Identify that water quality can be determined by considering:
- concentrations of common ions
- total dissolved solids
- dissolved oxygen and biochemical oxygen demand
Perform first-hand investigations to use qualitative and quantitative tests to analyse and compare the quality of water samples
In describing water quality, the following properties are commonly used:
- Concentrations of Common Ions (generally measured in ppm).
- Total dissolved solids (TDS): A measure the mass of solids dissolved in a unit volume of water (generally measured in ppm).
- Hardness: A measure of the concentration of calcium and magnesium ions.
- Turbidity: A measure of the amount of colloidal suspended matter, which translates into a degree of cloudiness or transparency (measured in relative units called nephelometric turbidity units, or NTUs).
- Acidity: A measure of the concentration of hydrogen ions (measured in pH).
- Dissolved oxygen (DO): A measure of the concentration of oxygen (generally measured in ppm).
- Biochemical oxygen demand (BOD): A measure of the concentration of dissolved oxygen that is needed for the complete breakdown of the organic matter in a sample by aerobic bacteria (generally measured in ppm).
||Testing procedure(s) and/or equipment
|Concentrations of common ions||
||Common guidelines for potable water include:
|Total dissolved solids (TDS)||
|Dissolved oxygen (DO)||
|Biochemical oxygen demand (BOD)||Collection of two identical samples: