Pursuant to the District of Columbia Underground Storage Tank Regulations, Title 20 DC Municipal Regulations (DCMR) §§ 6206, 6208 and 6209 the Toxic Substances Division, Underground Storage Tank (UST) Branch has established numerical standards for soil, surface water and ground water quality. All soil and water samples must be analyzed by an EPA or DC-approved method, as directed by the LUST Case Manager of the District Department of the Environment. View the UST Soil and Groundwater Screening and Cleanup Standard [PDF].
§ 6206 DC Risk Based Corrective Action Guidance
The District of Columbia Risk-Based Corrective Action (DCRBCA) or Risk-Based Decision Making (DCRBDM) process can be used to develop site-specific risk-based screening levels (RBSLs) and site-specific target levels (SSTLs) for remediation. This approach is supported by the USEPA.
The guidance was developed for environmental professionals with working knowledge and experience in the areas of site assessment, site investigation, risk assessment, and remedial actions.
The DCRBCA process recognizes and balances (i) the need to protect public health, water resources, and the environment of the District, (ii) the variations in site-specific land use and hydrogeological characteristics, (iii) the existing laws and regulations of the District, and (iv) resource limitations. Appropriate risk and exposure assessment practices suggested by the USEPA and the American Society for Testing and Materials (ASTM) E1739-95 Standard have been integrated into this process.
It is also consistent with the District of Columbia’s overall objective of protecting public health, safety and welfare, the environment, and natural resources for present and future use. The process was developed and is administered by the District Department of the Environment (DDOE) Underground Storage Tanks Branch (USTB) within the Toxic Substances Division.
The intent of the DCRBCA process for USTs is to develop site-specific target levels protective of current and potential future (i) human health, (ii) environment, (iii) nuisance conditions, and (iv) explosive type situations. This guidance focuses on petroleum releases from USTs, however, it can be used for a variety of other chemicals.
§ 6208 - Tier 0 Standards
- 6208.1 was updated in the DC Risk-Based Decision-making Technical Guidance of June 2011.
For Soil:
- Total petroleum hydrocarbons (TPH) gasoline range organics (GRO) or diesel range organics (DRO) concentrations in soil shall be no greater than one hundred milligrams per kilogram (100 mg/kg);
- Individual constituent concentrations of BTEX in soil shall not exceed benzene (0.005 mg/kg), toluene (9.6 mg/kg), ethylbenzene (0.04 mg/kg), and total xylenes (3.86 mg/kg).
For groundwater:
The Tier 0 standards are the maximum contaminant levels (MCLs). If the maximum site concentrations meet these levels, the RP may request case closure. If these standards are not met, a tiered risk evaluation is appropriate.
§ 6209 - Tier 1 Standards
6209.1 The Tier 1 standards for water shall be as follows:
- The Tier 1 levels for ground water quality shall be the District of Columbia Water Quality Standards for Ground Water (21 DCMR Chapter 11) as outlined by the Director in the Risk-Based Decision-making Technical Guidance Document.
- The standard for total petroleum hydrocarbons (TPH) in ground water contaminated by non-gasoline petroleum contamination shall be one part per million (1 ppm).
- The Tier 1 levels for surface water quality are the District of Columbia Water Quality Standards (21 DCMR Chapter 11).
- Methyl tertiary-Butyl-Ether (MtBE) as adopted by the Director in the Risk-Based Decision-making Technical Guidance Document.
- Naphthalene as adopted by the Director in the Risk-Based Decision-making Technical Guidance Document.
Soil Quality Standards:
The standards for soil quality may not exceed the values listed in the Tier 1 quality standards for soil outlined in the Risk-Based Decision-Making Technical Guidance Document of June, 2011 (UST Soil and Groundwater Screening and Cleanup Standards [PDF]).
Surface Water Quality Standards:
The standards for surface water quality are the District of Columbia Water Quality Standards (21 DCMR Chapter 11).
Ground Water Quality Standards:
The standards for ground water quality for specific inorganic and organic compounds are the District of Columbia Water Quality Standards for Ground Water (21 DCMR Chapter 11). The maximum concentrations for the most common compounds of interest at LUST investigations: Lead, 50 ppb; Benzene, 5 ppb; Toluene, 1,000 ppb; Ethylbenzene, 700 ppb; and Total Xylenes 10,000 ppb.
Note: § 6202 of the DC UST Regulations states that "any responsible party or any authorized agent of a responsible party; any person who tests, installs, or removes tanks; any person who engages in site investigation, assessment, remediation, or geotechnical exploration; or any public utility company who knows, or has reason to know of a release from an underground storage tank must notify" the DC Fire Prevention Division (202) 727-1614, and this office (202) 535-2600 of the release or suspected release within 24 hours. During business hours, you must speak to a member of the DDOE’s UST-LUST Program, (202) 535-2600. After hours, notice may be given to the Mayor's Command Center (202) 727-6161.
http://www.dcregs.dc.gov/Gateway/ChapterHome.aspx?ChapterNumber=20-62