Download Methods of Monitoring Pollution

Methods of Monitoring
Pollution
Direct
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Performed by monitoring the level of the
pollutant itself
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Nitrates in a lake
Temperature in a stream
Direct measurements
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Measuring temperature in several locations along the
length of a river or at different times of the year
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Take a baseline measurement and then monitor
systematically to determine changes
Measuring nitrate levels/ammonia levels/ chloride
levels as an indication of nutrient overload
Measuring TSS or TDS as an indication of material
entering the lake or stream
Indirect
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Monitor the effects of the pollutants on other
factors
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Dissolved oxygen
BOD
Presence or absence of indicator species
BOD
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The measure of the amount of dissolved
oxygen that is used by aerobic bacteria to
break down the organic matter in a specific
volume of water.
The greater the organic matter (sewage,
agricultural run-off, fertilizer, etc.) the higher
the BOD
More BOD
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If DO equals or exceeds the BOD, the system
is considered healthy
If DO level is less than BOD, it is possible that
there is not enough oxygen to sustain larger
organisms like fish.
The process of accumulating large amount of
organic matter is called eutrophication
Measuring BOD
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Measure DO on day 1
again on Day 5
samples should be kept at 20oC in the dark
during that time
Factors Controlling BOD and DO
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A major source of DO comes from the
atmosphere
Moving water is able to dissolve more oxygen
Temperature is a major factor
BOD is affected by respiration or lack there of
by microorganisms and by increase in organic
matter, waste and sewage
Biotic index
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Indirect measurement involves monitoring
and measurement of organisms in the
ecosystem
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Indicator or index species
Species by their abundance or absence indicate the
level of pollution in an ecosystem
The diversity of species can indicate the
quality and overall health of the system
Important indicators
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Fish
Bottom fauna
Algae
Bacteria
Comparing the relative abundance of stoneflies,
mayflies, and caddisflies to midge and sludgeworms
Comparison of diatoms to blue-green algae
Measuring coliform levels can indicate the presence
of sewage dumping in the ecosystem
Overall diversity of the system is the best indicator presence is better than absence