Mercury volcanic emission

Cadmium (Cd) anode cells are at present manufactured based on nickel-cadmium, silver-cadmium, and mercury-cadmium couples. Thus wastewater streams from cadmium-based battery industries carry toxic metals cadmium, nickel, silver, and mercury, of which Cd is regarded the most hazardous. It is estimated that globally, manufacturing activities add about 3-10 times more Cd to the atmosphere than from natural resources such as forest fire and volcanic emissions. As a matter of fact, some studies have shown that NiCd batteries contribute almost 80% of cadmium to the environment,4,23 while the atmosphere is contaminated when cadmium is smelted and released as vapor into the atmosphere4 Consequently, terrestrial, aquatic, and atmospheric environments become contaminated with cadmium and remain reservoirs for human cadmium poisoning. 

Nriagu J. O. and Becker C. (2003) Volcanic emissions of mercury to the atmosphere global and regional inventories. Set Tot. Environ. 304, 3—12. 

Mercury is present in the atmosphere mainly due to volcanic emissions but also as a result of industrial pollution. The total amount of global emissions of mercury to the atmosphere are not accurately known at present, although there is evidence that the atmospheric concentration of mercury has increased by about 1% per year for the last 25 years. The volcanic emissions are very big, between 25 000 and 100 000 tonne/year. They are responsible for a base level of mercury concentration in the ground and water. Mercury from the atmosphere is enriched in the surface layers of the ground, where it forms complexes with humus. Rain water dissolves and transports humus to streams and lakes. Mercury is enriched in the top layers of the bottom sediments. 

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). 

INTRODUCTION 1.1 The Global Mercury Cycle FUNDAMENTAL GEOCHEMISTRY. 2.1 Solid Earth Abundance and Distribution. 2.2 Isotopic Distributions. 2.3 Minable Deposits. 2.4 Occurrence of Mercury in Fossil Fuels SOURCES OF MERCURY TO THE ENVIRONMENT. 3.1 Volcanic Mercury Emissions... 

Estimates of global volcanic sulfur emissions are summarized in Table 6. We have chosen a value of 9 X 10 t S yr as representative of the recent estimates. Therefore, by applying the determined Hg/S ratio, a global mercury flux from subaerial volcanism is estimated to be 45 t yr or 0.23 Mmol annually. These average emissions are only 5% of the natural flux of 5 Mmol yr estimated by Mason et al. (1994). Thus, and under long-term mean conditions, other types of terrestrial volatilization processes for mercury would dominate. Given this conclusion, it is important to place additional constraints on the validity of the 45 t yr estimate for subaerial volcanic mercury emissions. 

Second, the scale of volcanic mercury fluxes can be approximated indirectly. For example, using the Hg/Bi ratios listed in Table 4 as well as the Lambert et al. (1988) estimate for annual global bismuth emissions of 1,500 t, we obtain a range for the global volcanic mercury flux of 2-36tyr Hinkley et al. (1999) suggests that the Lambert et al. values are a factor of 3 or 4 too high. 

A comparable value of 18 t annually is obtained using Olafsson s (1975) estimate of mercury emissions (7 X 10 g Hg/6 X 10 " g ejecta) for the volcanic eruption at Heimay, Iceland, and an estimate of 6 km (—15 X 10 g) for annual, subaerial lava production (—20% of total annual lava production being subaerial Crisp, 1984 Varekamp, personal communication). 

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. (1981) Volcanic mercury emissions and the global mercury cycle. Programs and Abstracts, Symposium on the Role of the Ocean in Atmospheric Chemistry. lAMAP 3rd Scientific Assembly, Hamburg, Germany. August 17-28, 134p. 

Bargagli, R., Barghigiani, C., 1991. Lichen biomonitoring of mercury emission and deposition in mining, geothermal and volcanic areas of Italy. Environ. Monitor. Assess. 16, 265-275. 

One of the most hazardous heavy metal emitted to the atmosphere due to its toxicity is mercury. It is released to environment naturally and through human activities in three forms such as elemental (Hg ), oxidized (Hg ) and particulate (HgP). The examples of natural emission source are emission from ocean and volcanic eruptions, whereas, fuels used for energy production and raw materials used in industrial processes are anthropogenic source of mercury (Pacyna et al. 2006, Pirrone et al. 2010). The latest data revealed that the global pool of mercury mainly results from anthropogenic emissions... 

Occurrence of Mercury in Fossil Fuels SOURCES OF MERCURY TO THE ENVIRONMENT. 3.1 Volcanic Mercury Emissions... 

Witt M, Fischer TP, Pyle DM, Yang TF, Zelhner GF (2008) Fumarole compositions and mercury emissions from the Tatun Volcanic Field, Taiwan results from multi-component gas analyser, portable mercury spectrometer and direct sampling techniques. J Volcanol Geotherm Res 178(4) 636-643... 

---