NC0020354_Mercury Requirement_20020830

OF W gTFR Michael F Easley, Governor
William G Ross Jr., Secretary
y North Carolina Department of Environment and Natural Resources
r
j � Alan W. Klimek, RE, Director
p� Division of Water Quality
August 30, 2002
Subject: NPDES Mercury Requirement
Implementation of EPA Method 1631
Dear NPDES Permittee:
Mercury continues to be a water quality concern throughout North Carolina. Fish consumption advisories and
impaired stream segments as a result of elevated mercury levels have been issued for several locations. NPDES
permittees have worked with the state to reduce potential risks from this pollutant, including tasks associated with
collecting and reporting more accurate data. The most commonly used laboratory analysis for total mercury (EPA
Method 245.1) has a method detection level of 0.2 ug/1, while the current water quality standard is an order of
magnitude lower at 0.012 ug/l. Thus, true compliance with the water quality standard could not be fudged. A
more recently approved laboratory method (EPA Method 1631) should produce a detection level below the water
quality standard, which would allow the Division to assess potential water quality impacts from dischargers more
accurately. Therefore, this letter serves as notification to your facility that effective September 1, 2003, you will
be required to begin using EPA Method 1631 (or subsequent low-level mercury methods approved by EPA in
40 CFR 136) when analyzing for total mercury. Your facility is subject to this new requirement because either 1)
your facility has a current total mercury limit in its NPDES permit that is <0.20 ug/1: or 2) your facility has limited
instream dilution (i.e., the instream waste concentration (rWC) is >6%). This requirement complies with 15 A NCAC
2B.0505(e)(4), which requires that "test procedures must produce detection and reporting levels below the perrrut
discharge requirements."
Mercury Laboratory Analysis - EPA Method 1631
On June 22, 1999, the US EPA approved a new analytical method (EPA Method 163 1) for measuring very low
concentrations of mercury in water. Subsequent revisions to Method 1631 include Revision C (current approved
method) and Draft Revision D (scheduled for promulgation in October 2002). Method 1631 has a minimum level of
quantitation of 0.0005 ug/1 (0.5 ng/1), which is 400 -times more sensitive than Method 245.1. The new method
requires a clean laboratory environment which generally requires some lab retrofitting; thus, many permittees will
likely contract a commercial lab to perform the analysis. Based on data compiled by Ohio EPA, commercial labs
that are currently analyzing for EPA Method 1631 charge between $50-90 per sample, with turnaround times
ranging from 5-28 days. Currently there is one commercial lab certified by North Carolina for EPA Method 1631.
However, it is anticipated that several additional labs will also offer this analysis in the future as the demand for
this method increases. When selecting a lab to perform low level mercury analyses, the perrruttee should review the
lab's performance, experience, and reliability with the method, as well as cost considerations. Attachment A
provides additional information on this method.
Mercury Clean Sampling Techniques - EPA Method 1669
The greatest risk of contaminating the wastewater sample for low-level mercury analysis is during the sample
collection effort. Thus, those facilities subject to EPA Method 163I will also need to evaluate clean sampling
recommendations provided in EPA Method 1669. Attachment A provides highlights on this method.
NPDES Compliance
All mercury monitoring data subrrutted to the Division will be reviewed for compliance with current effluent limits.
If the permit contains monitoring only, the new method must still be used, and the need for a permit limit
will be evaluated at a later date by comparing a statistical evaluation of the effluent data with the water
quality standard and corresponding allowable effluent concentration. Therefore, the potential problem of
sample contarrunation cannot be overemphasized, since it could result in NPDES effluent limits for total mercury,
increased monitoring costs, and possibly unnecessary violations. All data submitted to the Division for NPDES
compliance monitoring requirements are the responsibility of the permittee. Therefore, facilities subject to this new
method are strongly encouraged to begin evaluating sampling methods and commercial labs before the deadline
date, to ensure that field staff are properly trained in the use of "clean sampling" techniques, and sampling and lab
procedures are fully developed to nunimize sample contanunation. _
NCDENR
N. C. Division of Water Quality 1617 Mad Service Center Raleigh, NC 27699-1617 [phone]
Customer Service 1 800 623-7748

NPDES Mercury Requirement
Page 2 of 3
Additional Information
For additional information and guidance regarding EPA Methods 1631/1669, the perrruttee may consult the
following resources:
North Carolina Division of Water Quality
Laboratory Analysis:
Roy Byrd, 919-733-3908, ext. 213
Lab Certification:
Lab Staff, 919-733-3908
Clean Sampling:
Sandy Mort. 919-733-2136, ext 245
NPDES Permitting:
Tom Belnick, 919-733-5083, ext 543
Pretreatment::
Tom Poe, 919-733-5083, ext 522
US Environmental Protection Agency
Method 1631/1669 Questions: Maria Gomez -Taylor, 202-566-1005
EPA Sample Control Center, 703-461-2100
Websites:
htti)://www.epa.state.oh.us/dsw/guidance/­­permit1Oatt3-pdf
The state of Ohio EPA provides an updated listing of laboratories providing contract services for EPA
Method 1631, including costs, turnaround time, and lab contacts. The labs are identified for informational
purposes only, and do not constitute an endorsement. The listed commercial laboratories may also provide
advice on training, equipment, and sampling techniques appropriate for Method 1631.
http•//www epa.gov / ost /methods/ 163 I.html
This EPA site provides information on the 1631 Method requirements and implementation guidance.
httT)://www.esb.enr.state.nc.us/lab
This DWQ site provides information on EPA Methods (including 1669 clean sampling techniques), and a
listing of state -certified labs for EPA Method 1631.
httT)://www.h2o.enr.state.nc.us/NPDES/NPDF-Sweb.html;click Documents
This DWQ website includes a copy of this letter plus a list of facilities currently subject to EPA Method
1631.
Conclusion
The Division realizes that changing the method of mercury measurement will not be without difficulty on the part of
the permittees. The requirement will affect approximately 155 facilities with mercury limits and/or monitoring
requirements. These permittees will need to evaluate available laboratories, costs, and sampling techniques. For
these reasons, the implementation date for EPA Method 1631 was delayed until September 1, 2003. The Division
thanks you for your cooperation and understanding in this matter. If you have any questions about the contents of
this letter, please contact the applicable staff listed above. _
Sincerely,,
J. William Reid, PE
Supervisor, Point Source Branch
cc (hardcopy). CLANC, c/o Lew Hicks. Environmental Chemistry Inc 6602 Windmill Way, Wilmington, NC 28405
cc (email) EPA Region 4. Marshall Hyatt. Scott Gordon Roosevelt Childress
DWQ Water Quality Section: Coleen Sullins. Regional Offices
DWQ Laboratory Section: Steve Tedder, Larry Ausiey Jim Meyer. Roy Byrd. Conrue Brower
DWQ Aquatic Toxicology Unit. Sandy Mort
DWQ Pretreatment Unit. Tom Poe
DWQ Modelmg/TMDL, Michelle Woolfolk
DWQ NPDES Compliance Unit, Shannon Langley
DWQ NPDES Unit
MCIC. Michael Johnson
NC League of Municipalities. Paula Thomas
Clean Water Fund of NC Hope Taylor
Severn Trent Lab, Ohio, Mark Bruce
AUG 2 2�ifl