340821-001 FINAL United Keno HHERA 4 May 2011

Human Health and Ecological Risk Assessment for the Historic Keno Hill Mine Site
at Flat and Christal Creek as compared to other reference and mine exposed areas. From the
observed correlation it was thought that the number of taxa decreased as the metals
concentrations in the water and stream sediment increased (Minnow 2009; Laberge 2008). A low
confidence in the bioassessment of Flat and Christal Creeks was expressed by Minnow (2010a)
in relation to the uncertainty of the appropriateness of the reference area and the absence of
replicate samples.
In the 2007 summer monitoring program 54,609 individuals were observed, which were
classified into 98 different taxonomic groups under five phyla (arthropoda, mollusca, annelida,
nematode, cnidaria). The benthic invertebrate communities were found to be healthy at the South
McQuesten River and Lightning Creek drainages, and there was a good representation of highly
sensitive insects in the area. A higher but less diverse population was observed at Christal Creek
(KV-6) near the outlet of Christal Lake. The populations at KV-9 (Flat Creek) were depressed
and the diversity was low, again thought to be as a result of the high concentrations of metals in
the sediment (Laberge 2008).
2.2.2 Terrestrial Environment
A total of three Terrestrial Effects Assessments reports have been prepared by Environmental
Dynamics Inc. (EDI 2008, 2009, 2010), investigating the extent of metal dispersion from the
Elsa tailings into the surrounding terrestrial ecosystem. The objective of the first study, Elsa
Tailings Environmental Effects Assessment - Phase 1 (EDI 2008), was to determine if, and to
what extent, aerial dispersion of metals had occurred using lichens as indicators of airborne
contamination. The second study, Elsa Tailings Terrestrial Effects Assessment - Phase 2 (EDI
2009), investigated impacts on plants traditionally harvested and consumed for medicinal
purposes by FNNND. Samples were collected from the same locations as in the Phase 1 study
(i.e., Elsa tailings), as well as two other areas (Mackeno Tailings and Minto Bridge) to further
understand natural properties of plants in and around the area. Minto Bridge was identified as a
site used by FNNND for traditional harvesting of medicinal plants. The third study, Elsa Tailings
Terrestrial Effects Assessment- Phase 3 (EDI 2010), was a follow up study to determine if the
elevated metals concentrations in plants observed in the Phase 2 assessment were due to
contamination in the soil, and to gain a superior understanding of the metal concentrations in the
area with respect to different disturbances (tailings and point source water discharges) (EDI
2010). Figure 2.4 summarizes the areas of Keno Hill that have been sampled, and identifies
which data are available for each area (i.e., soil, vegetation, lichen/moss).
In the Phase 1 assessment, lichen was sampled as it is an excellent indicator of airborne
contamination (EDI 2008). The tailing facilities cover approximately 118 ha, which contains
both dry tailings in the eastern half and three tailing ponds in the northwest section (EDI 2008).
Aerial contamination was indicated but was limited to the area around the eastern ‘dry’ portion
of the tailings facilities. There were concerns regarding the potential for ongoing contamination
340821-001 – FINAL – May 2011 2-11 SENES Consultants Limited