5.2 Detection and monitoring of pollution

Direct methods of monitoring pollution Air pollution -▪ Measure the

acidity of rain water to determine pH▪ Measure CO2, CO,

or NOx levels in the atmosphere using a gas sensor ▪ Measure

particulate matter suspended in the atmosphere

Direct methods of monitoring pollution

Soil pollution▪ Test for nitrates and phosphates (Using

LaMotte test kits)

Water pollution ▪ nitrate and phosphate tests ▪ fecal coliform tests▪ tests for heavy metals (Hg, Pb, As)

Direct methods of monitoring pollution

BOD (Biochemical Oxygen Demand)

BOD is the amount of oxygen required to support respiration by organisms living in a water sample. ▪ high BOD indicates there are many

organisms using oxygen for respiration▪ low BOD indicates relatively few

organisms needing oxygen for respiration▪ high BOD = low DO levels = high

pollutant levels, especially nitrate & phosphate▪ low BOD = high DO levels = low

pollutant levels

Indirect Method: The Biotic Index

A Biotic Index uses the presence or absence of key organisms to indicate the relative level of pollution in a stream.

Indirect method of measuring pollution Advantage: Easy to use, especially for

moderately or heavily polluted sites.Disadvantages: not specific enough,

doesn’t fully account for habitat quality

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Indicator Species Species that are

present either only in polluted areas or only in unpolluted areas. Lichens – Not present in

air pollution Rat-tailed maggot

and sludge worms – Found only in polluted water

Gammarus - small crustaceans that are not found in high levels of salinity.