Cook Inlet RCAC

Biological and Chemical Monitoring

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In 1991, the Environmental Monitoring Committee (EMC) initiated steps to develop and manage a comprehensive environmental monitoring program for Cook Inlet. The goal of this program is to determine if oil-industry operations in Cook Inlet are having adverse effects on the surrounding ecosystem and, if so, to document their sources, magnitude, and spatial and temporal trends. Based on a 1992 model recommended by Cook Inlet RCAC contractors, a pilot study was initiated in 1993 to provide data against which to evaluate a longer-term environmental monitoring program. Based on this model, further environmental monitoring studies were conducted in 1994, 1995, 1996, and 1997.

Two types of monitoring strategies were used. The Sediment Quality Triad (SQT) approach was employed to measure sediment hydrocarbon contamination, sediment toxicity, and signs of pollutant-related ecological stress. Water quality monitoring using Semi-permeable Polymeric Membrane Devices (SPMDs) and the 'mussel watch' approach was used to indicate whether bioavailable petroleum hydrocarbons were present in the water column. Related abiotic parameters were also measured, including sediment grain size and total organic carbon.

In 1998, an independent review was contracted to:

  • Summarize the existing data and results
  • Evaluate the methods and environmental monitoring approaches used to date
  • Evaluate how effectively the existing data could be used as baseline information against which future chronic or acute oil-industry impacts might be measure
  • Recommend further efforts for assessing temporal and spatial oil-industry impacts to the Cook Inlet environment

As a result of recommendations made by these contractors, as well as input from a public forum, the committee shifted focus of its monitoring efforts from subtidal SQT-type studies to obtaining baseline intertidal information which would be necessary to determine any future impacts of spilled oil to Cook Inlet’s shorelines. The lack of pre-impact data increased costs and reduced the statistical power of damage assessment studies after the Exxon Valdez Oil Spill.

The first step was to conduct reconnaissance surveys to identify potential populations of organisms that can be monitored over time and act as “sentinels” to future hydrocarbon contamination. Surveys were conducted in 2000 and 2002 where habitat was described and sediments and tissue samples (from clams, mussels, and polychates) were analyzed for hydrocarbons. A major data gap was identified for nearshore habitat during these surveys and, as a result, a shoreline habitat mapping program was initiated.

Currently, the environmental monitoring program includes aspects that encompass subtidal, intertidal, and habitat mapping and monitoring.

Overall Program Goals

  • Maximize the collection of pre-impact data prior to any catastrophic inputs of hydrocarbons or other potential oil industry related contaminants
  • Maximize the availability of pre-impact data, both spatially and temporally, to increase our ability to detect change
  • Make data accessible to resource agencies, the public and other organizations
  • Acquire shoreline habitat data
  • Educate stakeholders about our study results

In 2000, Cook Inlet RCAC conducted a pilot project for intertidal monitoring on Cook Inlet shorelines that include sites most likely to be impacted by an accidental release of crude oil. Most of the shoreline in the middle and upper inlet had not been surveyed and data on the resources living there and on sediment or beach characteristics were scarce. In addition, there was almost no data on concentrations of hydrocarbons or other potential contaminants to Cook Inlet; data that are necessary to be able to address our OPA 90 mandates. Surveys in this area would provide valuable information on intertidal assemblages on hard and soft substrates, characterize sediments and geomorphology of the shoreline, and identify biological resources that would be most appropriate as sentinel species. These same types of data were missing from almost the entire Exxon Valdez oil spill area before the spill. The lack of these data made the studies of most state and federal resource agencies and universities much more difficult and expensive.

Background data need to continue to be collected in order to expand the database to include all of Cook Inlet’s shorelines, to incorporate more intertidal species, and to allow us to monitor the habitats across time. To date, the small database of background sediment and tissue data show very low concentrations of hydrocarbons in sediments and in tissues. By expanding these data, we can assess whether this is true for all parts of Cook Inlet and will have the data necessary to track changes. These data will benefit anyone who may need these data in the future, including state and federal agencies, as well as the Cook Inlet oil industry.

Our previous surveys in subtidal areas provided invaluable data for these same users. We recently partnered with the Alaska Department of Environmental Conservation to conduct a Coastal Assessment of the Gulf of Alaska’s coastal bays and estuaries by looking at a suite of contaminants in benthic sediments and organisms. The study design was based on a probabilistic survey design which allowed us to “scale-up” from a suite of 50 sampling sites. We would like to conduct a similar assessment within Cook Inlet that would assess sediment, benthic, and water quality indicators within the context of the larger Gulf of Alaska study.

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