Mercury and selenium in fish of Fountain Creek, Colorado (USA): possible sources and implications

Abstract

Fountain Creek in Colorado USA is a major tributary that confluences with the Arkansas River at Pueblo, Colorado, the result being the tributary’s influence on Arkansas River water quality affecting down-stream users. In a previous study, we found that bryophytes (aquatic plants) accumulated selenium in Fountain Creek watershed and this finding prompted us to investigate the extent of the metalloid in the whole-body tissues of fish. One hundred 11 fish (six species) were collected and analyzed for Se by inductively-coupled plasma emission mass spectrometry. Analysis of all analytical data also showed mercury in all of the fish whole bodies and selected tissues. There was a general increase in selenium but a decrease in mercury in fish with downstream travel-distance. The highest whole-body selenium was in Pueblo, Colorado (3393 µg/kg, dry weight; 906 µg/kg, wet weight); the highest mercury in fish was in the Monument Creek tributary north of Colorado Springs, Colorado (71 µg/kg, dry weight; 19 µg/kg, wet weight). In four tissues of 11 female fish captured, selenium was highest in the livers at eight sites but highest in the ovaries at three sites. Mercury was highest in the epaxial muscle at all sites. Selenium availability could be due to the watershed lithology and land uses; however, mercury could be carried by atmospheric deposition from coal-fired power plants and historic mining activities. Selenium in fish tissues and water samples were compared to U.S. national water quality criteria.

Mercury and Selenium in Twelve Cutthroat Trout Tissues from High‐Elevation Colorado Lakes, USA: Intraspecific and Interspecific Comparisons

“…In the Nimmo et al. () study, Brown Trout muscle and liver had concentrations of 66.6 and 66.3 μg/kg ww, respectively; in our study, mean muscle and liver concentrations were also closely paired, with the three means ranging from 49.86 to 65.00 μg/kg ww (Table ). In a similar study of THg concentrations in 12 tissues of Brown Trout from upper Fountain Creek, Herrmann et al.…”

“…The THg ww concentrations of four tissues (ovary, skin, muscle, and liver) for 11 females of five warmwater and one coldwater fish species from an urbanized, high‐gradient Colorado Front Range stream (three reaches of Fountain Creek) were reported by Nimmo et al. (); muscle had the highest concentration in all, ovary had the lowest concentration in all, and skin and liver had intermediate values. The mean muscle concentration for all females of the six species was 63.7 ± 30.5 μg/kg ww (mean ± SD); the epaxial muscle concentrations (mean ± SD) in Cutthroat Trout from our three lakes were 63.05 ± 33.27 μg/kg ww at GRSA, 63.93 ± 23.03 μg/kg ww at ROMO, and 49.86 ± 22.67 μg/kg ww at TRAP.…”

“…() and Nimmo et al. () are notable exceptions by reporting Se levels for 4–12 tissues. In ovary/egg and liver tissues of Brown Trout from urbanized Fountain Creek, mean Se levels were 8,514 and 15,393 μg/kg dw, respectively; all other tissues in Brown Trout had Se levels no greater than 7,586 μg/kg dw.…”

“…; Nimmo et al. ). In the present study, we attempted to answer the following questions: (1) “How are THg and Se differentially accumulated and distributed among 12 internal and external tissues of wild Cutthroat Trout from three presumably pristine lakes in the montane and subalpine zones of Colorado?”; (2) “What were the baseline concentrations of THg and Se in 12 Cutthroat Trout tissues during the period 2010–2012 from three remote, high‐elevation lakes, and how did they vary compared to other Cutthroat Trout and Brown Trout populations?”; and (3) “How did Se : Hg molar ratios vary among the 12 tissues at each site and collectively and with other trout ratios?” We hypothesized that both THg and Se would bioaccumulate differentially in Cutthroat Trout by tissue type and would occur in a similar rank order regardless of site location, with THg bioaccumulating most in kidney and Se bioaccumulating most in liver.…”

Selenium Speciation in the Fountain Creek Watershed (Colorado, USA) Correlates with Water Hardness, Ca and Mg Levels

“…Fountain and Monument Creeks were sampled for dissolved Se in the past [ 3 , 4 , 18 , 19 , 21 , 37 , 44 , 45 , 46 ]. High levels of Se were reported (3.4–12 µg/L) [ 3 ] with up to 64 µg/L [ 3 ] between Colorado Springs and Pueblo, Colorado.…”