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Why was this BUI originally listed as impaired?
- The Detroit River has had a long history of environmental problems including combined sewer overflows, degradation of habitat, and presence of toxic contaminants (e.g., mercury, polychlorinated biphenyls (PCBs), and metals) in water and sediment. This degraded aquatic environment has resulted in the bioaccumulation of these contaminants within fish and wildlife that use the river.
- Degraded aquatic environment has resulted in the bioaccumulation of these contaminants within fish and wildlife that use the river.
- Many of these contaminants have been found to be detrimental to fish and human health.
- It should be noted that this BUI was only found to be impaired for fish only and not wildlife.
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This BUI will be considered to be ‘not impaired’ when….
When consumption advisories for indicator fish species (e.g. walleye, brown bullhead, smallmouth bass and largemouth bass) given for the sensitive population in the AOC are similar to upstream and downstream non-AOC Great Lakes reference areas due to contaminants from locally-controllable sources
What is being done?
- 1996-2023 City of Windsor Bioaccumulative Pollutant Monitoring: Results from this program indicated substantial improvements in PCB concentrations in Canadian waters of the Detroit River, with levels declining by more than 78 percent over the 27-year monitoring period (Drouillard, et al., 2016).
- 2000 Health Canada Angler Survey for the Detroit River: Found that nearly half of respondents had not eaten Detroit River fish in the previous year, primarily due to concerns about pollution, while those who did eat local fish reported it tasted good, was fresh, and was an affordable source of protein. The most commonly consumed species included yellow perch, walleye, white bass, rock bass, and smallmouth bass, with most consumers eating between 1 and 11 fish meals annually.
- 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.
- 2011 City of Windsor’s Retention Treatment Basin: Designed to reduce the volume of untreated wastewater entering the Detroit River because of combined sewer overflows
- 2015 Angler/Creel Survey: Found that anglers spent more than 600,000 hours fishing, with the highest effort occurring in April and May. White Bass were the most harvested species, Walleye were the most targeted fish, and while over 100,000 Smallmouth Bass and 4,000 Muskellunge were caught, nearly all Muskellunge and 97% of Smallmouth Bass were released.
- 2019 Detroit River Canadian Cleanup Fish Consumption Survey: Found that many respondents who ate fish from the river, 211 of 231 (91%), said that they eat less than 8 meals per month, the threshold used in this assessment. The most popular species consumed included walleye, yellow and white perch and white/silver bass.
- 2025 Assessment of Beneficial Use Impairment (BUI) #1: Fish Consumption Advisories in the Detroit River: The Restrictions on Fish and Wildlife Consumption BUI (fish only) was evaluated using a tiered BUI framework assessment to compile and interpret multiple lines of evidence. Though there were some failures within the tiers for the indicator species, historical data indicate that there are declining, or stable, concentrations of PCBs and mercury in the Canadian portion of the Detroit River AOC. Overall, the assessment report concludes that this BUI should be redesignated as unimpaired.
- Ongoing: Mussel biomonitoring of legacy contaminants in the river such as mercury and polychlorinated biphenyls (PCBs)
- Ongoing: Ministry of the Environment, Conservation and Parks fish advisory program
- 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
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