Mercury (Hg) was examined in top-predator fish, bed sediment, and water from streams that spanned regional and national gradients of Hg source strength and other factors thought to influence methylmercury (MeHg) bioaccumulation. Sampled settings include stream basins that were agricultural, urbanized, undeveloped (forested, grassland, shrubland, and wetland land cover), and mined (for gold and Hg). Each site was sampled one time during seasonal low flow. Predator fish were targeted for collection, and composited samples of fish (primarily skin-off fillets) were analyzed for total Hg (THg), as most of the Hg found in fish tissue (95–99 percent) is MeHg. Samples of bed sediment and stream water were analyzed for THg, MeHg, and characteristics thought to affect Hg methylation, such as loss-on-ignition (LOI, a measure of organic matter content) and acid-volatile sulfide in bed sediment, and pH, dissolved organic carbon (DOC), and dissolved sulfate in water. Fish-Hg concentrations at 27 percent of sampled sites exceeded the U.S. Environmental Protection Agency human-health criterion of 0.3 micrograms per gram wet weight. Exceedances were geographically widespread, although the study design targeted specific sites and fish species and sizes, so results do not represent a true nationwide percentage of exceedances. The highest THg concentrations in fish were from blackwater coastal-plain streams draining forests or wetlands in the eastern and southeastern United States, as well as from streams draining gold- or Hg-mined basins in the western United States (1.80 and 1.95 micrograms THg per gram wet weight, respectively). For unmined basins, length-normalized Hg concentrations in largemouth bass were significantly higher in fish from predominantly undeveloped or mixed-land-use basins compared to urban basins. Hg concentrations in largemouth bass from unmined basins were correlated positively with basin percentages of evergreen forest and also woody wetland, especially with increasing proximity of these two land-cover types to the sampling site; this underscores the greater likelihood for Hg bioaccumulation to occur in these types of settings. Increasing concentrations of MeHg in unfiltered stream water, and of bed-sediment MeHg normalized by LOI, and decreasing pH and dissolved sulfate were also important in explaining increasing Hg concentrations in largemouth bass. MeHg concentrations in bed sediment correlated positively with THg, LOI, and acid-volatile sulfide. Concentrations of MeHg in water correlated positively with DOC, ultraviolet absorbance, and THg in water, the percentage of MeHg in bed sediment, and the percentage of wetland in the basin.
At its Aug. 19 meeting, the authority’s board of directors discussed water conservation in response to a recent letter written by six major Front Range water providers to the Colorado Water Conservation Board and Interbasin Compact Committee which addressed several topics related to filling Colorado’s “water supply gap.”
“Right now, nobody’s worried about conservation because it’s been raining,” said Dana Duthie, general manager of Donala Water and Sanitation District.
Most water providers in the authority, however, rely on non-renewable aquifer water, which is unaffected by rain. Duthie added, water rationing will become more attractive to consumers when rates start going up. Water rates will have to be raised by two to four times what they are now for that to work, said Monument Public Works Director Rich Landreth.
Bids for aerial spraying of 1,500 acres of tamarisk between Holly and the Kansas border came in at half the cost that was expected. “It gives us great encouragement that something can be done,” County Commissioner Henry Schnabel said. “It’s left us scrambling to find more acres.” Schnabel was addressing the Lower Arkansas Valley Water Conservancy Board, which earlier had contributed $10,000 to the project. The county, working with several other agencies that have put about $260,000 toward the project, was expecting to pay $160 per acre for the spraying. Instead, the bids were opened Monday and Tri-Rotor Helicopter Spraying of Ulysses, Kan., bid just $85.49 an acre for the service. The company guaranteed an 85-percent kill rate and can tailor the spraying to avoid cottonwoods along the river, Schnabel said. “The spraying is critical on that reach, because the tamarisk is so tall that Holly would flood if there were another 1965-type flood,” Schnabel said.
Across the state line, Kansas also is killing tamarisks as part of the effort.
Proceeds will benefit the Blue River Restoration Fund used to construct fish habitat enhancement structures, expand public access areas and maintain the Lower Blue’s Gold Medal Trout designation. Two Colorado-based bluegrass bands — Head for the Hills and Spring Creek — will perform on the Silverthorne Pavilion lawn on Aug. 28 at 6 p.m. Spring Creek will take the stage around 8 p.m.
Fowler wants to use a patented process that uses single-cell algae to put oxygen into the water, rather than mechanical processes typically used in lagoons, said Wayne Snider, town administrator. Fowler has nine lagoons and will spend about $15,000 on the pilot program by BiO2 Solutions [Ed. website is still under construction.].
iO2 is using a patented process developed by Lonnie Losh, who said he stumbled across the idea while dealing with wastes from his family’s cattle and hog operations near Strasburg, east of Denver. “What we have come up with is a reliable way to treat lagoon waste and return it to the river,” said Losh, president and co-founder of BiO2. Losh said the algae used in his process do not form the filmy layer sometimes associated with algae in ponds, but penetrate the water more deeply to improve oxygenation. Losh partnered with wastewater treatment engineers to expand the treatment to municipal or industrial systems as well as agriculture. The algae, which are grown in greenhouses and mixed into ponds through diffusion equipment, improved oxygen levels above state standards, reduced ammonia concentrations and lowered costs 80 percent in trials at Wray, Guthrie said. The system could also improve how communities such as Fowler use their water, since discharges from lagoons could be year-round instead of annually.
…in a move uranium-mine opponents fear might prove Powertech is trying to skirt around clean-water standards, the company Wednesday asked state Division of Reclamation, Mining and Safety, or DRMS, officials to allow it to change original water-quality information for the mine site while uranium is being mined…
Before mining begins, the law requires Powertech to collect “baseline” water quality data, or information on the state of the water before it is contaminated by mining, then restore the water to that same quality after mining ends. In comments sent to the state Aug. 12, Powertech officials wrote it should be able to revise its baseline water quality data during the mining process “if new water-quality information comes to light” as an effect of mining. Powertech President Richard Clement said Thursday geology varies in a mining area, and it might be necessary to present the state with new information about the original water quality at the mine that could change the company’s groundwater restoration plan.
“Powertech is still making arguments to undermine groundwater quality protections,” said Matt Garrington of Environment Colorado. “They asked the Mining Division yesterday to be able to move the standard for groundwater during the mining project. They’re still making that argument in this process, and it’s crazy.”
“I’m not sure of their intent in the long term,” said Colorado Mined Land Reclamation Office Director David Berry. “Our intent would be information can no longer be baseline if it’s disturbed by an operation. We’re pretty steadfast in that.”
A day after making its argument, Powertech reversed its opinion. “It was made very clear by the DRMS that they determined that the issue has been established, so we have no further objection,” Clement said Thursday.
Powertech also quibbled with the state’s definition of the surface and groundwater the company might affect with its uranium mining. The rule the state is writing says potentially affected surface and groundwater includes the water found on the land at the mining site and “in surrounding areas.” In its comments to the state, Powertech called that definition “amorphous.”