Between 2007 and 2018, the National Park Service and its partners in association with NOAA’s National Mussel Watch Program collected bay mussel (Mytilus trossulus) tissue samples from Alaska's southeast and southwest coastal waters. The researchers analyzed the samples for a suite of chemical contaminants to create a baseline of contaminant concentrations from this region and to compare these concentrations to national Mussel Watch Program data.

Why We Care
The marine coastlines in the national parks of southeast and southwest Alaska receive cumulative contamination from various diffuse sources, making them susceptible to chronic pollution. They are also susceptible to catastrophic releases, as in the case of the Exxon Valdez oil spill in 1989. Documenting contaminant concentrations provides a baseline of information that can be used to evaluate the study area over time and in comparison to other regions.

What We Did
Our report summarizes contaminant results from marine sampling conducted between 2007 and 2018 by the National Park Service Southeast Alaska Network (SEAN) and Southwest Alaska Network (SWAN) and their partners in association with NOAA's National Mussel Watch Program. SEAN and SWAN partnered with the Mussel Watch Program to measure a comprehensive suite of contaminants in bay mussels (Mytilus trossulus) at 42 targeted sites across the networks. The researchers analyzed mussel samples for trace metals (Arsenic, Cadmium, Copper, Lead, Mercury and Nickel), total Butyltins, total Chlordanes, total Chlorobenzenes, total DDTs, total Dieldrins, total Endosulfans, total HCHs, Mirex, Chlorpyrifos, total PAHs, total PBDEs, total PBBs, and total PCBs. The team summarized contaminant concentrations from this study and compared them to long-term NOAA National Status and Trend monitoring data for each group of contaminants.

What We Found
With the exception of PAHs and trace metals, which were detected at 100 percent of the sites, all of the other contaminants were detected at varying frequencies. PBBs, Mirex and Endosulfans were not detected in any of the samples and Chlorpyrifos was only detected in five samples across four sites. Chlordanes were present at 79 percent of the sites while Butyltins were only detected at 20 percent of the sites. Overall, the majority of the concentrations can be considered to be at background levels when compared to the long-term NOAA National Status and Trends monitoring data for blue mussels nationwide.

Benefits of Our Work
This report represents a rich source of information to help support the parks' responses during unforeseen catastrophic marine pollution events and guide future sampling site choices and frequency.

Map of SEAN's six long-term marine contaminants monitoring stations in Glacier Bay National Park and Preserve, Klondike Gold Rush National Historical Park, Sitka National Historical Park, and one site in Skagway Harbor (sampled in partnership with the Municipality of Skagway). Red dots represent bay mussel tissue analysis collection sites.

Map of SWAN long-term marine contaminants monitoring stations in Katmai National Park and Preserve and Kenai Fjords National Park, and sites in Prince William Sound and Kachemak Bay sampled in partnership with Gulf Watch Alaska. Red dots represent bay mussel tissue analysis collection sites.