Characterizing Aquatic Health Using Salmonid Mortality, Physiology, and Biomass Estimates in Streams with Elevated Concentrations of Arsenic, Cadmium, Copper, Lead, and Zinc in the Boulder River Watershed, Montana

Abstract

Abandoned tailings and mine adits are located throughout the Boulder River watershed in Montana. In this watershed, all species of fish are absent from some tributary reaches near mine sources; however, populations of brook trout Salvelinus fontitalis, rainbow trout Oncorhynchus mykiss, and cut‐throat trout O. clarki are found further downstream. Multiple methods must be used to investigate the effects of metals released by past mining activity because the effects on aquatic life may range in severity, depending on the proximity of mine sources. Therefore, we used three types of effects—those on fish population levels (as measured by survival), those on biomass and density, and those at the level of the individual (as measured by increases in metallothionein, products of lipid peroxidation, and increases in concentrations of tissue metals)—to assess the aquatic health of the Boulder River watershed. Elevated concentrations of Cd, Cu, and Zn in the water column were associated with increased mortality of trout at sites located near mine waste sources. The hypertrophy (swelling), degeneration (dying), and necrosis of epithelial cells observed in the gills support our conclusion that the cause of death was related to metals in the water column. At a site further downstream (lower Cataract Creek), we observed impaired health of resident trout, as well as effects on biomass and density (measured as decreases in the kilograms of trout per hectare and the number per 300 m) and effects at the individual level, including increases in metallothionein, products of lipid peroxidation, and tissue concentrations of metals.

Biomonitoring of Lead, Zinc, and Cadmium in Streams Draining Lead-Mining and Non-Mining Areas, Southeast Missouri, USA

“…Our approach was to conduct a comprehensive survey of metal concentrations in stream food webs, including plant biomass, aquatic invertebrates, and fish. Foodweb biomonitoring has proven to be a valuable component of research on the ecological effects of mining, as it provides information on spatial and temporal variation of metal levels, trophic pathways of metal exposure, and hazards of toxicity to fish and invertebrates (Besser et al, 2001;Farag et al, 1999;Farag et al, 2003). We determined concentrations of Pb, Zn, and Cd in samples collected in fall 2001 and fall 2002 from streams in the vicinity of the Viburnum Trend mining district and in the prospecting area.…”

Biomarkers of metals exposure in fish from lead-zinc mining areas of Southeastern Missouri, USA

“…Maximum liver Cd concentrations in our stoneroller and sunfish were substantially lower than those in the rainbow trout from the Boulder River site, which were about 100 mg/g dw. Our liver Zn maxima were somewhat lower than those from the Boulder River (Farag et al, 2003, which were about 200 mg/g dw, but maximum liver Pb concentrations in our fish of both species selected as ''high Pb'' (maxima 3.41-7.79 mg/g dw) were substantially greater (maxima o1.0 mg/g dw; Farag et al, 2003). The Boulder River fish, like those from the Clark Fork, had also been exposed to comparatively high Cu concentrations (Farag et al, 2003).…”

“…Our liver Zn maxima were somewhat lower than those from the Boulder River (Farag et al, 2003, which were about 200 mg/g dw, but maximum liver Pb concentrations in our fish of both species selected as ''high Pb'' (maxima 3.41-7.79 mg/g dw) were substantially greater (maxima o1.0 mg/g dw; Farag et al, 2003). The Boulder River fish, like those from the Clark Fork, had also been exposed to comparatively high Cu concentrations (Farag et al, 2003). Collectively, these results indicate that metals other than Pb caused the lipid peroxidation reported by Farag et al (1995Farag et al ( , 2003.…”

“…The Boulder River fish, like those from the Clark Fork, had also been exposed to comparatively high Cu concentrations (Farag et al, 2003). Collectively, these results indicate that metals other than Pb caused the lipid peroxidation reported by Farag et al (1995Farag et al ( , 2003.…”

“…Using similar methods, Farag et al (1995Farag et al ( , 2003 detected significantly (Po0.05) greater hepatic lipid peroxidation in brown trout (Salmo trutta) and rainbow trout from mining-contaminated sites on the Clark Fork River and in the Boulder River system of Montana than at reference sites. Liver Cd concentrations averaged about 2.5 mg/g dw and liver Pb about 1.0 mg/g dw in brown trout from the Clark Fork site, which are substantially lower than the concentrations in our stoneroller.…”