Editorial: Mercury rising?

Saturday, Feb. 17, 2007 | 7:16 a.m.

A new UNR study suggests that the airborne mercury levels near Nevada's gold mines are higher than previously thought and also could exist in tailings, rock dumps and leech heaps - areas not required for testing under state emissions reporting requirements enacted last year.

According to a story by the Las Vegas Sun on Wednesday, mercury levels outside four of the 10 mines tested were five times higher than the amount of mercury that occurs in the environment naturally. Levels at three other mines were significantly higher than that - including readings taken a mile away from one mine that showed mercury levels at twice the federal limits for toxic exposure. Mercury levels were at or below naturally occurring thresholds at the three remaining mines.

Mercury is released during gold refining. The study released this week was done by a UNR natural resource and environmental science professor using a relatively inexpensive, off-the-shelf mercury analyzer - a model that has received high accuracy marks from the Environmental Protection Agency, the Sun's Lisa Mascaro reports. Readings were taken outside the gates of the mines, in parking lots and on access roads.

However, the study also monitored mercury levels near active leech heaps, which are not measured under state requirements. Levels there were, in some cases, 12 times higher than naturally occurring levels, the Sun reports. Conservationists say mercury emissions have poisoned fish and waterfowl in Idaho and Utah - toxins that also could settle in Nevada. The UNR report shows downwind concentrations are higher than those upwind from the mines and recommends that mine leech heaps, tailings and rock dumps also be tested.

Last March the Nevada Environmental Commission required that mines monitor and test for airborne mercury emissions and report their findings to the state annually. At the time, Nevada regulators and mining industry officials told the Sun that no link had been proved between Nevada's mines and mercury levels in neighboring states. However, that doesn't mean there is no link, Nevada Environmental Protection Division Administrator Leo Drozdoff also said at the time, adding that "much more research needs to be done."

In a March editorial, the Sun called for the state to conduct such research. While this latest UNR study isn't as comprehensive as what we would like to see from the state, it does suggest that mercury levels are far higher than what has been reported and are emitted into the environment in other parts of the mining process that currently are not tested.

Dante Pistone of the Nevada environmental protection division told the Sun that the state doesn't see a need to require more frequent and varied testing of mercury emissions. Clearly, the UNR study suggests that the opposite may be true. State environmental protection officials should be taking the mercury contamination risk more seriously and studying it more closely.