Ringed Seal

Author: (Contaminants & Remediation Directorate)
Date: (March 2004)

PDF Version   (165 Kb, 2 pages)

The ringed seal is included in the traditional diet of the Inuvialuit, and is an important part of their health, culture and economy. People in the Northwest Territories are becoming more aware of contaminants in the environment. This fact sheet will describe what types of contaminants are in ringed seals, how they get there, and what this means to the health of the people who eat them.

Contaminants in ringed seals come mostly from the fish they eat.

For a variety of reasons, ringed seals are able to build up contaminants at higher levels than many other types of wildlife. Ringed seals are more exposed to some contaminants since they are high in the ocean food chain. This is a long food chain with several steps.

In the ocean, tiny plants and animals take up contaminants from their environment. Over their lifetimes, fish eat millions of these small plants and animals, and build up their contaminants. Ringed seals then eat the fish, and build up the contaminants even more. This process, where levels of contaminants increase when animals (predators) eat other animals (prey), is called biomagnification.

Also, contaminant levels in an animal can slowly build up over time, if the animal continues to eat foods with contaminants. This is called bioaccumulation. Since ringed seals can live quite long lives, they can build up elevated levels of contaminants over time.

Persistent organic pollutants (POPs) are contaminants that can build up in ringed seals.

Most contaminants in ringed seal are not present at levels high enough to cause concern. However, a few contaminants are present in ringed seals at levels to which people should be made aware.

PCBs, and the pesticides DDT, HCB, HCH and chlordane can be found in ringed seals. These are examples of POPs (see PCBs, DDT and POPs fact sheets). They are long-lasting chemicals made by humans, that can build up in animal fat.

PCBs, and pesticides like DDT, HCB and chlordane, build up through the food chain and concentrate mostly in fatty tissues like blubber. Since ringed seals have much fat, they tend to have higher levels of PCBs than land animals. These POPs generally come from other countries or southern locations through air currents. There are also a small number of contaminated sites in the Northwest Territories that contain PCBs.

Ringed seals have lower levels of POPs than other marine mammals.

Levels of PCBs in ringed seals are generally lower than levels in polar bears and beluga, since polar bears can build up the PCBs from all the seals they have eaten over time. Also, it has been found that ringed seals in the Baltic Sea have at least 10 times higher levels of all POPs than in Canadian Arctic ringed seals.

Biomagnification

It is important to note that scientific research has indicated that PCB and DDT levels in ringed seals from the Inuvialuit region have dropped since the 1970s, following bans on PCB and DDT production and use. Levels of POPs such as chlordane and HCH are not found to be declining in ringed seal. Some new contaminants are being found in ringed seal but more research is needed to see if levels are increasing.

Heavy metals are contaminants that can build up in ringed seals.

Mercury and cadmium (see heavy metals fact sheet) are metals that can build up in organs of ringed seals. Unlike POPs they do not build up in fatty tissues. Mercury and cadmium are contaminants that can come from natural sources, such as weathering of rocks, but human activities in other countries can add to the natural levels. Mercury is naturally high in parts of the Northwest Territories.

Mercury concentrations have increased in ringed seals over the past 10 to 25 years. Cadmium (see heavy metals fact sheet) is also found in ringed seal, particularly in the liver.

Exposure to contaminants when eating ringed seal varies.

The levels of contaminants people are exposed to when eating ringed seal depends on many things. Different parts of the seal may have different levels and types of contaminants. For example:

• Meat has lower PCB and pesticide levels than blubber.
• Meat has lower cadmium and mercury levels than liver and kidneys.

Good News...

Ringed seal is a healthy and nutritious food to eat!

All living things including ringed seal do contain some contaminants. Health advisories however, have never been issued as the benefits of eating ringed seal are greater than potential risks from contaminants.

• Ringed seal is a good source of protein.
• Its liver and eyes are high in vitamin A.
• Ringed seal meat is also very high in iron.

Ringed seal is a delicious and affordable food that is good for you in many ways. Eating it helps keep people connected with the land and their cultures. Hunting for ringed seal helps keep people fit and healthy too.

For more information please contact:

Contaminants Division
Department of Indian Affairs and Northern Development

(867) 669-2699
Box 1500,
Yellowknife, NT X1A 2R3

QS-Y223-014-EE-A1