Establishing Ground Water Cleanup Standards Under WAC 173340720

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Establishing Ground Water Cleanup Standards Under
WAC 173-340-720

• Pete Kmet, P.E.
• Department of Ecology
• Toxics Cleanup Program
• [phone] pkme461_at_ecy.wa.gov

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Establishing Ground Water Cleanup Standards under
WAC 173-340-720

• Key Differences
• Two types of groundwaterpotable and nonpotable
• Harbor Island exemption remains. Added
  hydraulic connection as criterion for determining
  eligible sites
• Changed several Method A table values

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Establishing Ground Water Cleanup Standards under
WAC 173-340-720

• Key Differences (cont.)
• Cleanup level cannot result in non-aqueous phase
  liquid (NAPL) forming in or on groundwater
• If contaminants are likely to reach surface
  water, need to check surface water standards
• Equation for petroleum mixture TPH cleanup levels
  provided

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Establishing Ground Water Cleanup Standards under
WAC 173-340-720

• Key Differences--Point of Compliance
• May also have conditional POC off property in
  three circumstances
• Property abuts surface water
• Property near, but not abutting surface water
• Areawide brownfield (multiple sites impractical
  to address separately)
• Can use upland monitoring wells to address
  surface water POC

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Establishing Ground Water Cleanup Standards under
WAC 173-340-720

• Cleanup Standard Concentration
• Point of Compliance
• ARARs
• Must use reasonable maximum exposure
• (defined as drinking water for most sites)

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Establishing Ground Water Cleanup Levels under
WAC 173-340-720
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Establishing Ground Water Cleanup Levels under
WAC 173-340-720

• Ground Water is Considered Potable Unless
• Not used as a current source of drinking water
• Not a potential future source of drinking water
  for any of the following reasons
• Yield lt 0.5 gpm
• Poor natural background quality
• Technically impossible to use due to depth or
  location

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Establishing Ground Water Cleanup Levels under
WAC 173-340-720

• Ground Water is Considered Potable Unless
• Contaminants unlikely to be transported to ground
  water that is a current or potential future
  source of drinking water

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Establishing Ground Water Cleanup Levels under
WAC 173-340-720

• Harbor Island Exemption-- Extremely low
  probability of use as drinking water supply
• Not a current source of drinking water
• Contaminants unlikely to be transported to ground
  water that is a current or potential future
  source of drinking water
• Known or projected points of entry to surface
  water
• Surface water not classified as potable
• Sufficiently hydraulically connected to make use
  not practicable

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Establishing Method A Ground Water Cleanup Levels
under WAC 173-340-720(3)

• Method A can be used at the following sites
• At sites with few hazardous substances
• AND
• Undergoing routine cleanup action OR
• Numerical standards are available for all
  indicator hazardous substances

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Establishing Method A Potable Ground Water
Cleanup Levels under WAC 173-340-720(3)
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Establishing Method A Potable Ground Water
Cleanup Levels under WAC 173-340-720(3)
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Establishing Method A Potable Ground Water
Cleanup Levels under WAC 173-340-720(3)
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Establishing Method B Ground Water Cleanup Levels
under WAC 173-340-720(4)
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Establishing Method B Ground Water Cleanup Levels
under WAC 173-340-720(4)
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Establishing Method B Ground Water Cleanup Levels
under WAC 173-340-720(4)
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Establishing Method C Ground Water Cleanup Levels
under WAC 173-340-720(5)

• Method C can be used where
• All practicable methods of treatment have been
  used institutional controls established and one
  of the following conditions exist
• Method A or B below technically possible conc.
• Method A or B below area background
• Method A or B poses greater overall threat

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Establishing Method C Ground Water Cleanup Levels
under WAC 173-340-720(5)

• Essentially the same as Method B except for
• Somewhat less stringent assumptions are used in
  the calculation of a cleanup level
• The allowable cancer risk is higher
• (1 X 10-5)

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Establishing Ground Water Cleanup Levels for TPH
Mixtures under WAC 173-340-720

• Must evaluate noncarcinogenic effects of TPH
  Mixture as a whole
• Must evaluate ARARs, noncarcinogenic and
  carcinogenic effects for individual TPH
  components
• Need either measured or predicted ground water
  composition including TPH fractions and
  components
• May need to evaluate biodegradation

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Establishing Ground Water Point of Compliance
under WAC 173-340-720
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Establishing Point of Compliance for Ground Water
Discharging to Surface Water under WAC
173-340-720
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Establishing Point of Compliance for Ground Water
Discharging to Surface Water under WAC
173-340-720
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Establishing Point of Compliance for Ground Water
Discharging to Surface Water under WAC
173-340-720
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Establishing Ground Water Cleanup Standards under
WAC 173-340-720

• Compliance Monitoring
• Ground water testing required
• Surface water testing (if surface water being
  used as point of compliance)
• Statistical test for each well location (can also
  use sampling and analysis guidance schedule)

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Establishing Ground Water Cleanup Standards under
WAC 173-340-720

• Summary
• Highlighted key differences
• Establishing cleanup levels under Method A
• Establishing cleanup levels under Methods B and
  C.
• Special considerations for TPH mixtures
• Point of Compliance options
• Compliance monitoring requirements