EPA awards US$4.5 million contract for sediment cleanup in St. Louis River AOC

The US Environmental Protection Agency (EPA) has awarded a US$4.5 million contract to remediate contaminated sediment in the St. Louis River Area of Concern (AOC) on Lake Superior.

The St. Louis River AOC is one of 43 toxic hotspots identified by the United States and Canada in the Great Lakes basin, and is the second largest AOC in the United States.

The EPA and the Minnesota Pollution Control Agency (MPCA) will fund the work through a Great Lakes Legacy Act cost-sharing partnership.

The project will remediate approximately 42,000 cubic metres of contaminated sediment in the Azcon/Duluth Seaway Port Authority slip, an active 2.6-hectare shipping slip located in the Duluth-Superior Harbor. The sediment is primarily contaminated with polycyclic aromatic hydrocarbons, or PAHs.

Approximately 460 cubic metres of the most contaminated sediment in the slip will be removed and properly disposed of. The remainder will be capped in place with clean sediment to prevent exposure to aquatic organisms.

The cap will be armoured with stone to protect against damage from vessel traffic.

The MPCA has agreed to contribute up to US$1.575 million to the total project cost of US$4.5 million.

The cleanup will reduce toxins in the benthic (i.e., bottom dwelling) community, macroinvertebrates which live in the sediment, and provide an important food source for fish. As a result, toxins will be reduced in fish, making them safer to eat.

The project is slated to begin this summer with the help of the US Army Corps of Engineers (USACE).