Unit C Section 2.1

Question 1

What is a ozone layer?

Answer 1

• Ozone (O3(g)) forms a layer that shields Earth from much of the damaging ultraviolet (UV) radiation from the Sun.
• The ozone layer is 15 to 50 km above Earth’s surface,
• but ozone also exists at ground level and can be harmful.

Question 2

What is the meaning of monitoring?

Answer 2

Monitoring means keeping track of something for a specific purpose

Question 3

Can clarity be a good indicator of clean water?

Answer 3

• Clarity is not a good indicator of water quality.
• Clearwater can sometimes be harmful to humans and other organisms.
• For example, lakes affected by acid rain are crystal clear and lifeless.

Question 4

Water quality is determined according to:

Answer 4

Water quality is determined according to what the water is used for

Question 5

Both provincial and federal governments set guidelines for water quality in five categories of water use:

Answer 5

• human drinking water
• recreation such as swimming
• livestock drinking water
• irrigation
• protection of aquatic life

Question 6

How do scientists monitor water quality:

Answer 6

by biological and chemical indicators

Question 7

BIOLOGICAL INDICATORS:

Answer 7

Scientists use organisms that live in water to help determine water quality.

Question 8

What are the organisms that are used as biological indicators:

Answer 8

These indicator organisms include fish, plants, worms, insects, plankton (microscopic algae and tiny animals), protozoa, bacteria, and viruses.

Question 9

What are Microbiological Indicators:

Answer 9

• Microscopic organisms such as bacteria can cause serious health problems if they are present in large enough numbers.
• Too many microscopic organisms such as bacteria is an indicator of bad water quality.

Question 10

What are Invertebrates:

Answer 10

Invertebrates are animals without backbones

Question 11

Why are invertebrates used as indications for water?

Answer 11

They are used for monitoring because different invertebrates prefer different living conditions.

Water temperature and pH can also affect the types of
organisms found in an area.

Question 12

Invertebrate examples:

Answer 12

insects, crustaceans (such as shrimp), worms, and mollusks (such as clams)

• water boatman
• mosquito larva
• water strider
• flatworm
• leech
• midge larva
• mayfly nymph
• clam
• caddisfly larva
• dragonfly nymph

Question 13

How much should the pH of water be to see less fish?

Answer 13

If the pH of the water in an aquatic environment is below 5.0, you will not find many fish there, especially young ones.

Question 14

Which insects are good indicators for acidic environments?

Answer 14

Some insects such as mayflies are also very sensitive to acidic environments and environments that have
little dissolved oxygen

Question 15

The diversity of all organisms decreases……….

Answer 15

as acidity increases and dissolved oxygen decreases

Question 16

What is an indicator for little dissolved oxygen?

Answer 16

few insects and many worms may mean that the water contains little dissolved oxygen.

Question 17

What is an indicator of good water quality?

Answer 17

A pond that supports a wide variety of organisms probably has good water quality for allowing organisms to survive

Question 18

Is a pond with indicators for good water quality safe for humans?

Answer 18

it cannot be considered safe for humans to drink until it is tested to make sure.

Question 19

Is water only made up of H2O?

Answer 19

Pure water is made up of only H2O(l) molecules, but water in the environment is never completely pure.

Question 20

The concentration of what affects water quality?

Answer 20

Water can contain many different

organic and inorganic compounds

Question 21

The most commonly monitored as

indicators of water quality:

Answer 21

• dissolved oxygen
• plant nutrients such as nitrogen and phosphorus
• acidity
• pesticides
• heavy metals
• salts such as sodium chloride and magnesium sulfate

Question 22

What are parts per million?

Answer 22

The concentration of chemicals in the environment is usually measured in parts per million (ppm)

or milligrams per liter

Question 23

How is parts per million calculated?

Answer 23

One part per million means that one unit of an element or chemical can be found in one million units of solution.

Question 24

How are parts per million calculated?

Answer 24

One part per million means that one unit of an element or chemical can be found in one million units of solution.

Question 25

How is oxygen dissolved into water

Answer 25

As the water churns over and around rocks, oxygen from the air is dissolving into it

Question 26

The level of dissolved oxygen in water depends on:

Answer 26

* temperature * turbulence due to wind or the speed of moving water * the amount of photosynthesis by plants and algae in the water * the number of organisms using up the oxygen

Question 27

Which amount of ppm is able to support most organisms that live in lakes and streams.

Answer 27

Five milligrams per liter (equal to 5 ppm) of dissolved oxygen

Question 28

2 ppm of dissolved oxygen is able to support which invertebrates?

Answer 28

Midge larvae and some worms can survive

Question 29

4 ppm of dissolved oxygen is able to support which invertebrates?

Answer 29

Freshwater shrimp, midge larvae, and worms can survive

Question 30

6 ppm of dissolved oxygen is able to support which invertebrates?

Answer 30

Mayflies, stoneflies, and beetles begin to disappear

Question 31

8 ppm of dissolved oxygen is able to support which invertebrates?

Answer 31

Large numbers of diverse invertebrates

Question 32

What types of rivers have better excess to air?

Answer 32

Rapids expose more water surface to the air than smooth river flow does.

Question 33

What is one factor that can affect dissolved oxygen?

Answer 33

One factor that can affect dissolved oxygen is an increase in phosphorus and nitrogen in the water.

Question 34

How can phosphorous and nitrogen get into the water?

Answer 34

- Sewage outfalls (acidic rain or snow falls) | - runoff from fertilized fields

Question 35

How can phosphorous and nitrogen affect the oxygen in water?

Answer 35

- Higher concentrations of these nutrients in water cause increased growth of algae and green plants - As more algae and plants grow, more die. - This dead organic matter becomes food for bacteria that decompose it. - With more food available, the bacteria increase in number and use up the dissolved oxygen in the water. - When the dissolved oxygen content decreases, many fish and aquatic insects cannot survive.

Question 36

In which types of water can magnesium phosphate combine?

Answer 36

Basic water

Question 37

what effect does magnesium phosphate have on water?

Answer 37

Magnesium phosphate does not dissolve in water so it forms a precipitate, causing the water to appear cloudy

Question 38

What is the pH of normal rain and snow?

Answer 38

5.6 because carbon dioxide from the air dissolved in them to form weak carbonic acid

Question 39

How can precipitation be considered acid snow or rain?

Answer 39

Precipitation with a pH lower than 5.6 is considered acid rain or snow

Question 40

At what ph of water will most fish start to disappear?

Answer 40

Most fish disappear if the water’s pH falls to 4.5.

Question 41

In the Canadian shield, what is not able to neutralize the acid?

Answer 41

The thin soils and the chemical composition of the rocks

Question 42

What is spring acid shock?

Answer 42

acidic deposits build up in ice and snow in the winter. In spring, when the ice and snowmelt, the acid meltwater flows into aquatic systems. This quickly creates a concentration of acid that can dramatically lower the pH of the water in a pond, slough, lake, or river for a short period of time.

Question 43

How can spring acid shock affect aquatic life?

Answer 43

It can seriously affect the eggs of aquatic organisms, as well as the young offspring of spring-spawning fish.

Question 44

What is the disadvantage of pesticides?

Answer 44

-Some pesticides have had longer-term harmful effects because they remained in the environment after they were no longer needed. -even these shorter-lasting pesticides may cause pesticide-resistant pests to develop. -insects reproduce rapidly, so many generations can be exposed to an insecticide in one season. -new insecticides must be developed -shorter-lasting pesticides may not disappear entirely from the environment.

Question 45

Scientists are finding that water samples may contain very low concentrations of many different pesticides How is this a problem?

Answer 45

One pesticide at a very low concentration might not be harmful. However, several pesticides together might mix to form a much more toxic or poisonous substance.

Question 46

Toxicity:

Answer 46

Toxicity describes how poisonous a | substance is.

Question 47

What are toxins?

Answer 47

Toxins or poisons are substances that produce serious health problems or death when introduced into an organism

Question 48

In order to compare toxins, scientists use a measurement called

Answer 48

LD50

Question 49

What does LD50 stand for?

Answer 49

“LD” stands for “lethal dose” | and the “50” represents 50%

Question 50

How is LD50 used?

Answer 50

LD50 is the amount of a substance that causes 50% of a group of test animals to die if they are given a specified dose of the substance all at once.

Question 51

Why is LD50 used?

Answer 51

LD50 testing allows scientists to compare toxicity | because they are comparing the dosage that will produce the same outcome: death.

Question 52

What animals is LD50 usually used on? | And on which body part?

Answer 52

LD50 testing is usually done on rats and mice. the usual ways are by mouth or applied to the skin the more toxic the substance is, the lower its LD50 number is.

Question 53

Why are some metals called heavy metals?

Answer 53

- They are called heavy metals because they have a density of 5 g/cm3 or more - This means they are five or more times heavier than an equal volume of water

Question 54

Examples of heavy metals:

Answer 54

copper, lead, zinc, mercury, cadmium, and | nickel.

Question 55

Where do heavy metals occur?

Answer 55

These metals occur naturally in rocks, soil, and sometimes in water.

Question 56

Why do water quality monitoring includes checking concentrations of heavy metals?

Answer 56

Heavy metals can be toxic to a wide range of organisms, including humans

Question 57

How are heavy metals found in water?

Answer 57

acidic water can dissolve lead in pipes. Cadmium is present in some fertilizers as an impurity. Plants growing in basic soils are able to take in this cadmium

Question 58

How are heavy metals harmful?

Answer 58

- high levels of heavy metals over long periods, they may experience serious health problems. - It can affect normal development and cause permanent brain damage or even death