study guide ch1

Question 1

Hydrologic Cycle

Answer 1

-evaporation of ocean waters(88%)-desalination process
-evapotranspiration (12%)- evaporation of water and transpiration of water from leaves
-over oceans- less precipitation than evaporation
-over land- more precipitation than evaporation
-to maintain balance there must be runoff water returned to oceans by stream and groundwater flow

Question 2

Surface water supplies

Answer 2

RIVERS:
-high sediment loads
-variable flow rate

LAKES AND RESERVOIRS:
-impacted by microbiology activity
-eutrophication related to high nutrient levels

WATER AFFECTED BY:
-human activities in the watershed associated with the river or lake
-geological properties of the watershed

WATERSHED:
-land areas that catch rain or snow and drain to specific marshes, streams, riers, lakes, or groundwater

Question 3

Color of water

Answer 3

-true color results from dissolved material, usually organic compounds
-apparent color results from suspended particles

Question 4

turbidity of water

Answer 4

-a measure of the amount of suspended solids of water

Question 5

taste and odor of water

Answer 5

-taste results from the presence of salts and specific metals such as iron, copper, manganese, zinc
-an result from the water treatment
-odors usually result from the presence of decaying organic matter-bacteria

Question 6

solids determination

Answer 6

-all contaminants in water other than dissolved gasses
Total suspended=total dissolved solids
TOTAL SOLIDS (TS):
-weigh a ceramic bowl, evaporate water sample and reweigh

SUSPENDED SOLIDS (SS):
-weigh a filter, pull known volume of water through filter and evaporate water

Question 7

dissolved oxygen

Answer 7

-necessary for the aerobic respiration of aquatic organisms
-amount of dissolved oxygen in water depend on: amount of O2 in air and solubility of O2 in water
-20 degrees C at sea level water will contain 9mg/L of oxygen

Question 8

oxygen sag curve

Answer 8

dissolved organics or high temperature water will cause a depletion of dissolved oxygen

Question 9

temperature

Answer 9

-the solubility of gases decreases and the solubility of minerals increases with an increase in temperature

Question 10

calcium carbonate

Answer 10

neutralizes acids and keeps water slightly basic

Question 11

hardness

Answer 11

caused by the presence of multivalent metallic ions calcium(Ca2+) and magnesium(Mg2+)

Question 12

biochemical oxygen demand (BOD)

Answer 12

-measures the amount of oxygen consumed by bacteria/microorganisms while they decompose organic matter
-aerobic microorganisms break down organic matter and use oxygen for respiration
-more waste in water=more oxygen required

Question 13

indicator organisms

Answer 13

E.coli
-If significant amount is present, other pathogenic organisms
can be assumed to be present as well

Question 14

groundwater use

Answer 14

-groundwater is 98% of all freshwater available on earth, and has been used for 6,000 years
-1/3 of drinking water supply in the us is groundwater
-tripled in past 40years
-50% of us population drinks groundwater

Question 15

well types

Answer 15

WATER TABLE WELL:
-drilled into an unconfined aquifer(less deep)
-water is at level of the water table
AETESIAN WELL:
-tapped confined aquifer(very deep)
-water may rise above the regional water table

Question 16

sources of dissolved oxygen

Answer 16

atmospheric re-aeration, photosynthesis, advection(churning)

Question 17

sinks of dissolved oxygen

Answer 17

dissolved organics, high temperature, nitrification

Question 18

Steps for BOD test

Answer 18

1. prepare a water-solution containing nutrients
2. use an aeration stone to bubble air through water
3. obtain samples and add a known amount to 300 ml bottles
4. fill the rest of the bottle with nutrient-rich, dilution water
5. if no natural microbes, add culture
6. measure the dissolved oxygen content
7. stopper the bottle and store at 20 degrees celsius fpr 5 days
8. after 5 days, measure the dissolved oxygen content in both bottles again
9. calcualte BOD