Mining firm's studies show high level of chemical

Article Last Updated: 12/17/2005 01:55 AM

New tests, more alarm
By Judy Fahys
The Salt Lake Tribune
Salt Lake Tribune 

The deepest waters of the Great Salt Lake may contain even more toxic mercury than previously known. That's according to water tests done by Kennecott Utah Copper last summer, two years after samples that triggered alarms about mercury throughout Utah. 

  Kennecott's numbers are the highest experts have ever heard of for any open water in the United States. But the scientists and policymakers who have seen the newly released results say it's too soon to jump to conclusions. 

  They say the new numbers just confirm the need for greater understanding of mercury in the Great Salt Lake, and would like in-depth studies on why the levels are so high and what hazards the toxic methylmercury poses to people and the environment. 

  "I would say we have a fairly urgent need to know," said David Krabbenhoft, a U.S. Geological Survey scientist known as "Mr. Mercury" because of his expertise in mercury pollution. 

  Kennecott scientist Bill Adams cautioned against reading too much into the new numbers, the results of samples the company took while doing routine monitoring of its own impacts on the Great Salt Lake. The copper company, whose operations are not thought to be adding mercury to the lake, took more than two dozen samples and had a Seattle lab analyze them. 

  "There is a lot of work to be done," he said. 

  What Kennecott found is overall levels of mercury are high, just like in the samples taken by geochemists for the U.S. Geological Survey from the Great Salt Lake in 2003. 

  Mercury levels measured by Kennecott ranged from 2.7 to 96.6 nanograms per liter. 

For comparison, averages considered high in western Maryland lakes were generally between 5 and 10 nanograms per liter. The levels the Geological Survey found in 2003 in the Great Salt Lake were 50 or lower. 

  Even more interesting - and probably more worrisome - were the levels of toxic methylmercury the Kennecott tests showed. 

  When mercury is chemically transformed to methylmercury, it absorbs easily into living tissue and builds up in the food chain. It causes birth defects and death in birds and fish. In humans, high levels can cause brain and nervous system damage.
  Victims might experience nausea, muscle weakness and memory loss, but the likelihood of getting contaminated with Great Salt Lake methylmercury is considered very low because few people, if any, rely on on the lake for food or drinking water.
  Samples taken in shallow parts of the Great Salt Lake were high, between .58 and 7.4 nanograms per liter. But the samples taken in the lake's "deep brine layer," about 20 feet below the surface, were as high as 80.5. Krabbenhoft noted that .5 is considered a "level of substantial concern" in waters where there are fish. 

  Kennecott's Great Salt Lake numbers also stood out when scientists looked at the percentage of methylmercury to total mercury. The British Columbia environment agency in Canada says, basically, that aquatic life is safe when methylmercury levels are less than 5 percent of the total mercury. 

  Kennecott's four samples from the deep brine layer ranged from 51 percent to more than 91 percent. 

  "Any one of those numbers is extraordinarily high," said Krabbenhoft. 

  An expert on the chemical peculiarities of the Great Salt Lake, Kennecott's Adams noted - as did all the scientists called to comment on the latest data - that there are simply too few samples to draw any conclusions. 

  The new samples say little, if anything, about where the mercury is coming from, how it circulates in the Great Salt Lake ecosystem or how it's affecting the creatures that rely on the lake. He noted that brine shrimp Kennecott also tested this summer had levels well below the U.S. Environmental Protection Agency standard of 1 nanogram of mercury per gram of body weight. 

  "There's not," Adams concluded, "a looming crisis out there at the moment."
  Don Hayes, a civil and environmental engineering professor at the University of Utah, agreed snap judgments would be unwise. 

  He is part of a team of scientists developing standards for the Great Salt Lake, which is too salty to be compared with freshwater systems. 

  "There are a number of factors going on, and the lake is a very large and complex system," he said, suggesting the timing of the samples, the location of the samples and differences in sampling techniques could account for the different results.
  "It does say that mercury is there," he said. 

  Kennecott's new numbers come after a year of worrisome superlatives for Utah.
  In February, a Utah-based USGS geochemist and a federal biologist published a report that showed high numbers for mercury in the Great Salt Lake. 

  Over the summer, state wildlife, health and environment officials issued the state's first fish consumption alerts for three bodies of water. 

  Then, as the duck-hunting season got under way in October, the state warned hunters not to eat two species of ducks that spend time on the Great Salt Lake.
  State and federal scientists already are at work developing plans for how to tackle all the questions raised by the mercury identified in the unique Great Salt Lake ecosystem. The 15-member Statewide Mercury Work Group is zeroing in on what questions to ask and what science program is needed to answer them. 

  "We need to initiate a systematic study here to understand what's going on," said John Whitehead, who leads the group for the Utah Division of Water Quality.
Could the high mercury be seasonal? Is it coming from Nevada gold ore processors or drifting in from China? Does the Bear River carry mercury into the lake, or the Jordan or the Weber? Is it city runoff or industrial? No one can say yet.

 
  "So, there's a lot of possibilities there," Whitehead said. "We may never know all the answers." 

     HYPERLINK "http://farns9.iserver.net/imanager/wizards/mm_compose.cgi?mbox=&mpos=1&send_to=fahys@sltrib.com" \t "linkWin" fahys@sltrib.com
  Sources: U.S. Geological Society, Kennecott
   
What is mercury 

A heavy metallic chemical element that is liquid at normal temperatures. It has several industrial uses, including ore and metal processing.
How does it become methylmercury?
Mercury enters the environment, attaches to particles and combines with dissolved

organic carbon to form methylmercury.
Why are high levels of methylmercury a concern?
The most toxic form of mercury, it enters the food chain through algae, brine shrimp and other organic matter, which are eaten by birds or other animals.
What happens next?
More in-depth studies likely will be called for in an effort to better understand the

readings and mercury's interaction in the lake.