Geology topics

Trevor M. Selch

Publications and source records attributed to Trevor M. Selch.

5 recordsLinked to original sources

USGS2026

Selenium and mercury tissue partitioning and trophodynamics in the Lake Koocanusa (USA–Canada) fish community

Mining-related contaminants such as selenium (Se) and mercury (Hg) accumulate in aquatic organisms and transfer through aquatic food webs, where they can exert toxic effect undermining the ecological health of aquatic resources. Yet, how Se and Hg co-distribute within food webs and within individual organisms remains poorly understood. We compiled muscle and ovary Se and Hg concentration data from fishes captured in Lake Koocanusa—a North American reservoir receiving elevated Se and Hg inputs from coal mining operations in the Elk River Valley, Canada—to provide insights into the co-processing of Se and Hg within fish and among fish species, including how ecological or seasonal factors shift these distribution patterns. Se and Hg concentrations (ranges: 0.21–38.7 μg Se g −1 dry weight and 0.01–0.84 μg Hg g −1 wet weight), as well as Se:Hg molar ratios, varied substantially between tissues and among species, reflecting biological and ecological differences. Our results suggest that the decoupling of Se or Hg deposition in fish muscle versus ovary may reflect different pathways of impairment, at the individual and population levels, and that interspecific and tissue-specific variability makes it challenging to set a universal Se:Hg threshold for the protection of aquatic organisms.

British Columbia, Montana↗

USGS2025

Preparation and analysis methods for fish tissue collected from Lake Koocanusa, Montana

Lake Koocanusa, a reservoir, receives mine wastes from metallurgical coal mines in the Elk River Valley of British Columbia, Canada. Selenium and other elements discharged by the mines into the waters of the United States can pose unknown risks to aquatic life. The U.S. Geological Survey Wyoming-Montana Water Science Center can collaborate with Montana Fish, Wildlife and Parks and other State and Federal agencies to design studies and to collect fish tissues to help fill this knowledge gap. This report describes the processes, techniques, and methods used to collect and analyze fish tissue collected from Lake Koocanusa; and procedures used to review and manage data, including quality assurance and quality control procedures used by the U.S. Geological Survey Wyoming-Montana Water Science Center and supporting analytical laboratories. These fish tissue collections began in 2021.

Montana↗

USGS2019

Influence of season, sex, age and diet composition on mercury concentration in Walleye Sander vitreus

We collected Walleye Sander vitreus (May–October) from Bitter and Twin lakes, South Dakota to assess seasonal- and diet-related variation in tissue mercury (Hg) concentration. The average Hg concentration in Walleye was 43–68% higher in the spring for Bitter ( p < 0.008) and Twin Lakes ( p < 0.017) compared with summer or autumn months. Bioenergetics analysis of Bitter Lake Walleye showed that consumption of fish prey (primarily Fathead Minnow Pimephales promelas ) increased from late summer through winter and was linked to increased Hg accumulation in Walleye the following spring. Mercury concentration varied significantly with Walleye age but was similar for comparably-aged male (0.62 μg/g) and female fish (0.62 μg/g). However, after adjusting for Walleye size (total length, mm), mean Hg concentration was greater in male (0.66 μg/g) compared with female (0.50 μg/g) fish, likely due to slower growth rate of male Walleye. At 425 mm, male Walleye in Bitter Lake were approximately 1 year older than female fish. These findings show that diet, age, and gender-related growth affect Hg concentration in Walleye and are important factors to consider in fish contaminant monitoring programs.

South Dakota↗

USGS2019

Application of multistate modeling to estimate salmonid survival and movement in relation to spatial and temporal variation in metal exposure in a large mining-impacted river

We used telemetry and multistate modeling to estimate survival and movement of brown trout Salmo trutta and westslope cutthroat trout Oncorhynchus clarkii lewisi in relation to dissolved copper concentrations in 189 km of the upper Clark Fork River, Montana, a mining-impacted river in western Montana. Annual survival estimates for both brown trout (range, 0.27-0.53) and westslope cutthroat trout (range, 0.001-0.34) over the three-year study were low and variable within the study area, with survival negatively related to level of copper exposure. Survival probability for brown trout and westslope cutthroat trout in the uppermost river segment, where dissolved copper concentrations frequently exceeded acute criteria for aquatic life (range, 31-60 d >13.4 µg·L-1), was 2.1 times and 122 times lower, respectively, compared to survival rates in the lowermost segment that had relatively low dissolved copper (0 d exceedance of acute concentration). Seasonal differences in survival also appeared to be related to copper exposure level. Lowest survival for both species occurred in the spring-summer period when dissolved copper concentrations were elevated coincident with higher discharge. Movement among study segments was generally low, and cutthroat trout in particular showed low movement into the uppermost river segment with the most elevated copper levels. Both species showed high rates of movement into tributaries, which coincided with their respective spawning migrations rather than as an apparent avoidance of elevated copper levels. Our research design provided an uncommon opportunity to directly relate the degree of contaminant exposure to estimates of fish survival and movement at a population-level over a large spatial scale. This linkage between survival rate and level of copper exposure for both brown trout and cutthroat trout in the upper Clark Fork River suggests that additional removal of tailings deposits could improve survival rates.

Montana↗

USGS2013

Fate of geothermal mercury from Yellowstone National Park in the Madison and Missouri Rivers, USA

Mercury is a worldwide contaminant derived from natural and anthropogenic sources. River systems play a key role in the transport and fate of Hg because they drain widespread areas affected by aerial Hg deposition, transport Hg away from point sources, and are sites of Hg biogeochemical cycling and bioaccumulation. The Madison and Missouri Rivers provide a natural laboratory for studying the fate and transport of Hg contributed by geothermal discharge in Yellowstone National Park and from the atmosphere for a large drainage basin in Montana and Wyoming, United States of America (USA). Assessing Hg in these rivers also is important because they support fishery-based recreation and irrigated agriculture. During 2002 to 2006, Hg concentrations were measured in water, sediment, and fish from the main stem, 7 tributaries, and 6 lakes. Using these data, the geothermal Hg load to the Madison River and overall fate of Hg along 378 km of the Missouri River system were assessed. Geothermal Hg was the primary source of elevated total Hg concentrations in unfiltered water (6.2–31.2 ng/L), sediment (148–1100 ng/g), and brown and rainbow trout (0.12– 1.23 µg total Hg/g wet weight skinless filet) upstream from Hebgen Lake (the uppermost impoundment). Approximately 7.0 kg/y of geothermal Hg was discharged from the park via the Madison River, and an estimated 87% of that load was lost to sedimentation in and volatilization from Hebgen Lake. Consequently, Hg concentrations in water, sediment, and fish from main-stem sites downstream from Hebgen Lake were not elevated and were comparable to concentrations reported for other areas affected solely by atmospheric Hg deposition. Some Hg was sequestered in sediment in the downstream lakes. Bioaccumulation of Hg in fish along the river system was strongly correlated (r 2 =0.76–0.86) with unfiltered total and methyl Hg concentrations in water and total Hg in sediment.

Montana, Wyoming↗