Mercury in the atmosphere

Landis MS, Vette AF, Keeler GJ. 2002. Atmospheric mercury in the Lake Michigan Basin influence of the Chicago/Gary urban area. Environ Sci Technol 36(13) 3000-3009. 

Ames, M., Gullu, G. and Olmez, I. (1998) Atmospheric mercury in the vapor phase, and in fine and coarse particulate matter at Perch River, New York. Atmos. Environ., 32,865-872. 

Keeler GJ, Hoyner ME, Lamborg CH. 1994. Measurements of atmospheric mercury in the Great Lakes basin. In Watras CJ, Huckabee JW, eds. Mercury pollution integration and synthesis. Boca Raton, Florida Lewis Publishers, 231-241. 

Valente RJ, Shea C, Humes KL, Tanner RL (2007) Atmospheric mercury in the Great Smoky Mountedns compared to regional and globed levels. Atmos Environ 41 1861-1873... 

A mercury barometer. This is the type of barometer first constructed by Torricelli. The pressure of the atmosphere pushes the mercury in the dish to rise into the glass tube. The height of the column of mercury is a measure of the atmospheric pressure. 

The apparatus shown in Figure 4-2C differs in that the right-hand tube is open. In this type of manometer, atmospheric pressure is exerted on the right-hand mercury column. Hence the pressure in the flask plus the height of the mercury column equals atmospheric pressure. In the example shown, the pressure is 755 — 650 = 105 mm, the same as pictured in the closed-end manometer, Figure 4-2B. 

We want to find the relation between the height, h, of the column of mercury in a barometer and the atmospheric pressure, P. Suppose the cross-sectional area of the column is A. The volume of mercury in the column is the height of the cylinder times this area, V = bA. The mass, ttt, of this volume of mercury is the product of mercury s density, d, and the volume so m = dV = dhA. The mercury is pulled down by the force of gravity and the total force that its mass exerts at its base is the product of the mass and the acceleration of free fall (the acceleration due to gravity), g F = mg. Therefore, the pressure at the base of the column, the force divided by the area, is... 

The height of the mercury in the system-side column of an open-tube mercury manometer was 10. mm above that of the open side when the atmospheric pressure corresponded to 756 mm of mercury and the temperature was 15°C. What is the pressure inside the apparatus in millimeters of mercury and in pascals ... 

A student attaches a glass bulb containing neon gas to an open-tube manometer (refer to Fig. 4.5) and calculates the pressure of the gas to be 0.890 atm. (a) If the atmospheric pressure is 762 Torr, what height difference between the two sides of the mercury in the manometer did the student find ... 

When Robert Boyle conducted his experiments, he measured pressure in inches of mercury (inHg). On a day when the atmospheric pressure was 29.85 inHg, he trapped some air in the tip of a J-tube (1) and measured the difference in height of the mercury in the two arms of the tube (/ ). When b =... 

While the natural exchange of mercury between the land and atmosphere and the atmosphere and oceans is balanced, human activity has tipped this balance. There is now about three times more mercury in the atmosphere and fluxes of more than four times to and from the atmosphere. 

The average residence times for mercury in the atmosphere, terrestrial soils, oceans, and oceanic sediments are approximately 1 yr, 1000 yr, 3200 yr, and 2.5 x 10 yr, respectively. (See Bergan et al. (1999) for more details on atmospheric residence times.)... 

The air around us is a huge reservoir of gas that exerts pressure on the Earth s surface. This pressure of the atmosphere can be measured with an instmment called a barometer. Figure 5 shows a schematic view of a simple mercury barometer. A long glass tube, closed at one end, is filled with liquid mercury. The filled tube is inverted carefully into a dish that is partially filled with more mercuiy. The force of gravity pulls downward on the mercury in the tube. With no opposing force, the mercury would all ran out of the tube and mix with the mercury in the dish. 

The mercury does fall, but the flow stops at a fixed height. The column of mercury stops falling because the atmosphere exerts pressure on the mercury in the dish, pushing the column up the tube. The column is in balance when the height of the mercury column generates a downward force on the inside of the tube that exactly balances the force exerted by the atmosphere on the outside of the tube. 

Keeler GJ, Glinsom G, Pirrone N. 1995. Particulate mercury in the atmosphere its significance, transport, transformation and sources. Water Air Soil Pollut 80 159-168. 

Lindberg SE, Brooks SB, Lin C-J, Scott KJ, Landis MS, Stevens RK, Goodsite M, Richter A. 2002. The dynamic oxidation of gaseous mercury in the Arctic atmosphere at polar sunrise. Environ Sci Technol 36 1245-1256. 

Wildlife indicators of mercury exposure and trends are important elements of a comprehensive approach to assess mercury in the environment and the monitoring of trends that may assist regulators and the regulated community in long-term evalnation of the need and usefulness of mercury somce controls. It is important to understand, however, that bioindicator data alone are insufficient to answer snch critical qnestions as identification of mercniy sonrces, or the relative importance of local, regional, and global inputs of mercury somces to atmospheric deposition and errvirorrmerrtal loading in specific areas. 

A manometer is a device employing the change in liquid levels to measure gas pressure differences between a standard and an unknown system. For example, a typical mercury manometer consists of a glass tube partially filled with mercury. One arm is open to the atmosphere and the other is connected to a container of gas. When the pressure of the gas in the container is greater than atmospheric pressure, the level of the mercury in the open side will be higher and... 

However, when the pressure of the gas is less than atmospheric pressure, the level of the mercury in the side connected to the gas will be higher, and... 

Roos-Barraclough F, Martinez-Cortizas A, Garcia-Rodeja E, Shotyk W (2002) A 14 500 year record of the accumulation of atmospheric mercury in peat volcanic signals, anthropogenic influences and a correlation to bromine accumulation. Earth Planet Sci Lett 202 435 -51... 

Generally, cyclohexyne is an unstable molecule because of its ring strain. However, it can be stabilized by coordination to transition metals.35 The reduction of 1,2-dibromocyclohexene by sodium/mercury in the presence of a nickel-bromide complex afforded the Ni-alkyne complex 66 as a thermally stable and isolable compound (Scheme 22).36 Complex 66 smoothly reacted with C02 under atmospheric pressure to give nickelacycle 67 in good yield. Dimethyl acetylenedicarboxylate was inserted into the vinyl-nickel bond in 67 to give the seven-membered oxanickelacycle 68. 

Much of the Hgt pool was found in the upper part of the soil, which is rich in organic matter. This pattern is likely due to an elevated atmospheric deposition of Hgt over the extended period and immobilization of mercury by organic functional groups and accumulation of organic matter as part of the soil-forming process. The retention of mercury in the mor humus layer was almost complete due to the very strong association between Hgt and humic substances. 

Mercury is a naturally occurring element. Natural emissions of mercury, e.g. from ore deposits and from volcanic activity, are variously estimated at amounts between 2500 and 5500 tonnes/year and are thus similar in magnitude to anthropogenic emissions, which are currently estimated at some 3600-4100 tonnes/year world-wide. Some 30000 tonnes of mercury are readily available in the environment, i.e. in the atmosphere or in the mixing zone of the oceans, with tens of millions of tonnes in the upper layers of the continental masses and still more in the deep oceans (see Table 2.1). 

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