Section 20-6205. COMPREHENSIVE SITE ASSESSMENT

 

6205.1Within sixty (60) days after submission of a workplan pursuant to § 6203.14, the responsible party shall submit a Comprehensive Site Assessment to the Director in a form satisfactory to the Director. A Comprehensive Site Assessment shall not be required if the Initial Site Assessment demonstrates that further assessment is not needed.

 

6205.2Unless otherwise directed by the Director, the responsible party shall perform a Comprehensive Site Assessment in the time and manner set forth in this section. A Comprehensive Site Assessment shall include, at the minimum, a background search; a complete on-site investigation that fully defines the extent of the release; potential exposure as a result of the release; the levels of Chemicals of Concern and a proposal for the corrective action plan. If an off-site impact occurs or is indicated, the responsible party shall include an off-site investigation as necessary on a case-by-case basis. The following elements shall be included when preparing a Comprehensive Site Assessment, as appropriate to the conditions of the site:

 

(a)The nature of the release, including the chemical compounds present, their concentrations, quantity released if known, and their physical and chemical characteristics related to potential human health and environmental impacts and clean-up procedures;

 

(b)Data from available sources or site investigations concerning the following factors: surrounding land use; water quality; use and approximate location of wells potentially affected by the release; subsurface soil conditions; climatological conditions; locations of all subsurface utilities that are potential pathways, including sewers, water and gas pipelines, other conduits; and land use;

 

(c)The results of the site investigation and any information gained while performing initial abatement measures pursuant to § 6203;

 

(d)The results of the free product investigations required under § 6203.12;

 

(e)The areal extent of the release to the degree sufficient to define or determine the physical characteristics and behavior of the impacted soil or ground water including the following: future migration potential; horizontal extent of the release if a characteristic of the chemicals of concern; whether the chemicals of concern are distributed homogeneously or heterogeneously; and vertical delineation on a case-by-case basis when indicated by the presence of wells, aquifers or other water sources in addition to ground water.

 

(f)The physical characteristics of the site, including characteristics affecting the occurrence, distribution, and movement of the released contaminant and characteristics affecting access to the site which may influence the feasibility of investigation and remediation procedures;

 

(g)A qualitative evaluation of the potential risks posed by the release including identification of environmentally sensitive receptors, and estimate of the impacts to human health and the environment that may occur as a result of the release;

 

(h)Comparison of contaminant levels to District soil and groundwater quality risk based screening levels contained in § 6209; and

 

(i)Any other information requested by the Director or deemed useful or necessary by the responsible party.

 

6205.3Activities shall be conducted in accordance with an appropriate Health and Safety Plan. The Health and Safety Plan shall be available for inspection by the Director.

 

6205.4Upon receipt of the Comprehensive Site Assessment, the Director:

 

(a)Shall review and approve the Comprehensive Site Assessment; and

 

(b)May require the responsible party to conduct additional field studies and collect data.

 

6205.5The responsible party may request an extension of the sixty (60) day deadline set forth in § 6205.1 by submitting a written request for an extension to the Director no later than forty-five (45) days after submission of the workplan. The request shall include the following:

 

(a)A summary of all work performed and all information gathered to date pursuant to § 6205.2;

 

(b)A summary workplan for the additional assessment activities required; and

 

(c)A proposed schedule for completion of the remaining assessment activities and submission of the completed site assessment report.

 

6205.6The Director may grant or deny the request for extension, or grant the extension with modifications to the work plan or schedule.

 

source

Final Rulemaking published at 40 DCR 7835, 7888 (November 12, 1993); as amended by Final Rulemaking published at 46 DCR 7699 (October 1, 1999).