Emission from volcanoes

Gerlach, T.M. (1991) Present-day CO2 emission from volcanoes. EOS (Trans Am. Geophys. Union), 72,... 

The second important source for the hydrosphere and the oceans are asteroids and comets. Estimating the amount of water which was brought to Earth from outer space is not easy. Until 20 years ago, it was believed that the only source of water for the hydrosphere was gas emission from volcanoes. The amount of water involved was, however, unknown (Rubey, 1964). First estimates of the enormous magnitude of the bombardment to which the Earth and the other planets were subjected caused researchers to look more closely at the comets and asteroids. New hypotheses on the possible sources of water in the hydrosphere now exist the astronomer A. H. Delsemme from the University of Toledo, Ohio, considers it likely that the primeval Earth was formed from material in a dust cloud containing anhydrous silicate. If this is correct, all the water in today s oceans must be of exogenic origin (Delsemme, 1992). 

Toluene is released into the atmosphere principally from the volatilization of petroleum fuels and toluene-based solvents and thinners and in motor vehicle exhaust. It is also present in emissions from volcanoes, forest fires and crude oil. It has been detected at low levels in surface water, groundwater, drinking-water and soil samples (United States National Library of Medicine, 1997). 

By far the most important compound of oxygen and hydrogen is water, HzO. Water is essential to life as we know it and possibly to life anywhere in the universe. A lot of it arrived on Earth from outer space in the form of comets, which are like huge dirty snowballs. When the Earth was young, comets collided with it frequently, and each one brought huge amounts of water to the planet. Another source of water was the rocks from which the young Earth initially formed. The water locked up inside these solids is released when they melt in the depths of the Earth. The emission from volcanoes—even today—contains vast quantities of water. 

See also in this series the chapter of C. Oppenheimerand G. Sawyer devoted to fluorine emissions from volcanoes. 

Chloromethane (CH3CI) is produced by giant kelp and algae and also found in emissions from volcanoes such as Hawaii s Kilauea. Almost all of the atmospheric chloromethane results from these natural sources. 

In summary, it has been demonstrated that Hg/S ratios measured for a variety of volcanic plumes and fumaroles, when indexed to estimates of global sulfur emissions from volcanism, yield a mean volcanic mercury flux of 0.23 Mmol (45 t), which is consistent with other estimates and observations. Accordingly, average yearly mercury emission from volcanoes is small... 

Fitzgerald W. F. (1996) Mercury emissions from volcanos. In Abstr. 4th Int. Conf. on Mercury as a Global Pollutant. Hamburg, Germany, August, pp. 4-7. 

In many industrial areas, emissions of gaseous oxides of sulfur (SOx), especially sulfur dioxide (S02), also rival natural sulfur gas emissions from volcanoes, wetlands, and oceans. SOx are produced from the oxidation of sulfur in fuels, especially coals and residual oils, and are responsible in large part for acid rain (Section 4.6.3). In fuels, sulfur typically occurs either in organic compounds (organic S) or as pyrite (FeS2). SOx also are formed from the refining of the ores of the many metals that occur in the form of metal sulfides [e.g., copper (Cu), lead (Pb), and nickel (Ni)]. 

Prepare a source concentration matrix for the stratospheric aerosol. Take into account as sources the tropospheric aerosol, emissions from volcanoes, meteoritic material, and high-flying aircraft. 

The value derived by Peterson and Junge (1971) for the rate of particulate emissions from volcanoes is based on the long-term burden of particulate matter in the stratosphere combined with an assumed stratospheric residence time of 14 months. This gives a lower limit of 3.3 Tg/yr. If 10% of volcanic particulates, on average, reaches the stratosphere, the total emission rate would be 33 Tg/yr. Goldberg (1971) took instead the rate of accumulation of montmorillonite in deep-sea sediments as an indicator for average volcanic activity. His estimate of 150 Tg/yr must be an upper limit. The estimate of 10 Tg/yr adopted by Peterson and Junge (1971) for meteorite debris imparted to the stratosphere is due to Rosen (1969). 

Table 10-9. Measured or Estimated Rates of S02 Emissions from Volcanoes ...

The major anthropogenic sources of sulfur dioxide emissions are fossil fuel and biomass burning, iron and non-ferrous metal smelting and sulfur acid production. The natural emissions from volcano eruptions and massive forest fires should be also taken into account if any occur in the considered period. 

It is chemically quite inert, having a higher ionization potential than other electropositive elements. Natural sources include ocean emission, degassing of the earth s crust, weathering, emission from volcanoes, geothermal zones, and Hg mineralized areas. 

Gasparon M, Hilton DR, Vame R (1994) Crastal contamination processes traced by helium isotopes— Examples from the Simdaarc, Indonesia. Earth Planet Sci Lett 126 15-22 Gerlach TM (1991) Present-day CO2 emissions from volcanoes. EOS Trans, Am Geophys Union 72 249-255. 

Volcanoes regulate the climate through CO2 emissions. Carbon dioxide emissions from volcanoes are given as 75 Tg yr by Textor et al. (2004) and as 200-500 Tg yr by Bickle (1994). The Mt Etna CO2 plume emission and diffuse emission combined to amount to 25 Mt yr (Gerlach 1991). 

CO2 is generated on Earth by burning organic material, breathing, and emissions from volcanoes and man-made machines, which includes emissions due to industrial processes and transportation. On the other hand, CO2 is consumed by the process of photosynthesis and by dissolution in the oceans. On a balance, its quantity should more or less be constant and not deviate much from the 0.035% value. However, in between the years 1900-1960, the CO2 percentage increased by 7.4%, which still does not look too impressive. However, it is calculated that an increase of 15% in the percentage of CO2 will cause warming of the Earth by 4°C, which will result in major disasters on the planet. 

A particularly important consequence of the release of gaseous pollutants into the atmosphere is the local acidification of the environment. Rainwater reaching Earth s surface has a pH of about 5.6 (it is lower than 7 because of the dissolved carbon dioxide). In some parts of North America, Europe, and even Asia, however, acidic rainwater of pH < 5.6 is quite widespread. This is believed to be due to the presence of acidic gases, particularly oxides of sulfur (SOjc) and oxides of nitrogen (NO ) in the atmosphere. The contribution of HCl, if any, is relatively minor. A biogenic contribution to acidification caused by emissions from volcanos or forest fires also exists, but is relatively small. 

The mercury burden of the environment derives predominantly from natural sources [3]. Input into the atmosphere occurs by degassing of the earth s crust and emissions from volcanoes and by soil erosion into the surface waters. Mining is not the only anthropogenic source for mercury. The ubiquitous occurrence of traces of mercury in the whole earth s crust leads via the combustion of fossil fuel, the smelting of iron and other metals, as well as the production of cement to the release of large quantities of mercury vapor into the atmosphere and in this way increases the total amount of mercury in the ecosphere [4,5]. 

The main emission source of sulfur dioxide SO2 is anthropogenic fossil fuel combustion, and the emissions from volcanoes and biomass burning are added to it (Bates et al. 1992). Atmospheric SO2 reacts with OH,... 

Gerlach, T. M., Present-day COj emissions from volcanoes. Eos, Transactions, American Geophysical Union. 

Gases in air and dissolved in aquatic systems (O2, CO2, NH3) and gaseous emissions from volcanoes, industry, cars, and firing processes (NOx, SO2, CI2, HCHO, etc.). 

---