Virginia Administrative Code › Title 9 - ENVIRONMENT › Agency 20 - VIRGINIA WASTE MANAGEMENT BOARD › Chapter 160 - VOLUNTARY REMEDIATION REGULATIONS › Section 9VAC20-160-90 - Remediation levels

Current through Register Vol. 40, No. 24, July 15, 2024
A. The
				participant, with the concurrence of the department, shall consider impacts to
				human health and the environment in establishing remediation levels.
B. Remediation levels based on human health
				shall be developed after appropriate site characterization data have been
				gathered as provided in
				9VAC20-160-70. Remediation levels
				may be derived from the three-tiered approach provided in this subsection. Any
				tier or combination of tiers may be applied to establish remediation levels for
				contaminants present at a given site.
1. Tier
				I remediation levels are based on media backgrounds levels. These background
				levels shall be determined from a portion of the property or a nearby property
				or other areas as approved by the department that have not been impacted by the
				contaminants of concern.
2. Tier II
				remediation levels are derived assuming that there will be no restrictions on
				the use of groundwater, surface water, and soil on the site.
a. Tier II groundwater remediation levels
				shall be based on the most beneficial use of groundwater. The most beneficial
				use of groundwater is for a potable water source, unless demonstrated otherwise
				by the participant and accepted by the department. Therefore, they shall be
				based on (i) federal Maximum Contaminant Levels (MCLs) or action levels for
				lead and copper as established by the Safe Drinking Water Act (
				42 USC §
												300(f) ) and the National
				Primary Drinking Water Regulations ( 40 CFR Part 141 ) or, in the absence of a
				MCL, (ii) tap water values derived using the methodology provided in the
				Regional Screening Level Table, Region III, VI, and IX, United States
				Environmental Protection Agency, December 2009, using an acceptable individual
				carcinogenic risk of 1 X 10-5 and an individual
				noncarcinogen hazard quotient of 0.1.
b. Tier II soil remediation levels shall be
				determined as the lower of the ingestion or cross-media transfer values,
				according to the following:
(1) For ingestion,
				values derived using the methodology provided in the Regional Screening Level
				Table, Region III, VI, and IX, United States Environmental Protection Agency,
				December 2009.
(a) For carcinogens, the soil
				ingestion concentration for each contaminant, reflecting an individual
				upper-bound lifetime cancer risk of 1 X
				10-5.
(b) For noncarcinogens, 0.1 of the soil
				ingestion concentration, to account for multiple systemic toxicants at the
				site. For sites where there are fewer than 10 contaminants exceeding 0.1 of the
				soil ingestion concentration, the soil ingestion concentration may be divided
				by the number of contaminants such that the resulting hazard index does not
				exceed 1.0.
(2) For
				cross-media transfer, values derived from the USEPA Soil Screening Guidance
				(OSWER, July 1996, Document 9355.4-23, EPA/540/R-96/018) and USEPA Supplemental
				Guidance for Developing Soil Screening Levels for Superfund Sites (OSWER,
				December 2002, Document 9355.4-24) shall be used as follows:
(a) The soil screening level for transfer to
				groundwater, with adjustment to a hazard quotient of 0.1 for noncarcinogens, if
				the value is not based on a MCL; or
(b) The soil screening level for transfer to
				air, with adjustment to a hazard quotient of 0.1 for noncarcinogens and a risk
				level of 1 X 10-5 for carcinogens, using default
				residential exposure assumptions.
(c) For noncarcinogens, for sites where there
				are fewer than 10 contaminants exceeding 0.1 of the soil screening level, the
				soil screening level may be divided by the number of contaminants such that the
				resulting hazard index does not exceed 1.0.
(3) Values derived under subdivisions 2 b (1)
				and (2) of this subsection may be adjusted to allow for updates in approved
				toxicity factors as necessary.
c. Tier II remediation levels for surface
				water shall be based on the Virginia Water Quality Standards (WQS) as
				established by the State Water Control Board (9VAC25-260), according to the
				following:
(1) The chronic aquatic life
				criteria shall be compared to the appropriate human health criteria and the
				lower of the two values selected as the Tier II remediation level.
(2) For contaminants that do not have a
				Virginia WQS, the federal Water Quality Criteria (WQC) may be used if
				available. The chronic federal criterion continuous concentration (CCC) for
				aquatic life shall be compared to the appropriate human health based criteria
				and the lower of the two values selected as the Tier II remediation
				level.
(3) If neither a Virginia
				WQS nor a federal WQC is available for a particular contaminant detected in
				surface water, the participant should perform a literature search to determine
				if alternative values are available. If alternative values are not available,
				the detected contaminants shall be evaluated through a site-specific risk
				assessment.
3. Tier III remediation levels are based upon
				site-specific assumptions about current and potential exposure scenarios for
				the population or populations of concern and characteristics of the affected
				media and can be based upon a site-specific risk assessment. Land-use controls
				can be considered.
a. In developing Tier III
				remediation levels, and unless the participant proposes other guidance that is
				acceptable to the department, the participant shall use, for all media and
				exposure routes, the methodology specified in Risk Assessment Guidance for
				Superfund, Volume 1, Human Health Evaluation Manual (Part A), Interim Final,
				USEPA, December 1989 (EPA/540/1-89/002) and (Part B, Development of Preliminary
				Remediation Goals) Interim, USEPA, December 1991 (Publication 9285.7-01B) with
				modifications as appropriate to allow for site-specific conditions. The
				participant may use other methodologies approved by the department.
b. For a site with carcinogenic contaminants,
				the remediation goal for individual carcinogenic contaminants shall be an
				incremental upper-bound lifetime cancer risk of 1 X
				10-5. The remediation levels for the site shall not
				result in an incremental upper-bound lifetime cancer risk exceeding 1 X
				10-4 considering multiple contaminants and multiple
				exposure pathways, unless the use of a MCL for groundwater that has been
				promulgated under 42 USC
				§
												300g-1 of the Safe Drinking Water Act
				and the National Primary Drinking Water Regulations ( 40 CFR Part 141 ) results
				in a cumulative risk greater than 1 X
				10-4.
c.
				For noncarcinogens, the hazard index shall not exceed a combined value of
				1.0.
d. In setting remediation
				levels, the department may consider risk assessment methodologies approved by
				another regulatory agency and current at the time of the Voluntary Remediation
				Program site characterization.