Old Crow River, Tributary, and Thaw Slump Sampling 2019, Yukon, Canada

Water grab samples collected ~weekly (total and routine parameters) and ~monthly (dissolved parameters) at the west bank of the Old Crow River mouth from May 28 – October 8, 2019 (Figure 1 of Staniszewska et al. 2022). The sampling location is 14 km downstream (7 km linear distance) of the Water Survey of Canada gauge station (09FC001; 67°35'20" N, 139°47'30" W), Yukon, Canada. Water samples were also collected from eight tributary creeks that drain into the Old Crow River, upstream and downstream of four large active retrogressive thaw slumps along the Old Crow River mainstem, as well as the thaw slump meltwater between 21 and 28 July 2019. All water samples were collected in precleaned polypropylene bottles (for routine parameters, trace elements, and nutrients) or Teflon-capped amber borosilicate glass bottles double-bagged in polypropylene (for mercury and methylmercury) following EPA Method 1669 (U.S. Environmental Protection Agency, 1996). Samples intended for total analysis were immediately acidified to 0.1% v/v with trace metal grade HNO3 (for trace elements and nutrients) and HCl (for mercury and methylmercury, to 0.2% and 0.4% v/v respectively) for the purpose of sample preservation. Samples were stored at 4 °C and transported to the laboratory, where samples intended for dissolved parameters were filtered through 0.45 µm HCl-washed cellulose nitrite filters and acidified. Field blanks were rinsed and filled at the bank of the river on a monthly basis. Duplicates were collected for the first month of weekly grab sampling events at the river mouth. River water samples were analyzed for a broad suite of parameters, including turbidity; pH; conductivity; alkalinity; total dissolved solids; total suspended solids; organic and inorganic carbon; major ions (Al, Ca, K, Mg, Na, SO4, Cl); stable hydrogen and oxygen isotopes; total and dissolved nitrogen and phosphorus species; 31 total and dissolved trace elements; and total and dissolved mercury and methylmercury by standard methods. Samples analyzed for total trace elements were processed by microwave digestion prior to analysis by inductively coupled plasma mass spectrometry (ICP-MS). This bundle contains four datasets: (1) Real-Time Provisional 2019 Hydrometric Data for Water Survey of Canada Station: OLD CROW RIVER NEAR THE MOUTH (09FC001) [YT], (2) Hydrochemistry data for Old Crow River mouth, collected between May and October, 2019, (3) Hydrochemistry data for tributary creeks to Old Crow River, collected between July 21 - 27, 2019, and (4) Hydrochemistry data for thaw slump upstream, downstream, and rill samples, collected between July 21 - 27, 2019.