International Joint Commission Beneficial Use Impairment Criteria
Summary table of Beneficial Use Impairments in the Toronto and Region Area of Concern.
| Beneficial Use Impairment | Status of Toronto and Region AOC |
| Eutrophication or undesirable algae | Impaired |
| Beach closings | Impaired |
| Restrictions on fish or wildlife consumption | Impaired |
| Degradation of benthos | Impaired |
| Restrictions on dredging activities | Impaired |
| Loss of fish and wildlife habitat | Impaired |
| Degradation of fish and wildlife populations | Impaired |
| Degradation of aesthetics | Impaired |
|
Degradation of phytoplankton and zooplankton communities |
Requires further assessment |
| Bird or animal deformities or reproductive problems | Not impaired |
|
Fish tumours or other deformities |
Not impaired |
| Restrictions-drinking water consumption-taste/odor problems | Not impaired |
| Added costs to agriculture or industry | Not impaired |
| Tainting of fish and wildlife flavor | Not impaired |
Identified Beneficial Use Impairments in the Toronto and Region Area of Concern and associated International Joint Commission (IJC) guidelines for changing a BUI classification from "impaired" to "not impaired" (delisting).
| Beneficial Use Impairment (Status of Toronto and Region AOC) |
Stage 1 Analysis (1989) |
Progress/Status (Moving Forward, 2007) |
Delisting Guideline (IJC, 1991) |
| Eutrophication or undesirable algae (Impaired) |
Phosphorus often exceeds Provincial Water Quality Guideline of 0.02 mg/L across the waterfront. Algal and weed problems are restricted to the western shoreline because of a lack of suitable substrate and wave action in other areas. |
Phosphorus levels in the watersheds frequently exceed the PWQO. Along the waterfront, phosphorus levels generally meet the PWQO. Algal growth continues to be a problem along the waterfront, especially in the western part of the AOC. Mixed. Improvement in regulations; however, complex issues in nearshore have exacerbated levels of nutrients. |
When there are no persistent water quality problems (e.g. dissolved oxygen depletion of bottom waters, nuisance algal blooms or accumulation decreased water clarity, etc.) attributed to cultural eutrophication. |
| Beach Closings (Impaired) |
Frequent beach closings as a result of stormwater and CSO contamination |
City of Toronto now has seven beaches that have been awarded international Blue Flag status, recognizing their good water quality. City of Toronto beaches are posted due to high bacterial levels from multiple sources. Wastewater infrastructure improvements (ie. construction of the Western and Eastern tunnels) also helps improve water quality at Toronto beaches as does educating residents as to the implications of feeding the birds. Better understanding of the sources of bacteria has helped improve management of the beaches. |
When waters, which are commonly used for total-body contact or partial body-contact recreation, do not exceed standards, objectives, or guidelines for such use. |
| Restrictions on fish or wildlife consumption (Impaired) |
Human consumption advisories exist for the larger sizes of several species because of mercury, PCB and mirex levels. Evidence indicates that this is not attributable to local causes and needs to be dealt with on a lake-wide level. |
Levels of contaminants have decreased since the 1980s but the rate of decrease has slowed in the last decade. Consumption advisories persist; generally the larger sizes of some fish species and top predators are of more concern due to the bioaccumulation of toxics. Mercury, PCBs, dioxins and furans cause major consumption restrictions throughout Lake Ontario, further assessment is needed to confirm that these advisories are due to lakewide concern rather than a regional one. While contaminant levels have declined somewhat; |
When contaminant levels in fish and wildlife populations do not exceed current standards, objectives or guidelines, and no public health advisories are in effect for human consumption of fish or wildlife. Contaminant levels in fish and wildlife must not be due to contaminant input from the watershed. |
| Degradation of benthos (Impaired) |
Benthic communities in embayments and near river mouths are dominated by species indicative of organic enrichment. Densities are lower than in the past, suggesting some improvement. Benthos bioaccumulate metals and trace organics. |
In the watersheds, impairment of benthic communities varies, with Highland Creek showing the most impairment and the Rouge and Humber Rivers showing the least. Along the waterfront impairment of benthic communities is still seen in areas enriched with nutrients (e.g., near CSOs, in the Keating Monitoring programs are in place to obtain better data and determine trends |
When the benthic macroinvertebrate community structure does not significantly diverge from unimpacted control sites of comparable physical and chemical characteristics. Further, in the absence of community structure data, this use will be considered restored when toxicity of sediment-associated contaminants is not significantly higher than controls. |
| Restrictions on dredging activities (Impaired) |
Sediments in most embayment areas exceed Ontario's open water disposal guidelines. Dredging has been subject to Environmental Assessment in the past and is likely to be in the future. |
Contaminant levels have improved in surficial sediments. When navigational dredging is required, contaminant levels and bioavailability is sampled to determine if material is required to be contained in the Confined Disposal Facility in Tommy Thompson Park. Dredgeate which meets guidelines is used in the creation of waterfront parks. Hotspots of contaminated sediment are often associated with sewer outfalls. Some progress made since 1989. |
When contaminants in sediments do not exceed standards, criteria, or guidelines such that there are restrictions on dredging or disposal activities. |
| Loss of fish and wildlife habitat (Impaired) |
Historic loss of habitat. Loss of riverine habitat continues. Contamination of existing or newly created habitats is of concern. |
Watersheds: Uplands and upstream riverine habitat continues to decline due to urbanization, in particular in headwater or intermittent streams; however, regulations have recently been strengthened to better protect floodplains and wetlands from development. Waterfront: Habitat improvement and creation are major considerations of the waterfront revitalization effort, resulting in significant gains in fish and wildlife habitat. Mixed. Gains from habitat restoration and creation are outweighed by continued urbanization. |
When the amount and quality of physical, chemical, and biological habitat required to meet fish and wildlife management goals have been achieved and protected. |
| Degradation of fish and wildlife populations (Impaired) |
Historic degradation and loss of species dating back to the 1800s. Continued impact from urbanized area today. |
Fish and wildlife populations continue to decline in general due to the impacts of urbanization in the watersheds. This is being partly offset through stream restoration, wetland creation and barrier mitigation projects. However, of the 243 species found in the RAP Region 128 are of Regional concern. Declining. Gains from habitat restoration and creation are outweighed by continued urbanization. |
When environmental conditions support healthy, self-sustaining communities of desired fish and wildlife at predetermined levels of abundance that would be expected from the amount and quality of suitable physical, chemical and biological habitat present. An effort must be made to ensure that fish and wildlife objectives for Areas of Concern are consistent with Great Lakes ecosystem objectives and Great Lakes Fishery Commission fish community goals. Further, in the absence of community structure data, this use will be considered restored when fish and wildlife bioassays confirm no significant toxicity from water column or sediment contaminants. |
| Degradation of aesthetics (Impaired) |
Aesthetic concerns relate primarily to debris and litter. Turbidity is also a concern near river mouths and in the vicinity of lakefilling operations. Weed growth is a concern along the western shoreline. |
No formal assessment done. Anecdotal evidence suggests that algae growth continues Some progress made since 1989. |
When the waters are devoid of any substance which produces a persistent objectionable deposit, unnatural color or turbidity, or unnatural odor (e.g. oil slick, surface scum). |
| Degradation of phytoplankton and zooplankton communities (Requires further assessment) |
Requires more assessment. Lake-wide factors, physical factors and local pollution sources influence communities. Information is currently insufficient to determine the relative significance of local sources. |
Definitive assessment has not been done. Requires further Assessment. |
When phytoplankton and zooplankton community structure does not significantly diverge from unimpacted control sites of comparable physical and chemical characteristics. Further, in the absence of community structure data, this use will be considered restored when phytoplankton and zooplankton bioassays confirm no significant toxicity in ambient waters. |
