BLOCK 9: ENVIRONMENTAL HEALTH - Unit 4: Potable Water (complete)

Question 1

Where surface and ground water are available, ___________ water is generally preferred.

Answer 1

GROUND WATER

An underground source, or aquifer, usually provides higher quality water.

Question 2

The portion of rain and melting snow that becomes surface water. Topography and gravity control the movement of this water.

Answer 2

RUNOFF

Question 3

An area or region drained by a river, river system, or other body of water.

Answer 3

WATERSHED

Question 4

A base may get its water from _______________ or _______________

Answer 4

GROUND WATER or SURFACE WATER

Question 5

_______________ contain more fresh water than all the rivers and lakes in the world combined.

Answer 5

AQUIFERS

Question 6

What are the 2 types of aquifers?

Answer 6

CONFINED and UNCONFINED

Question 7

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.

Answer 7

Zone of Aeration (Vadose)

Question 8

The area in the ground, below the zone of aeration, where all the pore spaces are filled with water.

Answer 8

Zone of Saturation

Question 9

Ground water in water-bearing, or permeable, rock or unconsolidated material such as sand, silt, or gravel that transmits water to springs and wells.

Answer 9

AQUIFER

Question 10

Aquifers in which an impermeable dirt/rock layer exists that prevents water from seeping into the aquifer from the ground surface located directly above.

Answer 10

CONFINED AQUIFER

Question 11

Those aquifers into which water seeps from the ground surface directly above.

Answer 11

UNCONFINED AQUIFER

Question 12

Water moves through the ground and through aquifers much like water on the surface moves, except that it travels much more __________.

Answer 12

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.

Question 13

What are the advantages of ground water?

Answer 13

Question 14

What are the disadvantages of ground water?

Answer 14

Question 15

What are the advantages of surface water?

Answer 15

Question 16

What are the disadvantages of surface water?

Answer 16

Question 17

A physical characteristic caused by mud, sand, silt, clay, or organic matter causing water to appear cloudy or murky, giving it an apparent color.

Answer 17

TURBIDITY

Question 18

Flowing water, especially ground water containing carbon dioxide (CO2), dissolves minerals as it flows through the soil and produces _______________.

Answer 18

HARDNESS

Question 19

Results from the bicarbonates of calcium and magnesium.

Answer 19

CARBONATE HARDNESS

Question 20

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).

Answer 20

ALKALINITY

Question 21

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.

Answer 21

WATER ACIDITY

Question 22

The concentration of a __________ dissolved in water is dependent upon the chemical characteristics of the gas, concentration in the atmosphere, atmospheric pressure, and temperature.

Answer 22

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).

Question 23

Aerobic degradation of waste products in water _______________ DO levels.

Answer 23

DECREASES

Question 24

The ability of water supplies to produce massive epidemics is well known. Water can be a carrier of many _______________ responsible for intestinal diseases.

Answer 24

PATHOGENS (WATERBORNE)