Warnings will be posted for Las Vegas Wash, Lake Mead water

      Signs warning people that water in Las Vegas Wash and part of Lake Mead's Las Vegas Bay is unfit for swimming or body contact will be posted by the end of next month, a National Park Service biologist said Thursday.
      Wildlife biologist Bill Burke said his agency decided to post the shoreline because of heightened awareness this year about water quality problems in the wash stemming from urban runoff and treated sewage discharges from three plants.
      He said up to eight signs that say, "Notice: The water contains contaminants from urban areas and treated sewage," will be posted at access points from where Las Vegas Wash flows beneath the North Shore Road bridge to about a mile downstream from where the wash enters Las Vegas Bay and for about another half-mile along the bay's western shoreline below Las Vegas Bay Campground.
      "We at least want to post it to let people know what the source of this water is," Burke said following Thursday's multi-agency Water Quality Forum, where he made the announcement.
      His announcement follows the latest water monitoring reports from wastewater dischargers that show fecal coliform bacteria in the wash at the North Shore Road bridge was not fit for body contact on 19 or 26 monitoring days last year, even though water released by the plants upstream met or exceeded water-quality guidelines for fecal coliform.
      Because of the potential for contamination from uncontrolled, natural sources, the state has no bacteriological standards for natural bathing areas, such as Lake Mead. Only swimming pools are regulated.
      Fecal coliform can be an indicator that pathogens might have evaded disinfection at sewage treatment plants. But in this case, officials for sewage treatment plants that monitor water quality in the wash and Lake Mead said the elevated levels probably stem from wildlife along the wash and pets and humans who defecate and urinate near storm runoff channels.
      State environmental officials have designated the wash and the western boundary of Las Vegas Bay Campground as an area for no contact with the water but over the years no warning signs had been posted. The designation stems from the use of the wash as a channel for treated effluent.
      Forum members also discussed a recent bloom of algae in Las Vegas Bay that could have toxic effects on fish as this type of plant life, known as blue-green algae, dies off. When it comes in contact with fish gills, it can release a neurotoxin that affects their ability to breath.
      Biologist Larry Paulson, a water quality consultant, said last week's warm weather, calm conditions and the presence of nutrients discharged into Las Vegas Bay made it ripe for what's known as a freshwater version of red tide. A similar condition in 1972 did not kill fish, he said, noting that warm conditions next month could accelerate the algae bloom that has stained the bay with a reddish-brown color. Some of the algae with red pigments can migrate throughout the lake.
      Peggy Roefer, microbiology supervisor for the Southern Nevada Water System, said most samples collected Sunday turned up blue-green algae. In all, the counts were 467,000 algae cells per milliliter, of which all but 10,000 cells were blue-green. She said the system that delivers drinking water from the lake to Las Vegas Valley probably won't be affected as the algae bloom dies off because the treatment process can be adjusted to compensate for any undesirable tastes or smells that might result.
      Gail Kaiser, who operates Las Vegas Bay Marina, said the bloom has had "a great effect on business."