WATER QUALITY INDICATORS (mld)

​WATER QUALITY INDICATORS

8th Grade Science

8.E.1.3 Predict the safety and potability of water supplies in North Carolina based on physical and biological factors, including:

• Temperature  

• Dissolved oxygen  

• pH  

• Nitrates and phosphates  

• Turbidity  

• Bio-indicators

​Engaging Questions:

1. Can you tell the quality of water just by looking at it?

2. Which glass of water will you drink? Why?

3. What causes our water sources to be dirty?

4. Why is it important to keep our water sources clean?

​GLASS A

​GLASS B

Open Ended

Can you tell the quality of water just by looking at it? (Explain your answers)

​WATER QUALITY INDICATORS

• Temperature

• ​Dissolved Oxygen

• pH level

• Nitrates and Phosphates

• Turbidity

• Bioindicators

​I - DISSOLVED OXYGEN

• ​Oxygen found in the water is called “dissolved oxygen” because it is mixed into the water.

• High levels of dissolved oxygen indicate a healthy water system.

• Cold water can hold more dissolved oxygen than warm water

  can.

• As water temperatures increase, the dissolved oxygen level decrease.

• When fertilizers and nutrients get in the water, this increases plant growth. This will decrease the amount of oxygen in the water.

Multiple Choice

What is DISSOLVED OXYGEN?

• The amount of oxygen in land that goes into water

• The amount of oxygen dissolved in water

• The amount of oxygen dissolved in the soil

• The amount of oxygen dissolved in the atmosphere

Multiple Choice

Dissolved oxygen and water temperature are related.

• TRUE

• FALSE

Multiple Choice

What temperature of the water will hold more dissolved oxygen?

• HOT WATER

• HIGH TEMPERATURE

• LUKE WARM WATER

• COLD WATER

Multiple Choice

What is the relationship between temperature and dissolved oxygen in water?

• The higher the temperature, the more dissolved oxygen there is in the water.

• The lower the temperature, the more dissolved oxygen there is in the water.

• There is no relationship between temperature and dissolved oxygen.

• The higher the temperature, the more acidic the water is.

Multiple Choice

How can fertilizers in land negatively affect the dissolved oxygen in water?

• It increases the temperature of the water

• It decreases the amount of water because it promotes more evaporation

• It can promote the growth of plants and phytoplanktons that consume more oxygen

• It decreases the temperature of water

​II - pH LEVELS

• pH measures how acidic or basic (alkaline) the water is.

• High or low pH readings are signs of an unhealthy water system.

• Neutral water has a pH of 7. Most aquatic life functions best in water at a neutral or slightly basic (8 to 9) pH.

• ​0-6 pH level is acidic

• 8-14 pH level is basic.

Multiple Choice

Aquatic organisms survive best in water with which pH?

• 0-6 pH (ACIDIC)

• 9-14 pH (BASIC)

• 6-9 pH (NEUTRAL to SLIGHTLY BASIC)

Multiple Choice

A pH between 0-6 is considered as ____________.

• ACIDIC

• BASIC

• NEUTRAL

• SLIGHTLY BASIC

Multiple Choice

If we burn too much fossil fuels, the carbon dioxide released in the atmosphere and will mix to the water vapor creating _____________ which can negatively impact our water sources

• ALKALINE RAIN

• BASIC RAIN

• ACID RAIN

• NEUTRAL RAIN

​III - TURBIDITY

• Turbidity is a measure of how clear water is.

• Clear water has low turbidity and is desirable for an aquatic environments.

• High turbidity, or unclear water (think very cloudy), is a sign of an unhealthy water system.

• If the water is too dirty, there may not be enough light to support plant growth.

FACTORS THAT CAN INCREASE WATER TURBIDITY:

1. Silt and sediments from surface runoff

2. Too much nutrients promoting algal bloom (growth of algae)

Multiple Choice

High turbidity means ________________.

• very clear water

• very murky or cloudy water

• high amount of water molecules

• high amount of dissolved oxygen

Multiple Choice

Clear water has a _____________ turbity.

• LOW

• HIGH

• MEDIUM

• VERY HIGH

Multiple Choice

Which of the following can INCREASE the turbidity of the water?

• amount of water

• amount of dissolved oxygen

• amount of water vapor

• amount of sediments and silts

​IV - NITRATES

• Nitrogen is found in soil and is essential for plants to grow.

• Nitrogen can come from over-fertilized croplands, animal waste, and sewage.

• Too much nitrogen can cause an increase in algae growth.

• We know that this leads to less oxygen. Aquatic living things will start to die because there is a high competition in oxygen.

Multiple Choice

All of the following can contribute to the increase in nitrates

in the water EXCEPT __________________

• FERTILIZERS

• SEWAGE

• DISSOLVED OXYGEN

• AGRICULTURAL WASTE PRODUCTS

Multiple Choice

Too much nitrates can promote the growth of which microscopic living things?

• ALGAE

• AQUATIC PLANTS

• FISHES

• TURTLES

Multiple Choice

Why are too many nutrients (like nitrates and phosphates) bad for our waters?

• Nutrients decrease the pH of the water, causing it to become increasingly acidic

• Nutrients in the water cause too much algae growth, which decrease the level of oxygen in the water

• Nutrients change the salinity or saltiness of the water

• Wetlands filter out runoff that may contain nutrients

V - ​SALINITY

• SALINITY is the amount of salt in the water

• More rainwater --> more freshwater

• In a bay (Chesapeake Bay), the salinity is lower near where the rivers enter the bay.

• The salinity is higher near where the ocean water enters.

Multiple Choice

What is SALINITY?

• The amount of oxygen in water

• The amount of nitrates in water

• The amount of salt in water

• The amount of pH in water

Multiple Choice

The amount of salt in a bay increases the closer you get to ________.

• OCEANS

• RIVERS

• LAKES

• PONDS

Multiple Choice

What is the healthiest combination of water quality listed?

• low pH, high nitrates, neutral temperature

• as many nitrates as possible, low temp and low pH

• low temperature, neutral pH and low nitrates

• high temp, high nitrates and high pH

Multiple Choice

A body of water showed a high turbidity level, high levels of nitrates and phosphates, a pH of 7.5, and low dissolved oxygen levels. Would this body of water be considered healthy?

• YES, IT IS HEALTHY

• NO, IT IS NOT HEALTHY

​SOURCES OF POLLUTION

• POINT-SOURCE POLLUTION is pollution from one identifiable source, like a broken sewage pipe or leaking oil well

• NON-POINT SOURCE POLLUTION is pollution from many sources or a source that cannot be identified, like gasoline on a city street or fertilizer runoff from several farms

Multiple Choice

Pollutants entering waterways from a general area, such as runoff from farmland or suburban communities is considered as ______________.

• POINT SOURCE POLLUTION

• NON-POINT SOURCE POLLUTION

• TURBIDITY

• ACIDITY

Multiple Choice

A factory is located next to a river. The factory has a sewage pipe running straight out of the factory and into the river. This is an example of ________________________.

• POINT SOURCE POLLUTION

• NON-POINT SOURCE POLLUTION

• TURBIDITY

• ACIDITY