Lead anthropogenic

Figure 1. Spatial distribution of lead anthropogenic emission in Europe in 2002.

The spatial distribution of lead anthropogenic emissions in the Northern Hemisphere and particularly in Kazakhstan and Kyrgyzstan in 1990 is shown in Figure 15. As is seen the major emission sources were located in Europe. Some significant emissions were also in Eastern Asia and in North America. The total anthropogenic emission of lead in the Northern Hemisphere was about 146 kt/yr, the emissions of lead in Kazakhstan and Kyrgyzstan were 5.8 kt/yr and 0.7 kt/yr, respectively. 

Figure 15. Spatial distribution of lead anthropogenic emission in the Northern Hemisphere (a) and in Kazakhstan and Kyrgyzstan (b) in 1990 (Ilyin et al., 2004).

One of the potential benefits of hydrogen is a decrease in carbon emissions, thought to be the leading anthropogenic contributor to global climate change. Conventional ICE vehicles emit approximately 1.04 tons of carbon annually, based on the default assumptions about efficiency... 

For an excellent, comprehensive review of the chemistry, environmental, and anthropogenic release, environmental fate, and environmental and human health effects of lead, see Air Quality Criteria for Eead, Vol. I—IV, EPA-600/8-83/028a-dF, U.S. Environmental Protection Agency, Washington, D.C., June 1986, -Msd Air Quality Criteria for Eead Supplement to the 1986 Addendum, EPA-600/8-89/049F, U.S. Environmental Protection Agency, Washington, D.C., Aug. 1990. 

The majority of published °Pb reports address the utility of °Pb as a geochronological tool rather than as an element that is involved in complex biogeochemical cycles. Nonetheless, some of these studies do provide insight into the geochemical behavior of °Pb and °Po. Nearly all of the lead in the world s surface oceans is believed to be of anthropogenic origin—derived from combustion... 

Contemporary forest declines were initiated about 1950-1960, virtually simultaneously throughout the industrial world at the same time as damage to aquatic systems and structures became apparent. A broad array of natural and anthropogenic stresses have been identified as components of a complex web of primary causal factors that vary in time and space, interact among each other, affect various plant growth and development systems and may result in the death of trees in mountainous ecosystems. As these ecosystems decline, the alterations in forest ecology, independent of the initial causal complex, become themselves additional stress factor complexes leading to further alterations. 

The ratio of anthropogenic emissions to total natural emissions is highest for the atmophilic elements Sn, Cu, Cd, Zn, As, Se, Mo, Hg, and Pb (Lantzy and Mackenzie, 1979). In the case of lead, atmospheric concentrations are primarily the consequence of the combustion of leaded gasoline. For many years, lead was used as a gasoline additive, in the form of an organometal compound, tetraethyl lead. When the fuel was... 

Mercury, tin, lead, arsenic, and antimony form toxic lipophilic organometallic compounds, which have a potential for bioaccumulation/bioconcentration in food chains. Apart from anthropogenic organometallic compounds, methyl derivatives of mercury and arsenic are biosynthesized from inorganic precursors in the natural environment. 

Claude F. Boutron et al. Decrease in anthropogenic lead, cadmium and zinc in Greenland snows since the late 1960s. Nature. 353 (Sept. 12, 1991) 153-156. 

Lead is dispersed throughout the environment primarily as the result of anthropogenic activities. Environmental fate processes may transform one lead compound to another however, lead is not degraded and is still available for human exposure, even though the compounds containing it vary enormously. 

The primary source of lead in the environment has historically been anthropogenic emissions to the atmosphere. In 1984, combustion of leaded gasoline was responsible for approximately 90% of all anthropogenic lead emissions. EPA phased out the use of lead alkyls in gasoline, however, and by 1990, auto emissions accounted for only 33% of the annual lead emissions (EPA 1996h). Use of lead additives in motor fuels was totally banned after December 31, 1995 (EPA 1996f). The ban went into effect on February 2, 1996. Atmospheric deposition is the largest source of lead found in soils. Lead is transferred... 

Evans RD, Rigler FH. 1985. Long distance transport of anthropogenic lead as measured by lake sediments. Water Air Soil Pollut 24 141-151. 

Schalue B, Patterson CC (1980) The Occurrence of lead in the northeastern pacific, and the effects of anthropogenic inputs. In Brancia M, Konrad Z (eds) Lead in the marine environment. Pergamon Press, Oxford, pp 31-43... 

The work of the Harrison group on alkylleads in air is perhaps the most persuasive of the reports as to the advocation of an environmental methylating process. Some of the sites whose atmospheric lead was sampled were very remote, such as Harris Island, Outer Hebrides, UK. Air reaching this site should not have any anthropogenic content but concentrations of alkylleads were found to be in the 3-7 ngm-3 range61. There was a higher than normal ratio of alkyl to total lead present here also (from 10-30%). A maritime source of volatile alkyllead was proposed61,62. 

The major organolead compounds found in the environment are the tetraalkyllead compounds and their di- and trialkyl decomposition products. Elevated levels of tetraalkyl-leads have two possible sources either (i) anthropogenic leaded petroleum inputs or (ii) environmental methylation of natural lead compounds. While the former is well established, the latter is the subject of some controversy in the literature. Interest in the environmental methylation process derives from the increased toxicity of methyllead compounds compared to their inorganic analogs. 

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