Goal 5 - Bioaccumulation and Biomagnification
Biomagnification Bioaccumulation
What is a Pesticide?
Pesticides are chemicals
What do pesticides do?
Pesticides control “pests” (target population – what we want to kill).
What is a Pesticide?
Pesticides are chemicals
- Synthetic
- Inorganic compounds
What do pesticides do?
Pesticides control “pests” (target population – what we want to kill).
- Herbicides – pesticides to control unwanted plants.
- Insecticides – pesticides used to control nuisance insects.
Where do Pesticides Go?
Where do pesticides go?
Pesticides are useful when used properly, yet frequently they end up where they are not wanted.
Pesticides are useful when used properly, yet frequently they end up where they are not wanted.
- food supplies
- water supplies
- wildlife
- people
Bioaccumulation vs Biomagnification
What is Bioaccumulation?
An increase in concentration of a pollutant from the environment to the first organism in a food chain.
What is biomagnification?
The process where chemicals accumulate in organisms in increasingly higher concentrations at successive trophic levels is called biomagnification.
Results in storage of such toxic chemicals in organisms in higher concentrations than are normally found in the environment.
As you move up the food pyramid energy may go down but pesticide accumulation goes up.
An increase in concentration of a pollutant from the environment to the first organism in a food chain.
What is biomagnification?
The process where chemicals accumulate in organisms in increasingly higher concentrations at successive trophic levels is called biomagnification.
Results in storage of such toxic chemicals in organisms in higher concentrations than are normally found in the environment.
As you move up the food pyramid energy may go down but pesticide accumulation goes up.
What Does This Mean?
Bioaccumulation /Biomagnification
Together they mean that even small concentrations of chemicals in the environment can find their way into organisms in high enough dosages to cause problems.
What are the pollutants like?
In order for bioaccumulation to occur, the pollutant must be:
Together they mean that even small concentrations of chemicals in the environment can find their way into organisms in high enough dosages to cause problems.
What are the pollutants like?
In order for bioaccumulation to occur, the pollutant must be:
- Long-lived
- Mobile
- Soluble in fats
- Biologically active
What About DDT?
What is DDT?
DDT (dichlorodiphenyltrichloroethane) was applied to control insects that were damaging crops.
What is the effect of DDT?
In 1970’s it was discovered DDT entered the food chain – fish ate insects that were sprayed with the chemical; hawks, eagles, and pelicans (non target population – what we didn’t mean to hurt but we did) ate the fish.
What is the effect of DDT?
DDT became concentrated in the birds system, resulting in side effects such as thin eggshells.
Who is Rachel Carson?
Rachel Carson wrote a book about DDT and the breaking hawk eggs called “Silent Spring” in 1962.
Is DDT still in use today?
Laws in US now prohibit the use of DDT. DDT was banned in the US in 1972. DDT is not prohibited worldwide.
DDT (dichlorodiphenyltrichloroethane) was applied to control insects that were damaging crops.
- DDT was popular after World War II.
What is the effect of DDT?
In 1970’s it was discovered DDT entered the food chain – fish ate insects that were sprayed with the chemical; hawks, eagles, and pelicans (non target population – what we didn’t mean to hurt but we did) ate the fish.
What is the effect of DDT?
DDT became concentrated in the birds system, resulting in side effects such as thin eggshells.
- The weight of the adult bird would crush the egg in the nesting process. Impact on species was well documented.
Who is Rachel Carson?
Rachel Carson wrote a book about DDT and the breaking hawk eggs called “Silent Spring” in 1962.
Is DDT still in use today?
Laws in US now prohibit the use of DDT. DDT was banned in the US in 1972. DDT is not prohibited worldwide.
- Resident and migrating animal populations in countries that still allow the use of DDT are at particular risk.
- Even after the application of DDT is stopped, DDT and its by-products can effect the environment for decades.