St' Louis RiverInterlakeDuluth Tar Site

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St. Louis River/Interlake/Duluth Tar
Site (SLRIDT)

• Site Overview
• Dredge/Cap Hybrid
• Remedy Description

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• Industrial activities beginning in 1890s and
  lasting until 1961 contaminated the soil,
  groundwater, surface water and sediment at this
  site.

1939
1910

• Over 60 years of waste water discharges from
  the water gas, coking, and tar facilities
  formerly located on the Site resulted in
  extensive sediment contamination

1947
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Site Contamination

• Industrial waste discharge of coal tar and tar
  refining waste

• PAHs polyaromatic hydrocarbons
• Metals As, Cd, Cr, Cu, Pb, Ni, Zn and Hg

Metals -
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Stryker Bay Oil Blooms
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High Naphthalene Concentration
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Stryker Bay Depth
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SURCHARGE-CAPPING
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Surcharged Consolidation
Peat
Silt
Sand
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Stryker Bay Depth
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Greater than 8 feet finished water depth
Less than 8 feet finished water depth
CAD
Root Barrier
BAZ
5 Ft
BAZ
1 M
Environmental Media
4 Ft
BAZ
0.5 M
3 Ft
BAZ
2.0-2.5 Ft
IZ
IZ
IZ
IZ
Contamination
Contamination
Contamination
Contamination
5-Foot Cap
4-Foot Cap
3-Foot Cap
2.0-2.5-Foot Cap
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Treated CAD Water Discharge
Discharge with full treatment
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St. Louis River/Interlake/Duluth Tar
Site (SLRIDT)
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