EPAs Revised Minimum Quantification Levels

1
EPAs Revised Minimum Quantification Levels

• Scott Wilson

2
MQL Background

• First developed in 1992
• Adopted by EPA Region 6 states and most other EPA
  Regions
• Based on
• Atomic Adsorption Furnace
• Gas Chromatography/Mass Spectrometry

3
Revised MQLs

• In 2004, examined MQLs which were greater than
  water quality criteria (37)
• Examined newer methods and MQLs commonly achieved
  by labs
• Issues with Mercury

4
Revised MQLs

• Concentrated review on routinely achievable
  levels
• Routine levels were lower than previous MQLs for
  33 of the 37 parameters
• Routine levels were lower than criteria for 13
  parameters

5
Revised MQLs

• Based on
• Inductively Coupled Plasma Mass Spectrometry for
  metals (EPA method 200.8)
• Gas Chromatography/Mass Spectrometry for most
  organics (EPA Method 624/625)
• Gas Chromatography with Electron Capture Detector
  for pesticides (EPA Method 608)
• Spectrophotometric Method for Chlorine (EPA
  Method 330.5)

6
Revised MQLs

• Mercury
• Priority due to numerous fish advisories
  nationally
• Choice of EPA Methods 1631 or 245.7

7
Revised MQLs

• EPA has implemented in permits for New Mexico
• Specific Methods are not required
• Required to meet the MQL
• May use any EPA approved methods
• May obtain approval for alternative methods
• Other States are in the process of implementing
  revised MQLs

8

• Scott Wilson
• EPA Region 6
• telephone [phone]
• email wilson.js_at_epa.gov