Overview metadata of the supplemental data used for the Assessment of Hydrocarbon Concentrations in Southern Lake Powell (2016-2017)

This data release contains five datasets that were used in a Scientific Investigations Report to be published in 2018. These datasets are continuous temperature data, temperature profiles data, SPMD environmental concentration data in picograms per liter of water, SPMD environmental concentration data in nanograms per SPMD, and SPMD quality-control concentration data. SPMD Environmental Concentration, Continuous Temperature and Temperature Profile: Semipermeable membrane devices (SPMDs) and Onset Computer Corporation® TidbiT v2 temperature loggers were deployed together at 8 locations within southern Lake Powell to collect water concentrations of polycyclic aromatic hydrocarbons (PAHs) and to collect continuous water temperature data. At these locations, the instruments were either deployed on a fixed dock, a buoy, or a floating dock. Listed below are the 8 locations that the SPMDs and the continuous temperature sensors were deployed. The PAH environmental concentration data are reported in both the original units, as nanograms per SPMD (ng/SPMD) and converted to a concentration in picograms per liter of water (pg/L). Temperature profile data were collected at all 8 locations. This data was collected during deployment and retrieval of the SPMDs by using a Sea-Bird Electronics, Inc., model SBE25 CTD profiler™. • Antelope Marina (USGS 365759111254700); Fixed Dock • Dangling Rope Marina (USGS 370708111045100); Fixed Dock • Lone Rock Beach (USGS 370107111320500); Buoy • Padre Bay near Dominquez Butte (USGS 370321111171700); Buoy • Rainbow Bridge National Monument (USGS 370506110581600); Fixed Dock • Stateline Marina (USGS 370031111300100); Fixed Dock • Wahweap Marina (USGS 365933111285200); Fixed Dock • Warm Creek Bay (USGS 370333111262700); Floating Dock SPMD environmental concentration data, and continuous temperature data were collected during the time periods listed below. Temperature profile data were collected at the time of deployment and the time of retrieval of the SPMDs. • June 21, 2016 (deployment date) to July 20, 2016 (retrieval date) • April 18, 2017 (deployment date) to May 16, 2017 (retrieval date) • June 29, 2017 (deployment date) to July 26, 2017 (retrieval date) SPMD Quality-control Concentrations: The following are the different types of quality-control data that were collected during the duration of this study: • Field Replicates • Field Blanks • Laboratory Blanks • Laboratory Fabrication Blanks • Laboratory Matrix Spikes • Performance Reference Compounds • Photolysis Marker