water quality unit - learning set 3 (nov. 09)

8/14/2019 Water Quality unit - Learning Set 3 (Nov. 09)

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What is the Water Like in Our River? Learning Set 3 - Page 53LEARNINGSE

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LEARNING SET 3:

WHAT AFFECTS WATER QUALITY?

CONTENTSScience Understanding for Teachers Page 55

Lesson 8: Fertilizer Investigation Page 69

Lesson 9: pH Investigation Page 73

Lesson 10: Variables Affecting Water Quality Page 76

Lesson 11: Revisiting the Fertilizer and pH Investigations Page 81

Lesson 12: Water Quality Testing Page 83

Lesson 13: Analyzing Water Quality Tests and Making Conclusions Page 86

Lesson 14: Bioindicators Page 89

Lesson 15: What Do Organisms Tell Us Page 95

What is the Water Like in Our River? Learning Set 3 - Page 54


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SCIENCE UNDERSTANDING FOR

TEACHERS

PurposeIn this learning set, students investigate specific water quality variables. They measure temperature,dissolved oxygen (DO), biological oxygen demand (BOD), fecal coliform, pH, turbidity, phosphates

and nitrates. The combined effects of these variables determine overall water quality. Using test

results for each variable, students create an overall, weighted Water Quality Index (WQI). This

numerical value can be translated into a qualitative statement about water quality in their river.

Next, students investigate overall habitat quality through the biodiversity in their river. Using

bioindicator organisms and tolerance values, students determine the overall Pollution Tolerance

Index (PTI) of their river. Students learn that the presence or absence of various indicator organisms

can be an indication of habitat quality, including water quality through biological response. Studentsare looking for agreement between what the PTI and WQI methods indicate about the health of the

river.

Dissolved OxygenDissolved oxygen (DO) refers to the concentration of molecular oxygen (O

2) dissolved in river water.

Aquatic animals need oxygen to breathe and live, but they cannot use the oxygen in a water

molecule (H2O). It is bonded too strongly to the hydrogen atoms (2H). Aquatic animals can only use

oxygen in its elemental form (O2).

Most of the oxygen incorporated into the water originates from the atmosphere. However, plant

production of oxygen through photosynthesis also provides a substantial fraction of total dissolved

oxygen.

The amount of oxygen (O2) that can dissolve into water is largely dependent on the temperature and

the physical churning or turbulence of the water. Cool waters can dissolve more oxygen than warm

waters. Likewise, quickly flowing, turbulent areas (i.e. cascades and riffles) have higher

concentrations of dissolved oxygen than slowly moving or still water (i.e. pools and glides).

Dissolved oxygen (DO) is essential for the survival of aquatic animals. Organisms such as fish and

some macroinvertebrates use their gills to extract dissolved oxygen from the water to breathe and

live. As a result, the concentration of oxygen strongly influences which organisms are able to survive

in the river. The general trend is for a greater diversity of animals to live in well oxygenated water

than in poorly oxygenated water.

Rivers should be saturated with dissolved oxygen by the very nature of their movement. Rivers that

fall below 90% saturation are considered to be under serious environmental strain.



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Biological Oxygen DemandThe Biological Oxygen Demand (BOD) of a river is the amount of oxygen used by microorganisms

while decomposing organic matter. Microorganisms break down organic matter and combine it with

oxygen (oxidation). As organic material and decomposition increase, biological oxygen demand

increases and dissolved oxygen decreases.

BOD measurements are used to assess the level of organic pollution in aquatic ecosystems. High BODvalues most often point to considerable sewage contamination. However, it can also be an indication

of increased organic material and decomposition, from excess nutrients (e.g. fertilizer runoff) in the

river. Reservoirs or lakes created by damming a river can also have a high BOD. Rivers that are forced

to be still are robbed of their natural potential to oxygenate the water through movement.

Remember that moving water incorporates more dissolved oxygen than still water.

High levels of organic waste and BOD deprive other animals of the dissolved oxygen they require for

survival. Some animals are more tolerant of low oxygen levels, such as carp, catfish, sewage worms

and midge larvae.

Other animals,

such as trout,

caddisflies and

stone-flies, require

much more oxygen

to survive.

Fecal Coliform

Fecal coliform (FC)is a type of bacteria found in the digestive system and feces of humans and other animals. These

bacteria can enter the river through sewage overflow, direct human and animal deposit and

agricultural runoff containing animal wastes.

Fecal coliform bacteria do not cause illness. However, they are easy to measure and are often found

in conjunction with pathogens that can make people sick. Therefore, in the interest of practical

monitoring, fecal coliform bacteria are measured as an indication of the severity of harmful



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pathogens. A high concentration of fecal coliform indicates that a high concentration of pathogenic

organisms may be present.

National Coliform Standards in colonies/100 mlDrinking water 1 TC* Total body contact (swimming) 200 TC Partial body contact (boating) 1000 TC

Treated sewage discharge 200 TC

*Total Coliform (TC) includes bacteria from cold-blooded animals and various organisms. According to

some research, total coliform counts are normally about 10 times higher than fecal coliform (FC)

counts.

*= Return

The Michigan standard for fecal coliform in industrial output is 200 FC/100 ml of water. This standard

is seasonally applicable (i.e. when beaches are open) and can be suspended November 1st

through

April 30th

. The standard can also be exceeded if due to uncontrollable non-point sources, flooding,

accident, or emergencies that affect a sewer or wastewater treatment system, according to theEnvironmental Protection Agency (EPA). With such loose regulation, Michigan fecal coliform standards

are ineffective and associated pathogens are often spewed into Michigan waterbodies.

pHThe pH test measures how acidic or basic a sample is. The pH scale ranges from 0 (very acidic) to 14

(very basic). Neutral samples have a pH of 7.

The pH test measures the concentration and ratio of free hydrogen ions (H+) to free hydroxide ions

(OH-). Neutral samples have a pH of 7 with equal and low concentrations of H

+and OH

-ions. If a

sample has more OH-than H

+ions, it is considered basic and has a pHgreater than 7. If a sample has

more H+than OH

-ions, it is considered acidic and has a pH less than 7.

It is important to

remember that the pH

scale is log scale. For

every unit of change on

the pH scale, there is a

ten-fold change in

acidity. For example, a

sample with a pH of 6 is

10 times more acidic

than a sample with a pH

of 7 and 100 times more

acidic than a sample

with a pH of 8.



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Changes in acidity can be

particularly devastating to

aquatic plants and animals.

Most living things have adapted

to a specific range of pH

values. Although the range may

be fairly large, deviation fromthis range can have immediate

and dire consequences for

stream organisms.

Spring snowmelts can create

very acidic conditions in the

river. As the snow melts, it

releases the acidic water it

contained originally, plus all

the dry deposition that settled

out of the air and into the snow

during the winter. As a result,

spring snowmelts can create immediate flashes of very acidic water. Rivers can handle gradually

melting snow packs more effectively than sudden, large pulses of acidic inputs.

Michigan is fortunate to have soils with a natural buffering capacity to counter acidic inputs. During

the last glaciation, basic soil and rock (i.e. calcium carbonate) were carved from the Canadian shield

and transported to Michigan in the moving ice. As the ice retreated, it left this basic material and

the ability to moderate acidic inputs. As a result, our soils and streams are naturally, slightly basic

and able to handle minimal acidic inputs. Other areas are not as fortunate. Areas such as the

Adirondack and Catskill Mountains in New York, the mid-Appalachian highlands, and the mountainous

areas of the Western United States are suffering from acid rain inputs into their lakes and streams.

They did not receive the benefits of processed basic materials, and are further impacted in locations

with non-porous bedrock. In places like the Adirondack Mountains, water accumulates on the rocky

surface of the area, collecting dry deposition from the atmosphere and acid rain. As a result, one of

the most acidic lakes reported by the US EPA can be found in the Adirondack mountains. That is Little

Echo Lake with an average pH value of 4.2.

The natural buffering capacity of the stream can be exhausted. If we continue to add acidic

pollutants to our rivers, we will eventually exceed the soils ability to mitigate our inputs. Therefore,

it is important to plan for the future. Legislation that limits pollutants causing acid rain (e.g.

nitrogen and sulfur oxides from automobiles and coal-burning power plants), preserves stream and

air quality.

The discussion of stream pH is an excellent opportunity to connect this learning set to the What is

the Air like in Our Community? curriculum if you have already done it. Air pollution and acid rain

are the primary sources of acidity in our lakes and rivers.


pH ranges that support aquatic life (Stapp and Mitchell, 1995).


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Phosphates and NitratesPhosphates and nitrates are negatively charged, nutrient ions necessary for the growth of plants and

animals. Phosphate (PO4

-) is composed of one phosphorous atom and four oxygen atoms. Nitrate

(NO3

-) is composed of one nitrogen atom and three oxygen atoms.

Phosphates are essential in the metabolic reactions and growth of plants and animals. Theconcentration of phosphate is normally the growth-limiting variable in fluvial ecosystems because

it is naturally scarce. Phosphates are attracted to soil particles and organic material. Therefore, soil

is the largest natural sink and input (through erosion) of phosphates in rivers. Plants quickly use up

the small amounts of phosphates that are released.

Nitrates also act like a plant and animal nutrient. All plants and animals require nitrogen to produce

proteins essential for growth. However, nitrates are naturally very abundant and do not normally

limit the growth of stream plants and animals. Therefore, stream organisms are not as sensitive to

increases in nitrates.

Phosphate increases are the biggest nutrient increase problem, because growth inhibition is lost and

more of each nutrient can be used. When this happens, plant populations explode. In fact,

phosphate increases are notorious for causing algal blooms, which color the water green. The

increased plant growth leads to a higher biological oxygen demand (BOD) as the plants begin to

decompose, which in turn leads to oxygen depletion in the river.

Human activities can increase phosphate and nitrate concentrations in fluvial ecosystems. These

nutrients are quite often found together. Agricultural sources include fertilizer, animal waste and

increased erosion by influencing the transport of phosphorous. Major nutrient sources in urban areasinclude treated and untreated sewage, laundry detergents, and fertilizer runoff.

Total SolidsTotal solids is a measure of suspended and dissolved solids in the water. Dissolved solids are those

that cannot be filtered from a sample of water. Suspended solids are those that can be filtered out

and removed. Total solids can be measured by evaporating off the water, leaving behind the

dissolved and suspended solids.

Dissolved solids include inorganic and organic

substances. Dissolved inorganic materials arefound in ionic form. Many of which are necessary

for the maintenance of aquatic life including

nitrates, phosphates, iron, sulfur and many other

ions found in a water body. Dissolved organic material originates as biological products of soil,

plants, and animal material. Dissolved organic material is roughly 50% carbon and can be used as a

food source for aquatic microorganisms.



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High concentrations of suspended solids can cause serious water quality problems. Suspended solids

include soil particles from erosion, organic material, industrial waste, sewage and plankton. High

concentrations of suspended solids decrease water clarity, blocking the transmission of light through

the water, hindering photosynthesis, and absorbing the suns energy as heat. At the same time,

suspended solids can bind to toxic substances and heavy metals. Also, by increasing water

temperature, suspended solids indirectly decrease dissolved oxygen.

TurbidityTurbidity is a measure of water clarity. The

greater the turbidity, the more murky or

cloudy the water. Measuring turbidity is an

indication of the abundance of total solids in

the water. Turbid water can hinder

photosynthesis lowering dissolved oxygen. As

a result, turbid water is often(but not always)

poor quality water.

TemperatureTemperature measures how hot or cold something is and can be defined operationally as what a

thermometer measures. Temperature changes can have direct and indirect impacts on aquatic

organisms and water quality.

Many rivers are groundwater fed and therefore cold. As a result, many stream organisms are adapted

to consistently cold temperatures. As we continue to decrease the influence of groundwater and add

thermal pollution, we are increasing water temperatures, while decreasing the survival chances of

many aquatic organisms.Thermal Pollution Water has a very high heat capacity, making it resistant to temperature changes.

Compared to other substances, it takes more energy to raise the temperature of one gram of water

by 1 C. This physical property of water moderates daily and seasonal climactic changes in

temperature.

Large waterbodies also have considerable thermal inertia, a combination between the heat capacity

and the size of the waterbody. As the size of the waterbody increases, it is more difficult to change

the overall water temperature. Therefore, thermal interia is influential in sizable rivers and lakes. As

a result of thermal inertia, large waterbodies are naturally warmer than the air in the winter and

cooler in the summer.

This property of water has made it an attractive heat sink for industrial processes that require

cooling. Industrial activities, such as power plants, can use river water to cool machinery.

Afterwards, the water is put back into the river. The water that is released is often much warmer

than it was prior to extraction. Industrial cooling is a major source of thermal pollution. Measuring

water temperatures above and below a suspected source of thermal pollution can indicate the

source and magnitude of thermal pollution.



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Urbanization alters the water cycle and increases water temperatures. Urbanization often removes

streamside vegetation. This eliminates a source of shade that would normally cool the river. Urban

pressures also increase erosion by increasing surface runoff and removing vegetation. This results in

high concentrations of suspended solids (i.e. turbidity), which also increases water temperatures.

Urban pressures also result in greater temperature variation by increasing surface runoff. Urban

runoff can be colder than groundwater in the winter, or much warmer in the summer as it moves

over heated impervious surfaces, such as roads and parking lots. The net result of increasing urban

pressures is warmer average temperatures with greater variation.

Direct Impacts Water temperature is one factor that determines which organisms are present in the

river. Aquatic animals can be very sensitive to temperature changes. A week or two of high

temperatures each year may make a stream unsuitable for the existence of sensitive organisms, even

though temperatures are within an acceptable range throughout the rest of the year.

Different species have different temperature

requirements, but all species can tolerate slow,

seasonal changes better than rapid changes.Thermal stress and shock can occur when

temperatures change more than 1 to 2 C in 24

hours. High water temperatures increase the

sensitivity of aquatic animals to toxic waste,

disease and parasites. This can be a result of

increased parasite populations, or increased

susceptibility during thermal stress or shock.

Optimum water temperatures may change for

each stage of life. For instance, fish eggs andlarvae usually have narrower temperature

requirements than adult fish.

Temperature changes can alter animal behavior. Temperature cues biological functions in many

aquatic animals, such as hibernation and emergence, feeding, reproduction and metabolism.

Changing water temperature can entice animals to behave in ways that are not optimal for their

survival, such as migrating when they should be hibernating. Some organisms do not perform vital

functions at all (e.g. reproduction) until temperature cues are just right. As a result, altering

temperature can change animal behavior and ultimately jeopardizes their long-term survival.

Indirect Impacts Elevated water temperatures directly and indirectly decrease dissolved oxygen in

the stream. Warmer temperatures decrease dissolved oxygen by increasing plant production,

decomposition and the BOD of the river. Likewise, increasing water temperatures increase animal

metabolism and respiration. This also leads to the depletion of dissolved oxygen in the river.



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Water Quality Index (WQI)Students will determine the overall Water Quality Index (WQI) for their river. This index is

determined by the weighted influence of 8 water quality variables. These variables include

temperature, dissolved oxygen (DO), biological oxygen demand (BOD), fecal coliform, pH, turbidity,

phosphates and nitrates.

In order to create an overall WQI, raw water quality measurements are translated into comparable

numerals. Each test result is translated into a ranking through the tables provided for each

variable. This results in 8 ranks, one for each variable. Each variable is also weighted. Weighting

each

variable

depicts the

fact that

each

variable

influences

water

quality to a

different

degree.

Each rank is

multiplied

by the

respective

weight for

each

variable.

The sum of

the products

is the WQI

value. This

value can be

translated

into a

qualitativestatement

about water

quality

(i.e.

excellent,

good, fair

and poor).What is the Water Like in Our River? Learning Set 3 - Page 62


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Biodiversity and Bioindicators Biodiversity refers to the variety of living things in a given area.

Biodiversity and individual populations are maximized when habitat conditions are optimal. As a

result, biodiversity is often used as an indication of habitat quality, including water quality.

When habitat conditions change, plant and animal communities are impacted according to their

pollution tolerance. While very tolerant species can withstand large changes in their environment,

intolerant species may be eliminated from the changing habitat. As a result, the presence or absence

of certain plant and animal species can be an indication of overall habitat quality. Species that react

in predictable ways to changes in their environment are known as bioindicators.

Creatures that are very

sensitive to changes or

variation in water quality

may be exterminated from

the river. These species

will be replaced by

organisms that are more

tolerant of changing

conditions. Unfortunately,

once exiled from the river, it is unlikely that the sensitive species will ever be able to return. As a

result, changing river conditions can result in extinction from that site and possibly all other sites as

well. The net result can be an immediate loss of biodiversity, and an eventual loss of life entirely.

Benthic Organisms as BioindicatorsBenthic macroinvertebrates are bottom dwelling, aquatic invertebrates (organisms without a

backbone) that can be seen with the unaided eye. These organisms are very important in the stream

food web and can be very sensitive to water quality changes. In many cases, benthics are the most

important organisms connecting the flow of energy between primary producers (plants) and larger

organisms. Many macroinvertebrates found in rivers are larval stages of terrestrial insects such as the

dragonfly and black fly. Other common benthic organisms include snails, worms, leeches and

crustaceans. Benthic macroinvertebrates are easy to collect and are often used to determine site-

specific, long-term water quality. Unlike, chemical and physical tests that determine present

concentrations of various pollutants, macroinvertebrate presence and absence provides information

about present water quality and past water quality through biological response. The use of

macroinvertebrates as bioindicators assumes that polluted sites have fewer organisms than clean

sites and that the presence or absence of a certain organism is a direct result of habitat quality.Also, the information provided by macroinvertebrate collections can be considered relatively site-

specific because many macroinvertebrates migrate only short distances.

Macroinvertebrates can be subdivided according to feeding guilds, groupings according to feeding

habits. The functional feeding groups are: shredders who eat and/or live in dead plant and animal

material, collectors who eat smaller pieces of dead organic material, filterers who filter out even

smaller particles out of the water, grazers and scrapers who eat only live algae, and predators who



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eat other benthics (live prey). Macroinvertebrates are often categorized by functional groups,

because it is difficult to identify them to family, genus or species. At times it is more important to

know the role that each individual plays in the stream ecosystem than its specific name.

Sampling Benthic Organisms

Benthic organisms can be located

and collected where they feed or

rest. Many benthic organisms can

be found hiding and feeding in

stream vegetation. Organisms

that require high levels of

dissolved oxygen can be found in

riffles where water is flowing

over rocks. Benthic organisms

that eat dead plant material are

often found under leaves near

the stream bank.

Macroinvertebrate populations

vary by season. Keep this in

mind. For instance, organisms

that feed on fall leaf litter are

very abundant in the fall of the

year. This does not mean that

collection is impossible at other

times of the year. Populations

may be maximized at certain

times of the year, but they are still present throughout the rest of the year. The real trouble may be

finding them in a life stage that you recognize. Do not get discouraged if you are having trouble

collecting benthic organisms. It can be difficult to sample the majority of the organisms that are

present and nearly impossible to collect them all.

Interpret the results of your collection as a whole. If you do not find a particular organism, it does

not mean that it is definitely not in the river. It simply means that you did not find one. If the

majority of the insects that you collect indicate that the water quality is fair, for instance, stick

with it. Do not change your evaluation simply because a few of the other organisms that indicate

fair water quality were not found.

Pollution Tolerance IndexStudents will be using a Pollution Tolerance Index (PTI) to do a qualitative study of benthic

biodiversity in their river. A PTI is useful for detecting moderate to severe pollution. It is based on

the presence of indicator organisms (i.e. bioindicators) and tolerance levels. Indicator organisms are



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those that react in predictable ways to habitat changes. This method assumes that the presence or

absence of a certain organism is a direct result of habitat quality, including water quality.

In order to create a PTI value, each organism is assigned a value relative to its sensitivity to water

quality changes. In this PTI, individual tolerance values/groupings range from 1 to 4. Low values are

assigned to tolerant organisms that can withstand severe water quality changes or degradation.

High values signify that the organism is very sensitive to changes in water quality and can be easily

eliminated from the site. As a result, the presence of organisms with high indicator values (e.g.

caddisfly larvae) implies that the river is healthy. The absence of many of these organisms indicates

poor stream health. Students determine the PTI for their stream using the illustrated key and

worksheet provided. First, students identify each organism by matching the organisms to the

pictures. As they identify each organism, they mark a one on the worksheet by its name. Each type

of organism only gets one number. Therefore, this method only provides information about

biodiversity and does not reflect the concept of abundance. Next, all the ones are summed up for

each group and multiplied by the group number (i.e. tolerance value). The sum of these values is the

overall PTI, which translates into a qualitative estimation of stream quality (i.e. excellent, good, fair

and poor).

Students are looking for agreement between the overall Water Quality Index and the Pollution

Tolerance Index. Hopefully, the two tests will result in the same qualitative statement about the



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health of the river. Keep in mind that the PTI relayed information about the entire health of the

stream ecosystem.

The WQI only assessed 8 water quality variables. The PTI actually tells you much more about stream

health, while the WQI gives a good indication of water quality specifically. If the WQI and PTI do not

agree, the difference can be an indication of the physical condition of the stream habitat, which can

be difficult to measure or quantify.

SummaryIn this learning set, students investigate the habitat quality of their river, including water quality.

Through benthic organism collections and water quality tests, students make the connection

between water quality, habitat quality and biodiversity. At the termination of this learning set,

students should have a good understanding of several water quality issues and the impact that they

have on aquatic organisms and human users.

Science Understanding Resources

Field Manual for Water Quality Monitoring from GREEN Chapter 3: Nine Water Quality Tests. Thischapter discusses physical and chemical factors, their sources and their effects and methods of

testing them. Chapter6: Benthic Macroinvertebrates. This chapter discusses multiple methods for

benthic macroinvertebrate collection and several specific organisms that students may find.

Nine Water Quality Tests Compiled by Karen Amati. Provides background for students about each of

the nine physical and chemical factors that impact water quality in terms of what they are, their

sources and their affects. The reading also describes how to perform each test in terms of how

students will perform the tests during the project.

Water Studies for Younger Folks: A Water Activities Manual for 5th

-8th

Grades The entire book gives

you and your students background information on the factors, how to test the factors, their sources,

and their effects.

Teacher Terms to Know

Acidic-having a greater concentration free hydrogen ions (H+) than hydroxide (OH

-) ions. [H

+]>[OH

-]

Algal bloom-rapid growth of algae stimulated by excess nutrients.

Basic-having a greater concentration of free hydroxide ions (OH-) than hydrogen ions (H

+) ions. [H

+

]


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Biological Oxygen Demand (BOD)-the amount of oxygen required by microorganisms for the

decomposition of organic material; same as biochemical oxygen demand

Buffering Capacity- ability to neutralize both acids and bases and thereby maintaining the original

acidity or basicity of the solution

Cascade-an area of a stream or river where the flows are very turbulent usually when moving over

large boulders and considerably changing elevation

Collector- organisms that eat small pieces of dead organic material

Dissolved Oxygen (DO)-molecular oxygen

(O2) dissolved in river water

Fecal Coliform- bacteria found in the colon and feces of humans and animals

Filterers- organisms that eat by straining small food particles out of the water

Glide-a area of a the stream having laminar flows, very smooth and continuous; where the surface of

the moving water appears very calm and flat

Grazers- organisms that consume live algae and diatoms

Heat Capacity- the amount of energy it takes to warm one gram of a liquid 1 degree Celsius.

Herbivore-eats plant material

Macroinvertebrate-invertebrates (organisms without a backbone) that can be seen with the unaided

eye

Metabolic reaction- the chemical changes in living cells by which energy is provided for vital

processes and activities and new material is assimilated

Nitrate-negatively charged, nutrient ion composed of one nitrogen atom and three oxygen atoms

(NO3

-).

pH- an expression of both acidity and alkalinity on a scale of 1 to 14, with 7 representing neutrality.

Numbers greater than 7 indicate alkalinity. Numbers less than 7 indicated acidity.

Phosphate-negatively charged, nutrient ion composed of one phosphorous atom and four oxygen

atoms (PO4

-).

Pollution Tolerance Index (PTI)- an estimation of habitat quality based on the presence and absence

of bioindicator organisms and tolerance values Pool-(1) a small and rather deep body of usually fresh

water (2) a quiet place in a stream

Predators- Animals that consume other living organisms

Primary Producers- living organisms that produce their own energy from sunlight by photosynthesis

(e.g. plants)



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Protein- naturally occurring substances that consist of amino-acid residues joined by pep-tide bonds

and contain the elements carbon, hydrogen, nitrogen, oxygen, and occasionally other elements.

Riffle- portions of the stream where the flow is slightly turbulent, usually when moving over rocks,

where the surface of the water appears to be rippling

Scrappers- Organisms with specially designed mouth parts adept to eating algae and other organic

materials pressed against other surfaces Shredders- organisms that chew and mine into dead organicmaterial

Temperature- degree of hotness or coldness measured on a definite scale (i.e. thermometer)

Thermal Inertia-the resistance to temperature change, increasing as the heat capacity and size of a

waterbody increases

Thermal pollution- significantly heated or cooled water in a natural waterbody at a temperature

harmful to the environment; temperate extremes

Thermal stress- when an organism goes into a state of shock due to rapidly changing or extreme

temperatures, increasing the organisms risk of further illness

Total Solids- In hydrology, dissolved and suspended materials in water

Turbidity- a measurement of the clarity of water. It is used as an indication of total suspended

solids.

Turbulence- the physical churning or movement of water; departure from a smooth flow

Water Quality Index (WQI)- an estimation of water quality based on the weighted influence of

measured water quality variables



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LESSON 8:

FERTILIZER INVESTIGATION

OVERVIEW AND OBJECTIVESLearning ObjectivesUsing information from previous class discussions on experimentation, students will develop an

investigation of the effects of fertilizer on plants.

Assessment CriteriaInvestigations will include independent and dependent variables, controls and student hypothesis.

Purpose

Students develop an understanding of the effects phosphates on water quality and aquatic plants.

The following are multiple options for how the experiments in Lesson 9 and 10 may be enacted.

First Option: one experiment (possibly fertilizer effects) is done as a whole class (modeling steps for

an experiment) while the other experiment (possibly acid effects) is conducted by small groups.

Second option: student groups select one of the two experiments to conduct.

Third option: is for the groups to develop their own experiments. Regardless of which option is

selected the main goal is to expose students to planning and conducting an experiment over an

extended period of time. The material illustrates option 1. This option has the most class supports.

The fertilizer experiment is used as a means to model the steps for conducting an investigation. The

teacher guides the class through this first investigation, modeling each step as well as providing

rationale for design. Working in small groups, students apply what they have learned about designing

and conducting investigations as they construct their acid investigations.

However, no matter which experiments you choose, each will continue THROUGH Learning Set 3

with students doing observations, recording data and then analyzing the data later in Learning Set 4.

PREPARATION

Set-UpSee Student Worksheets and be sure to have your materials ready ahead of time.

Special ConsiderationsThis lesson, along with the following investigation (Lesson 9) started during this Learning Set, require

extended time to collect data. Time needs to be set aside on a regular basis for students to make

their observations. You will need to monitor the jars and determine when sufficient data are

collected.



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Water will evaporate from the jars or test tubes, Be sure to add additional water that contains the

proper acid or fertilizer mixture.

Results from these experiments are needed for activities in Learning Set 3

Materials Ten jars

Distilled water Distilled vinegar and lawn fertilizer Duckweed (or other aquatic plant) "?" Investigation Sheets Student Worksheet/What Will Happen? Fertilizer Investigation

TimeTwo fifty-minute periods.

INSTRUCTIONAL SEQUENCE

INTRODUCING THE LESSON

Contextualizing the InvestigationsMake connections with the stream table activities.

During the stream table session, students explored how land cover may impact water quality due to

the presence of pollution. Specifically, they saw an example featuring fertilizers as non-point source

pollution.

Students will investigate the effects of two pollutants on aquatic plants. One pollutant will be

fertilizer and the other pollutant will be acid rain.

Explain that fertilizers contain compounds called phosphates and nitrates. These are the mainfertilizer ingredients we will examine.

CONDUCTING THE LESSON

Identifying VariablesPlace the question What effects do fertilizers (nitrates and phosphates) have on the health of

plants? to be investigated on the board. -Remind the class that nitrates and phosphates are the

main ingredients in fertilizer.

Hand out Student Worksheet/What will Happen? Fertilizer Investigation

Help the class identify the independent variable (you changed it variable). -Show the students the

materials and the experimental set-up. Ask the students What are we trying to find out? What

variable in our investigation are we studying to see if it causes a change or effect? This is called the

independent variable and it is the variable we will change. For example, we might use the variable

amount of fertilizer with three solutions, one which is low fertilizer, a second one that is medium

fertilizer and a third one that is high fertilizer.



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Help the class identify the dependent variable (it changed variable). What variable in our

investigation are we studying to see if it is affected or changed? This is called the dependent (it

changed) variable.

Independent and dependent variablesStudent understanding is facilitated by experiencing these important ideas in familiar language.

Refer to an independent variable as the "you changed it variable" and the dependent variable as the"it changed" variable." As the project progresses, press students to use scientific terms for these

concepts.

Model Investigative ProcessThe experiment is designed to provide an opportunity to emphasize the phases of an investigation.

The goal is to model the process for composing a hypothesis and identifying the variables. Students

are asked to use the process you described as a template for their work in small groups in composing

a hypothesis and identify variables for the second experiment.

RubricsPosting rubrics (evaluation criteria) is one method for supporting student learning. Having students

conduct self assessments and peer reviews of their work is another method for supporting students in

learning how to learn. By making assessment clear from the beginning, you can help students

become more planful and deliberate about their learning.

This is the variable that we measure to see if it is affected. Example: In our experiment, plant

health is our dependent variable. How can we measure a change in plant health? (i.e. number of

leaves, color of plant, height of plant?)

Students design a controlled experiment. The simplest form of an experiment manipulates orchanges one variable at a time. What variables should remain constant or unchanged (amount

of water, number of plants in a jar, amount of sunlight, etc.)? -These variables are called control

variables.

Developing an HypothesisRefocus the class on the investigative question you placed on the board. (What effects do fertilizers

have on the health of plants?)

Students write their prediction about what will happen to the health of the plants when the amount

of fertilizer is increased. Students then share their predictions with the class.

Students rewrite their prediction in a proper hypothesis form. If needed, review what makes a good

hypothesis with students. For Example: If the amount of fertilizer increases then the color of the

plant will become more yellow.

Focus the class on the key features of a good hypothesis. Emphasize that a good hypothesis can be

supported or rejected by data.



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ProcedureFocus the class on the materials used for the experiment. Demonstrate the set up for the students

and have them follow along. Check for student understanding.

Making ObservationsDiscuss with the class how to make quality observations. -What will they observe? -How often willthe observations be made? -How can we organize our data?

Guide the class to record the following in their observations: -Record the data. -Write a description

indicating the size and color of the plant. -Students should draw their observations as well.

Determine with the class when and how frequently observations will be made. Be sure observations

are made at the start of the investigation. It is useful to post the schedule for observations some

where in the room

CONCLUDING THE LESSONClass reviews hypothesis.

Students record initial observations.

Review when future observations will be done.



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LESSON 9:

PH INVESTIGATION

OVERVIEW AND OBJECTIVESLearning ObjectivesUsing information from previous class discussions on experimentation, students will develop an

investigation of the effects of pH on plants.

Assessment CriteriaInvestigations will include independent and dependent variables, controls, and student hypothesis.

Purpose

Students explore the effects of acid on water quality.

PREPARATION

Materials Ten jars Distilled water Distilled vinegar and lawn fertilizer Duckweed (or other aquatic plant) Student Worksheet/What Will Happen? Acid Investigation

TimeOne fifty-minute period.


INTRODUCING THE LESSONAs a class, review the variables for the investigation.

Independent (you changed it) Variable: something you changed e.g. amount of fertilizer

Dependent (it changed) Variable: something measurable e.g. amount or health of the duckweed

(number of leaves, and/or color)

Control Variables: things kept the same, e.g. size of container, type of plant, amount of light, etc.

CONDUCTING THE LESSONAsk the class if they remember any sources of acid rain and if they are present in our community.

Pose to the class the question What effects will acid have on plants?

Discuss with the class what they know about acid rain and how it might affect plants.



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Explain to the class that they will do a similar investigation as the fertilizer experiment except this

time we will use different amounts of acid. The acid simulates the affects of acid rain.

Identifying the VariablesStudents take out their Student Worksheet/What Will Happen? Acid Investigation.

Place the question (What effects will acid have on plants?) to be investigated on the board. Inform

the class that pH is a measure of acids and bases. -Review the pH scale. A low pH indicates a strong

acid while a high pH indicates a base. Water is neutral at a pH of 7.0.

Help the class identify the independent variable (you changed it variable). Show the students the

materials and the experimental set-up. Ask the students what questions they are trying to answer.

What variable in the investigation are they studying to see if it causes a change?

Students work in groups to identify the variables in the experimental set-up, the independent,

dependent, and control variables. Remind the students to think about how the experimental set-up

will help answer the question.

Monitor students work and decide if a full class discussion is necessary or collect the work and offer

students feedback so they can refine their work for home session.

Developing a HypothesisPrompt students to reflect about what they already know about pH (acids and bases) and then to

think about how acid will affect the health of the plants.

Students write a hypothesis individually, then share in pairs to rework their hypothesis.

Remind students of the key features of a hypothesis.

Walk around the class monitoring the students work.

Based on your monitoring, decide if the entire class needs to work through the hypothesis again.

Alternatively, collect the work and offer students feedback to refine their next hypothesis.

ProcedureFocus the class on the materials used for the experiment.

Assess if the students are able to go forth with the set up themselves

Making ObservationsReview what makes good observations, how often to make the observations, and how students can

organize their observations.

Students should -Record the data. -Write a description indicating the size and color of the plant. -

Draw their observations of the plant.



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Determine with the class when and how frequently observations will be made. Be sure observations

are made at the start of the investigation.

Start the pH InvestigationAs a group review the variables for the investigation.

Independent (you changed it) Variable: amount of acid

Dependent (it changed) Variable: amount or health of the duckweed (# of weeds, and/or color)

Control Variables: size of container, type of plant, amount of light, amount of fertilizer, etc.

CONCLUDING THE LESSON

Have groups record initial observations with the class.

Review when future observations will be done.



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LESSON 10:

VARIABLES AFFECTING WATER QUALITY

OVERVIEW AND OBJECTIVESLearning ObjectivesUsing ideas generated in class and manipulatory oxygen probes, students explain how new variables

affect water quality.

Assessment CriteriaThe variables affecting water quality will include, total solids, turbidity, fecal coliform and dissolved

oxygen. Student explanations will include how each variable affects both plant and animal life.

PurposeStudents learn about and test for the various chemical and physical variables that affect water

quality.

Variables introduced in this session include: Total Solids Turbidity Fecal coliform Dissolved Oxygen Biological Oxygen Demand

Set aside 5 -10 minutes each day for students to continue making observations of their experiments.

This can either be done at the beginning or end of the class period.

PREPARATION

Set-upTeacher should review experiments, create notes of their interpretation and experiment with

computer probes

Materials Water Quality Jars Flashlight Four Water samples of various temperatures Dissolved oxygen probes Student Reader/Testing Your Water

TimeTwo fifty-minute periods.

Dont forget to provide students time to make their experimental observations.



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INSTRUCTIONAL SEQUENCE - Day 1

INTRODUCING THE LESSONWhat are some investigations that we have recently conducted hat might effect water quality?

Fertilizer (containing Nitrates and Phosphates) Acids (pH)

Soils (erosion and deposition)

Discuss with the class some substances that might be found in our river, for example, if you used a

strainer in our river what might you find? or if we took a bucket of water from our river what

would we find in the bucket other than just clear water?

How might substances get into the water? Reflect back to the stream table activity. Focus thestudents on the concepts of:

Run-off, which can create non-point source pollution Combined sewer overflows, a point source pollution Erosion Deposition Affects of land cover and use

Based upon our experiments, models, walks, and videos, what are some possible effects of these

substances being in the water?

Fertilizer increase in plant (algae) growth pH - decrease in plant growth (less food and habitat) pH - decrease in biodiversity (some organisms can only live in neutral water) Soil- murkyness, plants decrease, block up some organisms gills Sewage- increase algae and bacteria and poison organisms

Have students (either as whole groups or one per group) select one of the terms below and read the

appropriate sections in the reader and answer the questions at the end of their section to present to

the class.

Total Solids Turbidity Fecal Coliform

Establishing links to the Driving QuestionFacilitate connection to the driving question. This may be accomplished by revisiting past activities

(river tank, water jars, virtual tour/video or walk) and asking probing questions such as:

What is the turbidity of the water? Was the river murky?

Was there a lot of "stuff" suspended floating in the water?

Do you think that the river absorbs a lot of light? Do you think that there is a high or low amount of total solids in the river? Why?

CONDUCTING THE LESSONRetrieve the water quality sample jars used at the beginning of the project. These jars can be used

as examples of turbidity and total solids. Turn off lights and shine the light through the turbit, and

clear jars. If time permits create a jar with solids in it, use sand or twigs.



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Ask students how plants would grow in each?

How would the solids in the water affect plants and organisms?

What might cause the material to get into the water? -Have you ever seen a river that looks like the

murky jar?

Ask the students how might we prevent water from having high turbidity, high total solids or high

levels of fecal coliform? (Optional- in groups, have students come up with measures or ways humans

can prevent rivers from having unnaturally high levels of the variables listed above. Discuss what

local communities and students can do to prevent pollution in water ways.)

CONCLUDING THE LESSONUsing new concepts have students answer either as an exit question or in their journals: -How do

total solids and turbidity affect how much light penetrates the water? -How do total solids and

turbidity affect the temperature of the water?

How does Fecal Coliform get into the water? What are some measures we can take to prevent high turbity, total solids and fecal coliform

from getting in the water? How do you think total solids and turbidity impact the quality of the water?

HOMEWORKAssign the Student Reader/Testing Your Water.

INSTRUCTIONAL SEQUENCE Day 2 (Cont.)

INTRODUCING THE LESSONAsk class to describe water quality variables identified yesterday. -What are these variables?

(Turbidity, total solids, fecal coliform) -How do they get in to the water? -What are some of theireffects?

Go over questions from Student Reader/Testing Your Water.

CONDUCTING THE LESSONTransition the class by explaining that today we will continue our talk about substances in the water

that affect water quality.

Ask the class what do fish and humans have in common? (They both breath air.) How do fish breath

under water, where do they get oxygen?

Introduce the following terms by either writing them on the board or at student tables.

Dissolved oxygen Biological oxygen demand

Explain why DO is necessary for aquatic life.



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Guide the class through the difference between dissolved oxygen and the oxygen atom found in the

water molecule. -Can someone describe the chemical formula for water? -If we could use a really

powerful microscope to see molecules, what would oxygen dissolved in water look like? -Emphasize

that the oxygen molecule is a different and separate than the compound water.

(Optional Activity)

Using ball and stick models or gumdrop models to illustrate the mixture of water and oxygen willreinforce the difference between dissolved oxygen and the oxygen atom in the water molecule.

Using these models, place ten to twelve water molecules and 3 or 4 oxygen molecules in a container

to represent the dissolved oxygen mixture.

Relationship Between Temperature and DOIn front of the room, set up four different glasses of water of differing temperatures (ie: from very

cold, cold, room temperature, and hot.)

Set up the dissolved oxygen and temperature probes on a computer along with a method for

displaying.

Review with your students molecular motion and change in energy levels with change in state of

matter (solid:molecules barely move and are close together, liquids: some movement and molecules

are farther apart, gas: molecules move fast and are as far apart) -when heat is added molecules

move faster and farther apart when heat is taken away, or made cooler, molecules slow down and

come closer together when water is cold, oxygen slows down and can be closer together, where as

when it heats up oxygen will move faster and want to be farther apart. Cold water can then hold

more dissolved oxygen than warm water.

Have the class make a hypothesis on which water jar will have the highest dissolved oxygen.

Use the probes to measure dissolved oxygen and temperature. Start with the coldest jar and move to

the hottest jar.

Prompt the students to note the results on the computer screen. Hold a brief class discussion on the

results and have students record in their notebook.

Relationship Between Amount of Stirring and DO.Maintain set-up and select the jar at room temperature.

Record the DO to start which will serve as the baseline.

As you are waiting have the students set up their graphs in their journal to record the various levels

of DO

Vigorously stir water and then record DO.

Ask students when would a river be stirred up like the water in the jar? Prompt students to suggest

rapid streams, after a storm, streams with many rocks and boulders and mountain streams.



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DO might be difficult for students to comprehend especially the relationship between temperature

and levels of DO. Share with students examples they might be familiar to help students make this

concept relevant. For example, the most abundant fish populations come from the depths of the

cold Atlantic and Pacific oceans. Many organisms cant live where companies dump warm wastewater back into rivers. Blue ribbon trout streams are usually very cold and have abundant amounts of

oxygen.

Discuss with students whether stirring or water being tumbled around is good for organisms. See side

bar, for example you can mention many good fishing streams have much mixing of the water, or why

storms are important to lakes, so that the water can be mixed and oxygen added.

Hold a brief class discussion on the results and have students record the data in their journal or in a

graph.

CONCLUDING THE LESSONPose the following questions to students in a classroom discussion:

How do these demonstrations relate to an actual river and to our river? What affects the amount of dissolved oxygen? Is water with low amounts of oxygen good quality water? How is dissolved oxygen used? Where does the oxygen come from?



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LESSON 11:

REVISITING THE PH AND FERTILIZER

INVESTIGATIONS

OVERVIEW AND OBJECTIVES

Learning ObjectivesUsing data from their investigation students will formulate a conclusions to their experiments.

Assessment CriteriaConclusions will be based on and supported by data and meet the guidelines for a good conclusion

(see below).

PurposeStudents analyze their data and construct conclusions for the Fertilizer and pH investigations.

Class discussions facilitate student reflection concerning the various project activities and how they

connect to the driving question. These guided discussions introduce students to the other variables

that affect water quality, how these substances might get into the river and their possible

environmental effects.

PREPARATION

Special ConsiderationsIf experiments have not shown significant change, add to the computer model first, then re-evaluate

experiments.

Materials Retrieve experiment - test tube or jars Optional graphing paper

TimeOne fifty-minute period.


INTRODUCING THE LESSONReview with the class the key aspects of the investigation -Purpose -Hypothesis -Procedure

Have students retrieve experiment (test tubes or jars).



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Analyzing DataAs a class have students take a look at their data noticing any patterns or trends they can find in

their observations. (Optional-Hand out graphing paper)

Have students work in groups to graph their data and answer the following questions: -How does the

amount of fertilizer (causal, independent variable) affect the growth of the duckweed (dependent

variable)? -What evidence in your observations support your statement? -Was your hypothesis

supported or not supported?

Have students discuss the group questions: Ask for individual groups to share their interpretation of

the data. As a class, discuss findings. Have groups call on each other to compare results.

Conclusion (Suggested Rubric Guidelines)Support the class in composing a proper conclusion. A good conclusion has: (either write on the board

or hand out rubric)

A description of the purpose of the investigation. A statement of your hypothesis. A statement describing if your hypothesis was supported or not supported by your data. Evidence (observations and data) which links to either support or disprove your hypothesis. A statement of how the investigation relates to the driving question. What you would do to improve the investigation, or what other questions has this investigation

caused you to think about?

Work with the students through the above process to build their conclusion. Use student observations

and probing questions to facilitate the conclusion building process.

If students are having difficulties, post 2 different conclusions: one excellent and one sub par todemonstrate a good conclusion and a not so good conclusion, and have students identify the correct

and incorrect aspects in each.


Review with the class the key features of a conclusion. Student volunteers share conclusions. Class assesses conclusions using conclusion rubrics. Provide student opportunity to revise.

HOMEWORKStudents work on their pH conclusion for home session.

Class offers feedback the next day so students can revise their conclusions.



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LESSON 12:

WATER QUALITY TESTING

OVERVIEW AND OBJECTIVESLearning ObjectivesUsing the water quality test kits and equipment, students will become adept at measuring water

quality variables. (lab skills).

Assessment CriteriaStudents will be proficient using water quality tests and equipment.

Purpose

During this lesson, students test the variables they have been studying on river water samples. Thereare two options for testing river water:

Take a trip to your river and conduct water tests the field. Teacher obtains local water samples and students complete water tests in class. (Create a

teacher video if feasible.)

Working in groups, students perform five water quality tests on water samples from their river.

Students perform the tests for nitrates, phosphates, fecal coliform, turbidity, and pH while the

teacher performs DO, BOD, and temperature tests at the time of the water sampling from the river.

The water quality of their local river, based on each individual test, is ranked on a scale of excellent

to poor (4-1).

PREPARATION

Special ConsiderationsRead through preparation in the Appendix and familiarize yourself with each test. Make sure you are

comfortable with how each test works in order to answer student questions on procedures.

Materials 1-5 gallon bucket of river water. (Optional)Video of water sampling. Low Cost Water Quality Monitoring Kits Student Worksheet/Water Testing

TimeTwo fifty minute periods.



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INTRODUCING THE LESSONReview and discuss with students the variables they have been investigating that affect water

quality, prompt them to reflect on their computer models (ie. dissolved oxygen, fecal coliform,

nitrates, phosphates, etc.)

Inform the students that now that they are familiar with what affects water quality it is time to test

their rivers water quality.

Briefly introduce the final water quality testing methods, which will depend on which water quality

test kit you obtain.


Construct a prediction

Individually have students review their conclusions from previous direct water quality measuringactivities (e.g. River Walk, Is it Drinkable?)

Based upon their conclusions from these activities have the students construct a prediction for water

quality of the river based upon the chemical tests that they will complete.

Setting Up the TaskAt this point if you are going to the river youll want to give your students more specific directions as

to who will be responsible for what materials, observations, data recording, etc.. Either way, be sure

to demonstrate and have students practice the water testing techniques before you go to the river.

After the students have completed their predictions, demonstrate in greater detail the testingkit materials and the general procedure to the testing series: nitrates, phosphates, pH, fecalcoliform, temperature, dissolved oxygen, BOD, turbidity, and total solids.

Hand out Student Worksheet/Water Testing Within groups students decide who will perform each test -The name of the person performing

the test is placed next to the name of the test on the River Testing packet. -Everyone shouldhave an opportunity to perform at least one test

Teacher checks to see if groups have distributed testing roles.(be sure you have enough directions to

distribute, make extras if needed) . Student testers review their specific test procedure(s). Teacherdetermines if groups are ready to test water.

Testing the River WaterWorking in groups, students perform the series of water quality tests. Teacher walks around room

monitoring student activity.

Students record data in their investigation packets, journals or on worksheet sheets.



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When groups have completed testing, have them clean up.

Support students in sharing data. This may be facilitated by using a classroom chart. An example

chart may include: -rows for each water quality test -columns for each group to place the results -

allow one column for class average

Final TestingGroups share data and record it on the classroom chart. Have students give a summary of the

variable they were testing.

Have students copy classroom chart.



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LESSON 13:

ANALYZING WATER QUALITY TESTS AND

MAKING CONCLUSIONS

OVERVIEW AND OBJECTIVES

Learning ObjectivesUsing data collected from the water quality tests, students will analyze the classes results and draw

conclusions.

Assessment CriteriaStudents analysis will be based on the class average and will include accurate ranking of each test

on a scale of 1- 4. 4 being excellent, 1 being poor.

PurposeStudent will analyze, interpret and draw conclusion from their data as to the quality of water in

their local river.

PREPARATION

Special ConsiderationsRead through preparation in the Appendix and familiarize yourself with each test. Make sure you are

comfortable with how each test works in order to answer student questions on procedures.

Materials Student notes, worksheets or observations from water testing.

TimeOne fifty minute period.


INTRODUCING THE LESSON

Review the collected data. -Place classroom chart on overhead -Review with students the varioustests they conducted -Ask students why they think we have a class average column on the chart.

Explain that this helps us to be more scientific ally accurate. For example, you can ask the students

if the teacher only picked one students grades to represent that of the who class, would that be

very accurate of all students grades? No, you would take the average of the class. This is why we

take an average of the water tests, one group might have not done the procedure correctly or

misread the instrument.



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Making Meaning of the data collectedPlace an overhead of the Physical and Chemical Test Ranking Chart up in front of the class (if one is

not included make one from the information in your water testing kit). In most kits, these can be

found at the end of the booklet describing the procedures for water testing.

Student results from yesterdays test are ranked on a quantitative scale of 1-4. 1 being poor, 4 being

excellent.

Model how the students will use their readings to determine the proper ranking number, 1-4.

Then have the students work in their groups to rank each test on the scale of 1-4.

Teacher checks for student understanding. Groups share rankings for each test -Peers discuss and

class consensus is reached

Calculating Overall Water Quality RankingExplain to the class that each variable we tested affects water quality differently. Some variables

are more important or have a larger impact than other variables.

Each test has a weighing variable which indicates how important the factor is in determining the

overall water quality. For example, some organisms can are better adapted to handle total solids in

the water (weighted .08) or levels of nitrates (weighted .10) but can not withstand much drop in

dissolved oxygen (weighted .17). Different organisms adapt in different ways to handle various water

quality variables. We will learn about such organisms in the next lesson.

Teacher places a copy of the weighted water quality chart in front of the class.Class discusses the meaning of the weights. -Look at the weighting variable. Are they all the same? -

Are they different? How are they different?

If the weighting variable for DO is .17 and the weighting variable for total solids is .07. Whatdoes this tell you about how important each variable is in determining water quality?

Calculating the overall water quality ranking: (calculators are helpful but not necessary) -Model how each ranking is weighted for example, BOD and temperature. (This can be veryconfusing for student ) Multiply the ranking value for DO by its weighting variable and recordthe product.

Have each group do the remaining weighting of each variable. Students should record theirresults on their sheets. -Have the groups calculate the overall water quality ranking by adding

the weighted rankings and recording the result on their data sheets. Have the students compare the overall water quality ranking to the following scale and record

their result.

Make sure the students wrote down their totals.

Explain that what they did is very similar to what scientist do when monitoring the quality or various

streams and river.



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Preparing to Write the Conclusion Review with the students what should be in their conclusion. Key ideas may include: -Review

criteria for a quality conclusion -Focus student attention upon the previously posted conclusionrubric

Add one additional criteria to the conclusion: How does our results from this series of waterquality tests compare with the results from our previous tests? (River Walk Observation, Is itDrinkable Observation)

Conclusion criteria: -Make a claim related to your hypothesis -Provide evidence to support your

claim: use data you have collected Write your claim clearly. It needs to be a complete thought, and written in precise scientific

language. Anyone who picks this up should be able to understand what you write. Students write a statement of error or limitations for their experiment.


Writing ConclusionHave individual students write a conclusion.

Have students share conclusions with two to three peers. Peers offers feedback based upon therubric.

Students revise conclusions.

HOMEWORKIf students have access to computers have them do a web search for stream monitoring sites and

have the students compare what they did and their procedures with what they found on various

websites.



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LESSON 14:

BIOINDICATORS

OVERVIEW AND OBJECTIVESLearning ObjectivesUsing ideas generated in class and possible collecting of organisms, students will describe which

macroinvertebrates are indicators of water quality.

Assessment CriteriaStudent descriptions will include the ideas of pollution tolerance and sensitivity, habitat

requirements and biodiversity.

PurposeDuring this lesson, students use the biodiversity of aquatic organisms as an additional method to

determine water quality in their local river. The collected organisms are identified and sorted by the

students. The results are then analyzed and conclusions are made about water quality.

PREPARATION

Special ConsiderationsPrepare an aerated water tank in the classroom for keeping live benthics a before collection

organisms, make sure there are many hiding places in the tank, some organisms will prey on others.

Student permission slips will be needed if going to the river.

Teacher will have to decide between taking a sampling trip to the river with the class, or collecting

the samples a head of time. Have materials prepared for the option you choose.

Have the sorting kits already set up or together before the students get into groups. Read through

Macroinvertebrate Identification and Sorting Guide Sheets to familiarize yourself with the process of

sorting and ranking.

Materials Aquarium tank for housing the collected organisms in the classroom D frame collecting nets, or other dip nets jars or containers to keep organisms in while

traveling gloves and goggles waders (optional) Sorting kit, each containing the following: -ice cube trays or 14 petri dishes -spoons, forceps

and turkey baster -magnifying glass -gloves and goggles -large shallow light colored pan Student Worksheet/Macroinvertebrate Identification and Sorting



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TimeTwo fifty minute periods.

Anchoring ExperienceExamining the living organisms in their river connects students to the river in their community.

Students should reflect back on the observations they made during the river walk, video, and/orvirtual tour.

Option ONETaking the students on the sampling trip will bring the students closer to their river.

Option TWOAlthough not as exciting as participating in the sampling, a video of the sampling will bring closer to

their river and the activity.


INTRODUCING THE LESSONReview with the class the previously developed definitions for water quality and some of the water

quality testing methods they discussed at the end of the previous session.

Inform students that an additional method for testing water quality is doing an investigation using

organisms that live in the river as indicators of water quality


MacroinvertebratesPrompt students to brainstorm responses to the following questions. -What types of organisms live in

and around the water? -Why would these animals be important? -What do living things need to

survive?

Introduce the term Macroinvertebrate and explain that this group of bugs is an indicator ofwater quality.

Explain that these bugs, macroinvertebrates play a key role in stream health and and as indicators

of water quality because they differ in their ability to tolerate pollution. Some are tolerant ofpollution and others are not.

Further explain that many macroinvertebrates live along the sides and bottom of streams and rivers.

Since each type has a different degree or tolerance for pollution, their presence or absence can be

an indication of the quality or health of the river or stream. -Discuss the important role of

macroinvertebrates at the base of the food chain for other organisms in the river ecosystems, and

that they make up a good part of the biodiversity in rivers



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Discuss with the class the concepts of "biodiversity" and why it is important for not only rivers but all

natural areas to have bio diversity.

Student Investigation Ask your students to think back to their river walk. Did they see any signs of biodiversity? Ask for examples? Could we tell by looking at the river if there were any macroinvertebrates? -How might we find

out if there are any in our river?

Prompt the students to respond that they need to do an investigation.

Inform the students that they will be conducting an investigation of the macroinvertebrates in theirriver.

Have students make hypothesis and predictions regarding what biodiversity they think they will find.

Preparing to Collect the OrganismsBefore the organisms are collected the teacher must decide how the collection is to be conducted.

There are two options 1) the teacher does the collection or 2) the students do the collecting.

Describe for the class the several different sampling locations (river bottom, bank, in vegetation,

and under rocks).

Ask students why several different locations are sampled (to obtain a larger and more diverse

sample.

If students are collecting the organisms then a description of the collecting procedures needs to be

completed. Additionally, you will need to go over safety rules for conduct at the river.

Review with the class the collection procedures, transportation and containers for the organisms.

Assign roles and responsibility ties for the students while they are on their collection trip.

Describe and/or demonstrate the collection equipment. The D-frame net is a simple way of

collecting benthic macro-invertebrates. The D- frame net is design so that the flat area at the front

of the net can be placed at the bottom of the river reducing the loss of organisms underneath the

net. You can use this net to collect samples from the bottom of the river as well as along the banks

of the river and in vegetation. WEARING GLOVES AT ALL TIMES

Discuss the proper procedure for handling the macroinveterbrates from the net to the containers.

Possible Alterations

One possible extension to this activity is to have students compare the different sampling locations.

Have the students make predictions about the organisms from these different locations Will they be similar or different? Why? Will they have special adaptations? What kinds? Have students record predictions and rationale.

Biodiversity

refers to the range of organisms present in a given location. When pollution changes environmental

conditions, some organisms can not survive. A few organisms can tolerate a range of conditions.

Therefore the more different types of organisms that are found, the less pollution there is.What is the Water Like in Our River? Learning Set 3 - Page 91


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ContextualizationIf organisms were collected by the teacher, show a video tape or other method to indicate where the

organisms came from.

Methods of CollectingThere are multiple methods of collecting benthic macroinvertebrates. For other methods of

collection, see the Field Manual for Water Quality Monitoring by GREEN.

Gloves and GogglesIf students will be participating on the collection of the organisms, students should wear gloves and

goggles.

If you have waders then this activity is best done in the water. If you do not have waders then you

can still get some sampling done from the bank of the river.

Either from within the river or from the bank, place the net at the downstream side of the sampling

area with the opening facing upstream. Hold the net perpendicular to the flow and as close to the

bottom of the river as possible depending on your position.

Hold the net for a short period of time. After good flow has moved through the net. Take the net out

and place what ever you collected in a large bucket with some water in it.

Repeat the sampling until you have collected a large enough sample for your classes with which to

work.

If you are able to go into the river and have some assistance, sample again with the net. Hold the

net close to the bottom of the river as you did before, but this time have your partner stand three

feet in front of the net and twist their feet into the bottom of the river. This action will free

sediment from the river bottom and dislodge more macro invertebrates.

Bank of RiverWalk along the bank of the river. Choose an area along the bank and simply place the net along the

side of the bank with the opening of the net facing upstream. Rub the net along the side of the bank

disturbing any sediment.


and place whatever you collected in a large bucket with some water in it.

Repeat the sampling until you have collected a large enough sample for your classes with which to

work..

In VegetationChoose an area that has a large amount of vegetation. Place the net in the water by the vegetation

so that the opening faces upstream. Firmly rub/brush the vegetation with the net, disturbing any

organisms that may be hiding or attached to the vegetation. Move the net up and down and side to

side.



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and place whatever you collected in a large bucket with some water in it.

Repeat the sampling until you have collected a large enough sample for your classes to work with.

Under RocksWearing gloves, pick up any stones or rocks greater than 2" in diameter. Rub it to remove any

organisms that may be present and place them in the collecting bucket.

Upon ReturnUpon returning from the collection, place the organisms into a previously prepared river tank.

Habitat Comparison Option: (Optional- Several tanks may be utilized if the teacher wishes to have

separate tanks for different collection locations. This option allows for students to make comparisons

between the organisms of different locations)

Setting up the classBreak students into groups.

Provide each group with an Identification and Sorting guide and a sorting kit, and a large pan with

Macroinvertebrates.

Teacher models the process first, followed by the students.

Using their identification and Sorting guides students count each different type of organism in each

group (one, two, and three).

Students place a check mark next to each type of macroinvertebrate found. Teacher monitors the

progress of the groups.

Checking Student Results and Sharing DataWhen most groups have completed the activity, the teacher leads the class in a brief sharing of their

data.

Teacher uses overhead or large chart and asks groups to identify one organism they found.

Ask other groups if anyone else counted the organism.

If agreement, mark on class chart.

Repeat steps with the next group or organism.

SortingTo facilitate the identification and sorting,you can use two methods:

Write the name of each type of organism at the bottom of each compartment of the tray so as

students sort they can also identify them one by one.



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Biotic Index for Sample Is an index that indicates water quality based on the pollution tolerance of

macroinvertebrates

Identification and SortingBiting OrganismsCaution students that some organisms may pinch or bite. They should be handled with spoons or

tweezers.

Wearing goggles

will keep river water from being splashed into students eyes.

Wearing Gloves will protect students from any pathogens in the water. Students should wash their

hands with a disinfectant soap after handling the Organisms.



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LESSON 15:

WHAT DO ORGANISMS TELL US?

OVERVIEW AND OBJECTIVESLearning ObjectivesUsing data from collecting macroinvertebrates or teacher given data, students will analyze and make

a conclusion about the quality off water in their river.

Assessment CriteriaConclusions will be based on the good conclusion rubric utilized throughout the unit, and will

include the data from the macroinvertebrate collection.

PurposeStudents use the results from the collection of macro invertebrates or teacher data re analyzed an

conclusions are made about water quality.

PREPARATION

Set-up See EPA Website on Bioindicators

Materials Refer to Lesson 14 for this Student Worksheet/Macroinvertebrate Sorting and Identification

TimeOne fifty minute period.

Biodiversityrefers to the range of organisms present in a given location. When pollution changes environmental

conditions, some organisms can not survive. A few organisms can tolerate a range of conditions.

Therefore the more different types of organisms that are found, the less pollution there is.


INTRODUCING THE LESSONUsing their Pollution Tolerance Index sheet students analyze their data.

When each group of benthics have been multiplied, the sum of all three groups is calculated and

placed in the appropriate box on the data sheet.



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Students then take their total and rank the quality of water based on the scale provided. Students

circle the corresponding water quality ranking.

Have each group give their biotic index and list them on the board and then take an average of all

the groups to create a final biotic index.


Drawing ConclusionsWork wit

water quality unit - learning set 3 (nov. 09)

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