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alkaline fly ash that is subsequently removed by a fabric filter bag house (EPRI 2008). <br /> Nevertheless, combustion of coal at the Craig Generating Station could result in some amount of <br /> selenium moving beyond pollution control processes, being emitted, and subsequently deposited <br /> on the landscape. <br /> 4.2 Effects to Endangered Fish <br /> 4.2.1 Mercury <br /> Mercury is an environmental contaminant that can have adverse effects on riparian and aquatic <br /> wildlife (Scheuhammer et al. 2012; Wentz et al. 2014). Elevated levels of mercury in living <br /> organisms in mercury-contaminated areas may persist for as long as 100 years after the source of <br /> pollution has been discontinued (Eisler 1987). Eisler(1987, p. iii) states: <br /> Most authorities agree on six points: (1) mercury and its compounds have no known <br /> biological function, and the presence of the metal in the cells of living organisms is <br /> undesirable and potentially hazardous; (2)forms of mercury with relatively low toxicity can <br /> be transformed into forms of very high toxicity, such as methylmercury,through biological <br /> and other processes; (3) mercury can be bioconcentrated in organisms and biomagnified <br /> through food chains; (4) mercury is a mutagen,teratogen, and carcinogen, and causes <br /> embryocidal, cytochemical, and histopathological effects; (5) some species of fish and <br /> wildlife contain high concentrations of Hg that are not attributable to human activities; (6) <br /> anthropogenic use of Hg should be curtailed, as the difference between tolerable natural <br /> background levels of Hg and harmful effects in the environment is exceptionally small. <br /> Aquatic systems receive mercury by direct deposition from the atmosphere and from overland <br /> transport from within the watershed (EPA 1997). Mercury primarily enters aquatic systems in an <br /> inorganic form where it can adsorb to suspended solids and settle to the bottom (EPA 1997). It <br /> can also be photo reduced in the upper few centimeters of the water's surface and then evade to <br /> the atmosphere. RGM at the sediment water boundary can be transformed into McHg by <br /> sulfate-reducing bacteria, but this process can also go the other direction, depending on <br /> site-specific conditions. The most important areas for methylation are anoxic areas of the <br /> aquatic environment, such as wetlands or poorly mixed aquatic areas. The vast majority of <br /> mercury in fish tissue is in the form of McHg (EPA 1997). Rates of methylation processes and <br /> bioaccumulation typically vary and depend on many factors. <br /> The potential effects of mercury on fish are numerous. Lusk(2010) describes the potential <br /> affects as: <br /> 1. Potent neurotoxin: <br /> a. Affects the central nervous systems (reacts with brain enzymes,then lesions); <br /> b. Affects the hypothalamus and pituitary, affects gonadotropin-secreting cells; <br /> c. Altered behaviors: Reduced predator avoidance, reproduction timing failure; <br /> d. Reduced ability to feed (emaciation and growth effects). <br /> 2. Endocrine disruptor <br /> a. Suppressed reproduction hormones in male and female fish; <br /> b. Reduce gonad size and function, reduced gamete production; <br /> 48 <br />