Water Quality Indicators

Water quality is often described by the concentration of different chemicals of interest. Determining whether water quality is “good” or “bad” depends on the purpose of the assessment—for example, water with naturally elevated concentrations of some metals may not be suitable for drinking water, but may be suitable for industrial uses. Assessing water quality generally involves comparing measured chemical concentrations with natural, background, or baseline concentrations and with guidelines established to protect human health or ecological communities. This section describes some of the chemical indicators commonly used to describe and assess water quality, including:

• Temperature and dissolved oxygen
• Conventional variables (pH, total dissolved solids, conductivity, and suspended sediment)
• Nutrients
• Metals
• Hydrocarbons
• Industrial Chemicals (PCBs and dioxins/furans)