Bioaccumulation Gradual build up of Chemicals (stored in the fatty tissue) in the organism. This process eventually leads to birth defects (failure to reproduce) through 1. Food intake 2. Skin contact 3. Respiration Example: Decline of Amphibian population- frog. - How? Why? And what is the importance?
Extinction of Frog (not in your notes) Amphibian are sensible to chemical change. Since the 80s the world amphibian population has declined and birth deformities have increased.
This may due to : drought, increased UV rays, pollutions habitat loss, parasites and disease
Keystone Species: species that can greatly affect population numbers and the health of an ecosystem. Note: Entire ecosystems can be affected if a keystone species is affected by bioaccumulation. Eg. bioaccumulation of PCBs in the B.C. Orcas. PCBs will affect the reproductive cycles of Orcas until at least 2030, even though they were banned in ‘77.
PCBs and DDTs Chemicals like PCBs and DDT & other insecticides are called persistent organic pollutants (POPs). – POPs contain carbon, & remain in water & soil for many years; used to control mosquitos – DDT, even at low levels (5 ppm) causes nervous, immune & reproductive system disorders in animals. – ppm = parts per million
ppm (parts per million) one ppm means 1 particle of a given substance is mixed with 999,999 other particles Equivalent to one drop of dye mixed with 150L of water
IIn Class Assignment… Use page 97 to 98 to complete the table in class- “heavy Metal chart” - 10 min
Bioaccumulation 1. POPs (Persistent Organic Polymers ): are carbon containing compounds that remian in the soil for many years. DDT was used to control mosquitoes but it biomagnifies and hurts plant and animals. 2. Heavy Metals: Some heavy metals are good for human health in small quantities, but if they are released in our atmosphere, they can biomagnify and be harmful. 3 harmful metlas are lead, cadmium and mercury. 3. Lead: electronic wastes make up 40% of lead found in landfills. It is extremely toxic and can cause anemia, nervous system damage, sterility in men, low fertility rates in women, impaired mental development and kidney failure.
4. Cadmium : Released in the manufacturing of plastic and rechargeable batteries. It effects organism growth and raised death rates. IN human, it comes from cigarette smoking. Cadmium can damage your immune system, nervous system and DNA 5. Mercury: mercury poisoning can affect nerve cells, the heart, kidney and lungs. It can also suppress the immune system
Biomagnification the consumers in each trophic level receive larger doses of accumulated chemicals than the one before it. The bioaccumulation of PCBs begins with the absorption of the chemicals by microscopic plants and algae.
Reducing the effect of the pollutants If chemicals are trapped in the soil, they cannot enter the food chains as easily. Bioremediation: micro-organisms or plants are used to help clean up, and are then removed from the ecosystem. Example: The oil industry will often use bacteria to “eat” oil spills.