Environmental Health Midterm (Week 3) Flashcards
(34 cards)
What are the three sources of drinking water?
- Rain Water
- Surface Water
- Ground Water
What source and percentage does CT get the majority of their drinking water?
- Surface Water (83%)
What two states made it illegal for drinking water to be taken from surface water sources that receive industrial or sewage wastes?
CT & RI
What are the single home and individual water usage per person per day?
Individual: 100 gallons
Single Home: 300 gallons
How many countries and how many people around the world don’t have safe drinking water?
55 Countries, 1 Billion
What are some of the uses for water?
- Agriculture
- Power
- Industrial Process
- Cooling
- Dilution
- Recreation
- Transportation
What is the water body make up of surface water?
97% lakes, rivers, rain water, salt water
3% fresh water (ice, ground, surface)
Where does CT get its drinking water?
- 83% public water systems, surface water supplies, ground water supplies.
- 17% public wells
What are the two water companies that control drinking water for CT?
- CT Water Company
- Aquarian
Who regulates drinking water? Who regulates bottled water?
Drinking Water: DPH
Bottled Water: EPA & DCP (Consumer Protection)
What does it mean when water is called “hard”? What do you use to remove it?
Has more calcium and magnesium levels. Use sodium to remove them.
What are some physical characteristics of water?
- color
- odor
- taste
- turbidity
- hardness
- ph
How to assure safety of drinking water?
Standards, monitor, sampling, lab limitations
What are some water treatment methods?
- Physical (settling/coagulation to remove organic matter), (filtration: rapid sand/slow sand), (aeration)
- Disinfection (chlorination, turbidity, fluoridation, softening, iron removal
- Reverse osmosis/distillation
What are the requirements regarding fluoridation?
- No national requirements
- CT requirements: apply fluoridation if the water supply serves 20+K
What are some distribution problems for water supplies?
- Meters (pipes leak, know how much)
- Interconnections (connections to share water)
- Cross connections (potable connections)
- Backsiphonage (small hole water from building goes back to main supply)
- Irrigation wells (permit must be separate from other water supplies)
- Process wells (used for processing not drinking)
What are the three types of water systems?
- Community (large)
- Non-Transient Non-Community (people not moving)
- Transient Non- Community (moving)
What’s the maximum contaminant level (MCL)?
- Health based standard established by EPA
- max level allowed of contaminate in water that’s delivered to any consumer
- states can adopt this or set their own as long as they are as strict as the federal MCLS
What’s the difference between acute and non-acute contaminants?
Acute: ecoli, nitrate, copper
non-acute: coliform
What are coliform organisms used for? Advantages/Disadvantages?
- Their presence indicates contamination may be entering the water system. Don’t cause disease.
- Advantages: easy to collect sample, test reliable, results obtained quick within 24 hrs, test easy to conduct, inexpensive, not pathogenic
- Disadvantages: indicates fecal contaminations and can pose health risks, increases likelihood that other disease pathogens may be present, does not distinguish between pathogenic and non pathogenic coliform
What do you do if a sample tested positive for total coliform bacteria?
- Analyze for ecoli
- Inspect water system
- Corrective maintenance
- Disinfect, purge, resample
What are the sources of ecoli?
- septic systems
- rodents
- submerged well heads in areas where animal feces are present and storm water run-off enters the well
What do you do when a sample tests positive for ecoli?
- immediately inform the public not to drink or use for food unless boiled for at least 5 mins
- strongly recommended only bottled water be used for drinking or food preparation
What is the process/issuing of a boil water advisory?
- When: test +ve for ecoli
- By whom: by the water company but must be approved by DPH
- Termination: when everything is resolved, must be advised by DPH
- Impact: community impact
