Stream measurements of total dissolved solids (TDS), pH, sulfate, and trace metals and measurement locations in northwest Alaska, USA, north and west of Red Dog Mine.

Across 200 km2 north and west of Red Dog Mine, well beyond the influence of mining activity, Teck Alaska Incorporated (Teck) has measured total dissolved solids (TDS) at 53 water quality stations, some for over 30 years.Red Dog MineRed Dog Mine, 130 km N of Kotzebue (68.0675, -162.8472, 218-300 m asl) extracts lead-zinc sulfide ore and trucks the concentrate on an 80-km gravel road to a Chukchi Sea port. Following deposit discovery in the 1950s, drilling-based exploration began in 1980, road, port-site, and mine construction in 1987, and mining in 1989. Bons Creek Wx (68.0291, -162.9118, 296 m asl), near the mine, has recorded air temperature and precipitation since 1992.Environmental monitoring The mine’s operating company, Teck Alaska Incorporated (Teck), its predecessor Cominco, and the State of Alaska have undertaken or contracted water quality and aquatic biota studies in nearby undisturbed catchments as controls on mining-effects since 1982. Water quality monitoring expanded in 2011 following increases in naturally occurring ARD along Ikalukrok Creek above the Red Dog Creek confluence (68.0892, -162.9484, 197 m asl), and across a 200 km2 area upstream, W, and N of the mine and its infrastructure. The file "TDS.csv" presents measurements of total dissolved solids (TDS) from n = 53 water quality stations (coordinates in file "Water_monitoring_station_locations.csv") sampled with a YSI ProDSS multi-parameter meter over time periods that varied by station.Ikalukrok Creek has served as a control stream against mining effects for over 30 years. The file "pH_Sta207.csv" presents pH measured instream several times each year (2015–2020) at Ikalukrok Creek Station 207 (68.1540, -162.8615). Stream pH was measured using a YSI meter multiple times at Ikalukrok Station 207 May–Oct 2015–2023.The file "Teck_metals_Ikalukrok_Sept_2020.csv" consists mostly of sites along Ikalukrok Creek sampled in 2020 for metal and sulfate. It presents data collected by Kuna Engineering (https://kunaeng.com/services/environmental-services/) as contracted by Teck, to determine SO4-2 and metal concentrations at multiple locations. We selected eight locations along upper Ikalukrok Creek above Red Dog Creek and one near the mine. Water samples were collected with helicopter support over the course of two days. Samples for total solids were collected directly into appropriately preserved bottles (i.e., acidified with 1% nitric acid for metals), while dissolved solid samples were collected in unpreserved containers and transported same-day-collected to Red Dog, where they were filtered (0.45 mm) into acidified containers.