Long-Term Environmental Monitoring

The major environmental monitoring activities of the Council are conducted through the long-term environmental monitoring project, known as LTEMP. This project has gathered data on the presence of hydrocarbons in sediments and mussels in the region since 1993.

The project quantifies the amount of hydrocarbons, provides a benchmark for assessing the ongoing impacts of routine tanker and terminal operations, and identifies physical and biological changes taking place in the region’s ecosystem.

Establishing consistent baseline data helps us identify and assess trends over time. This data would enable us to accurately assess oil recovery in the event of a future spill. Long-term environmental monitoring also provides a context for more site-specific studies and research.

Mussels were selected as the indicator species for LTEMP because they are:

  • indicator species
  • important subsistence food
  • important prey of sea birds and sea otters
  • commonly found throughout Prince William Sound and downstream habitats

By law, the Valdez Marine Terminal is allowed to discharge small amounts of oil pollution each day into Port Valdez. Occasionally, there are also relatively small oil spills from the terminal that reach the marine waters of Port Valdez. The Council works both to prevent accidental releases and to understand how long-term low inputs of crude oil impact the ecosystem. 

Results from the Council’s studies indicate a variety of sources of hydrocarbons in Prince William Sound including the Exxon Valdez spill in 1989, operations at the Alyeska terminal, combustion sources, boating and shipping activities, normal oil seepage or coal deposits, biological processes, and atmospheric fallout.

Generally, the hydrocarbon levels detected under LTEMP have been relatively low. The stations farthest from the Alyeska terminal show low hydrocarbon levels, while those closest to the terminal show higher levels. Concern over the hydrocarbon levels at the terminal prompted the council to add an additional sampling effort at the two Port Valdez stations in the fall of each year.

LTEMP results are summarized in a year-end report and periodically peer reviewed. The program underwent a full data analysis and summary in 1998. Results from a 2000 review of the two Port Valdez monitoring sites suggest that Alaska North Slope crude oil residues from the terminal’s ballast water treatment facility have accumulated in the port’s intertidal mussels.

A reduced sampling frequency for LTEMP began in FY2010, as provided for in a new sampling plan accepted by the Board at its January 2009 meeting following a full programmatic review begun in 2007. The new sampling plan requires one sampling session per year at the two Port Valdez sites and the Knowles Head site. Then, every fifth year all 10 sites will be sampled.

Importance of Adequate Baseline Data

The Cook Inlet Regional Citizens’ Advisory Council has its own environmental monitoring program, similar in scope to LTEMP. Together, the data produced by the two programs provide some of the only multi-year data for coastlines downstream from the most industrialized and populated areas in Alaska.

The growth in commercial and recreational use of the northern Gulf of Alaska increases the complexity of determining adequate baseline data. Prince William Sound’s sensitive coastal marine environments are experiencing increased pressures on what is already intense use. Evidence of this increase in pressure can be found in the growing numbers of large and small passenger cruise ship traffic, the extension of the longevity of the trans-Alaska pipeline and its shipping activity, the Whittier road access that is adding to the increase in numbers of visitors to Prince William Sound, state oil and gas lease sales, new ports, increases in recreational uses, and demands for new access to fishing sites

Annual Long Term Environmental Monitoring Project Reports and Data

Long Term Environmental Monitoring Program 2021 Technical Supplement 5.8 MB | September 30, 2022
Long Term Environmental Monitoring Program 2021 Summary Report 2.1 MB | May 30, 2022
Full Report: Mussel Chemistry and Transcriptomic Response after a Minor Alaskan Oil Spill 7.7 MB | September 22, 2021
Executive Summary: Mussel Oiling and Genetic Response to the April 2020 Valdez Marine Terminal Spill 0.5 MB | August 20, 2021
Long Term Environmental Monitoring Program: 2020 Sampling Results and Interpretations 5.2 MB | April 1, 2021
Using Mussel Transcriptomics For Environmental Monitoring In Port Valdez Alaska - 2019 And 2020 Pilot Study Results 2.9 MB | February 17, 2021
Metagenetic Analysis of 2018 and 2019 Plankton Samples from Prince William Sound, Alaska 1.7 MB | September 18, 2020
Long Term Environmental Monitoring Program: 2019 Sampling Results and Interpretations 6.7 MB | May 7, 2020
Port Valdez Mussel Transcriptomics 0.9 MB | November 20, 2019
Long-Term Environmental Monitoring Program: 2018 Sampling Results and Interpretations 5.8 MB | August 1, 2019
Long-Term Environmental Monitoring Program: 2017 Sampling Results and Interpretations 3.9 MB | September 1, 2018
LTEMP 2015 Sampling Results and Interpretations 4.1 MB | December 1, 2016
LTEMP 1993-2015 (Excel Spreadsheet) 5.4 MB | January 8, 2015
Long Term Environmental Monitoring Fact Sheet - Updated Dec 2014 0.4 MB | December 8, 2014
LTEMP Results And Interpretations From Sampling, 2008-2013 2.3 MB | March 8, 2013
LTEMP 2008-2012 5.6 MB | December 8, 2012
LTEMP Data Sets 1993-2009 3.3 MB | November 29, 2010
LTEMP 2006-2008 5.8 MB | December 20, 2008
LTEMP Program Review 0.3 MB | October 1, 2007
LTEMP 2005-2006 4.6 MB | December 1, 2006
LTEMP Ecology Of Tidal Flat Communities of the Copper River Delta 0.5 MB | April 11, 2006
LTEMP Errata For Kinnetic Laboratories Report 0.1 MB | March 1, 2006
LTEMP Kinnetic Laboratories Reference Oils Report 1.7 MB | March 1, 2006
LTEMP 2000-2002 Appendix B And C 4.7 MB | December 28, 2005
LTEMP 2004-2005 2.2 MB | February 10, 2005
LTEMP 2003-2004 2.5 MB | December 28, 2004
LTEMP 2002-2003 Summary 0.1 MB | December 28, 2003
LTEMP 2002-2003 1.3 MB | December 28, 2003
LTEMP 2000-2002 Appendix D 2.4 MB | December 28, 2002
LTEMP 2000-2002 Appendix A 3.7 MB | December 28, 2002
LTEMP 2000-2002 13.7 MB | December 28, 2002
Assessing Transport And Exposure Pathways and Potential Petroleum Toxicity to Marine Resources in Port Valdez, Alaska, 2001 0.6 MB | December 8, 2001
LTEMP 1999-2000 3.8 MB | December 28, 2000
LTEMP 1998-1999 2.1 MB | December 28, 1999
LTEMP Caged Mussel Study From Applied Biometering 6.5 MB | February 16, 1999
LTEMP 1997-1998 1.7 MB | December 28, 1998
LTEMP 1993-1996 Non-technical 0.8 MB | December 28, 1996
LTEMP 1993-1996 9.3 MB | December 28, 1996
LTEMP Data Sets Metadata 89 KB | December 26, 1990
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