title: Perchlorate in Lake Water from an Operating Diamond Mine.
abstract: Mining-related perchlorate [ClO4(-)] in the receiving environment was investigated at the operating open-pit and underground Diavik diamond mine, Northwest Territories, Canada. Samples were collected over four years and ClO4(-) was measured in various mine waters, the 560 km(2) ultraoligotrophic receiving lake, background lake water and snow distal from the mine. Groundwaters from the underground mine had variable ClO4(-) concentrations, up to 157 μg L(-1), and were typically an order of magnitude higher than concentrations in combined mine waters prior to treatment and discharge to the lake. Snow core samples had a mean ClO4(-) concentration of 0.021 μg L(-1) (n=16). Snow and lake water Cl(-)/ClO4(-) ratios suggest evapoconcentration was not an important process affecting lake ClO4(-) concentrations. The multiyear mean ClO4(-) concentrations in the lake were 0.30 μg L(-1) (n = 114) in open water and 0.24 μg L(-1) (n = 107) under ice, much below the Canadian drinking water guideline of 6 μg L(-1). Receiving lake concentrations of ClO4(-) generally decreased year over year and ClO4(-) was not likely [biogeo]chemically attenuated within the receiving lake. The discharge of treated mine water was shown to contribute mining-related ClO4(-) to the lake and the low concentrations after 12 years of mining were attributed to the large volume of the receiving lake.
authors.affiliation: †Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.|‡Lianna Smith Consulting, Ottawa, Ontario, Canada K1S 4Y5.
authors.forename: Lianna J D
authors.initials: LJ
authors.lastname: Smith
authors.affiliation: †Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Ptacek
authors.affiliation: †Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: David W
authors.initials: DW
authors.lastname: Blowes
authors.affiliation: †Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Groza
authors.affiliation: †Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.|§Alberta Innovates, Technology Futures, Calgary, Alberta, Canada T2L 2A6.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Moncur
mesh_terms: D002170:Canada; D018130:Diamond; D004784:Environmental Monitoring / Q000379:methods; D060106:Lakes / Q000032:analysis*; D008906:Mining; D015873:Northwest Territories; D010472:Perchlorates / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: D010472:Perchlorates; D014874:Water Pollutants, Chemical; D018130:Diamond; C494474:perchlorate