SACRAMENTO, Calif. -- Data collected by experts from the UC Davis School of Medicine have revealed that except for some heavily used areas, streams and lakes in the high country of the Sierra Nevada are generally clean and fresh.
The good news for campers can be found in a pair of studies published in the latest issue of the quarterly medical journal Wilderness and Environmental Medicine. UC Davis physician Robert Derlet and pathology researcher James Carlson present data gathered from nearly 100 locations throughout the
Running counter to popular belief, the two researchers downplay the risk of picking up Giardia in backcountry drinking water. In the
"What's impressive is that more than half of our water sampling sites had no water quality problems whatsoever," said Derlet, a professor of emergency medicine at the UC Davis School of Medicine and an avid backpacker with 30 years of experience hiking in
Derlet has spent the past five years on water quality studies in the
"For these two studies, we looked at nearly 100 streams and lakes over the 400-mile long mountain range," observed Derlet, who has given presentations to wilderness rangers about infectious diseases and backcountry medicine. "We've also analyzed water at many more
The UC Davis physician says his studies are only a snapshot in time, and that all streams and lakes tested in wilderness areas typically contain a certain amount of naturally occurring aquatic bacteria. Low levels of coliform bacteria actually can be part of the natural environment. If bacteria were not present in the water, it would jeopardize the balance of the aquatic ecosystem, including everything from frogs to fish.
Currently working with renowned
* Lakes are typically 'cleaner' than creeks, possibly because the ultraviolet rays of sunlight work better at killing off bacteria in calm waters of a lake than in the tumbling flows of a stream;
* Algae growth in backcountry waterways appears to be getting worse;
* Bacteria readings appear higher at the beginning of spring runoff rather than later in the summer when water levels are lower and water quality is thought to be poorer;
* Valley air pollution could be contributing to water quality problems in the
Source: UC Davis