chapter 9- Water quality

Uses for water in US

average person- 100 gals of water per day

average resident- over 100,000 gals per year.

• 50-70% used for outdoor purposes

aquifer

a layer or section of earth or rock that contains freshwater known as ground water

hydrologicla cycle

the natural cycle by which water evaporates from oceans and other water bodies, accumulates as water vapors in clouds and returns to oceans and other bodies of water as precipitation 

nonrenewable water

what in aquifers and other natural reservoirs that is not reccharged by the hydrological cycle or is recharged so slowly that significant withdraw from human use causes depeltion 

renewable water

freshwater that is continuously replenished by the hydrological cycle for wthdraw within resonable time limits 

water scarcity

removal of freshwater from human use from any natural source or reservoir

water stress

a country faces water stress when its annual supply of renewable freshwater is between 1000 and 1700 cubic meters per person 

cyrptosporidium infection in water

a water borne protozoan parasite causing diarrheal illness. often linked to contaminated drinking water

drinking water overall

about 2/3 of the human body is made up of water

• a human can survive for about a week without water

• two main sources of drinking water; surface water- all water on the surface ground water- water contained in the interconnected pores in an aquifer.

africa and near east currently has severe water shortages, contaimination- chemical and nutrients, rubber heavy metals, sodium

20% of the worlds population lacks safe drinking water 

Events realted to oil spills 

March 24, 1989: exxon valdez tanker ran agound in Alaska, causing the largest oil spill in US water as of that time 

April 20, 2010: the deepwater horizon oil platform exploded causing historys largest accidental marine oil spill as of mid 2010

disinfection of water 

water disinfection by products. chemicals used to disinfect water include cholorine, chloromines, dioxide and ozone 

Example: chlorine is associated with THMs which are among the most common and widely measured DBPs