AP Environmental Science: Unit 8 Review - Aquatic & Terrestrial Pollution 

Sources of Pollution

• point source - single source clearly identified
• non-point source - can not be traced back to a single source

Human Impacts on Ecosystems

• coral bleaching - coral expels symbiont out of its cell
• increased sediment in waterways - can reduce light infiltration, can affect primary producers and visual predators
• oxygen sag curve- plot of dissolved oxygen levels versus the distance from a source of pollution,  closer to the source of pollution, the lower the oxygen concentration

Oil Pollution

• effect on organisms - cause organisms to die to lower survival, oil can coat the feathers of birds and fur of marine mammals
• effect on humans - economic consequences on the fishing and tourism industries

Nutrient Pollution and Eutrophication

• eutrophication -  increase in nutrients in aquatic environments can lead to algal blooms --> algal bloom dies --> microbes digest algae and oxygen in the water  --> decrease in dissolved oxygen levels --> large die offs of aquatic organisms
• anthropogenic causes - agricultural runoff and wastewater release
• hypoxic waterways - bodies of water that are low in dissolved oxygen
• dead zones - areas of low oxygen in the oceans caused by nutrient pollution
• oligotrophic waterways - have low amounts of nutrients, stable algae populations, high dissolved oxygen

Thermal Pollution

• thermal pollution - occurs when heat released into the water produces negative effects to the organisms in that ecosystem
• affects -  concentration of dissolved oxygen (DO), warm water contains less than cold

Bioaccumulation and Biomagnification

• bioaccumulation - absorption and concentration of certain elements or compounds by cells in a living organism
• biomagnification - increase in concentration of substances per unit of body tissue that occurs in successively higher trophic levels of a food chain or in a food web

Persistent Organic Pollutants

• persistent organic pollutants (POPs) - synthetic, carbon-based molecules that do not easily break down in the environment
• toxic - accumulates in organisms fatty tissues

Solid Waste Disposal

• solid waste - discarded material that is not a liquid or gas
• landfills - can contaminate groundwater and release harmful gases
• sanitary municipal landfill - consists of a bottom liner (plastic or clay), a storm water collection system, a leachate collection system
• electronic waste - may contain hazardous chemicals such as lead and mercury, can leach from landfills into groundwater if they are not disposed properly

Waste Reduction Methods

• recycling - process by which certain solid waste materials are processed and converted into raw materials to make new products, cons: pricy
• composting - process where organic matter such as food scraps, paper, and yard wastes decompose into a product that can be used as fertilizer, cons: odor, animals
• e waste - can be reduced by recycling and reuse
• incinerating - decreases the volume of trash but the heat can also be used to make electricity
• landfill cap - once the landfill has been capped,  habitat can be restored into useful land like a park
• landfill gases - combustion of gases like methane produced from decomposition of organic material in landfills can be used to generate electricity

Sewage Treatment

• primary treatment - physical removal of large objects, often through the use of screens and grates, followed by the settling of solid waste in the bottom of a tank.
• secondary treatment - biological process in which bacteria break down organic matter into carbon dioxide and inorganic sludge, which settles in the bottom of a tank
• tertiary treatment - the use of ecological or chemical processes to remove any pollutants left in the water after primary and secondary treatment
• the treated water is exposed to one or more disinfectants like chlorine, ozone, or UV light to kill bacteria, before releasing

Pathogens and Infectious Diseases

• LD50 - amount of a substance lethal to 50% of a population
• vectors - organism that can transmit diseases between humans
• cholera - cause: bacterial disease from infected water symptoms: diarrhea, vomiting, dehydration
•  tuberculosis - cause:  breathing in the bacteria from body fluids of an infected person symptoms: bacteria attack on lungs
• SARS- cause: inhaling or touching infected fluids symptoms: pneumonia & flu-like 
• MERS - cause: inhaling or touching fluids from infected animals/humans symptoms:  flu-like 
• plague - cause: bite of an infected organism or through contact with contaminated fluids symptoms: flu-like 
• malaria - cause: bites from infected mosquitoes symptoms: flu-like 
• west nile virus - cause: bites from infected mosquitoes symptom: flu-like 
• zika - cause: bites from infected mosquitoes or sexual contact symptoms: birth defects like microcephaly
• dysentery - cause: ingesting water contaminated with untreated sewage symptoms: diarrhea & vomiting