Texas Commission on Environmental Quality (TCEQ). Class C Water License Exam

How is the acceptable concentration of iron in treated water typically measured?

1. mg/L

2. g/L

3. ppb

4. ppt

The correct answer is: mg/L

The acceptable concentration of iron in treated water is typically measured in milligrams per liter (mg/L). This unit is commonly used in water quality assessments because it provides a clear representation of the concentration of a substance in a liquid solution. Iron can have significant effects on both water quality and taste, so monitoring its levels in drinking water is crucial. Using mg/L allows for easy comparison and regulation within the context of public health standards, as well as meeting the requirements set forth by various environmental agencies. While parts per billion (ppb) and parts per trillion (ppt) are also units that can be used to measure concentrations of substances in water, they are generally employed for measurements of very low concentrations or trace levels of contaminants rather than for iron at levels typically encountered in treated water. Grams per liter (g/L) is not suitable for this context, as it represents a much larger concentration than what is relevant for monitoring iron in drinking water. Thus, mg/L is the most effective and commonly accepted measure for this purpose.