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Why was this BUI originally listed as impaired?
- The initial cause of impairment of this BUI in the Detroit River AOC was related to the additional costs associated with disposing of dredged material in confined disposal facilities rather than in open water.
- Disposal of sediment on the Michigan side of the Detroit River and in the lower section of the Canadian side were not suitable for open water disposal because of heavy metals, PCBs, and contaminants.
- Consequently, the sediment was disposed of in confined disposal facilities, which would have been more costly at the time than open water disposal.
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This BUI will be considered to be ‘not impaired’ when….
There are no limitations on the disposal of sediments removed for routine navigational dredging
What was done?
- 2004 DRCC Mercury & Chemical Waste Collection: Through this program, over 90kg of mercury from local households was collected, eliminating the potential for improper disposal of mercury into the environment
- 2008 Turkey Creek Sediment Remediation: Data analysis showed that concentrations of PCBs in sediment, water, and forage fish have decreased over time at the remediated areas (Benoit & Burniston, 2019). PCB concentrations in sediment at the mouth of Turkey Creek have also shown improvements over time.
- 2013, draft guidance from the Canada Ontario Agreement federal and provincial RAP management was produced. The following guidance from that document is applied in this BUI assessment report: “Restrictions on Dredging Activities” BUI may be considered “not impaired” in AOCs where dredging for commercial navigation may be undertaken and the agency responsible for the dredging activities requires that the dredged material be disposed of in an existing, regulated management facility in accordance with provincial and/or federal guidelines and regulations.”
- Due to changes in sediment management quality guidelines and regulations, the use of a confined disposal facility is no longer considered a restriction on dredging. Open water disposal is now a much more restrictive, and a non-viable option for the Detroit River, and in most places in the Great Lakes it is not allowed or actively discouraged. Future dredging and disposal of the dredged material in the Detroit River AOC will continue in accordance with appropriate provincial and/or federal guidelines and regulations and on sound environmental best management practices.
- Based on the 2013 guidance, it is recommended that the Restrictions on Dredging Activities BUI be re designated to ‘not impaired’ in the Detroit River Canadian AOC.
- Upgrades to sewers and wastewater treatment plants such as the Lou Romano and the Amherstburg Wastewater Treatment Plant and the creation of stormwater retention ponds to help settle out contaminated sediment before entering the river
- Ongoing: Mussel biomonitoring of legacy contaminants in the river such as mercury and polychlorinated biphenyls (PCBs)
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