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EPA’s Revised Minimum Quantification Levels. Scott Wilson. 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. Revised MQLs.
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EPA’s Revised Minimum Quantification Levels Scott Wilson
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
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
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
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)
Revised MQLs • Mercury • Priority due to numerous fish advisories nationally • Choice of EPA Methods 1631 or 245.7
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
Scott Wilson EPA Region 6 telephone: 214-665-7511 email: wilson.js@epa.gov