ALMN NAWQA Surface-Water Study Component
Bed-Sediment and Tissue Study

Overview

Selected trace elements and organic compounds were measured in streambed sediments and fish tissue at a network of 19 sites. This network was established as part of the NAWQA Program in the ALMN Basin. The 19 sites were selected to provide a broad spatial coverage within the Study Unit. Ten sites are co-located with the Basic Fixed-Site and Intensive Fixed-Site network. These 10 co-located sites were selected to examine specific land-use related issues. The remaining sites were selected downstream of small urban/industrial areas in the basins (8 sites) and in a basin with low human population density as a reference site (1 site).

Bed-sediment samples were used to assess the sediment-size fraction less than 64 microns (0.064 mm) for trace elements, and the less than 2 mm size fraction for organic compounds. Composite bed-sediment material was collected from 10 to 15 depositional areas at each site. Composite samples of 5 to 10 whole fish were analyzed for synthetic organic compounds while composite samples of dissected livers of 5 to 10 fish were used for the trace elements analysis. Each composite consisted of only one species of fish. The species of fish used for each analysis is recorded in the data tables (see Data link below). Duplicate composite samples were taken at two sites to compare variation within a species at a site. At two sites duplicate collection of two different fish species were made. Composite samples of each species were analyzed from these sites to examine between species variation.

     A map showing the location of Bed-Sediment and Tissue Study sites is available for viewing:  

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