BLOCK 9: ENVIRONMENTAL HEALTH - Unit 4: Potable Water (complete) Flashcards
Where surface and ground water are available, ___________ water is generally preferred.
GROUND WATER
An underground source, or aquifer, usually provides higher quality water.
The portion of rain and melting snow that becomes surface water. Topography and gravity control the movement of this water.
RUNOFF
An area or region drained by a river, river system, or other body of water.
WATERSHED
A base may get its water from _______________ or _______________
GROUND WATER or SURFACE WATER
_______________ contain more fresh water than all the rivers and lakes in the world combined.
AQUIFERS
What are the 2 types of aquifers?
CONFINED and UNCONFINED
The area in the ground where most of the pore spaces are filled with air. Some water is also present. Also known as the unsaturated or under-saturated zone. The
vadose extends from the top of the ground surface to the water table.
Zone of Aeration (Vadose)
The area in the ground, below the zone of aeration, where all the pore spaces are filled with water.
Zone of Saturation
Ground water in water-bearing, or permeable, rock or unconsolidated material such as sand, silt, or gravel that transmits water to springs and wells.
AQUIFER
Aquifers in which an impermeable dirt/rock layer exists that prevents water from seeping into the aquifer from the ground surface located directly above.
CONFINED AQUIFER
Those aquifers into which water seeps from the ground surface directly above.
UNCONFINED AQUIFER
Water moves through the ground and through aquifers much like water on the surface moves, except that it travels much more __________.
SLOWLY
If the soil is sand and gravel, the water can move as much as five feet per day. However, more often, ground water moves just a few inches or less per day.
What are the advantages of ground water?
What are the disadvantages of ground water?
What are the advantages of surface water?
What are the disadvantages of surface water?
A physical characteristic caused by mud, sand, silt, clay, or organic matter causing water to appear cloudy or murky, giving it an apparent color.
TURBIDITY
Flowing water, especially ground water containing carbon dioxide (CO2), dissolves minerals as it flows through the soil and produces _______________.
HARDNESS
Results from the bicarbonates of calcium and magnesium.
CARBONATE HARDNESS
Closely related to hardness, this is due mainly to carbonates, bicarbonates, and hydroxide ions (OH-). CO2 gas is absorbed by rain or surface water to form carbonic acid (H2CO3), which reacts with minerals to form bicarbonates (HCO3)(e.g., calcium or magnesium bicarbonate and sometimes sodium bicarbonate).
ALKALINITY
The H2CO3 formed in water is an unstable compound. Just as it is formed from CO2 and water, it also breaks up into its component parts when there is insufficient alkali to combine with.
WATER ACIDITY
The concentration of a __________ dissolved in water is dependent upon the chemical characteristics of the gas, concentration in the atmosphere, atmospheric pressure, and temperature.
GAS
Primarily of interest are the gases oxygen, hydrogen sulfide, and carbon dioxide (CO2). Dissolved oxygen (DO) is the amount of oxygen dissolved in water, expressed in milligrams per liter (mg/L).
Aerobic degradation of waste products in water _______________ DO levels.
DECREASES
The ability of water supplies to produce massive epidemics is well known. Water can be a carrier of many _______________ responsible for intestinal diseases.
PATHOGENS (WATERBORNE)
