Mercury vapor plumes

The parameters which control the dispersion of mercury vapor plumes still require definition. No plume from an industrial source was tracked... 

The use of high-sensitivity, portable, rapid-response gas-analyzing equipment has led to the detection of several previously unknown elemental mercury plumes associated with both natural and industrial sources. In Northern California these anomalies were detected in a brief reconnaissance program and hence represent only a sampling of the mercury vapor plumes likely to exist in the area. An inventory of elemental mercury plumes can be obtained in any area by using a high-sensitivity, portable, rapid-response mercury detector mounted in a mobile laboratory for measurement while in motion. 

Only elemental mercury vapor was measured. Thus, these data alone cannot be taken as a guide to the total mercury content in the air. The rapid disappearance of the anomalous plumes may reflect not just the dispersion or deposition of the mercury but also the chemical combination of the elemental form into a combined form undetectable by the instrumentation. The rapid disappearance of the Berkeley plume as it blew across the freeway may indicate a chemical reaction catalyzed by the exhaust emissions from the freeway traflSc. 

The measurements in Richmond indicate that the dispersal pattern of mercury vapor is similar to that of any other effluent gas. Because of the availability of roads it was possible to map the distribution pattern of this plume for over a mile. 

After the large eruption of Mount St. Helens in 1980, gas samples from the volcano were taken by sampling the downwind gas plume. The unfiltered gas samples were passed over a gold-coated wire coil to absorb mercury (Hg) present in the gas. The mercury was recovered from the coil by heating it and then analyzed. In one particular set of experiments scientists found a mercury vapor level of 1800 ng of Hg per cubic meter in the plume at a gas temperature of 10 "C. Calculate (a) the partial pressure of Hg vapor in the plume, (b) the number of Hg atoms per cubic meter in the gas, (c) the total mass of Hg emitted per day by the volcano if the daily plume volume was 1600km. ... 

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