State managers must assess contamination at abandoned mines, sewage outfalls, harbors, and other sites. We are determining the physical and chemical properties of sediments; measuring the chemical contaminants in sediment, fish, and mussels; describing the biodiversity and benthic organisms; and testing sediment toxicity. Our results are being used to assess the impact of pollution in the coastal zone and provide baseline data for assessing coastal development and climate change.
Why We Care
The type and distribution of organisms found in coastal sediments are influenced by habitat type and chemical pollution. Many chemical contaminants accumulate in coastal sediments and in the tissue of benthic animals. Moving up the food chain, contaminants can become more concentrated in seafood such as fish and shellfish. To help manage the use of coastal and ocean resources, we need to understand what chemicals are present, where they are distributed, and whether they are toxic to the organisms living in the sediments.
What We Did
This study builds on the National Status and Trends (NS&T) bioeffects assessment of the northern side of Kachemak Bay, completed in 2007, and an assessment in the deep central portion of Kachemak Bay, conducted in 2008 in collaboration with the Cook Inlet Regional Citizens Advisory Council (CIRCAC). It is a joint project with the Alaska Department of Environmental Conservation.
We’re conducting a baseline environmental characterization of the fjords and embayments along the south shore of Kachemak Bay and the outer Kenai Peninsula using the sediment quality triad approach. The triad includes: sediment chemistry, sediment toxicity, and benthic invertebrate community structure. Concentrations of over 120 organic and metallic contaminants are being analyzed. Sediment toxicity is being assessed using amphipod bioassays with sediment from the abandoned mine sites. Fish and mussels from selected locations are undergoing contaminant body burden analyses.
Joint field operations were completed in 2009 with the assistance of the NOAA Kasitsna Bay Laboratory and the Kachemak Bay Estuarine Research Reserve.
What We Are Finding
Thus far, we have found that organic contaminants were elevated in the vicinity of Seldovia Harbor.
We will be integrating the chemical, physical and biological data and assigning each site an index score. The benthic habitat conditions will then be compared among sites.