| Abstract/Description or Keywords |
The 2007 to 2011 KSM Project surface water quality baseline program was designed to collect baseline water quality data for streams, rivers, and lakes within the Project study area. At each site, water quality samples were collected to characterize the natural spatial and temporal variation present in these systems. Stream Water Quality: Weekly, monthly, and quarterly water quality samples were collected at key stream sites related to the proposed mining area and the tailing management facility (TMF). Fifty-one stream and river sampling sites were sampled within the Mitchell/Sulphurets/Unuk, Teigen/Snowbank/Bell-Irving, and Treaty/Bell-Irving River watersheds. Two reference streams were included and site selection incorporated Project design updates. Streams in the Project area were typically near-neutral to slightly alkaline, with moderately hard to soft waters. Turbidity and total suspended solids (TSS) concentrations were largely associated with the hydrological regime with increased sediment loads during freshet and the fall period of high rainfall. Due to the mineralization of the Project area, peaks in TSS resulted in elevated metal concentrations. Streams were rich in total phosphorus; however, very little bioavailable orthophosphate was observed. Low total organic carbon (TOC) concentrations were observed at most streams. The exception to the typical stream characteristics was the upper Mitchell Creek watershed where naturally occurring acidity and poorly buffered conditions were observed. These sites were more influenced by groundwater seepage and naturally occurring acid rock drainage (ARD) than seasonal TSS concentrations. High flow periods typically diluted metal concentrations at the acidic sites. Concentrations of metals were generally highest at those sites close to the deposit areas in Mitchell and Sulphurets creeks. The lowest metal concentrations were typically observed in the Teigen/ Bell-Irving watershed. Concentrations of many metals naturally exceeded provincial and federal water quality guidelines for the protection of aquatic life, reflecting the naturally high mineral content of the KSM Project waters. Guideline exceedances were most commonly observed for total and dissolved aluminum, total cadmium, total and dissolved iron, total lead, total selenium, and total zinc. Dissolved metals which are more biologically available generally contributed substantively less to the total metal load than particle-associated metals. The exceptions were the acidic Mitchell Creek sites where most metals were primarily in the dissolved phase, and for antimony, cadmium, molybdenum, selenium, and uranium that were predominantly in the dissolved phase at all sites. The spatial and temporal trends observed for metal concentrations were similar among baseline years. Lake Water Quality: Annual water quality sampling was performed at four lakes from 2008 to 2010 in August or September. Sulphurets and Knipple Glacier lakes are higher altitude, glacier-fed lakes, while West Teigen and Todedada lakes are lower altitude, with vegetated riparian zones. Sulphurets and Knipple Glacier lakes were characterized by high levels of suspended solids and high concentrations of particulate metals. Concentrations were frequently higher than water quality guidelines and were greatest in Sulphurets Lake, which is near the deposit area. Total and dissolved aluminum, total copper, total cadmium, total chromium, and total iron frequently exceeded guidelines at Sulphurets and Knipple Glacier lakes. West Teigen Lake and Todedada Lake were characterized by lower suspended solid concentrations, higher concentrations of total organic carbon, and lower concentrations of metals. |
