chapter 22 Flashcards
water pollution
any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or that makes the water unsuitable for desired uses
escherichia coli (E. Coli)
-is in our bodies normally, however pathogens can enter food, water, and pools by human wastes
biological oxygen demand (BOD)
-the amount of dissolved oxygen consumed by aquatic decomposers
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point sources
- discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into bodies of surface water
ex: factories, sewage, treatment plants, underground mines and oil tankers
non-point sources
- scattered and diffused discharge that cannot be traced to any single site
ex: acid deposition and runoff of chemicals into surface water from croplands, livestock feedlots, logged forests, urban streets, lawns, golf courses and parking lots
oxygen sag curve
- the breakdown of degradable wastes by bacteria depletes dissolved oxygen
- recues or eliminates populations of organisms w high oxygen requirements until the stream is cleansed of wastes
eutrophication
the nutrient enrichment of lakes, mostly from runoff of plant nutrients such as nitrates and phosphates from surrounding land
cultural eutrophication
when human activity can greatly accelerate the input of plant nutrients to a lake
degradable wastes
- rid themselves naturally
ex: manure, paper wastes, biodegradable plastics
non-degradable wastes
- contaminants that stay permanently
ex: toxic lead, arsenic and fluoride
harmful algal blooms
- red, brown or green toxic tides
- release waterborne and airborne toxins that damage fisheries, kill fish-eating birds, reduce tourism and poison seafood.
oxygen depleted zones / dead zones
- form mostly in temperate coastal waters and in land locked seas
- these zones cause most of the aquatic life living there to die or have to switch habitats
ways to reduce these zones:
- reducing nitrogen inputs into water
- planting forests and grasslands to soak up excess nitrogen and keep it out of waterways
- restoring coastal wetlands
- reducing discharge and reduce the burning of fossil fuels
London Dumping Convention of 1972
- 100 countries agree not to dump highly toxic pollutants and radioactive wastes in the open sea
- these arguments are hard to monitor and enforce
integrated coastal management
when citizens groups, communities, state legislatures and the federal government have worked together to reduce pollution inputs into the bay
strategies:
- establishing land use regulations
- reduce runoff
- banning phosphate detergents
- upgrading sewage treatments plants
- restore wetlands
dredge spoils
materials, often laden with toxic metals, scraped from the bottoms of the harbors and rivers to maintain shipping channels
Exxon Valdez
- 1989 a tanker ran off the coast of Alaska and spilled 11 million gallons of crude oil
- clean-up that lasted over 20 years
- baseline was missing in Alaska
Prestige
An oil tanker that sank in 2002, and leaked about twice as much oil as the Exxon Valdez.
Oil Pollution Act 1990
- strengthened EPA’s ability to prevent and respond to catastrophic oil spills
- established a trust fund to clean up spills
Clean Water Act 1972
supports the “protection and propagation of fish, shellfish and wildlife and recreation in and on the water”
-issued water quality standards that defined acceptable limits of various pollutants
discharge trading policy
- uses market forces to reduce water pollution in the U.S
- under this program a water pollution source is allowed in its permit by buying credits from permit holders with pollution levels below their allowed levels
septic tank
- septic tank systems are used for the disposal of domestic sewage and wastewater in rural or suburban areas.
- separates solids from liquids, digests organic matter and discharges the liquid wastes in networks of buried pipes
primary sewage treatment
- physical process that uses screens and a grit tank to remove large floating objects and solids.
ex: settling tank allows suspended solids to settle out as sludge
secondary sewage treatment
- biological process in which aerobic bacteria remove BODS.
ex: wastewater is trickled through beds of of gravel covered with aerobic bacteria or by passing it through an aeration tank.
advanced sewage treatment
-series of specialized chemical and physical processes that remove pollutants after going through primary and secondary treatment.
