Supplemental Attach 1-2006-Eldred Rock Review of Debris Remove.pdf

DEPf. OF ENVIRONMENTAL CONSERVATION

DIVISION OF SPILL PREVENTION AND RESPONSE

CONTAMINATED SITES PROGRAM

Mr. Mark Ridgway United States Coast Guard Civil Engineering Unit Juneau Post Office Box 217 4 7 Juneau, Alaska 99802-1747

April 21, 2006

Re: Review of Debris Removal Report and Requirements for Closure USCG Eldred Rock Light Station, reckey: 1997110122305

Dear Mr. Ridgway:

FRANK H. MURKOWSKI, GOVEflNOR

555 Cordova Street Anchorage, Alaska 99501

PHONE: (907) 269-7500

FAX: (907) 269-7649

http://www.state.ak.us/dec/home.htm

File no.: 1508.38.008

The Alaska Department of Environmental Conservation ( department) has completed review of the Debris Removal Report for the USCG Eldred Rock Light Station site near Haines, Alaska, prepared by Jacobs Engineering Group, Inc. and dated April 2005. This report details debris removal actions which are not regulated by 18 Alaska Administrative Code (AAC) 75.325-.390, the site cleanup rules, and was submitted to the department as a courtesy. The department appreciates the information. While reviewing the Debris Removal Report, the department also reviewed the rest of the site file. The department has made the following determinations about the site based upon its review of file reports, specifically the Environmental Characterization and Recommended Actions Report, prepared by CH2M Hill, dated July 2004.

The Eldred Rock Light Station is located on a small 2.4 acre island in Lynn Canal, 25 miles south of Haines and 50 miles northwest of Juneau. It was an operational light station from 1906 to 1973, and has been operating as an automated system since then.

Three (3) site characterization actions have been conducted at Eldred Rock. A Phase I Environmental Site Assessment was conducted in May 1997, a Phase II investigation in August 1997, and a Phase III in 2002. Multiple environmental issues were highlighted to be of concern; however most of those were outside the regulatory authority of the site cleanup rules. However, the discovery oflead contaminated soil from lead-based paint and petroleum-contaminated soil from fuel storage tanks and a floor drain are under governed by the site cleanup rules.

Soil samples were collected during each of the investigations and analyzed for diesel-range organics, residual-range organics, lead, volatile organic compounds, semi-volatile organic compounds or total organic carbon. For those contaminants of concern which were found exceeding the department's default cleanup levels, the maximum concentrations detected were: diesel-range organics: 6000 milligrams per kilogram (mg/kg), residual-range organics: 20,000 mg/kg, and lead: 1600 mg/kg. No volatile organic compounds or semi-volatile organic compounds were detected above the default

() Printed on recycled paper

Mr. Mark Ridgway Eldred Rock Light Station

April 21, 2006 Page2 cleanup levels. Total organic carbon was calculated to be 20%. Several samples were treated with silica gel prior to analysis for diesel-range organics and residual-range organics; these results were generally one-half the concentration of the untreated samples. No groundwater samples were collected as groundwater was not found to be present at the site. Bedrock was located at a general depth of two

(2) feet below ground surface.

Determination The department has made a determination that the concentrations of diesel-range organics do not pose an unacceptable risk to human health or the environment. The detected concentrations of diesel-range organics are below the human health ingestion and inhalation values of 18 AAC 75.341, Table B2.

The migration-to-groundwater pathway is not applicable as there is no groundwater at the site and rainfall generally runs off the site to surface water. Alaska Surface Water Quality Standards of total aromatic hydrocarbons and total aqueous hydrocarbons will not be exceeded as soil sampling did not detect any volatile organic compounds or semi-volatile organic compounds. Petroleum hydrocarbons will likely be held in by the high organic content in the soil so that contaminant migration to surface water does not occur.

This determination is based upon the current location of the soil and may not be appropriate if the soil is moved to another location. For sites with soil containing concentrations of contaminants of concern which exceed the department's most restrictive cleanup levels of 18 AAC 75.341, Tables Bl and B2, specifically 230 mg/kg diesel-range organics, 8300 mg/kg residual-range organics, and 400 mg/kg lead, the department now requires that the presence of the soil be tracked so that in the future it can be managed in accordance with 18 AAC 75.325(i).

Reguirements for Conditional Closure Concentrations of residual-range organics exceed the default cleanup level of8300 mg/kg, which is based upon the ingestion pathway. Additional sampling, cleanup, or discussion should be held in order to address this small area of contamination.

A proposal should be made regarding the presence of lead contaminated soil. The department and the Coast Guard are currently discussing a method of determining lead exposure areas to be applied to Coast Guard sites. The proposal regarding the lead contaminated soil at Eldred Rock Light Station should be developed in line with the new exposure area determination method when it is finalized.

The department has previously requested that the Coast Guard determine a method of tracking the presence of this soil to ensure that it does not inadvertently become excavated and disposed of in an inappropriate manner. Implementation of this tracking system and the inclusion of this site on that system will be required before the department can issue a conditional closure letter.

If you have any questions about this site, please do not hesitate to contact me at 269-7545 or Anne Marie Palmieri, ofmy staff, at 766-3184.

Sincerely, ,J\wAti~f~(~ ~/John Halverson

Environmental Program Manager