2.3 Flashcards
What are pesticides?
Chemicals used to eliminate pests, such as insecticides that kill insects and herbicides tags kill weeds.
What was introduced to the environment by humans that has caused huge changes?
Synthetic (man made) chemicals.
What is bioaccumulation?
The gradual build up of synthetic and organic chemicals in living organisms
What goes wrong in order for a chemical to accumulate?
If the chemicals are taken up faster than they are broken down and excreted.
How do chemicals enter organisms?
Through food intake, skin contact, or respiration.
Can chemicals be stored in the fat tissues of animals?
Yes
How do synthetic and organic chemicals effect animals?
They harm the nervous, immune and reproductive systems of animals.
What happens if synthetic and organic chemicals are bio accumulated?
They can cause birth defects and cause the animals to be unable to reproduce.
What are keystone species?
Species that greatly effect the population numbers and health of an ecosystem.
What is a keystone species in British Columbia?
SALMON
What is biomagnification?
The process in which chemicals not only accumulate, but become more concentrated at each trophic level
When do chemicals bioaccumulate and become biomagnified?
When they are stored in plant tissue and in the fat tissue of animals.
How are chemical freed of an animals body?
They have to be broken down for energy
What are PBCs?
They are polychlorinated biphenyls, which are synthetic chemicals that were widely used from the 1930s to the 1970s.
What were PBCs used for?
Heat exchange fluids, paints, plastics, and lubricants for electrical transformers.
What is a half life?
The amount of time it takes for a substance to decrease by half.
What effect do PBCs have on humans?
They suppress the immune system and cause cancer.
What animals was hit the hardest by PBCs?
ORCA WHALES
Why are PBCs so harmful to orca whales?
They are at the top of the food chain in the ocean, so they receive the highest concentration of chemicals like PBCs through bioaccumulation and biomagnification .
What class of compounds do PBCs belong to?
Persistent organic pollutants, or POPs.
What are POPs?
Carbon containing compounds that remain in water and soil for many years.
What is the ,easing way many POPs enter the ecosystem?
Insecticide sprays
What is a DDT?
A dichlorodiphenyl trichloroethane, which is an insecticide.
Where does DDT bioaccumulate?
In plants, the fatty tissue of animals that eat the plants, in streams, and lakes.
How is chemical accusation measured?
In ppm, A.K.A. parts per million.
At what level of ppm is DDT considered harmful?
5 ppm
What are the effects of DDT on animals?
Causes nervous system, immune system ad reproductive disorders.
What are heavy metals?
Metallic elements with a high density that are toxic to organisms at a low concentration. They don’t degrade and cannot be destroyed.
Where can heavy metals be found?
In water and in air
What are the three most polluting heavy metals?
Lead, Cadmium, and Mercury
What level of ppm is lead usually present in?
15ppm - 40 ppm.
What was lead used for in the past?
Insecticides, paints, gasoline, lead acid batteries, and electronics.
At what level of ppm is lead toxic?
0.0012ppm
What effects does lead have on humans?
Anemia, nervous system damage, sterility in men, low fertility rates in women, impaired mental development and kidney failure.
Where is cadmium found?
It is found in earth’s crust and is released into the environment by weathering, volcanos, and forest fires.
What effect does cadmium have on abiotic and biotic factors of an ecosystem?
It contaminates pa,nuts through take up and then those plants are eaten by animals. It is also toxic to earthworms and other soil organisms at low levels.
What effect does cadmium have on humans?
Cadmium poisoning through smoking, infertility, and damage to central nervous systems, immune systems and DNA
How much Mercury is released through natural sources (volcanoes, geothermal springs, and rock weathering) each year?
6000 tonnes
What percent of mercury released is from coal burning?
40%
How does Mercury effect organisms?
It changes compounds, and bioaccumulates in the brain, heart, kidneys and vertebrates.
How does Mercury effect humans?
It effects nerve cells, the heart, kidneys, and the lungs. It also suppresses the immune system.
What are some of the causes of amphibian loss?
Prolonged drought, increased ultra violet due to depletion of the ozone layer, habitat loss, pollution, over hunting, parasites, and diseases caused by viruses and fungi.
