Lecture on Environmental Science and Pollutants

Three ways animals absorb substances from the environment:

Ingestion: Animals can consume substances along with food, allowing toxins to enter their systems.
Diffusion: Substances can passively diffuse through biological membranes, entering the animal's bloodstream or tissues directly from the environment.
Active Transport: Some substances are absorbed against their concentration gradient using energy, often transporting essential nutrients into cells.

Bioaccumulation happens immediately after a toxin enters the environment: False
Methylmercury is more toxic than regular mercury: True
Mercury pollution only affects fish, not the people who eat them: False
Mercury can stay in a fish's body only for a few days: False
In the Great Lakes, mercury comes mostly from farms and fertilizers: False

Can DDT remain in the soil or water for more than 10 years? Yes, DDT is known for its persistence in the environment.
Was DDT banned in the United States in the 1950's? False, DDT was banned in the U.S. in 1972.
Can lead exposure affect brain development and learning in children? Yes, lead exposure has detrimental effects on cognitive development in children.
Do scientists find traces of DDT in tropical jungles only? Fiction, traces have been found in various environments, not limited to tropical regions.

Primary Topics of Discussion:

What do we use to test each?

Concentration: Measured in Parts Per Million (ppm) and Parts Per Billion (ppb).
Dilution: A method to determine concentration by measuring how much a substance is diluted in a solution.

Persistent Pollutants: These are substances that remain in the environment for extended periods and can accumulate in the food chain.
Non-Persistent Pollutants: Substances that decompose quickly and do not accumulate significantly in the environment.

Ozone: A gas that occurs both in the upper atmosphere and at ground level, where it can be harmful to health.
CFCs: Chlorofluorocarbons used in refrigeration and aerosols, known for their role in ozone depletion.
Nitrogen Dioxide: A reddish-brown gas with significant health impacts and a contributor to smog and acid rain.
Sulfur Dioxide: A gas that contributes to the formation of acid rain and respiratory problems.
Carbon Monoxide: A colorless, odorless gas resulting from incomplete combustion, harmful to health when inhaled.

Bioaccumulation: The process where organisms accumulate toxic substances faster than they can eliminate them.
Biomagnification: Occurs when the concentration of toxic substances increases at each successive level of the food chain, leading to higher toxicity levels in top predators.

Algal Blooms: Rapid algae growth resulting from excess nutrients (nitrates and phosphates) in water bodies, leading to detrimental effects on water quality and aquatic life.
Eutrophication: The process by which a body of water becomes overly enriched with minerals and nutrients, promoting excessive algae growth.

Increased carbon dioxide in the atmosphere can dissolve in oceans, leading to lower pH levels in water, adversely affecting marine ecosystems.

Greenhouse Effect: A natural process that warms the Earth's surface when the sun's heat is trapped by greenhouse gases.
Enhanced Greenhouse Effect: The additional warming of the Earth's atmosphere due to human-made increases in greenhouse gases, leading to climate change.