080121-08MN006-Sabina Hackett River Project Proposal ... - NIRB

Description of the Existing EnvironmentMajor nutrients (nitrate, total phosphate, silicate) also followed the same general pattern, withconcentrations being lowest in shallow waters and highest at depth. The pycnocline acts as abarrier to water mixing, and waters above the pycnocline typically become depleted in nutrientsby phytoplankton during the summer, sun-lit months.Physical parameters such as pH, TSS, and turbidity did not show strong profile trends.For metals, only 2007 data are available. The concentration of metals in pristine marine watersis typically low, and the interference caused by seawater anions and cations make it difficult (butnot impossible) to achieve low detection limits. The detection limits achieved for the 2001 studywere too high, and all 2001 metal values were reported as below the detection limit.However, above-detection limit values were measured during the 2007, and profile metal datawere obtained for several metals. Element concentration-depth profiles can be classified intothree categories; conservative, recycled, and scavenged (Open University, 1989).Aluminum and manganese had clear ‘scavenged’ element concentration-depth profiles, havinghigh concentrations in surface waters, decreasing to lower concentrations at depth.Arsenic, cadmium, and molybdenum had clear ‘recycled’ element concentration-depth profiles,having low concentrations in surface waters, increasing to high concentrations at depth.Chromium, copper, iron, and nickel all had concentration-depth profiles that did not follow adistinct trend. The remaining metals had values at or near the analytical detection limits.Besides traditional oceanographic processes affecting the metal concentrations in the waters inBathurst Inlet near the port site, estuarine processes and major river inflows will also affect metalconcentrations during the open-water season. Metal data obtained during the 2007 surveyrepresent the first set of data collected for Bathurst Inlet. Results will be presented in a MarineBaseline Report for the Hackett River Project (Rescan 2008b).6.1.11.4 Marine Sediment QualityThree major sources of riverine sediments exist in close proximity to the proposed BIPR portsite: Western River, No Name Creek, and Amagok Creek. Sediment is deposited into BathurstInlet from No Name Creek (Plate 6.1-13). Sediment deposition occurs primarily during freshet.A delta has formed at the mouth of the Western River, indicating a significant sediment loadcarried by the river’s runoff.It is probable that fine river-derived sediments are transported seaward in the surface layer of theestuarine system in Bathurst Inlet. Fine sediments will flocculate as they enter the marineenvironment so that deposition should be more pronounced as surface seawater salinityincreases. Shoreline erosion and ice scouring also likely contribute to sediment loading andtransport into the water column.Sediment in the immediate vicinity of the proposed port site consisted mainly of gravel (particlesize between 2 and 64 mm) and cobble (particle size between 64 and 256 mm) (Rescan 2008b).January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 6–25 Rescan Environmental Services Ltd. (Proj. #833-2)