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Factories, power plants, sewage treatment plants, underground coal mines, & oil wells are included.
Nonpoint sources of water pollution
Scattered or diffuse sources that have no specific location where they discharge into a particular body of water.
Air pollution that is carried & precipitated into watershed or directly onto surfaces waters.
Most serious water pollutant in terms of human health worldwide. Main source is from untreated sewage. Water is tested for the presence of Coliform Bacteria (which is present in the human gut) but is itself not harmful.
Organic wastes which use up DO when decomposed.
BOD Biochemical Oxygen demand
A standard test of the amount of dissolved oxygen consumed by aquatic microorganisms over a 5 day period.
Dissolved oxygen (DO)
Measured to asses the health of a water body. Good = 5 or 6 ppmHypoxic less than 3 ppmAnoxic = less than 2 ppm which will mainly suppor worms, bacteria, fungi, & other detritus feeder & decomposers.
Increased nutrients flows brought about by humans causes “blooms” of algae followed by a decomposition of this algae which uses us DO in the water.
Increase in dinoflagellate populations. Usually associated with increase nutrients or lower water quality.
Many metals such as mercury, lead, cadminum, & nickel are highly toxic in levels of ppm.
Famous case: Minimatta Japan where brain damage & birth defects resulted from mercury released into the ocean. People ate fish that had bioaccumulated the metal.
Salts can be harmful in higher concentrations and are especially prevalent where irrigation in arid lands has left salts behind due to evaporation.
Acids and bases
Realeased as a result of coal burning – acid rain or NOx from high temperature burning – nitric acid.Acidic water leaches aluminum into the water which clogs fish gills. Also some fish & juveniles have narrow pH tollerances.
Highly toxic in ppb or quadrillion (dioxin) are released by industries that make plastics, pesticides, pharmaceuticls & pigments. Many cause cancer, birth defects, genetic disorders & cancer.
Runoff of soil that blocks sunlight & clogs fish gills. Phosphorus (a nutrient responsible for eutrophication) bonds to soil particles.
Water temperatures that cause harm to aquatic organisms. Comes from altering vegetation cover & runoff patterns or using the water for industrial cooling.
TMDL (Total maximum daily loads)
State are required to to identify waters are not meeting water quality goals & to develop TMDL’s for each pollutant & each listed water body. Both point and nonpoint sources are considered as well as seasonal variation. (Spring runoff from snow melt will increase fertilizer.)
BPT (Best Practicable control teachnology)
For specific “point” sources of pollution such as industrial discharge pipes or sewage outfalls the Clean Water Act requires discharge permits & the best technology used to control it.
BAT (Best available economically achievable technology)
National goals for toxic substances and zero dicharge for 126 priority toxic pollutants. Requires use of the BAT. Clean water act.
Municipal sewage treatment
Primary treatment- 1st ste that physically separates large solids from the waste stream. Uses grating & settling tanks.Secondary treatment- biological degredation of dissolved organic compounds.
Tertiary treatment – uses bacteria or chemicals to remove excess nitrogen or phosphorus.
A hybrid between tradition septic tank & full sewersystem. A tank collects & digests solid waste just like a septic system but the liquids are pumped to a central treatment plant. This is used when the area does not have enough area for a drainfield.
Using living things to breakdown wastes.
Can be done in a closes sytem where there is no space available for lagoons. Duckweed is often used in lagoons & then harvest and sold as animal feed.