Bio-magnificationHow chemicals enter food webs…

Process describes how harmful chemicals enter and build up in food webs. Chemical concentrations are highest and most damaging at the top.

biomagnification causes accumulation of toxins in the food chain

• toxins increase in toxicity as they move up the food chain.

• Chemicals are filtered out of the water by phytoplankton and are passed with predation.

Fat and Water Soluble Chemicals• fat soluble - build up in food chains, cannot

be excreted from the body– DDT kills insects, but hurts ecosystems– PCB’s are man-made chemicals– heavy metals like lead, mercury, chromium

(Brian – mercury poisoning)

• water soluble – can be released in sweat and urine

The good ole days…

DDT- used by farmers.

• used in WWII to help control malaria, dengue fever, and typhus

• synthetic insecticide in the 1940’s-1960’s

• banned as an insecticide in early 1970’s due to harm on the environment

• ban helped bald eagle population rebound

• still legal to use for vector control

(bugs that carry diseases)

PCB’s

Organisms higher on the food chain have higher concentrations. Longer lived organisms have more time to accumulate them.

Organisms can have mutations

• on a lake in northern Wisconsin with a surface area of 27 acres. Figure 2. The droplet of mercury shown in this slide is about 1 gram; the same amount that is in a standard mercury thermometer and the total amount that is deposited annually

Mercury Contaminated Fish

Muskegon Lake• The US Environmental Protection Agency (EPA) and

the Michigan Department of Environmental Quality (MDEQ) have been working for several years to clean up the Muskegon Lake Area of Concern.

• The cleanup in Muskegon Lake is targeting contaminated sediment. While this work will greatly benefit the environmental future of Muskegon Lake, the fish in the lake will not immediately be free of chemicals. It will take time for the ecosystem to be restored.

•

• Although eating fish is still a healthy choice for you and your family, it is important to be sure you're choosing, cleaning and cooking the fish the right way to reduce chemical contaminants before you eat it.

Be safe when you eat fish…5 Simple Tips for Eating Safe Fish Trimming and Cooking • Cut off all the fat (see page 4 for directions). • Remove or poke holes in the fish’s skin before cooking. This will help the fat and chemicals drain off the fish. • Bake, broil or grill the fish on a rack. Throw away the drippings. • Do not eat the guts, head, skin, bones or dark fatty areas. • Do not re-use the oil that was used to deep or pan fry fish.

Choose wisely…

• 3. Eat smaller, younger fish. Bigger and older fish have had more time to collect more chemicals in their bodies.

• 4. Don't eat fatty fish like carp and catfish from polluted waters. Most chemicals (except for mercury) collect in the fat. Buy catfish from your grocery store instead.

• Do not eat any of the internal organs of any fish from any water body (example: liver).

Fish Advisory

• ▲ No eating restrictions. ▼ One meal per week.

• ● One meal per month. ■ Six meals per year.

• ◆ Do not eat these fish.