Testing the Waters

Water quality is a relative term—not a clearly defined, single set of guidelines applicable in all circumstances. Water that is of acceptable quality for irrigating a field of soybeans is not necessarily safe or palatable for drinking. Before water quality can be assessed the intended use must be known and an acceptable range of standards must be set. In a sense, water quality can be thought of as water suitability. Once the intended use is known and an appropriate set of standards selected, the process of water monitoring begins. A wide array of factors can be tested, ranging from temperature, color and turbidity to bacterial counts, dissolved gases and hardness. Typically, some subset of factors will be monitored—again depending on intended use. As an example, if a lake were being assessed relative to the habitat requirements of a particular fish, relevant factors might include: dissolved oxygen, temperature, salinity, pH and turbidity. The goal being a reasonable and relevant characterization of the water. The state of the art of water quality testing permits nearly anyone, regardless of experience, to conduct basic tests at minimal expense. Water quality monitoring is an ideal pursuit for students at all levels as it opens up enormous opportunities for learning about their natural environment and how to protect it. Let’s discuss some basic water quality factors, what they can tell us and how to test for them.