"Phosphorous levels" refers to the amount of phosphorous present in a substance or a system. It is a measure of the concentration or quantity of phosphorous in a specific context, such as in soil, water, or a person's body. Full definition
This photograph of a chart in the Water Environmental Protection Department's report to county legislators shows the drop in phosphorous levels in Onondaga Lake. (syracuse.com)
Furthermore, nitrogen and phosphorous levels of less than 10 and 3 mg / l respectively are obtained. (cstwastewater.com)