Chemical Monitoring Waivers

1
Chemical Monitoring Waivers

• Dennis Nelson
• Amy Parmenter
• Tom Pattee
• Springfield Regional Office

2
Chemical Waivers Available

• Inorganic Chemicals
• History of no MCL violations
• Organic Chemicals
• History of no detections and
• Part of a wellfield, or
• Drinking Water Protection Plan, or
• Chemical Use in the area, and if desired,
• Susceptibility of aquifer

3
Inorganic Chemicals

• Antimony-Thallium
• Initial monitoring surface water annually
  groundwater every 3 years
• Waiver granted if 3 consecutive samplings yield
  no concentrations at MCL or higher
• Monitoring frequency under waiver as determined
  by Department, but usually once every 9 years for
  both surface- and groundwater

4
Inorganic Chemicals

• DMCA requires written request for the waiver
• If waiver request related to sanitary survey
• County should attach note or cover letter
  indicating monitoring change necessary and send
  to DMCA
• Becomes a priority for entry into SDWIS
• If waiver request from system
• PWS sends DMCA an email, or a letter or Fax of
  waiver request form (from DWP home page select
  Forms/Tools/Factsheets then Chemical
  Monitoring then Chemical Monitoring Request
  Form)
• If supporting IOC data not in SDWIS, it must be
  included

5
Organic Chemical Monitoring Waivers Available

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

6
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• Generally not eligible for waiver if detection
• If detection, quarterly monitoring required
• If after four quarters for surface water or two
  quarters for groundwater, reliably and
  consistently below MCL, may be reduced to annually

7
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• SOC/VOC
• Four consecutive quarterly samples
• If no detection of VOCs during initial monitoring
  then
• Annually for SWGW
• Every 3 yrs for GW if 3 annual w/no detection
• If no detection of SOCs
• 2 consecutive quarters in compliance period if
  gt3300 population
• 1 sample in compliance period if lt3300 population

8
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• Wellfield determination (333-061-0058)
• Criteria
• Within 2500 feet unless low-impact area
• Same and only the same aquifer (SWA)
• Different entry points
• Sample at most susceptible well
• Annual nitrate at each well in wellfield
• Department discretion

9
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• Initial monitoring may be reduced from 4 to 1
  quarter if no detections and if in wellfield and
  new source does not significantly modify DWSA(s)
• Proposed rule change or in an area well
  characterized by the Department based on history
  of results and source water assessments

10
Organic Chemical Monitoring Waiver

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• VOCs and SOCs
• If a water system has a DEQ-approved Drinking
  Water Protection Plan
• Monitoring reduced from once every 3 years to
  once every 6 years
• Considering substituting significant
  implementation for approved plan, and
• Not highly susceptible

11
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• Use defined as the application, storing,
  distributing, disposing, or transporting of
  chemical
• Because of widespread use of VOCs, generally not
  eligible for Use Waiver
• Generally applied to groundwater-based systems

12
Organic Chemical Monitoring Waivers
PCS inventory from Source Water Assessment Report

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

13
Organic Chemical Monitoring Waiver

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Plan
• Chemical Use
• Aquifer susceptibility

• Based on PCS inventory
• Water system asked to confirm land use activities
• If irrigated agriculture then Use Waiver Guidance
• http//oregon.gov/DHS/ph/dwp/tools.shtml and
  select SOC Use Waiver Guidance

14
Organic Chemical Monitoring Waiver

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection
• Chemical Use
• Aquifer susceptibility

• Chemicals determinated as used monitored every
  3 years
• Chemicals determined as not used monitored 1/9
  years
• Benzo(a)pyrene, adipate and phthalate not
  eligible
• PCBs used only if identified source in DWSA

15
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection Area
• Chemical Use
• Aquifer susceptibility

• All organic chemicals
• Based on
• Depth to aquifer
• Permeability of vadose
• Local recharge
• Individual chemical mobility
• Individual chemical persistance
• Depending on susceptibility of aquifer to
  specific chemicals, monitored 1/3, 1/6, or 1/9
  years

16
Organic Chemical Monitoring Waivers

• History of chemical results
• Initial monitoring
• Wellfield/DWSA
• Drinking Water Protection
• Chemical Use
• Aquifer susceptibility

• Evaluation of the aquifer sensitivity in Source
  Water Assessment Report
• Determination of chemical specific
  susceptibility?
• Susceptibility guidance available from Department
• Consultant should assist

17
Organic Chemical Monitoring Waivers

• Source Water Assessment results indicate that
  many small rural water systems not near irrigated
  agriculture and probably eligible for Use Waiver
• Department limited by resources (staff)
• Counties should encourage their systems to
  contact Springfield Office (DN), however, for
  waiver consideration.

18
Contacts

• Springfield Office at 541-726-2587
• Region 1 and general questions Dennis Nelson ex
  21
• Dennis.o.nelson_at_state.or.us