Hydrocarbons forests

The measurements refer to nine 600-liter canister samples, three collected south and six north of the ITCZ, analyzed according to the method of C.A.M. Brenninkmeijer [C.A.M. Brenninkmeijer, Journal of Geophysical Research, 98 10595 (1993) C.A.M. Brenninkmeijer et al., Chemosphere Global Change Science, 1 33 (1999)]. CO can result from biomass burning and die oxidation of natural hydrocarbons. Forest emissions of hydrocar-bons, however, are small, whereas hydrocarbon oxidation is minimal during winter. 

An extensive source of natural pollutants is the plants and trees of the earth. Even though these green plants play a large part in the conversion of carbon dioxide to oxygen through photosynthesis, they are still the major source of hydrocarbons on the planet. The familiar blue haze over forested areas is nearly all from the atmospheric reactions of the volatile organics... 

Forests can act as sources of some of the trace gases in the atmosphere, such as hydrocarbons, hydrogen sulfide, NO, and NH3. Forests have been identified as emitters of terpene hydrocarbons. In 1960, Went (10) estimated that hydrocarbon releases to the atmosphere were on the order of 108 tons per year. Later work by Rasmussen (11) suggested that the release of terpenes from forest systems is 2 x 10 tons of reactive materials per year on a global basis. This is several times the anthropogenic input. Yet, it is important to remember that forest emissions are much more widely dispersed and less concentrated than anthropogenic emissions. Table 8-2 shows terpene emissions from different types of forest systems in the United States. 

The environmental occurrence of polycyclic aromatic hydrocarbons is mainly associated with dispersion of oil products and with various types of combustion. For these chemicals a kind of pre-industrial background exists, due to forest fires or to domestic wood burning. The sediments of the deepest strata were certainly deposited in the nineteenth century, when no significant industrial activities had been initiated. The ratio between PAH concentrations found in the sediments dated to this century, and the deepest ones, vary from 1.7 to 30, increasing from the beginning of the... 

Both classes of hydrocarbon occur naturally, notably in oil and coal deposits. Aromatic compounds are also products of incomplete combustion of organic compounds, and are released into the environment both by human activities, and by certain natural events, for example, forest tires and volcanic activity. 

The largest releases of polycyclic aromatic hydrocarbons (PAHs) are due to the incomplete combustion of organic compounds during the course of industrial processes and other human activities. Important sources include the combustion of coal, crude oil, and natural gas for both industrial and domestic purposes, the use of such materials in industrial processes (e.g., the smelting of iron ore), the operation of the internal combustion engine, and the combustion of refuse (see Environmental Health Criteria 202, 1998). The release of crude oil into the sea by the offshore oil industry and the wreckage of oil tankers are important sources of PAH in certain areas. Forest hres, which may or may not be the consequence of human activity, are a signihcant... 

The Great Smoky Mountains are so named because of a haze that is usually present. This is caused by hydrocarbon emissions from trees. The concentrations are sometimes so high that the forest areas are in violation of the clean air standards... 

Munch, D. 1993. Concentration prohles of arsenic, cadmium, chromium, copper, lead, mercury, nickel, zinc, vanadium and polynuclear aromatic hydrocarbons (PAH) in forest soil beside an urban road. Sci. Total Environ. 138 47-55. 

Lee, S.D. and L. Grant (eds.). 1981. Health and Ecological Assessment of Polynuclear Aromatic Hydrocarbons. Pathotex Publ., Park Forest South, IL. 364 pp. 

McMahon, C.K. and S.N. Tsoukalas. 1978. Polynuclear aromatic hydrocarbons in forest fire smoke. Pages 61-73 in P.W. Jones and R.I. Freudenthal (eds.). Carcinogenesis —A Comprehensive Survey. Vol. 3. Polynuclear National Symposium on Analysis, Chemistry, and Biology. Raven Press, New York. 

Lopez-Avila et al. [59] used microwave assisted extraction to assist the extraction of polyaromatic hydrocarbons from soils. Another extraction method was described by Hartmann [60] for the recovery of polyaromatic hydrocarbons in forest soils. The method included saponification of samples in an ultrasonic bath, partitioning of polyaromatic hydrocarbons into hexane, extract cleanup by using solid-phase extraction, and gas chromatography-mass spectrometric analysis using deuterated internal standards. Polyaromatic hydrocarbons were thermally desorbed from soils and sediments without pretreatment in another investigation [61]. 

Following an aviation kerosin spill, hydrocarbons were detected in trout stream sediments and fish up to 14 months after the spill [13]. After a fire at a weed treatment plant in 1970 a large area of mixed forested ecosystem became contaminated with polycyclic aromatic hydrocarbons and creosote [66], High polyaromatic concentrations in stream sediments adversely affected micro- and meiobenthic communities at all trophic levels. Stein et al. [67] have studied the uptake by bethnic fish (English sole, Parophrys vetulus) of benzopyrene and polychlorinated biphenyls from sediments. Accumulation of contaminants from sediments was a significant route of uptake by English sole. 

The possibility of widespread haze formation by sunlight irradiation of terpenoid compounds from vegetation was first suggested by Went. Went, Rasmussen and Went, and Rasmussen estimated the annual worldwide contribution of forest hydrocarbon emission and con-... 

Fatty adds, 48,346-47,353 Flame kmization detectioa, for hydrocarbons, 271 Forests... 

Environmentalfy relevant metabolites include hydrocarbons released fcomEucalyptus forests. They imdergo oxidation by aerial dioxygen to give carboxylic acids that form aerosols, influencing adversely tte climate (Kavouras 1998). 

Lamb, B D. Gay, H. Westberg, and T. Pierce, A Biogenic Hydrocarbon Emission Inventory for the U.S.A. Using a Simple Forest Canopy Model, Atmos. Environ., 27, 1673-1690 (1993). 

In addition to hydrocarbons, biogenic processes also produce a number of oxygen-containing organics. One of the most important appears to be 2-methyl-3-buten-2-ol (MBO), first identified in a forested area by Goldan et al. (1993) ... 

Contrasts between subsurface microbial communities and their metabolic adaptation to polycyclic aromatic hydrocarbons at a forested and an urban coal-tar disposal site. Microbial Ecology, 24, 199-213. 

Long-term exposure of microbial populations to certain toxicants often is necessary for adaptation of enzymatic systems capable of degrading those toxicants. This was the case with the Exxon Valdez oil spill in Alaska in 1989. Natural microbial populations in Prince William Sound, Alaska, had developed enzyme systems that oxidize petroleum hydrocarbons because of long-term exposure to natural oil seeps and to hydrocarbons that leached from the pine forests in the area. Growth of these natural microbial populations was nutrient limited during the summer. Thus the application of nutrient formulations to the rocky beaches of Prince William Sound stimulated microbial growth and helped to degrade the spilled oil. 

Barr et al. (2003) performed an analysis of the impact of phytogenic aerosol (PhA) which is defined as forming mainly due to monoterpene oxidation (primarily, a- and /3-pinenes), on the radiative regime of the ABL over the forest in the eastern part of Canada. In the forest ecosystem the level of emissions to the atmosphere of biogenic hydrocarbons is moderate, with the concentration of a- and /3-pinenes constituting about 1.6 ppb. NMHC oxidation resulted in the formation of PhA at a number density of particles of about 5 108 cm 3. For a given concentration and size distribution of aerosol, its impact on the short-wave radiation transfer in the ABL was assessed. 

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