This book has described a variety of environmental pollutants and their effects on people and other organisms. In laboratories throughout the world, professional scientists are regularly collecting samples from all sectors of the environment and analysing them for pollutants. Sometimes the analytical results are presented in court to prosecute polluters, whilst in other laboratories the data are used to find safe levels so that the environment is not adversely affected. In most laboratories, the analytical instruments used are complex and expensive, and are capable of rapidly measuring trace quantities of pollutants. It is possible, however, to obtain an indication of the quality of air, water and land with simple techniques and some of these are described in this chapter. Suggestions are made as to some investigations that can be carried out in school or college laboratories.

One important point to make is that such investigations should be kept small and simple to begin with. It can be very frustrating to set out with an idea of, say, studying a range of pollutants in various rivers and then to find that you run out of time and have few results to complete a project. Start off small and build on the project as experience is gained. For example, you could assess the impact of a discharge on a stream by collecting samples upstream and downstream of the effluent and of the effluent itself, and analysing the samples for three or four types of chemicals. If time permits, the project could be extended by looking at the variety of invertebrates upstream and downstream, or extending the number of chemical tests. You could collect samples during different flow rates and assess the effect of dilution on water quality.

Sewage effluent

In Chapter 2, the chemistry of sewage effluent was described and examples were given of the variety of different chemicals in good and poor effluents and in the receiving streams. There are relatively simple analytical measurements for the determination of some of these parameters, using equipment and chemicals usually available in school and college laboratories. This section describes the analytical procedures for the measurement of suspended solids, biochemical oxygen demand (BOD), dissolved oxygen, permanganate value (PV), pH, chloride and alkalinity. Each of these tests will yield valuable information on the quality of a river and the effect of a discharge on it.