Section 90. Remediation levels

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.

C. The participant shall determine if ecological receptors are present at the site or in the vicinity of the site and if they are impacted by releases from the site.

1. At sites where ecological receptors are of concern and there are complete exposure pathways, the participant shall perform a screening level ecological evaluation demonstrating that remediation levels developed under the three-tiered approach described in this section are also protective of such ecological receptors.

2. For sites where a screening level ecological evaluation has shown that there is a potential for ecological risks, the participant shall perform an ecological risk assessment demonstrating that remediation levels developed under the three-tiered approach described in this section are also protective of ecological receptors. If the remediation levels developed for human health are not protective of ecological receptors, the remediation levels shall be adjusted accordingly.

Historical Notes

Derived from Volume 13, Issue 18, eff. June 26, 1997; amended, Virginia Register Volume 18, Issue 18, eff. July 1, 2002; Volume 30, Issue 09, eff. January 29, 2014.

Statutory Authority

§ 10.1-1232 of the Code of Virginia.