Miscelaneous

Why do marine animals have a higher concentration of PCBs than smaller ones?

Why do marine animals have a higher concentration of PCBs than smaller ones?

There is a high concentration of PCBs in the sediments of many places in the oceans. This is because PCBs have a high affinity for organic, particulate matter. Thus, the effects of PCBs in benthos are greatly magnified as they accumulate in the tissue of higher trophic feeders, including you and I.

How are PCBs affecting orcas here in the Salish Sea?

Orcas ultimately consume the PCB-contaminated salmon that reach the Salish Sea. PCBs in orcas disrupt reproduction and impair the whale’s endocrine and immune systems (Setac 2008).

What happens when PCBs enter an orcas body?

Killer whales, also called orcas, absorb PCBs from their prey. The toxic chemicals then accumulate in their blubber. Mothers pass the compounds to their calves via the placenta and in milk. PCBs can impair reproduction and disrupt the endocrine and immune systems.

What happens to orca calves that have mothers with high PCB amounts in their bodies?

The chemicals dissolve readily in fat, which means they not only accumulate in an orca’s blubber, but also in its milk. Through milk, a mother orca can pass up to 70 percent of her PCB burden to her calf—a toxic heirloom that then becomes concentrated in a much smaller body.

What are PCBs and how do they affect marine life?

PCBs tend to act as endocrine disrupting compounds, which disrupt the hormone balance of animals. This might cause immunodeficiency and or reproductive problems (which have been demonstrated in marine mammals). These effects are suspected to occur at much lower concentrations than those which cause acute toxicity.

How do PCBs get into the ocean?

PCBs have been released into the environment through spills, leaks from electrical and other equipment, and improper disposal and storage. Once in the environment, PCBs can be transported long distances and they bind strongly to soil and sediment so they tend to be persistent in the environment.

Are orcas affected by plastic?

Plastics, toxins, and entanglements are just a few of the major threats to orca populations worldwide, and in many regions we still don’t know enough to understand the effects on these iconic and remarkable whales.

How do PCBs enter the body?

PCBs can enter the body by eating or drinking contaminated food, through the air we breathe, or by skin contact. PCBs are easily absorbed by the body and are stored in fatty tissue. PCBs are not eliminated well, so they can accumulate in the body.

How are PCBs stored in the marine environment?

Marine mammals are particularly susceptible to the accumulation of PCBs as it amasses through the fish that they eat (which also have high levels of PCB) and it gets stored in their blubber. Female dolphins will draw on their fat reserves – where PCB compounds are stored – to produce milk.

How are orcas being affected by PCB pollution?

An orca helps herd a school of herring in the deep waters of the Andfjorden in Norway. ( See more of orcas .) Lingering PCB pollution poses a serious threat to the marine mammals. They live in chatty groups, and can hunt in teams—sometimes working in tandem to create waves that dump unlucky prey off floating ice.

When did the UN ban the production of PCBs?

For the chemists out there, the chemical formula for a PCB is C12H10-xClx and is made up of 2 benzene rings that contain multiple bonded chlorine molecules. The UN banned the production of PCBs in 2001 with the Stockholm Convention on Persistent Organic Pollutants, some 22 years after production was banned in the USA.

Where are the Southern Resident killer whales protected?

Identified critical habitat for the Southern Resident Killer Whales. Canadian and transboundary waters in British Columbia are protected under the Species at Risk Act. Washington transboundary waters are protected under the Endangered Species Act. Source: Fisheries and Oceans Canada.