water quality
how much global freshwater is available to us?
0.01% which is 9000 cubic meters per person (1000 liters in one cubic meter or 264 gallons)
how long can a human survive without water?
1 week
how does human and animal activity contaminate groundwater?
1. chemicals and nutrients from fertilizers and nitrates from farms 2. rubber, heavy metals, and sodium from roads 3. petroleum by-products and organic chemicals from dry cleaners, service stations, and leaking underground storage tanks 4. chemicals used in the home (solvents, paints, used motor oil, lead, and copper) 5. heavy metals and toxic chemicals from factories 6. microbial pathogens from human and animal wastes
how much of human body made of water
2/3
how much of the population lacks safe drinking water
20%
How much freshwater is on Earth?
3% but only 1% is available to us which is surface water because 75% of it is frozen in the glacier ice caps
how much untreated sewage is discharged into rivers and streams in developing nations?
90%
what are the two major water quality water regulations?
Clean Water Act and Safe Drinking Water Act
waterborne diseases
Diseases caused by microorganisms that are transmitted in contaminated water. Infection commonly results during bathing, washing, drinking, in the preparation of food, or the consumption of infected food. eg cholera, typhoid, botulism.
what are some of the waterborne pathogens
Enteric protozoal parasites bacterial enteropathogens viral pathogens
what are important hydrological terms to know with the water supply?
Ground Water Surface Water Aquifer Hydrological Cycle water scarcity water stress
Aquifer
a layer of rock that contains groundwater
hydrological cycle (water cycle)
a pumping system driven by the sun which moves groundwater from the ocean to landmasses back into the ocean and replenishes freshwater supply (precipitation, evaporation, condensation)
surface water
all water on the surface (e.g., lakes, rivers, reservoirs, ponds, and oceans) as distinguished from subsurface or ground water
Coastal Health Act (beach act of 2000)
authorizes the EPA to conduct surveys of beaches
what are disinfectant by products?
by product that form from disinfecting agents used in potable water
what are the four stages of water treatment for residential consumption?
coagulation--aluminum sulfate is the coagulation agent sedimentation---used for secondary processing for additional skimming filtration----filtered to remove smaller impurities and is made with finer layers of sand and charcoal disinfection---water is treated with chlorine to destroy pathogens storage--
what are the sources of chemicals in the water supply?
natural and anthropogenic like DBPs and solvents. solvents contaminate the aquifers
what are the four types of disease causing agents that may be present in the water supply?
parasites bacteria viruses chemicals
why is water quality an important aspect of public health?
prevents waterborne disease especially among vulnerable groups can only survive without water for 1 week requirement of water per day is 2.5 liters to maintain health 2/3 of human body made of water average person uses 100 gallons of water per day needed for agriculture and industrial purposes
how is it possible for waterborne pathogens such as cryptosporidium to contaminate water that has been treated by modern treatment plants?
public swimming pools and water parks used by diapered children or can come from sewage contaminated water
water stress
temporary water shortages that are between 1000-17000 cubic meters per person
how is water treated from aquifers
ultrafine filters
how did dr. Frederick S. McKay contribute to water quality?
water fluoridation to prevent fluorosis
groundwater
water that is contained in the interconnected pores in an aquifer naturally supplying springs and wells
water scarcity
when a country's freshwater supply is less than 1000 cubic meters per person annually which can hinder a country's development