SOIL SAMPLES
TISSUE SAMPLES
Site Description
Sandy Beach is located on Douglas Island adjacent to the historic Treadwell Mine that was Shut down in 1917.
The beach is used by DIA tribal members for collection of traditional subsistence food resources as well as by the general public for recreational purposes.
Public facilities at the beach include picnic shelters, public bathrooms, and an upland trail system with multiple outlets onto the beach.
Summery
Analysis of these samples was performed to determine whether methylmercury, inorganic arsenic, and lead pose a potential risk to tribal members through direct contact or consumption of seafood.
Contaminants of potential concern in sediment included methylmercury, inorganic arsenic, and lead. Contaminants of potential concern in tissue included methylmercury and inorganic arsenic.
Both sediment and tissue samples were also analyzed for total mercury and total arsenic in order to determine the relative contributions of the methylated and inorganic metal species, respectively.
Based on these combined analytical results, Sandy Beach sediments, clam tissue, and crab tissue pose an exposure risk to humans. Sediments pose a threat through direct exposure to inorganic and total arsenic concentrations in sediments.
Clam and crab tissue from Sandy Beach sediments or the nearby offshore waters also contain concentrations of inorganic arsenic that exceed USEPA human health screening levels for the consumption of fish tissue.
Additionally high concentrations of arsenic in sediment may be related to poor crab and clam catches in the area directly offshore of Sandy Beach and along the lower beach face.
Looking over the Gastineau channel at Sandy Beach you can still fined Mine Debris from the historic Treadwill Mine.
Sampling
Site sampling was conducted at Sandy Beach in 2014 and in 2016
In 2014, A total of 6 Dungeness crab,12 clams, and 8 sediment samples were collected and analyzed from Sandy Beach area
In 2016, a total of 8 sediment samples were collected to further characterize the extent of possible contamination
In both events sample analysis was performed to determine whether methyl mercury, inorganic arsenic, and lead pose a potential risk to tribal members through direct contact with sediments or through consumption of local seafood
Kamal Lindoff, Environmental Director digs for clams to sample for heavy metal contamination in 2014.
Sampling Locations
Overview
Analytical Results
High levels of arsenic, inorganic arsenic, mercury and methylmercury were detected in most sediments and tissue samples at concentrations that exceeded human health screening levels and ecological screening levels.
The collective analytical results indicate that Sandy Beach sediments, clam tissue, and crab tissue pose a potential exposure risk to humans.
Bernadine DeAsis, Environmental Specialist & John Morris, Council Member carefully packages soil samples from Sandy Beach.
RIDOLFI Environmental Data Tables
2014 Sandy Beach Data Table
2016 Sand Beach Data Table
Tissue Samples Data Table
Analysis Poster
Created by Bernadine DeAsis, Environmental Specialist
Leave A Comment