Human activities pollution from

The monoaromatic compounds benzene, toluene, ethylbenzene and xylene, commonly found in crude oil, are often jointly called BTEX compounds. The most harmful of these compounds is benzene, which is a known carcinogen. BTEX compounds occur naturally near natural gas and petroleum deposits and are detected in the fumes of forest fires. Most of the highly volatile BTEX compounds released by human activity originate from fuel use and end up as pollutants in the air. Inhaling BTEX-polluted air is also the greatest hazard to humans by these compounds. BTEX compounds are water-soluble, and therefore, improper handling can also cause groundwater contamination. 

The levels of PAHs released into the environment fix)m various human activities especially from industrial sources in the Niger Delta area of Nigeria shows that the most polluted medium is the air followed by the soil and water media. Comparing the study locations there is an indication that Eleme (the most industrialized) as compared to Ahoada East (one of the least industrialized) recorded PAH levels 7- million fold higher in the air. Levels of PAHs in Eleme were 3-fold higher in surface water and 7 -fold higher in soil than the levels found in Ahoada East as clearly shown in Fig. 1. 

The SO2 in the atmosphere is derived from two sources. Firstly, from the aerial oxidation of H2S produced naturally (see later) and secondly from the combustion of sulphur-containing fuels. In industrialised countries the second source predominates, but on a global scale only about one-fifth of the total sulphur pollution is derived from human activity. In 1969, the total sulphur emission, expressed in terms of SO2, from burnt fuel in the UK was 6-06 X 10 tons. In densely populated countries sulphur pollution levels arc very much related to the domestic heating cycle, and in the UK maximum... 

Rain unaffected by human activity contains mostly weak acids and has a pH of 5.7. The primary acid present is carbonic acid, H2C03, a weak acid that results when atmospheric carbon dioxide dissolves in water. The major pollutants in acid rain are strong acids that arise from human activities. Atmospheric nitrogen and oxygen can react to form NO, but the endothermic reaction is spontaneous only at the high temperatures of automobile internal combustion engines and electrical power stations ... 

Acid rain. Natural (unpolluted) precipitation is naturally acidic with a pH often in the range of 5 to 6 caused by carbonic acid from dissolved carbon dioxide and sulfurous and sulfuric acids from natural emissions of SO and H2S. Human activity can reduce the pH very significantly down to the range 2 to 4 in extreme cases, mainly caused by emissions of oxides of sulfur. Because atmospheric pollution and clouds travel over long distances, acid rain is not a local problem. The problem may manifest itself a long way from the source. Problems associated with acid rain include ... 

Environmental chemical releases due to human activities may be accidental (usually acute) or as an attendant consequence of some planned activity (usually chronic). Traditionally, spills have been separated from steady discharges because of statutory distinctions, but any integrated pollutant assessment must... 

As a consequence of human activities, large quantities of inorganic pollutants coming from different sources (e.g., domestic, industrial, etc.) are released into the Ebro River, where a fraction of them can be accumulated in sediments. In this... 

These gases are also classed as primary pollutants because they are emitted directly from the source and then react to produce secondary pollutant, such as acid rain (Speight, 1993). The emissions may include a number of biologically active substances that can pose a major health concern. These gases are classed as pollutants because (1) they may not be indigenous to the location or (2) they are ejected into the atmosphere in a greater-than-natural concentration and are, in the current context, the product of human activity. Thus, they can have a detrimental effect on the environment in part or in toto. 

A variety of human activities increase erosion and sedimentation rates. For example, soil typically erodes from cultivated land five to 10 times as fast as from noncultivated land. Construction sites lose soil 100 times as fast and mined land more than 500 times as fast as land that is undisturbed. Besides greatly increasing water pollution, this erosion accelerates the loss of valuable farmland. By some estimates, as much as 3.3 billion tons (3 billion metric tons) of topsoil is lost to such processes in the United States each year. Overall, the major anthropogenic sources of erosion (and, as a consequence, sedimentation) are certain types of agriculture (such as row cropping), livestock operations, logging, flooding from developed land, and construction projects. 

For one reason or another, but always because of threatening human activities, Atlantic and western Indo-Pacific coral reefs are in poor condition, except the Lakshadweep archipelago, which has been banned from tourism. East Asian coral reefs are under stress by blast and cyanide fishing activities. Threatening constructions over the reefs were made during the last world war, and aircraft carriers and ships that sunk still pollute large areas, particularly in the Solomon archipelago. Plutonium remains from nuclear explosions at Johnston Atoll also make conditions unsuitable for life to exist. 

Although there have been several studies examining emissions of criteria pollutants from some human activities (for example, in-use alternative fuel vehicles (AFVs)), little is known about overall total emissions of hazardous air pollutants (HAPs) (Wine-... 

Human activities harmfully influence the environment and nature in many ways. The production of undesirable wastewater, waste gas, and liquid plus solid residues seems to be inevitable during chemical processes. The public is more sensitive to pollution of the aquatic environment and the depletion of clean water resources, because they have an immediate impact on daily routine and recreational activities. However, air pollution has an adverse impact on our health in the short and long term, and the problems of the greenhouse effect and the destruction of stratospheric ozone could extinguish life from the face of the Earth. These problems are enhanced by overpopulation and urbanization. Today, urban areas can be seen as monsters that consume large amounts of energy, matter, and freshwater and release all kinds of waste into the environment. 

Atom for atom, bromine is even more efficient at destroying ozone than is chlorine. There has therefore been much concern that releases of volatile bromine compounds such as methyl bromide may contribute disporpor-tionately to thinning of the stratospheric ozone layer. Whereas there is no longer any doubt over the role of human activity in stratospheric pollution by CFCs, which are exclusively anthropogenic, attempts to assess the importance of human activity in pollution by methyl bromide have been confused by large natural releases of CH3Br from oceans and forest fires. Besides, unlike the case of CFCs released into the environment, a major fraction of the methyl bromide injected into soils to kill pests is destroyed in the ground. 

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