St. Louis River Biota Mercury Monitoring
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Purpose

Biota in the lower St. Louis River (estuary) will be sampled and tested for total and methyl mercury content. Burrowing mayflies will be the primary target organism. Composite samples will be collected from 88 sites. Consultations with other partners working on the St. Louis AOC (EPA, MPCA, UMD) have identified this project as having the greatest value to complement other ongoing monitoring in the St. Louis River estuary, including efforts to assess mercury bioaccumulation.

Objective

Fifty sites will be selected using a GRTS random, stratified method. These will allow evaluation of spatial patterns in mayfly Hg content, including comparisons between littoral ("flats") and pelagic (thalweg) sites, and different segments of the estuary.An additional 38 targeted sites will be selected, where high sediment Hg concentrations are known to exist to allow a comparison of mercury bioaccumulation in mayflies between highly contaminated and a range of lesser contaminated sites. Two year old burrowing mayfly nymphs will be collected at all sites where they are present. Alternative ecological equivalent organisms will be identified, and collected at sites where mayflies are not present. Sampling will be done in July, 2015.

Outcome

Consultations with other partners working on the St. Louis AOC (EPA, MPCA, UMD) have identified this project as having the greatest value to complement other ongoing monitoring in the St. Louis River estuary, including efforts to assess mercury bioaccumulation.

Study Design

Fifty sites will be selected using a GRTS random, stratified method. These will allow evaluation of spatial patterns in mayfly Hg content, including comparisons between littoral ("flats") and pelagic (thalweg) sites, and different segments of the estuary.An additional 38 targeted sites will be selected, where high sediment Hg concentrations are known to exist to allow a comparison of mercury bioaccumulation in mayflies between highly contaminated and a range of lesser contaminated sites. Two year old burrowing mayfly nymphs will be collected at all sites where they are present. Alternative ecological equivalent organisms will be identified, and collected at sites where mayflies are not present. Sampling will be done in July, 2015.

Related Reports

Run Project Summary Report
View Umbrella-Projects
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Competitive Projects
Undetermined
NOR_17_CMP15
2015
Complete
 
Reports and Documents
St. Louis River Estuary Mayfly Mercury Lab Report with Site Coordinates
Mercury Concentrations in Burrowing Mayfly Nymphs (Hexagenia limbata) in the St. Louis River Estuary
final SLR mayfly report
NOR_17_CMP15 status 10142016
NOR_17_CMP15 status 10142016
 
Activities & Recommendations
Monitor Aquatic Biology
Biota in the lower St. Louis River (estuary) will be sampled and tested for total and methyl mercury content. Burrowing mayflies will be the primary target organism. Composite samples will be collected from 88 sites.