ACCESS NUMBER: 30830

STUDY TITLE: Sediment Quality in Depositional Areas of Shelikof Strait and Outermost

Cook Inlet

REPORT TITLE: Sediment Quality in Depositional Areas of Shelikof Strait and Outermost

Cook Inlet, Final Report

CONTRACT NUMBER): 1435-01-97-CT-30830

SPONSORING OCS REGION: MMS Alaska Outer Continental Shelf Region

APPLICABLE PLANNING AREA(S): Shelikof Strait and Lower Cook Inlet, Alaska

FISCAL YEAR(S) OF PROJECT FUNDING: 1997, 1998, 1999, 2000

COMPLETION DATE OF REPORT: May 2001

CUMULATIVE PROJECT COST: $1,426,000

PROJECT MANAGER(S): Arthur D. Little, Inc

ADDRESS: Acorn Park Drive, Cambridge, MA 02140

PRINCIPAL INVESTIGATOR(S)*: Dr. Paul D. Boehm, ADL; Dr. John Trefry, FIT; Dr. Robert Spies, AMS

KEY WORDS: acid volatile sulfide/simultaneously extracted metals (AVS/SEM), Alaska, alkylated PAHs,

aluminum, amphipod, antimony, arsenic, barium, baseline environmental conditions, benthic environment,

beryllium, biological analyses, biomarkers, biota, bottom-feeding fish, cadmium, calcium, cesium-137,

chemical body burdens, chemical analyses, chromium, coal seams, Cook Inlet, copper, Cytochrome P450

(CYP1A) induction, deposition, environmental risk, fish tissue, Gulf of Alaska, inorganic, iron, Kenai

Peninsula, lead, lead-210, magnesium, manganese, marine environment, mercury, metals, Minerals

Management Service (MMS), nickel, offshore oil exploration and production, oil and gas transportation, oil

seeps, oil and gas operational discharges, oil and gas production, oil industry contaminants, oil and gas

exploration, Outer Continental Shelf (OCS) leases, P450, petroleum hydrocarbons (PHC), polynuclear

aromatic hydrocarbons (PAHs), potassium, reporter gene system (RGS), river runoff, sediment core

dating, sediment, sediment cores, sediment profile imagery (SPI), selenium, Shelikof Strait, silver,

steranes/triterpanes (S/T), subtidal bottom sediment, surface sediment, thallium, tin, toxicity tests,

toxicological analyses, vanadium, zinc

BACKGROUND: Oil and gas exploration, production, and transportation activities in Cook Inlet, Alaska

have the potential for impacting marine resources. Though these operations are well-managed and are

regulated so as to minimize the input of pollutants to the marine environment, the longer-term

accumulation of pollutants in depositional areas on the sea floor is an area of concern when contemplating

future Outer Continental Shelf (OCS) leases.

TheMineralsManagementService(MMS)program“SedimentQualityinDepositionalAreasofShelikof

Strait and OutermostCookInlet,”consistedofatwo-year study to provide and update environmental

information to support future MMS oil- and gas-leasing decisions in the outermost Cook Inlet/Shelikof

Strait planning area. As part of this study, a scientific crew on board the Research Vessel (R/V) Alpha

Helix, collected samples for biological, chemical, and toxicological analyses from the program study area

during two sampling surveys. The first survey was conducted from July 7 to July 17, 1997 and the second

undertaken the following year, from June 27 to July 5, 1998. Such uses of this information include

environmental risk assessments, environmental impact statements, and other pre- and post-leasing

decision documents. This study was initiated to establish baseline environmental conditions prior to any

oil- and gas-leasing activities. The results of the entire two-year field survey data are described in this

report.

OBJECTIVES: Because of the need to definitively examine the distribution and environmental risk of
anthropogenic chemicals (i.e., metals, petroleum hydrocarbons including polynuclear aromatic

hydrocarbons [PAHs]) in advance of any future oil and gas E&P activities that could potentially affect the

lower Cook Inlet and Shelikof Strait, MMS contracted with Arthur D. Little, Inc. (ADL) to undertake a

two-year study in the region. The objectives of the study were to:

· Evaluate the Shelikof Strait and outermost Cook Inlet as potential depositional areas or "traps" for

oil industry contaminants

· Determine whether contaminant concentrations in sediments of these areas pose an

environmental risk

· Determine whether contaminants in these areas have accumulated relative to pre-industry

concentrations

· Determine whether any increases can be correlated with specific discharge events or activities

(e.g., the Exxon Valdez oil spill)

· Determine the importance of other hydrocarbon and metal sources to the sediments

DESCRIPTION: The design of the data acquisition/field program for the two-year study focused on two

facets. The first was the deep subtidal bottom sediments of the region as the focal point of any long-range

contaminant deposition. The design was intended to obtain both chemical (i.e., exposure) and biological

(i.e., effects) data on surface sediments. It also was directed at looking at historical deposition in the study

area through the use of dated sediment cores. The second facet addressed the status of chemical body

burdens in bottom-feeding fish and indicators of sublethal effects. These "biomarker" measurements

were made to address their exposure to contaminants.

The field sampling design included:

· Separation of the study area into four zones, each assumed to be relatively homogeneous

· The selection of a group of random sediment stations in each zone from a large number of

candidate stations, each station representing a replicate of that zone

· The selection of fixed or biased stations at key locations from which we wanted to obtain data

· The selection of a limited number of stations from each zone (including the fixed stations) from

which to take replicates to examine within-station variability

· The selection of additional sampling stations in the Gulf of Alaska off the Kenai Peninsula to

represent "upstream" source material

· The selection of additional stations south of Shelikof Strait to examine longer-range transport

· The field-truthing of the suitability of each station prior to sampling

· The sampling of stations for surface sediments; selected locations for sediment coring; and

selected locations for obtaining fish samples

· The selection and sampling of potential contaminant sources -- oil seeps; river runoff; coal seams;

and oil and gas operational discharges

The analytical design centered on organic (i.e., petroleum-related) and metal parameters as measured in

sediment, sediment core, fish tissue, and source samples. The design consisted of the following

measurements:

· Petroleum hydrocarbons (PHC), including PAHs of petroleum and other origins, and

steranes/triterpanes (S/T) in sediments and PAHs in fish tissue

· The use of detailed alkylated PAHs and S/T to elucidate source characteristics of source samples

and source identification in the field samples

· Major and trace metals including silver, aluminum, arsenic, barium, beryllium, calcium, cadmium,

chromium, copper, iron, mercury, potassium, manganese, magnesium, nickel, lead, antimony,

selenium, tin, thallium, vanadium, and zinc in sediments

· Acid volatile sulfide/simultaneously extracted metals (AVS/SEM) in sediments (Year 1 only)

· All metals except calcium, potassium, magnesium, and nickel in fish tissues

· Amphipod toxicity tests in sediments

· Reporter gene system (RGS) P450 measurements for sediment and fish tissue extracts

· Cytochrome P450 (CYP1A) induction determinations on selected tissues

· Dating of sediment cores by 210lead and 137cesium methods and analysis of core sections for

hydrocarbons and metals as in the surface sediments

· Sediment profile imagery (SPI) of surface sediments (Year 1 only)
SIGNIFICANT CONCLUSIONS: The comprehensive findings of this two-year investigation indicate that

the current concentrations of metals and PAHs in the Shelikof Strait and Outermost Cook Inlet are neither

linked to oil and gas development in the upper Cook Inlet, nor to the Exxon Valdez oil spill. The residues

that are present, from a combination of natural sources -- river inputs, oil seepages, etc. -- pose no

significant risk to the biota and the benthic environment of outermost Cook Inlet and Shelikof Strait. The

degree of current risk is indeed very low and is similar to non-impacted coastal regions in Alaska and

elsewhere.

STUDY RESULTS: The surface sediments of outermost Cook Inlet and the Shelikof Strait are traps for

fine-grained sediment and are potential traps for contaminants from oil and gas production activities in

upper Cook Inlet. Nonetheless, based on evaluations of the organic and inorganic data, no contamination

in the surface sediments from oil and gas production activities in upper Cook Inlet was identified.

The concentrations of metals and organics (i.e., PAHs) in sediments in outermost Cook Inlet and Shelikof

Strait have not increased significantly since offshore oil exploration and production began in Cook Inlet

(circa 1963).

The composition (source[s]) of metals in the sediments of outermost Cook Inlet and Shelikof Strait do not

appear to have changed since offshore oil exploration and production began in Cook Inlet (circa 1963).

The composition of hydrocarbons in sediment cores shows subtle changes in outermost Cook Inlet over

the past 25 to 50 years, but these changes do not appear to be correlated with petroleum production

activities or spills.

The concentrations of organics (i.e., PAHs) and metals do not appear to pose any immediate ecological

risk to the marine environment in the study area.

STUDY PRODUCT(S): Sediment Quality in Depositional Areas of the Shelikof Strait and Outermost Cook

Inlet. Sediment Profile Imaging Report. 1999. Prepared by EVS Environmental Consultants under

contract to Arthur D. Little, Inc. for U.S. Department of the Interior, Minerals Management Service,

Anchorage, Alaska. OCS Study MMS 99-0003. 40 pp.

Sediment Quality in Depositional Areas of Shelikof Strait and Outermost Cook Inlet, Final Literature

Synthesis. 1998. Prepared by Arthur D. Little, Inc. for U.S. Department of the Interior, Minerals

Management Service, Anchorage, Alaska. OCS Study MMS 97-0015. 69 pp.

Sediment Quality in Depositional Areas of Shelikof Strait and Outermost Cook Inlet. Final Report. 2001.

Prepared by Arthur D. Little, Inc. for U.S. Department of the Interior, Minerals Management Service,

Anchorage, Alaska. OCS Study MMS 2000-024. multipaginated.

Boehm, P., Brown, J., Spies, R., Germano, J., Anderson, J., Stegman, J., Trefry, J., and Prentki, R. T.

1997. Sediment Quality in Depositional Areas of Shelikof Strait and Outermost Cook Inlet [Abstract].

Abstract Book Society of Environmental Toxicology and Chemistry (SETAC) 18th Annual Meeting. p.

16. Penasacola, FL, SETAC Press.

Boehm, P., Brown, J., Trefry, J., and Spies, R. 1999. Sediment Quality in Depositional Areas of Shelikof

Strait and Outermost Cook Inlet. MBC Applied Environmental Sciences. Alaska OCS Region Seventh

Information Transfer Meeting Proceedings. pp. 11-12. Anchorage, AK, United States DOI, MMS,

Alaska OCS Region.

Gray, R. L. 1999. A pH-Gradient Approach to the Acid Volatile Sulfide Technique for Determining

Sediment Quality for Trace Metals. M.S. Dissertation. 1998. Melbourne, FL, Florida Institute of

Technology.

Rember, R. D. 1998. Sediment Deposition in Outermost Cook Inlet and the Shelikof Strait, Alaska. M.S.

Dissertation. 1998. Melbourne, FL, Florida Institute of Technology.

Rember, R. D. and J. Trefry. 2005. Sediment and Organic Carbon Focusing in the Shelikof Strait, Alaska.

Marine Geology 224: 83-101.
Trefry, J. H. 2000. The Influence of Basin-Scale Processes on Sediment Metal Contamination. Coasts at

the Millennium. Proceedings of the 17th International Conference of the Coastal Society. pp. 713-

720. Alexandria, VA, The Coastal Society.

*PrincipalInvestigators’affiliationmaybedifferentthanthatlistedforProjectManager