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1

Acidity of water is

its quantitative capacity to react with a strong base to a designated pH. 

2

Acidity is a measure of 

an aggregate property of water 

3

Acidity is a measure of an aggregate property of water and can be interpreted in terms of 

specific substances only

4

Alkalinity is also known as 

the buffering capacity of a stream

5

alkalinity refers 

how well it can neutralize acidic pollution and resist change in PH

6

alkalinity measures 

the amount of alkaline compounds in the water, such as carbonate, bicarbonates and hydroxides. these compounds are natural buffers that can remove excess hydrogen, or H+, ions

7

BOD means

The Biological Oxygen Demand

8

BOD means

the amount of oxygen consumed by bacteria in the decomposition of organic material. 

9

BOD also includes

the oxygen required for the oxidation of various chemical in the water, such as sulfides, ferrous iron and ammonia. 

10

dissolved oxygen test tells you 

how much oxygen is available

11

BOD test tells you 

how much oxygen is being consumed

12

BOD is determined by

measuring the dissolved oxygen level in a freshly collected sample and comparing it to the dissolved oxygen level in a sample that was collected at the same time but incubated under specific conditions for a certain number of days.

13

The difference in the oxygen readings between the two samples in the BOD is recorded in units of

mg/L

14

Unpolluted, natural waters should have a BOD of 

5 mg/L or less

15

Raw sewage may have BOD levels ranging from

150 – 300 mg/L

16

conductivity is 

a measure of how well water can pass an electrical current. It is an indirect measure of the presence of inorganic dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, iron and aluminum. 

17

It is an indirect measure of the presence of inorganic dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, iron and aluminum. The presence of these substances increases 

the conductivity of a body of water.

18

................................like ..................................................do not conduct electricity very well, and thus have a ...................conductivity in water.

Organic substances

oil, alcohol, and sugar

low

19

Inorganic dissolved solids are essential ingredients for

aquatic life

20

Inorganic dissolved solids are essential ingredients for aquatic life. They

regulate the flow of water in and out of organisms’ cells and are building blocks of the molecules necessary for life. 

21

 A high concentration of dissolved solids, however, can cause

water balance problems for aquatic organisms and decrease dissolved oxygen levels

22

Temperature: Oxygen is more easily dissolved in

cold water

23

Flow: Oxygen concentrations vary with 

the volume and velocity of water flowing in a stream. 

24

Usually streams with ............................................................. are considered healthy streams. 

high dissolved oxygen concentrations (greater than 8 mg/L for Ozark streams)

25

Usually streams with high dissolved oxygen concentrations (greater than 8 mg/L for Ozark streams) are considered healthy streams. They are able to support a greater

diversity of aquatic organisms

26

They are able to support a greater diversity of aquatic organisms. They are typified by

cold, clear water, with enough riffles to provide sufficient mixing of atmospheric oxygen into the water.

27

In streams that have been impacted by any of the above factors, summer is usually the 

most crucial time for dissolved oxygen levels because stream flows tend to lessen and water temperatures tend to increase.

28

In general, DO levels less than .........are stressful to most aquatic organisms.

3 mg/L

29

Most fish die at 

1-2 mg/L

30

Most fish die at 1-2 mg/L. However, fish can move away from

low DO areas