Contains the full lesson along with a supporting toolkit, including teachers’ notes.
Biological Indicators
As a student I remember my ecology lecturer saying, when selecting a good, safe place to live, “All a person needs is air fresh enough for lichens to grow and water fresh enough for trout.” These are biological indicators of air and water quality and are a useful quick reference but they are no substitute for careful scientific measurements. They give an indication of long term conditions rather than present conditions.
Lichens are composite organisms consisting of symbiotic mutualistic algae and fungi. They are good indicators of air quality as they are generally very sensitive to sulphur dioxide (SO2) pollution and they can also accumulate radioisotopes from the atmosphere. The abundance of branched (fruticose) lichen is an indicator of air quality.
Pollutants
Particulates are very important as they can be drawn deep into our lungs. The smaller the particles the deeper they penetrate into the lungs and the more damaging they tend to be. These were of concern in the Bejing Olympics and were responsible for the city smog (a mixture of smoke and fog) of the 1950’s, which killed many thousands in London. Particulates are produced by the burning of solid fuels, especially bituminous coal, in open fires. Natural examples include volcanic ash from Eyjafjallajokull volcano in Iceland, and of course pollen produced in vast quantities from hay fields. Heavy metals including lead (Pb), mercury (Hg), cadmium (Cd) and nickel (Ni) are also important.
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