Code of Maine Rules › 06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL › Chapter 695 - RULES FOR UNDERGROUND HAZARDOUS SUBSTANCE STORAGE FACILITIES › Appendix 096-695-G - Minimum Standards for Site Assessments

Current through 2024-29, July 17, 2024
1. The site assessment shall be supervised
				by, and site assessment reports shall be certified by, an independent Maine
				Certified Geologist.
2. The site
				shall be sampled in sufficient density for substances which singly or in
				combination will indicate the presence of all known hazardous substances stored
				during the operational life of the tank or facility except for those substances
				which were assessed during a previous site assessment meeting the requirements
				of this rule and have not since been stored in the facility. A statistically
				significant sampling program acceptable to the Department must be completed to
				show that a site is not contaminated.
3. For tank removals the site assessment
				shall include a thorough visual inspection of the tank exterior for leaks,
				inspection of the open excavation for physical evidence of a leak, and soil gas
				screening if appropriate for the hazardous substance stored.
4. The site to be assessed shall be sampled
				in the areas where contamination is most likely to be present. If contamination
				is identified during a tank or facility closure, the site investigated shall
				extend beyond the known contaminated area to include the surrounding area
				possibly affected by the contamination. If environmental evidence of a leak is
				present on or off site the area investigated must extend beyond the location of
				the environmental evidence to include the surrounding area possibly affected by
				the contamination. If a site assessment is required due to confirmation of a
				leak without environmental evidence the site shall be sampled where
				contamination from the leak is most likely to be present.
5. Acceptable sampling methods include soil
				gas sampling; direct sampling of groundwater, backfill, and native geological
				materials; and alternative methods acceptable to the Department. If direct
				sampling methods are used the assessment should include below surface sampling
				of backfill and native geologic materials sufficient to detect vertical and
				lateral migration of contaminants. Sampling methods must be appropriate for the
				parameters being analyzed for, and the parameters being analyzed for must be
				appropriate for the hazardous substances stored. Sampling methods must also be
				appropriate for the hydrogeologic conditions at the site.
6. Samples shall be acquired, prepared,
				preserved, stored. transported, and analyzed by methods that will maintain
				sample integrity and meet analytical detection limits sufficient to determine
				the risk to public health and the environment.
7. If contamination is present the site
				assessment shall quantify and delineate the extent of free product and
				contaminated backfill, soils, surficial materials, bedrock and
				groundwater.
8. If contamination is
				present the site assessment shall include determination of the depth to water
				table and direction of groundwater flow.
9. If contamination is present the site
				assessment report shall describe soil, surficial materials, bedrock geology,
				hydrogeology and climate of the site. The site assessment shall also describe
				potential pathways for contaminant movement including sewer and utility
				lines.
10. If contamination is
				present the site assessment shall discuss the toxicity, mobility, and
				persistence of contaminants in relation to the hydrogeology of the site and in
				relation to potentially affected receptors.
11. If contamination is present the site
				assessment shall locate and describe potential receptors of contamination and
				shall describe the proximity of the contamination to private and public
				drinking water supplies, surface water bodies, and populated areas. The site
				assessment shall include a description of the classification under state and
				local classification systems, if any, of impacted or potentially impacted
				groundwater or surface water.
12.
				The site assessment report shall include specific recommendations for
				additional investigation and/or recommendations and rationales for site
				remediation including but not limited to free product removal, groundwater
				treatment, soil removal or treatment, control of vapors, surface water
				clean-up, or no action if justifiable by hydrogeologic, health, safety or other
				environmental criteria; descriptions of any remediation work completed or in
				progress; recommendations and rationales for further work or study as
				necessary; a map or drawing of the site showing components of the facility and
				sample locations; analytical results; data logs; a description of quality
				assurance/quality control procedures: and a summary of all work under taken as
				part of the site assessment including rationales for sample locations, sample
				parameters, and sampling methods.
13. A copy of the site assessment shall be
				sent to the department at the following address:
UST Program Administrator
DEP Bureau of Remediation and Waste Management
17 SHS
Augusta ME 04333
14.
				The Department reserves the right to reject unsatisfactory site assessments and
				require additional investigation, information and reporting. The Department
				also reserve the right to require, for Department review and approval, remedial
				action plans for cleanup of free product, contaminated soils and groundwater
				whenever it determines that sufficient data is available for remedial action
				design.
15. Nothing in this
				Appendix shall limit the Department's discretion or ability to order and/or
				undertake immediate remedial action at sites where evidence of contamination by
				a hazardous substance is present.
16. Determination of the action levels of
				hazardous substances that require remediation may be made by the Department on
				a case by case basis. At a minimum any concentrations of hazardous substances
				in the environment must be cleaned up to the extent necessary to protect human
				health. safety, and the environment.