Pollutant exposure

The effect of accumulation in various systems depends greatly on the quantity of pollutants involved. Many pollutants can be detected at concentrations lower than those necessary to affect human health. For pollutants which are eliminated slowly, individuals can be monitored over long periods of time to detect trends in body burden the results of these analyses can then be related to total pollutant exposure. Following are two examples of air pollutants that contribute to the total body burden for lead and carbon monoxide. 

Brysson and co-workers (7) conducted a study in St. Louis, Missouri, on the effects of urban air pollution on the tensile strength of cotton duck material. Samples were exposed at seven locations for up to 1 year. Figure 9-3 shows the relationship between tensile strength and pollutant exposure. For two levels of ambient air exposure, the materials exhibited less than one-half their initial tensile strength when exposed to air pollution for 1 year. 

Effects of indoor air pollutants on humans are essentially the same as those described in Chapter 7. However, there can be some additional pollutant exposures in the indoor environment that are not common in the ambient setting. From the listing in Table 23-1, radon exposures indoors present a radiation hazard for the development of lung cancer. Environmental tobacco smoke has been found to cause lung cancer and other respiratory diseases. Biological agents such as molds and other toxins may be a more likely exposure hazard indoors than outside. 

The conductivity of a surface varies with the long-term pollution exposure in the operating atmosphere and its average humidity. The previously mentioned creepage spacings change for different applications, such as industrial, telecom, etc. The designer must refer to the appropriate specification. 

Excursion limit A time-weighted average of pollutant exposure over a length of time specified by OSHA that cannot be exceeded during the working day. See Peak limit. 

This cascading effect may have been best demonstrated from interdisciplinary research addressing the consequences of chronic oxidant air pollution exposure to the mixed conifer forests of the San Bernardino Mountains of Southern California. Miller et al. (76) reported that chronic exposure to oxidant air pollutants resulted in decreased photosynthetic capacity, premature... 

Because the significance of exposure has only been considered over the past few years, there is not as wide a selection of exposure models available as that for fate models. The latter have been applied for several decades to the calculation of ambient exposure levels compared with some standard values. Papers illustrative of human exposure assessments in this symposium include one on airborne pollutant exposure assessments by Anderson (2), a generic approach to estimating exposure in risk studies by Fiksel (5), and a derivation of pollutant limit values in soil or water based on acceptable doses to humans by Rosenblatt, Small and Kainz (6). 

GEOGRAPHICAL PECULIARITIES OF BIOGEOCHEMICAL CYCLING AND POLLUTANT EXPOSURE... 

In accordance with the local maximum of precipitation and the relative low winter temperatures, the most favorable climate conditions for biogeochemical processes and pollutant exposure are in the western part of Spitzbergen Island. Three types of landscapes with corresponding ecosystems are widespread (Dobrovolsky, 1994). 

Pollutant Exposure and Chemical Composition of Plants Let us consider the influence of various exposure factors on the chemical composition of plant species in the arctic islands. It seems the most influential factor is the distance from the ocean shore. For example, in arctic willow growing a few meters from the tide line, the content of Zn, Cu, Pb, and Ni was higher than that of the same plant... 

A high amount of various nutrients and trace metals is retained in peat and dead plant residues and thus temporarily eliminated from the biogeochemical cycles and pollutants exposure to human and ecosystem health. The period of this elimination depends on the solubility of these metals. It has been shown (Dobrovolsky, 1994) that... 

BIOGEOCHEMICAL CYCLING OF ELEMENTS AND POLLUTANTS EXPOSURE IN FOREST ECOSYSTEMS... 

There is no doubts that these data are of the significance for pollutants exposure assessment and environmental risk calculations. 

Role of Aqueous and Aerial Migration in Pollutants Exposure It is well known that the total content of water-soluble solids in natural waters (TSS) is increasing with an increasing aridity. The concentration of some trace elements (heavy metals) correlates significantly with the total content of soluble solids. Comparison... 

The extraction by 1N NCI yields 5-10% of total heavy metal content. In case of Fe and Mn, these values are even higher. The maximum contents of mobile fractions of trace elements are monitored in the upper horizon. Thus, the role of evapotranspiration barrier in biogeochemical migration of elements in Dry Desert ecosystems pays a very important role in pollutants exposure. 

The various steppe plant species indicate the individual biogeochemical peculiarities related to pollutants exposure. For example, we can discuss the results from the South... 

Biogeochemical cycling of elements and pollutants exposure pathways in the tropical ecosystems, which occur between 30°N and 30°S, are both intensive and at high probability of risk for human and ecosystem health. The tropical belt receives about 60% of solar radiation inputting on the Earth s surface. The total area of tropical ecosystems is about 40 x 106 km2, with exception of the High Mountain and Extra-Dry Sandy Deserts with strongly depressed life processes. 

Biogeochemical Cycling and Pollutant Exposure in Tropical Rain... 

Chronic Obstructive Lung Disease (COLD) and Cor pulmonale COLD is known to be an outcome of chronic air pollution exposure. Although tobacco smoke is known to be the major risk factor, studies in India and Nepal have found that non-smoking women who regularly cook on biomass stoves exhibit a higher prevalence of COLD than would be expected, or which appears in women who use them less frequently. Indeed, due to indoor exposure, nearly 15% of non-smoking women in Nepal (20 years and older) had chronic bronchitis a very high rate for nonsmokers (ESCAP, 1995). 

Many quantitative aspects of exposure pathways and their relevant application during environmental risk assessment depend on regional biogeochemical peculiarities and should be undoubtedly considered on the regional scale. Accordingly this part includes some characteristic examples and case studies from local up to regional and continental dimensions. We discuss the importance of the trans-boundary of pollutant exposure as well as the application of critical load methodology for risk estimates. 

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