The Development of NPDES State Specific Analytical Methods Based on State’s Water Quality Standards

Collaborative Efforts to Improve Environmental Monitoring
Oral Presentation

Prepared by

Contact Information:; 563-554-9450


The individual states are developing Technology Based and Water Quality Based NPDES limits for method defined compounds (i.e. Total Nitrogen) and water quality selective species (i.e. Bioavailable Aluminum) that are neither defined nor have a specified method in 40 CFR § 136. As such, the individual states are either trying to fit existing EPA CWA analytical methods with correction factors applied (dissolved metals x correction factor = bioavailable metal) or trying to utilize multiple methods to produce a single result (total nitrogen = TKN + nitrate + nitrite). These fixes produce inaccurate results with bias and error that is not acceptable. The presentation will focus on analytical methods that were developed or are being developed under the EPA protocols at a state level to determine these types of analytes with validated results.