A goal of the Remedial Action Plan for the Thunder Bay’s Area of Concern has been to restore our area’s beneficial uses so that they are no longer impaired. Within Thunder Bay, twelve different beneficial use impairments were identified in the late-1980s in need of cleanup, or remediation.
A Beneficial Use Impairment (BUI) means a change in the chemical, physical, or biological integrity of the area sufficient to cause (among others): a degradation of aesthetics, fish tumours or other deformities, bird or animal deformities or reproduction, or a degradation of phyto- and zooplankton populations. Significant progress has been made in Thunder Bay to remediate the above BUIs.
Within Thunder Bay, twelve different beneficial use impairments were identified in the late-1980s in need of cleanup, or remediation. A Beneficial Use Impairment (BUI) means a change in the chemical, physical, or biological integrity of the area sufficient to cause (among other impairments): a degradation of aesthetics, fish tumours or other deformities, bird or animal deformities or reproduction problems, or a degradation of phyto- and zooplankton populations. Significant progress has been made in Thunder Bay to remediate the above BUIs.
Reports recommending the delisting these four of these BUIs as impairments are now available. Links to them can be found below.
Degradation of Aesthetics (link)
Based on the results of the 2012 Thunder Bay Aesthetics Survey and the 2015-16 Ice Free Survey, which found no evidence of no evidence of persistent objectionable deposits, unnatural colour or turbidity, or unnatural odour, it is determined that the Degradation of Aesthetics BUI delisting criterion has been met. Thus this BUI should be considered to be “not impaired” and can be removed from the list of environmental issues facing the Thunder Bay AOC.
Bird or Animal Deformities or Reproduction Problems (link)
The technical report ‘Assessment of the Wildlife Reproduction and Deformities Beneficial Use Impairment in the Thunder Bay Area of Concern‘ details the methods, field and laboratory analyses, results, discussion and conclusions of a three-year study undertaken in 2012, 2014 and 2015 by researchers within the Science and Technology Branch of Environment and Climate Change Canada (ECCC). The study assessed the status of the Bird or Animal Deformities or Reproduction Problems beneficial use impairment (BUI) in the Thunder Bay Area of Concern (AOC) by examining herring gull and double-crested cormorant colonies. Fish-eating wildlife such as herring gulls and double-crested cormorants are important indicators of exposure to persistent contaminants in the aquatic environment. The results of the three-year study clearly demonstrate that this BUI is not impaired within the Thunder Bay AOC.
Fish Tumours or Other Deformities (link)
In 2007, an analysis of 100 white suckers collected from Thunder Bay revealed a 2% tumour rate (Baumann 2010). In 2013, the analysis of 100 white suckers from Thunder Bay (with a median age of 9 years) revealed a tumor rate of of 1%, with one fish having a 1mm benign tumour. The 2% tumour rate in the 2007 sampled fish and the 1% tumour rate in the 2013 sampled fish are both well below the 5% threshold that experts have established for environmental impairment. The results from these two intensive surveys provide compelling evidence of improved fish health in the Thunder Bay Area of Concern, and clearly demonstrates that this BUI is not impaired within the Thunder Bay AOC. The full report can be found above.
Degradation of Phytoplankton and Zooplankton Populations (link)
Because no delisting criteria were developed for this BUI, the attached technical report “Assessment of the Degradation of Phytoplankton and Zooplankton Populations Beneficial Use Impairment in the Thunder Bay Area of Concern” completed by the Ministry of the Environment, Conservation and Parks (MECP) is a screening level assessment, which provides a general indication of the potential for ecological risk. The conclusion of this screening level assessment is that the phytoplankton and zooplankton populations are not impaired in the Thunder Bay AOC.
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