Environmental sources

Environmental sources Equipment sources 7 Further reading... 

Pesticides, including insecticides, herbicides, and fungicides, are widely used in agriculture, and the potential for these residues to accumulate in food has led to concern for human safety. Pesticide residues may enter food animals from environmental sources or from treated or contaminated feeds. Immunoassay development for pesticides has had major impacts for pesticide registrations, analysis of residues in foods, monitoring environmental contamination, determination of occupational exposure, and integration of pest management. 

Emphasizing source reduction and environmental source recycling over treatment and disposal. 

Sisson, P. R. Freeman, R. Lightfoot, N. F. Richardson, I. R. Incrimination of an environmental source of a Legionnaires disease by pyrolysis mass spectrometry. Epidemiol. Infect. 1991,107,127-132. 

Landrigan PJ, Froines JR, Mahaffey KR. 1985. Body lead burden Summary of epidemiological data and its relation to environmental sources and toxic effects Chapter 14. In Magaffev KR, ed. Dietary and environmental lead Human health effects. Amsterdam, The Netherlands Elsevier Sci Publisher BV, 421451. 

Analysis of Enantiomers from Plant and Environmental Sources... 

Like plasma and urine, matrixes from plant or environmental sources contain a vast diversity of components. Thus, achiral-chiral LC-LC is also useful for analysis involving samples from these sources. Stalcup et al. (1991) studied the enantiomeric purity of scopolamine extracted from Datura sanguinea in both homogenized plant leaves and commercial extracts. A reverse-phase separation on a C j g column separated the scopolamine from other alkaloid and matrix components while the enantiomeric separation (also in the reverse-phase mode) was carried out on two coupled [3-cyclodextrin columns or a single acetylated (3-cyclodextrin column. The single... 

There is one general way of introducing chemical energy into synthesis and use of it in pumps which is to transduce any environmental source to pyrophosphate. Once again is this a uniquely suitable route ... 

Now we will return briefly to Sections 3.8-3.11 and 4.6-4.8 where we considered the general problem of multiple flows, here of H, C, N, O, S and P. We observe immediately that all the products are from the same small molecule environmental sources and are required to be formed in relatively fixed amounts using the same source of energy and a series of intermediates. Controlling all the processes to bring about optimum cellular production are feedbacks between them and linked with the code which generates proteins, and here we note particularly enzymes, i.e. catalysts. The catalysts are made from the amino acids, the synthesis of which they themselves manage, while the amino acids control the catalysts so as to maintain a restricted balanced set of reaction pathways in an autocatalytic assembly. It is also the feedback controls on both the DNA (RNA) from the same units used in the... 

A wide variety of nitro PAHs have been isolated from different environmental sources including airborne particulates (27-34), coal fly ash (35-37), diesel emission particulates (38-41) and carbon black photocopier toners (42-43). Their presence has also been suggested in the smoke from nitrate-fortified cigarettes (44). The structures of the most commonly detected nitro PAHs are shown in Figure 1 and in each instance it is the kinetically-favored isomer that is found. 

Some naturally occurring extremely toxic and supertoxic chemicals are listed in Table 4.2, along with their environmental sources and toxicity targets. Some of these are toxins found in the venom of poisonous snakes or in the tissues of certain species of... 

The dramatic increase of severe or lethal infections caused by antibiotic-resistant bacteria triggered numerous studies on antibiotic resistance, not only from clinical but also from environmental sources. Nowadays it is clear that environment, and water in particular, plays a central role on antibiotic resistance dispersion to and from clinical settings. However, the current state of the art clearly suggests that only a small fraction of the environmental resistome is known. The modes and mechanisms of emergence, evolution and transmission of resistance determinants are still not very well understood. Although environmental pollution is recognized to play an important role on antibiotic resistance evolution and spreading, it is still very difficult to draw cause-effect relationships, which sometimes seems to be strain/species dependent. 

To date, the single most important commercial use of lead is in the manufacture of lead-acid storage batteries. However, for most of the twentieth century, the most important environmental source of Pb was gasoline combnstion. It is also used in alloys, such as fusible metals, antifriction metals, and solder. Lead foil is made with lead alloys. Lead is used for covering cables and as a lining for laboratory sinks, tanks, and the chambers in the lead-chamber process for the manufacture of sulfuric acid. It is used extensively in plumbing. Because it has excellent vibration-dampening characteristics, lead is often used to support heavy machinery. 

Although there is no reason to suspect that the pharmacokinetics of 1,4-dichlorobenzene differs in children and adults, scant data are available to support or disprove this statement. Studies of absorption, distribution, metabolism, and excretion in children would aid in determining if children are at an increased risk, particularly if conducted in an area where a high-dose acute or low-dose chronic exposure to an environmental source were to occur. With regard to exposure during development, additional research on maternal and fetal/neonatal toxicokinetics, placental biotransformation, the mechanism of... 

It is obvious that such an assessment is formidable, technically difficult, and extremely expensive. Since an environmental source assessment study is required to characterize the total pollution potential of all waste streams, the sampling program must be more extensive than those conducted for the acquisition of process or control engineering data. Assessment sampling is more complete in that all waste streams are sampled and no attempt is made to limit sampling to a preselected number of process streams. The sampling is also more comprehensive in that all substances of potential environmental concern must be detectable above some minimum level of concern. These requiements of completeness and comprehensiveness call for a strategy of approach in which the philosophy and structure ensure maximum utilization of available resources. 

Zook DR, Rappe C Environmental sources, distribution, and fate of polychlorinated dibenzodioxins, dibenzofurans, and related organochlorines. In Schecter A (ed.) Dioxins and Health, 80pp. New York, Plenum Press, 1994... 

To cope with their need for iron, microorganisms possess remarkably sophisticated mechanisms to scavenge iron from its plentiful, yet biologically inaccessible, environmental sources. Among the various mechanisms for iron uptake the most general is the use of iron sequestering agents. 

A Varimax rotation (Vl ) is often used to achieve it. However, simple structure may not be the most useful criterion for environmental source resolution since an element may be present in an aerosol sample because of its emission by several sources. The variance should, therefore, be spread over several factors rather than concentrated in one. 

Elements of the environment continually impact fuel performance. The effect of water, cold temperatures, heat, air, light, and external contamination can initiate a variety of problems. The first place to begin looking for the cause of a fuel handling or performance problem would be these environmental sources. 

The concept of designing products and processes that are robust, or stable, to environmental variation is clearly very important. Robust design enables the experimenter to discover how to modify the design of a product or process to minimize the effects due to variation from environmental sources that are difficult, if not impossible, to control. 

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