Water from fossil fuel combustion

Long-range atmospheric transport of Hg from fossil fuel combustion and solid waste incineration has increased Hg in freshwater and biota. In the United States, combustion of fossil fuels for power generation is estimated to generate about 30% of the total release of Hg into the atmosphere (Harriss and Hohenemser, 1978). One in every three lakes in the United States and nearly one-quarter of the nation s rivers contain various pollutants, including Hg (CNN, 2004). Forty States in the U.S. have issued advisories for methylmercury on selected water-bodies, and 13 states have statewide advisories for some or all sportfish from rivers or lakes (USGS, 2000). Fish consumption advisories for methylmercury account for more than three-quarters of all fish consumption advisories. 

Approximately 80% of the mercury released from human activities is elemental mercury released to the air, primarily from fossil fuel combustion, mining, and smelting, and from solid waste incineration. About 15% of the total is released to the soil from fertilizers, fungicides, and municipal solid waste (for example, from waste that contains discarded batteries, electrical switches, or thermometers). An additional 5% is released from industrial wastewater to water in the environment. 

Acidic precipitation is a growing environmental problem. Acid rain, snow or fog is formed when oxides of sulfur and nitrogen from fossil fuel combustion are oxidized in the atmosphere by ultra-violet light and ozone to give sulfuric and nitric acids. These acids then mix with atmospheric water to form acidic precipitation. Since the normal pH of atmospheric water is 5.6-5.7, precipitation having a pH below 5.6 is termed acid rain (J, ). 

The EPA Method 6 provides procedures for measuring sulfur dioxide emissions from stationary sources where the gas sample is extracted from the exhaust stack. Ammonia, water-soluble cations, and fluorides cause interferences with SOx measurements. Method 6A concerns sulfur dioxide, moisture, and carbon dioxide measurements from fossil fuel combustion sources by chemically separating the SO2 and CO2 components, where different reagent chemicals are used. Method 6C discusses the use of instrument analyzers to measure... 

Results from many studies have been reported on the types and levels of PAHs, with particular emphasis on B[a]P, B[a]A, chrysene, benz[e]acephenanthrylene (benzo[fc]fluoranthene), benzoMfluoranthene, indeno[l,2,3-C(i]pyrene, DB[fl,/t]A, and benzo[g/t/]perylene. As noted by Menzie et al. (2533), all of these PAHs have been identified in exhausts or effluents from fossil fuel combustion sources, in soils, sediments, and water, and in a variety of commonly used foodstuffs. 

Wik, M. I. Renberg, 1987. Distribution in forest soils of carbonaceous particles from fossil-fuel combustion. Water, Air Soil Poll. 33 127-129. 

About 90% of U.S. energy comes from fossil fuel combustion. Fossil fuels include petroleum, natural gas, and coal. Some fossil fuels, especially coal, contain significant amounts of sulfur impurities. During combustion, these impurities react with oxygen to form SO2. In addition, during combustion of any fossil fuel, nitrogen from the air reacts with oxygen to form NO2. The SO2 and NO2 emitted from fossil fuel combustion react with water in the atmosphere to form sulfuric acid and nitric acid. 

Industrial systems are largely dependent on the utilization of fossil fuels, so many environmental effects are due to fossil fuel extraction and combustion. Greenhouse-warming carbon dioxide emissions, acid gas emissions, smog-forming hydrocarbons and nitrogen oxides, and deterioration of atmospheric quality from particles released from fossil fuel combustion are all atmospheric effects associated with fossil fuel combustion. Coal mining activities have the potential to release acid mine water to the hydrosphere, petroleum production can release brines or result in ocean oil spills. 

Fuel cells are the cleanest and most efficient technologies for generating electricity from fossil fuels. Since there is no combustion, fuel cells do not produce any of the pollutants commonly emitted by boilers and furnaces. For systems designed to consume hydrogen directly, the only products are electricity, water and heat. 

Anthropogenic sources of fluoride include fossil fuel combustion and industrial waste. Hydrogen fluoride is water soluble and emissions are readily controlled by acid gas scrubbers. HF emission from coal combustion, that is considered to be the main anthropogenic source of HF, was estimated to be 0.18 Tg annually emission of HF from the combustion of petroleum and natural gas is almost certainly negligible [24]. Apparently only limited data are available concerning total annual emissions of HF from industrial operations however, there is evidence that emissions of fluorides have been declining [24,25]. 

Nitrous oxide is important not only as a greenhouse gas but, as discussed in Chapter 12, as the major natural source of NC/ in the stratosphere, where it is transported due to its long tropospheric lifetime (Crutzen, 1970). The major sources of N20 are nitrification and denitrification in soils and aquatic systems, with smaller amounts directly from anthropogenic processes such as sewage treatment and fossil fuel combustion (e.g., see Delwiche, 1981 Khalil and Rasmussen, 1992 Williams et al., 1992 Nevison et al., 1995, 1996 Prasad, 1994, 1997 Bouwman and Taylor, 1996 and Prasad et al., 1997). The use of fertilizers increases N20 emissions. For pastures at least, soil water content at the time of fertilization appears to be an important factor in determining emissions of N20 (and NO) (Veldkamp et al., 1998). 

---