From The Durango Herald (Dale Rodebaugh):
The monitor – atop an 8-foot-high platform – consists of a glass jar enclosed in a metal box, the roof of which retracts when a sensor detects precipitation. The sensor notes when it stops raining or snowing and the roof slides back to protect the jar from contaminants. Hydrochloric acid in the jar binds with the mercury to prevent it from evaporating. The jars are collected weekly and sent to Frontier GeoSciences in Seattle for analysis.
“After the mercury study by the Mountain Studies Institute in 2007 and 2008, we felt we should take a closer look,” [Bureau of Land Management hydrologist Kelly Palmer] said. “After all, we’re charged with protecting the pristine quality of Class 1 airsheds such as Mesa Verde and the Weminuche Wilderness.” Scientists suspect the main source of mercury is power plants in the Four Corners.
Over time, data on weekly and total mercury accumulation will give scientists a good picture of the situation in the San Juan Mountains and allow them to compare results with 120 similar sites in the country, including two in Alaska, Palmer said…
Later this summer, the Environmental Protection Agency will install an apparatus next to the mercury monitor to measure gaseous mercury, an airborne form of mercury that reacts rapidly with precipitation or particulate matter and can be deposited in wet or dry form. Roger Claybrooke, a meteorologist with the NADP, and a half-dozen BLM and Forest Service seasonal employees did the hands-on work June 30. In addition to installing the mercury monitor, they replaced an old rain gauge on a separate platform a few yards away. A third platform holds a monitor that measures sulfur, nitrogen and organic content in precipitation. The Claybrooke team also wired the instruments on the three stations to talk to one another. The rain gauge data should correlate with that of the mercury monitor on the amount of precipitation and when it fell.