OF LAKES AND STREAMS
One way to test for contamination in water from lakes, rivers and streams is with a bioassay.
A bioassay uses a living organism–usually a plant or a bacteria–as a test agent for the presence or concentration of a chemical compound or a disease. The idea is to choose a test agent that is very sensitive to the condition you are testing.
Have you ever read about how miners took canaries down into mines to act as early warnings of gas leaks? Because canaries are more sensitive to gas than people, the birds reacted to very small amounts of gas and gave miners a chance to escape. You could say canaries were a bioassay for underground gas. Read the rest of this entry