19 terms

Unit 7 Water Pollution

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point source pollution
Pollutants discharged from a single identifiable location (e.g., pipes, ditches, channels, sewers, tunnels, containers of various types).
non-point pollution
Pollution that enters a body of water from a large area, such as lawns, construction sites,roads, agriculture
water pollution
any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses.
dissolved oxygen
amount of available oxygen in water, a key indicator of water quality
oxygen demanding wastes
organic wastes that can be decomposed by aerobic bacteria, can deplete dissolved oxygen levels
BOD - biological oxygen demand
Oxygen is removed from water when organic matter is consumed by bacteria.
Degradable waste
can be chemically decomposed: decomposable plastic wastes
Photodegradable
product is decomposed (broken down) by exposure to light
Biodegradable
Capable of being decomposed by biological agents, especially bacteria
Biological magnification (biomagnification)
results when concentrations increase at increasing levels in the food chain
eutrophication
Natural nutrient enrichment of lakes
Cultural eutrophication
results when human activities accelerate the input of nutrients to a lake
thermal pollution
occurs when water is withdrawn, used for cooling purposes, and then heated water is returned to its original source
invasive species (alien species)
species that enter new ecosystems and multiply, harming native species and their habitats. Often introduced by humans.
Septic tank systems
are used to dispose of sewge & wastewater in rural & suburban areas
Primary sewage treatment
involves screens & settling tanks to remove solids from sewage.
Secondary sewage treatment
uses biological processes to break down biodegradable, oxygen- demanding wastes.
Clean Water Act
(CWA, 1972) set maximum permissible amounts of water pollutants that can be discharged into waterways; aims to make surface waters swimmable and fishable
Safe Drinking Water Act
(SDWA, 1974) set maximum contaminant levels for pollutants in drinking water that may have adverse effects on human health
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