HSC 156 Exam 3 SG


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What is the status of Lakes Mead & Powell?
Lake Mead and Lake Powell are shrinking from overuse and drought. They represent 85% of the storage system for the Colorado River.
What is Australia doing to combat a massive drought?
Australia banned car washing and watering lawns, used cisterns for rain water and in some cases treated sewage for drinking water; but they DID NOT initiate a massive well drilling campaign that will cost over 10 billion dollars
What percent of the earth's water is freshwater?
71% but on 3% is usable / accessible
Hydrologic Cycle
describes how water moves from one place to another: Water rises into the atmosphere by evaporation & transpiration and is purified, Water leaves the atmosphere by condensation & precipitation, and Surface water is never pure because run off deposits will enter and pollute the lakes, streams, ponds, etc.
Which is more likely to be polluted, surface water or ground water?
surface water
What is the mountain effect?
rain; Air picks up humidity & loses moisture as it cools going up the mountain, Deserts form on the leeward side of the mountain, the Rain shadow - The dry region down wind of a mountain range
What is meant by water infiltration?
water naturally cleaning by soil
Two ways that pollution of the water cycle occurs
point source and non-point source
point source water pollution:
pollution from factories, sewage treatment plants, oil tankers
non-point source water pollution:
(pollution that cannot be traced to a single source): runoff from feedlots, lawns, urban streets : big problem in US
What are the major categories of users of freshwater?
Irrigation for agriculture, Electrical power production, Industrial use, and Residential use
What is the maximum percentage of the average flow of a river that can be taken without facing future shortages and other problems?
30% - 35%
What are the 4 environmental effects of overdrawing groundwater?
1. Falling water tables & depletion due to overuse for crop production
2. Diminishing surface waters
3. Land subsidence & sinkholes
4. Salt water intrusion
Describe the 4 steps in water purification
1. Alum is added to water to coagulate suspended particles
2. These particles settle out and are removed
3. Water is then filtered & treated before it is piped for use
4. Treatment usually consists of chlorination
water pollution:
Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable
What is the number one use of water world-wide?
How much water is used by irrigation in agriculture?
700 gallons per day
How much water is used by electrical power production?
600 gallons per day
How much water is used by industrial use?
370 gallons per day
How much water is used by residential use?
100-200 gallons per day
What is the primary consideration in determining the amount of water purification?
is going to be drinking water for humans
What are 3 problems in water treatment?
1. Failure to kill microbes (fecal coliform test to monitor for contamination)
2. Chemical overdoses (high fluoride or high chlorine)
3. Chemical residuals (disinfection by-products)
Of the three water treatment problems, which is most likely to be a problem?
Failure to kill microbes ( fecal coliform test to monitor contamination)
What test is used to determine if sewage contamination is present in drinking water?
fecal coliform test- how we test water safety, tests presence of poop
Discuss the needs & prospects for obtaining more water
-In the 3rd World, access to safe drinking water supplies is limited- Less than 50% have safe supplies & This can lead to diseases such as cholera
-Growing populations create an ever-increasing demand for additional water for irrigation & industrial/municipal use
-Prospects for increasing the supply are poor
List 4 ways of reducing water demands
Through Drip irrigation systems and improvements in municipal systems
1. Use gray water on plants- waste water from sinks, brown water- waste water from toilets
2. Treat sewer water
3. Desalting water (not a practical or economic solution)- cost, causes air pollution
4. Reusing water in industry - requires them to treat the water to remove impurities
different zones when pollution is added to a river:
1. Decomposition
2. Septic
3. Recovery
4. Clean
low in nutrients, can see the bottom of the lake- not much algae
rich in minerals and nutrients, lake has a small out flow- making it highly concentrated with nutrients, lots of algae, septic water without much oxygen
Describe the effects of pollution on lakes:
Lakes cannot dilute pollutants as quickly as a flowing stream or river. As a result, lakes become high in nutrients and algae.
What is the Clean Water Act (CWA) of 1972?
First serious regulation. 1/3 of water was safe at the time and after this act 2/3 were safe. Doubled amount of safe waters.
1. Aimed at controlling the discharge of pollutants into: navigable waters, rivers, lakes, streams, & wetlands
2. Serious attempt, through federal regulations to control:
-polluting discharges that enter waterways
-interstate waters
-waters that are associated with commerce in the US
What substance was controlled in the Water Quality Act of 1987?
sludge (concentrated sewage)
What is the most important purpose of municipal sewage treatment?
1. It is designed to alleviate what problems related to sewage disposal? Health and aesthetic
2. It also significantly improves aesthetic problems related to sewage disposal
What are the 4 categories of pollutants in raw sewage?
1) Debris & grit (everything from pebbles to needles & syringes)- random objects
2) Particulate organic materials- poop
3) Colloidal & dissolved organic chemicals (much smaller than #2) - small and dissolved poop
4) Dissolved inorganic chemicals- nail polish remover- acetone
What is the level that most municipal systems reach?
Secondary treatment
What are 4 sludge treatment options?
1. Preliminary treatment removes for: grit and debris
2. Primary treatment: for particles
3. Secondary treatment (includes biological nutrient removal &
disinfection): get rid of colloidal dissolved organics- treated with other bacterial - add chlorine as a disinfectant
4. Tertiary treatment (this is cleansing of specific chemicals): removal of specific chemicals) Please note: most - don't typically use this method because it is too expensive - done if the city drinks the sewage water though - but we don't so no
Describe a typical septic treatment system?
designed to treat a house's sewage; sewage flows into the ground and flows through soil; cannot use chlorine to treat sewage in a septic tank
What kinds of toxic materials get into wastewater treatment system that can not be removed using secondary treatment?
specific chemicals such as acetone
What was the Safe Drinking Water Act of 1974?
1. EPA sets maximum contaminant levels for specified pollutants found in drinking water
2. Prescribed schedule for monitoring & testing treated water
3. Report water quality results to appropriate state agencies
What is storm water?
Water that runs off from roots, roads, streets- runoff from it- picks up pesticides, fertilizers, etc. that flows into nearby lakes and rivers
Why is storm water a problem?
Storm water runoff impacts both water quality and water quantity problems. taking over and depleting land; over watered mess
When and where is industrial pretreatment required?
must pretreat if they are dumping solvents into the water
What is a brownfield?
Polluted land, often abandoned, and difficult to sell- usually near communities
Describe the process of total product life cycle:
Raw materials are minded, transported, refined, transported, manufactured into a product, transported, used & disposed of
The accumulation of higher & higher concentrations of potentially toxic chemicals in organisms
Biomagnification occurs through bioaccumulation through several levels of the food webs
What was the Superfund?
EPAs largest ongoing program in which sites are analyzed in the following way:
(1) current & potential threat to groundwater supplies
(2) threat to human health
(3) immediate & severe threats-NPL (national priority list) sites
problem with the superfund:
sued the chemical companies or polluters to clean up the mess; took lots of court time and would sometimes lose
What is the National Priority List (NPL)?
national priority list of sites
What was the Resource Conservation and Recovery Act (RCRA) of 1976?
•Cornerstone legislation designed to prevent unsafe or illegal disposal of wastes on land
•EPA must identify hazardous waste
•Sets standards for hazardous waste
•Permits required for hazardous waste generators
What was the Underground Storage Tank (UST) standard?
Requires strict monitoring of fuel supplies, tanks, & piping so that leaks may be detected early
What are the Worker Right to Know standards?
•OSHA regulations require business & industries to make information regarding hazardous materials & suitable protective equipment available to all employees
•Employee responsibilities are to read the information & exercise proper precautions
Community Right to Know standards
•Also called SARA Title III - gives communities the right to know about releases of hazardous chemicals by local industries.
•It also requires that industries inform local fire departments and other emergency preparedness about the kinds of hazardous chemicals present on site.
What are 3 approaches to hazardous waste prevention?
1. Pollution avoidance- don't produce
2. Responsible care- use the least amount
3. Green products- use the most environmentally safe products
What did Kristianstad, Sweden do to manage solid waste?
Kristianstad did not close all waste incinerators due to air pollution concerns
They did:
1. build a biogas plant using household food waste
2. Use biogas to run most city buses
3. Produced methane gas from old landfill
What is Municipal Solid Waste (MSW)?
Total of all materials thrown away from households, cities, and towns; Also known as: (trash, refuse, garbage)
How do we dispose of MSW?
landfills and incineration
The amount of waste has grown steadily due to what? (4)
population growth, changing lifestyles- new and more products, increased use of disposable materials, excessive packaging
What are the two most common types of MSW?
paper and yard waste
What are 4 problems with landfills? (Be able to describe these problems)
Leachate, methane, settling, doesn't break down
What are the advantages & disadvantages of incineration?
no landfills and air pollution
What is the best method of dealing with refuse?
make less of it, reduce
What percentage of waste could be recycled?
What are the two kinds of recycling?
1. Primary recycling- Using recycled materials to make the same material
2. secondary recycling- using one old material to create something new
How do we encourage recycling?
1. Simplified system of collection
2. Pay as you throw- pay to throw away garbage but recycling is free
What is composting?
When organic waste is turned into humus by providing an ideal environment for decaying organisms
is the potential of something to do harm
includes the probability of some harmful event occurring (If you have no chance of being exposed to a hazard, it doesn't matter how dangerous it is. For you the hazard is not a risk.)
What is a hormone disrupter?
Any chemical that act like hormones (Hormones act as messengers to regulate
various bodily processes)
What have we learned about BPA?
hormone disruptor that will speed up hormonal aging; found in plastics; toxic to humans
are substances that cause mutations in the DNA- can result in cancer and birth defects
are substances that cause birth defects
are substances that cause cancer
4 categories of hazards:
chemical, biological, physical, and behavioral/voluntary/cultural
chemical hazards
toxins; mutagens, teratogens, carcinogens
biological hazards
transmissible or non-transmissible

• Bacteria
• Fungi
• Viruses
• Protozoans
• Worms
physical hazards
radiation, noise, heat
behavioral/cultural/voluntary hazards
drinking, smoking
LD 50
measures how toxic a chemical is; Kill _> 50% of test animals at LD50 at a given dose; Lethal (toxic) dose 50%- dose that kills half the rats
spread by mosquitos; prevalent in warm areas; will increase with global warming; Malaria is a parasitic disease that involves high fevers, shaking chills, flu-like symptoms, and anemia.
What happens to the level of oxygen in water due to the presence of pollution?
oxygen decomposes the substances in the sewage; oxygen is used up in this process and the water becomes septic; as water flows more oxygen is added and river is clean- rivers are self flushing
What are the 4 steps in wastewater purification/treatment?
1. Decomposition
2. Septic
3. Recovery
4. Clean
what percent of earth's freshwater is accessible?
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