Laserfiche WebLink
Y <br /> Mid-Continent Resources'Stream Impairment Study 2 <br /> Stream Impairment Study <br /> of Aquatic Life at Dutch and Coal Creeks <br /> June and September, 1994 <br /> Abstract <br /> A stream impairment study was conducted during the summer of 1994 to determine the <br /> potential effects of the discharge below the 016 outfall from Mid-Continent Resources'Dutch Creek <br /> Mine. Field investigations were conducted during high flow (June) and low flow (September) <br /> periods. Water and sediments samples were collected at seven stations for chemical analyses of <br /> organic and inorganic parameters and to determine toxicity to aquatic invertebrates. Samples were <br /> also collected for macroinvertebrate community analysis and observations made of habitat <br /> characteristics. <br /> Chemical anlayses detected no significant levels of either organic or inorganic contaminants <br /> at any of the studied sites. All sites were free of trace metals except for zinc and lead which were at <br /> levels below concentrations toxic to aquatic organisms. <br /> Toxicity was found to Ceriodaphnia dubia only at those stations where the flow was entirely <br /> due to discharge from the 016 effluent. No toxicity was measured during the high flow period at a <br /> station (Site 4) which was just above the confluence of the discharge channel with Dutch Creek <br /> although toxicity was measured during the low flow period. No aquatic toxicity was found at <br /> stations below the confluence of the discharge channel with Dutch Creek. <br /> Habitat along the discharge channel was good except for problems due to embeddedness and <br /> sulfate content in the discharge stream. The high sulfate content resulted in a white precipitate which <br /> formed along the banks of the discharge channel. During low flow periods, this precipitate was also <br /> noted just below the confluence of the discharge channel with Dutch Creek (Site 5). Benthic <br /> macroinvertebrate communities along the discharge channel were markedly different from those at <br /> the other sites. While the highest numbers of organisms were counted at these stations, the diversity <br /> was low and made up primarily of chironomids. Overall, Biological Indices were much lower along <br /> the discharge channel than at other stations. Effects were more pronounced during the fall than <br /> during the spring. These effects were attributed to high sulfate and alkalinity levels and poor <br /> substrate conditions. <br /> Benthic communities at other stream stations along Coal and Dutch Creeks were <br /> characterized by sediment tolerant species. These stations tended to have lower numbers of <br /> organisms than Sites along the discharge channel but showed a higher diversity and biological index. <br /> Although there were significant differences in biological parameters between spring and fall along the <br /> discharge channel, differences were less evident at the other stations sampled. <br /> The SeaCrest Group <br />