6209 TIER 1 STANDARDS

6209.1 The Tier 1 standards for water shall be as follows:

(a) 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 Decisionmaking Technical Guidance Document.

(b) The standard for total petroleum hydrocarbons (TPH) in ground water contaminated by non-gasoline petroleum contamination shall be one part per million (1 ppm).

(c) The Tier 1 levels for surface water quality are the District of Columbia Water Quality Standards (21 DCMR Chapter 11).

(d) Methyl tertiary-Butyl-Ether (MtBE) as adopted by the Director in the Risk-Based Decisionmaking Technical Guidance Document.

(e) Naphthalene as adopted by the Director in the Risk-Based Decisionmaking Technical Guidance Document.

6209.2 Until the Director adopts the Tier 1 quality standards for soil or outlined in the Risk-Based Decisionmaking Technical Guidance Document, the Tier 0 standards for soil shall serve as the interim Tier 1 soil standards.

SOURCE: Final Rulemaking published at 40 DCR 7835, 7895 (November 12, 1993); as amended by Final Rulemaking published at 46 DCR 7699 (October 1, 1999).