Mercury concentrations in fish and macroinvertebrates from the Duck Valley Reservation and nearby waters, southwestern Idaho and northern Nevada, 2007–2024

This data release contains mercury concentration measurements in fish and benthic macroinvertebrates collected from southwestern Idaho and northern Nevada between 2007 and 2024. The dataset primarily includes total mercury (Hg) concentrations in muscle tissue of rainbow trout (Oncorhynchus mykiss)—sampled from three reservoirs on the Duck Valley Reservation (Mountain View Reservoir, Lake Billy Shaw, and Sheep Creek Reservoir) during four sampling years (2007, 2009, 2013, and 2024). Additional data are provided for other commonly consumed fish species, including yellow perch (Perca flavescens), smallmouth bass (Micropterus dolomieu), and largemouth bass (Micropterus salmoides) when they were encountered as bycatch. Additional data is presented from Wild Horse Reservoir (sampled in 2007) and four sites on the Owyhee River (sampled in 2008) from Wild Horse Reservoir to the downstream extent of the Duck Valley Reservation. Lower trophic level samples include whole-body Paiute sculpin (Cottus beldingii) and composite macroinvertebrate taxa collected in 2008.

Fish samples were analyzed for total mercury using U.S. Environmental Protection Agency Method 7473 (thermal decomposition, amalgamation, and atomic absorption spectrophotometry). Macroinvertebrate samples were analyzed for total mercury and additional trace metals using acid digestion and hydride generation atomic absorption. Associated metadata include site locations, sampling dates, species, fish length and weight, and laboratory quality assurance/quality control information. These data support assessments of mercury exposure risk to human consumers and provide a baseline for evaluating spatial and temporal trends in mercury bioaccumulation in aquatic food webs of the Duck Valley Reservation and nearby waters.

Dataset credit: Sample collection and processing was made possible with assistance from Shoshone-Paiute Tribes. Sample analyses were donated in-kind by the U.S. Environmental Protection Agency Region 9 laboratory for samples collected in 2024.