Pollution indicators Part 1 Notes

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Water Quality

• _{The term used to describe the health}

(2)

Turbidity

• _{The measure of the clarity of the water} (how clear the water appears)

• _{Or another way to explain it: the measure} of the degree to which water looses its

transparency due to the presence of suspended particulates

• _{Particulates are tiny pieces of solid matter} suspended in a gas or liquid (like sand)

(3)

Secchi Disk

• _{Scientists use a secchi disk to measure} water transparency in oceans and lakes. • _{To do this the disk is mounted to a pole or}

(4)

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Turbidity Levels

• _{Ideal Level:} _{1 NTU}

• _{High Level:}_{5 NTU and up}

• _{NTU stands for Nephelometric Turbidity} Unit and refers to how much light reflects for a given amount of particulates using a nephelometer (a device that projects a

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Causes of Increased

Turbidity

• _{Increased levels of phytoplankton} • _{Sediment from erosion}

• _{Re-suspended sediments from the bottom} (stirred up by bottom dwellers)

• _{Waste discharge} • _{Algae growth}

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If turbidity is high

• _{High turbidity increases the absorption of} sunlight which makes the water

temperature rise.

• _{Warmer water has lower levels of}

dissolved oxygen which causes fish and larvae to die.

(8)

pH

• _{pH is the measure of how acidic or basic a} substance is

• _{Uses the pH scale, a rating of how acidic} or basic a substance is on a scale of 0 to 14, with 7 being neutral

• _{Any measure less than 7 on the pH scale is} acidic

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pH Levels in Earth’s

water

• _{Surface freshwater is usually between 6}

and 9

• _{Swamps may be as low as 4.3}

• _{Salt water is usually 8.1 but may go as low}

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Results of changes in pH

• _{A change in pH by 2 units results in a}

water system having 100 times a difference in acidity!

• _{Most aquatic life cannot withstand water} outside of the optimum pH levels which means they die.

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Dissolved Oxygen (D.O.)

• _{Measure of water quality indicating free}

oxygen dissolved in water

• _{Average D.O. level is 9.0 ppm}

• _{Must be 4-5 ppm to support diverse} population of fish

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Causes of changes in D.O.

• _{Turbulent actions (waves, rapids)}

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Results of changes in D.O.

• _{When the D.O. drops too low the fish die.} • _{When the D.O. is too high the water}

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Temperature

• _{Temperature is the measure of how hot or} cold something is.

• _{Remember it is a physical property.} • _{Water temperature that is below 32}

degrees Fahrenheit (freezing point) is not well tolerated by aquatic life.

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Causes of change in

temperature

• _{Source of water} • _{Time of year}

• _{Suspended sediment}

• _{Depth of water}

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Results of changes in

temperature

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Nitrates

• _{A compound that contains the nitrogen} based polyatomic ion NO₃

• _{Example is sodium nitrate}

• _{The max amount of nitrates in drinking} water is 10 mg/L.

(19)

Causes of changes in

nitrate levels

• _{Fertilizer runoff (farms and homes)} • _{Manure pits}

• _{Leaks in septic systems} • _{Animal waste}

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Results of changes in

nitrate levels

• _{Nitrates can increase the plant production} and fish population resulting in

overcrowding.

• _{If algae increases the D.O. levels can} decrease, killing fish.

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Indicator

• _{A chemical material or solution which can be}

used to show the endpoint of a chemical reaction or chemical concentration

• _{Usually shows a change in color} • _{Examples of different indicators:}

o _{litmus paper which is used to determine the pH}

of a substance

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Bio indicator

• _{Also called biological indicators}

• _{Are organisms or parts of organisms that are used}

to monitor the health of a water system, ecosystem or environment

• _{The organisms’ function, population, or status in}

an specific environment can tell scientists if there is a problem with their ecosystem.

• _{For example, an increase or decrease in an}

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Macro-invertebrates

• _{Macro-invertebrates are small, spineless}

creatures such as crustaceans, mollusks, worms, and insects.

• _{They are very useful bio indicators for a}

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Bio-indicator Levels

• _{If there is a high level of variety the water} quality is considered healthy.

• _{If there is a small level of variety the water} quality is considered poor and indicates

(25)

Causes & Results of

changes in bio indicators

• _{Cause: Pollution that results in changes in}

pH, temperature, D.O. or nitrate levels. • _{Result: The lack of a large number of}

different varieties of bio indicators