcas are impacted as they acquire and retain persistent organic pollutants through the foods they eat. These chemicals, which include PCBs, DDT and other pesticides, have been released into the environment where they accumulate in the tissues of marine life. Made from carbon-based petroleum products, they degrade extremely slowly and can persist in the environment for decades or more.

This diagram shows how small amounts of organic pollutants (the dark red dots) attach to phytoplankton (microscopic plants), at the base of the food web. When phytoplankton is eaten by tiny animals known as zooplankton the contaminants are passed to them. Zooplankton consume many times their own weight as they live and grow so over time their bodies will accumulate higher concentrations of contaminants than the organisms they eat. Zooplankton are then eaten by larger organisms, which are then eaten by fish such as salmon that orcas eat. Every step up the food web results in higher, more concentrated contaminant levels.

PCBs, known to be dangerous to humans for a long time, were used in the US from the 1920’s until they were banned in 1977. During this time, many PCB manufacturing plants nationwide carelessly dumped PCBs into nearby marine waters, and attempts to dispose of it by burning sent it into the atmosphere, dispersing it worldwide.
Urban bays in Seattle, Tacoma and Bremerton, WA have some of the highest levels of PCBs on the west coast. Elliot Bay, Sinclair Inlet and Commencement Bay are particular PCBs hotspots. There are also old PCB dumps on land, where surface water can carry the chemical into the Salish Sea, more than 30 years after it was banned. Biological effects of these compounds in animals (including humans) include cancer, endocrine system or immune system disruption, and interference with brain development in the fetus. In numerous studies on other marine animals, PCBs have been found to cause a weakened immune system, poor reproductive development and malfunction of the thyroid gland, all potentially serious conditions.

According to Environment Washington: Exposure to toxins and pollutants threatens the state's $147 million a year commercial and recreational fish industry as well as the state's $9.5 billion tourism industry - both built around the Sound. Research shows that 30 percent of Chinook salmon spends the entire marine part of their life in Puget Sound, rather than swimming out to sea. Due to the Sound's increased levels of pollution, their diets now have elevated levels of toxic chemicals.

Resident orcas depend on this salmon as their primary food source, and so consume extremely high levels of PCB. Thus, Orca whales in the Puget Sound are considered to be the most PCB-contaminated mammals on earth. And usually Male orcas of both resident and transient populations tend to have higher PCB levels than females, even though they eat the same food. This is because organic contaminants like PCBs are fat-soluble and are stored in an orca's fat deposits. When a female orca gives birth and nurses her young, most of her fat-soluble contaminants are passed to the calf through her milk. Usually this results in adult females having lower contaminant levels than adult males.

No one knows for sure what the consequences of this pollution will be yet, but one thing is for certain: it will not be pretty. There are many reasons that contribute to Orca endangerment. The high amount of pollution in the water creates toxins in their bodies. Another contributing factor to Orca endangerment is vessel traffic (includes boats of all sizes and boats that take groups of people whale watching). A great example of pollution is the use of plastic. Whales not only in the Pacific Northwest area are being affected by this type of pollution but all over the planet they have been found dead and washed up on shore with plastic bags in their stomachs.

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