Source anthropogenic

In 1995, approximately 1900 metric tons of anthropogenic mercury entered the atmosphere (mostly 75%) from the combustion of fossil fuels. About 56% of global mercury atmospheric emissions came from Asian countries, with Europe and North America combined contributing less than 25% gaseous elemental mercury (Hg) comprised 53% of total atmospheric emissions, gaseous Hg+ 37%, and particle-associated mercury the remainder. 

Large-scale mining of mercury in North America ceased around 1990 because of low prices and stringent environmental regulations. In the U.S., mercury is now produced only as a by-product from presently operating 

Atmospheric transport of anthropogenic mercury may contaminate remote ecosystems. In one case, a remote lake in northern Wisconsin with no surface inflow and negligible groundwater inflow received about 

0 mg Hg/ha during 1988-90, an input that could account for the elevated mercury burdens found in water, sediments, and fisb. 

Mercury emission from electric utilities is the largest uncontrolled source of mercury release into the atmosphere, and globally it accounts for up to 59% of the total annual atmospheric loading of mercury from both natural and anthropogenic sources. Coal-fired power plants are now considered the greatest source of environmental mercury in the U.S., and the only significant source that continues 

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The developed assay was successfully applied for the arsenite and arsenate determination in contaminated waters of the gold recovery plant and in snow covers of the industrial anthropogenic sources vicinities as well. The data produced are in a good agreement with the results of independent methods atomic absorptioin and atomic emission spectrometry and capillary electrophoresis. 

The places from which pollutants emanate are called sources. There are natural as well as anthropogenic sources of the permanent gases considered to be pollutants. These include plant and animal respiration and the decay of what was once living matter. Volcanoes and naturally caused forest fires are other natural sources. The places to which pollutants disappear from the air are called sinks. Sinks include the soil, vegetation, structures, and water bodies, particularly the oceans. The mechanisms whereby pollutants... 

A substantial portion of fhe gas and vapors emitted to the atmosphere in appreciable quantity from anthropogenic sources tends to be relatively simple in chemical structure carbon dioxide, carbon monoxide, sulfur dioxide, and nitric oxide from combustion processes hydrogen sulfide, ammonia, hydrogen chloride, and hydrogen fluoride from industrial processes. The solvents and gasoline fractions that evaporate are alkanes, alkenes, and aromatics with relatively simple structures. In addition, more complex... 

The primary constituents to be measured are the pH of precipitation, sulfates, nitrates, ammonia, chloride ions, metal ions, phosphates, and specific conductivity. The pH measurements help to establish reliable longterm trends in patterns of acidic precipitation. The sulfate and nitrate information is related to anthropogenic sources where possible. The measurements of chloride ions, metal ions, and phosphates are related to sea spray and wind-blown dust sources. Specific conductivity is related to the level of dissolved salts in precipitation. 

It is clear that both atmospheric and surface dusts are complex materials and not all that easy to describe. A summary is given in Fig. 2 of the sources of atmospheric and surface dusts and their inter-connection. Both natural and anthropogenic sources contribute to both dusts. The inter-connection between the two dusts is wet and dry deposition from the atmosphere to the ground, and the re-entrainment of surface dust through wind and human activity into the atmosphere. Dust is an important global component of our earth, and impinges on the wellbeing of people. 

As seen in Table 12-2, global NO production is dominated by anthropogenic sources. In an urban environment, virtually all NO is from fossil fuel combustion. 

Figure 13-6a (Ivanov, 1983) is a depiction of the natural global sulfur budget. Figure 13-6b depicts the budget with natural and anthropogenic sources. Table 13-2 serves to explain Fig. 13-6 and includes the wide range of estimates of various fluxes, and demonstrates the degree of uncertainty inherent in such approaches.

Despite the difficulties, there have been many efforts in recent years to evaluate trace metal concentrations in natural systems and to compare trace metal release and transport rates from natural and anthropogenic sources. There is no single parameter that can summarize such comparisons. Frequently, a comparison is made between the composition of atmospheric particles and that of average crustal material to indicate whether certain elements are enriched in the atmospheric particulates. If so, some explanation is sought for the enrichment. Usually, the contribution of seaspray to the enrichment is estimated, and any enrichment unaccounted for is attributed to other natural inputs (volcanoes, low-temperature volatilization processes, etc.) or anthropogenic sources. 

Table 15-1 Natural and anthropogenic sources of atmospheric emissions"...

Apart from CH3 Hg+, other forms of R-Hg+ have been found in the natural environment, which originate from anthropogenic sources but are not known to be generated from inorganic mercury. These forms have been found in terrestrial and aquatic food chains. A major source has been fungicides, in which the R group is phenyl, alkoxy-alkyl, or higher alkyl (ethyl, propyl, etc.). These forms behave in a similar manner... 

Concerning anthropogenic sources, methyl arsenic compounds such as methyl arsonic acid and dimethylarsinic acid have been used as herbicides, and were once a significant source of environmental residues. Dimethyl-arsinic acid (Agent Blue) was used as a defoliant during the Vietnam War. 

Atmospheric aerosols have a direct impact on earth s radiation balance, fog formation and cloud physics, and visibility degradation as well as human health effect[l]. Both natural and anthropogenic sources contribute to the formation of ambient aerosol, which are composed mostly of sulfates, nitrates and ammoniums in either pure or mixed forms[2]. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. That is, relative humidity(RH) history and chemical composition determine whether atmospheric aerosols are liquid or solid. Aerosol physical state affects climate and environmental phenomena such as radiative transfer, visibility, and heterogeneous chemistry. Here we present a mathematical model that considers the relative humidity history and chemical composition dependence of deliquescence and efflorescence for describing the dynamic and transport behavior of ambient aerosols[3]. 

Schuster PF, Krabbenhoft DP, Naftz DL, Cecil FD, Olson ML, Dewild IF, Susong DD, Green JR, Abbott ML. 2002. Atmospheric mercury deposition during the last 270 years a glacial ice core record of natural and anthropogenic sources. Env Sci Technol 36 2303-2310. 

Pirrone N, Costa P, Pacyna JM, Ferrara R. 2001. Atmospheric mercury emissions from anthropogenic sources in the Mediterranean region. Atmos Environ 35 2997-3006. 

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