Environmental contamination, widespread

Produced by fungi which can contaminate crops. Some, such as zearalenone, are oestrogenic DDT, lindane and beta-HCH are common, persistent environmental pollutants Widespread, persistent environmental pollutants... 

When DDT was widely used, it was released into the environment in a number of different ways. The spraying of crops, and the spraying of water surfaces and land to control insect vectors of diseases, were major sources of environmental contamination. Waterways were sometimes contaminated with effluents from factories where DDT was used. Sheep-dips containing DDT were discharged into water courses. Thus, it is not surprising that DDT residues became so widespread in the years after the war. It should also be remembered that, because of their stability, DDT residues can be circulated by air masses and ocean currents to reach remote parts of the globe. Very low levels have been detected even in Antarctic snow ... 

Polycyclic aromatic hydrocarbons (PAH) are widespread environmental contaminants and one of the most potent classes of carcinogenic chemicals. They are byproducts of combustion, and significant levels are produced in automobile exhaust, refuse burning, smoke stack effluents, and tobacco smoke. It is strongly suspected that PAH may play an important role in human cancer. 

PAHs are widespread environmental contaminants resulting from combustion, discharge of fossil fuels, and automobile exhausts [29]. As they are hydrophobic substances, they are strongly adsorbed to the organic fraction of SEs and soils. A different spatial distribution of PAHs was obtained for each of the three analyzed years. However, the upper course of the Ebro River was the most affected area by this contamination during the whole period of study. In Fig. 10, larger dots represent higher contributions of this PAHs contamination pattern than smaller dots. In the year 2004 (upper map on the left of Fig. 10), samples R0 (the closest to the river source) and T8 (an industrial place located in Navarra) were the most affected sites by PAHs contamination. As a result of its location, R0 was not... 

Widespread usage of the organotin compounds motivated numerous studies in order to elucidate environmental contamination and impacts [12, 280, 286-289]. The following is a summary of the impact of such usage ... 

As liquid chromatography plays a dominant role in chemical separations, advancements in the field of LC-NMR and the availability of commercial LC-NMR instrumentation in several formats has contributed to the widespread acceptance of hyphenated NMR techniques. The different methods for sampling and data acquisition, as well as selected applications will be discussed in this section. LC-NMR has found a wide range of applications including structure elucidation of natural products, studies of drug metabolism, transformation of environmental contaminants, structure determination of pharmaceutical impurities, and analysis of biofiuids such as urine and blood plasma. Readers interested in an in-depth treatment of this topic are referred to the recent book on this subject [25]. 

Production, Import/Export, Use, and Release and Disposal. Currently, heptachlor use in the United States is limited to fire ant control in power transformers (EPA 1990b). However, because of former widespread use of heptachlor and the persistence of heptachlor epoxide, these compounds and their degradation products can still be found at low levels in indoor air, water, soil, and food. Disposal methods are well documented in the literature however, more current information would be useful. Information on historical disposal practices would be helpful in evaluating the potential for environmental contamination. More information on the volume of heptachlor used in fire ant control would be useful in estimating potential occupational exposure. 

No information was found in the available literature on estimates of human intake of HDI Irom the various environmental media. Because the potential for significant widespread environmental contamination is expected to be very low, such estimates would appear to be needed primarily for populations living or working near potential emission sources of HDI. 

Exposure in humans could occur in persons living or working in the vicinity of hazardous waste sites if emissions to water, air, and soil are not adequately controlled. Chlorobenzene has been found at 97 out of 1,177 NPL hazardous waste sites in the United States. Thus, federal and state surveys suggest that chlorobenzene is not a widespread environmental contaminant. The chemical has not... 

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants (POPs) and widespread environmental contaminants, some of which may exhibit toxic, carcinogenic and mutagenic effects Because of their low water solubility and hydrophobic nature, PAHs are partitioned... 

The use of bioindicators and biomonitors for gathering environmental information is currently widespread, although some abuse of these terms is customary. The terms bioindicator and biomonitor are commonly but incorrectly taken to be synonymous a bioindicator provides qualitative information on the quality of the environment, whereas a biomonitor supplies quantitative data on environmental contamination.14 This section focuses on the latter, since the trace metal content of biota has been commonly used in biomonitoring programs of metal pollution in the marine environment and is considered to provide a time-integrated measure of metal bioavailability.1,15,16... 

Aryl halide derivatives of benzene and toluene have many uses in chemical synthesis as pesticides and raw materials for pesticides manufacture, solvents, and a diverse variety of other applications. These widespread uses over many decades have resulted in substantial human exposure and environmental contamination. Three example aryl halides are shown in Figure 1.17. Monochlorobenzene is a flammable liquid boiling at 132°C. It is used as a solvent, heat transfer fluid, and synthetic reagent. Used as a solvent, 1,2-dichlorobenzene is employed for degreasing hides and wool. It also serves as a synthetic reagent for dye manufacture. Bromobenzene is a liquid boiling at 156°C that is used as a solvent, motor oil additive, and intermediate for organic synthesis. 

Ironically, those pressures of the last 13 years or so have generated more information about the environmental toxicology of chlorinated insecticides than we may ever gain about other classes of pesticides or environmental contaminants. As a side-benefit, we now know that some xenobiotics may be transferred into global areas they were never intended to reach and we have developed the methodology needed to measure these low level contaminations It is also doubtful whether the extensive background contamination by PCB would have come to light so quickly without the widespread concern about OC ... 

High Evidence of widespread environmental contamination or presence of the substance in human populations and evidence of available substitutes... 

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