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REGION 6’s FIRST “WARNING”

EPA REGION VI MINIMUM QUANTIFICATION LEVELS (MQLs) WHAT THE “L” IS GOING ON? 25 th EPA Annual Pretreatment Workshop Addison, TX 8/5/09 Allen Gilliam ADEQ State Pretreatment Coordinator gilliam@adeq.state.ar.us. REGION 6’s FIRST “WARNING”. 4/10/06 EPA Region 6 “Claudia Hosch Memo”

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REGION 6’s FIRST “WARNING”

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  1. EPA REGION VI MINIMUM QUANTIFICATION LEVELS (MQLs)WHAT THE “L” IS GOING ON?25th EPA Annual Pretreatment WorkshopAddison, TX8/5/09Allen GilliamADEQ State Pretreatment Coordinatorgilliam@adeq.state.ar.us

  2. REGION 6’s FIRST “WARNING” 4/10/06 EPA Region 6 “Claudia Hosch Memo” (“for review and comment”) • “In 1992 Region 6 developed guidance on the use of MQLs and how they would be used in the NPDES permit decision making progress” • “…labs have made advancements in quantification levels thru method enhancements and EPA approved test methods have become more commonly available.” • “In a number of cases, the new MQL values are now below WQ criteria which were previously unattainable.” • “Most of our states have incorporated these MQL values into their permitting procedures…”

  3. Some Proposed Minimum Quantification Levels (MQLs)

  4. 8/23/07 - “Hanlon Memo” (EPA HQs) discussing Mercury compliance with Water Quality Standards to Regions “This memorandum clarifies and explains that, in light of existing regulatory requirements for NPDES permitting, only the most sensitive methods such as Methods 1631E and 245.7 are appropriate in most instances for use in deciding whether to set a permit limitation for Hg and for sampling and analysis of Hg pursuant to the monitoring requirements within a permit.”

  5. “Hanlon Memo” discussing compliance with WQ Standards (cont.) “For [delegated] States, EPA Regions…should strongly consider objecting to permits that are issued based on analytical data that is collected and analyzed using an EPA approved method not sufficiently sensitive or that do not require use of a sufficiently sensitive EPA approved method for monitoring…”

  6. Region 6 / States WQ Managers’ “Love-In” meeting excerpts (10/30/07) • MDL – Method Detection Level • minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is > 0 and is determined from analysis of a sample in a given matrix containing the analyte • LOD – Limit of Detection • approximately 3 times the standard deviation obtained from replicate measurements and may be described as that value determined to be statistically significant from the measurement of a reagent blank

  7. Region 6 / States’ WQ Managers’ “Love-In” meeting notes (10/30/07 cont.) • LOQ – Limit of Quantitaion • attempts to define a level of analyte that may be repeatedly measured • Region 6 has elected to define MQL as the lowest concentration at which a particular substance can be quantitatively measured • LOD = 3 standard deviations • LOQ = 10 standard deviations • LOQ = 10/3 LOD • LOD = MDL ??? • MQL = 3.3 MDL

  8. Some Final Region 6 MQLsOctober 30, 2007 “Existing” Revised ParameterMQL mg/lMQL mg/l Aluminum 100 2.5 Arsenic 10 0.5 Beryllium 5 0.5 Copper 10 0.5 Lead 5 0.5 (Method) Mercury 0.2 0.0005 / 0.005 (1631E / 245.7) Nickel 40 0.5 Selenium 5 5 Silver 2 0.5 Thallium 10 0.5 Cyanide 20 10

  9. WHAT DO THESE MQLs MEAN TO YOU? • Do you know your state’s permitting procedures (should be part of your “Continuing Planning Process” document req’d by 40 CFR 130.5)? • States’ procedures in Region 6 are somewhat similar • NPDES renewal? Majors must analyze / report results from a Priority Pollutant Scan (PPS) – One sampling event / 5 years

  10. PERMITTING PROCEDURESOne Sample (Hg for example) 1. Calculate “reasonable potential” to exceed WQ standard Hg Water Quality Standard = 0.012 mg/l Priority Pollutant Scan result X 2.13 (EPA’s statistical multiplier from their “Technical Support Document for WQ-based Toxics Control”. Arguable…) PPS Hg result = 0.006 mg/l 0.006 ug/l X 2.13 = 0.0128 mg/l) 2. Reasonable potential? 0.0128 > 0.012 mg/l? YES, Hg limit will be incorporated into permit.

  11. ARKANSAS WORST CASE “WQ LEVELS NOT TO EXCEED” 7Q10 = 0 CFS (Intermittent Stream)

  12. EXTRA “SCRUTINY” FOR THE PRETREATMENT CITIES? • Region 6 Pretreatment Cities required to do quarterly influent / effluent monitoring, maybe more? • Hopefully, you’re using the most sensitive methods for both (for most valid site specific removal efficiencies) • More data points for NPDES permit writer to use in calculating “reasonable potential”! • PLEASE use common sense clean sampling techniques

  13. MONITORING RESULTS FOR THE ANNUAL PRETREATMENT REPORT REPORTING YEAR: __________, 20 TO __________, _20____ TREATMENT PLANT: City of ____ NPDES PERMIT #AR00____ _____ AVERAGE POTW FLOW: MGD % IU FLOW: %

  14. PERMITTING PROCEDURES FOR LIMITED DATA SETS (<20) • Permit writer takes data points: • Calculates geometric mean (GM) a. GM = [ (X1)(X2)(X3)........(XN) ]1/N; • Multiplies GM X 2.13 to determine “reasonable potential”; • If reasonable potential exists  Permittee gets permit limit

  15. MONITORING RESULTS FOR THE ANNUAL PRETREATMENT REPORT REPORTING YEAR: __________, 20 TO __________, _20____ TREATMENT PLANT: City of ____ NPDES PERMIT #AR00____ _____ AVERAGE POTW FLOW: MGD % IU FLOW: %

  16. PERMITTING PROCEDURES FOR LIMITED DATA SETS (<20) for Hg • Permit writer takes data points: • Calculates geometric mean (GM) • GM = [ (.026)(.007)(.016)(.046) ]1/4 = 0.018(mg/l) • Don’t even have to calculate “reasonable potential” • WQ “level not to exceed” = 0.012(mg/l) • Reasonable potential definitely exists  Permittee gets permit Hg limit

  17. MONITORING RESULTS FOR THE ANNUAL PRETREATMENT REPORT REPORTING YEAR: __________, 20 TO __________, _20____ TREATMENT PLANT: City of ____ NPDES PERMIT #AR00____ _____ AVERAGE POTW FLOW: MGD % IU FLOW: %

  18. PERMITTING PROCEDURES FOR LIMITED DATA SETS (<20) for Cu • Permit writer takes data points (if there’s even one detect, “NDs” are treated as ½ MQL): • Calculates geometric mean (GM) • GM = [ (.25)(.25)(10)(12) ]1/4 = 1.65 mg/l • GM X 2.13 to determine “reasonable potential” = 1.65 X 2.13 = 3.5mg/l • WQ “level not to exceed” = 8.7mg/l • Reasonable potential does not exist  Permittee gets no Cu limit

  19. MONITORING RESULTS FOR THE ANNUAL PRETREATMENT REPORT REPORTING YEAR: __________, 20 TO __________, _20____ TREATMENT PLANT: City of ____ NPDES PERMIT #AR00____ _____ AVERAGE POTW FLOW: MGD % IU FLOW: % YOUR WORST NIGHTMARE!

  20. PERMITTING PROCEDURES FOR LIMITED DATA SETS (<20) for CN • Permit writer takes data points (if there’s even one detect, “NDs” are treated as ½ MQL): • Calculates geometric mean (GM) • GM = [ (5)(7)(5)(8.05) ]1/4 = 6.13mg/l • Don’t even have to calculate “reasonable potential” • WQ “level not to exceed” = 5.8mg/l Reasonable potential exists  Permittee gets CN limit

  21. MONITORING RESULTS FOR THE ANNUAL PRETREATMENT REPORT REPORTING YEAR: __________, 20 TO __________, _20____ TREATMENT PLANT: City of ____ NPDES PERMIT #AR00____ _____ AVERAGE POTW FLOW: MGD % IU FLOW: % NEED LAB EXPLANATION ON THIS ONE!

  22. PERMITTING PROCEDURES FOR LIMITED DATA SETS (<20) for CN • Permit writer takes data points (if the “NDs” > the MQL, values will be entered at the MQL): • Calculates geometric mean (GM) • GM = [ (10)10)(10)(10) ]1/4 = 10mg/l • Don’t even have to calculate “reasonable potential” • WQ “level not to exceed” = 5.6mg/l Reasonable potential exists  Permittee gets Se limit

  23. What the “L” is going on with this logic? • Do not sample effluent after a rain event or when your plant is suspected of being “upset” • Require your labs to explain why they could not meet the required MQL (“had to dilute because of matrix condition being turbid or suspected of containing matrix interferences….”) • Note to your permit writer: “results should not be used in calculating ‘reasonable potential’ because they were not representative” • Contest / ask permit writer about the rationale behind the “reasonable potential” multiplier of 2.13 (if your state uses it)

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