Poison , definition

C. Lapp, Modes d elimination des poisons. Definition de nouveaux coefficients toxi-cologiques. Ann Pharm Fr 6 150-165 (1948). 

Ammonia decomposition over Fe, Cu, Ag, Au, and Pt Hydrolysis of starch to glucose catalyzed by acids Mixture of coal gas and air makes a platinum wire white hot Measurements on the rate of H2O2 decomposition Selective oxidation of ethanol to acetic acid over platinum Comprehensive paper on the H2 + O2 reaction on platinum foils, including reaction rates, deactivation, reactivation, and poisoning Definition of catalysis, catalyst, and catalytic force First quantitative analysis of reaction rates Systematic studies on the concentration dependence of reaction rates First concise monograph on chemical kinetics Definition of order of reaction Arrhenius equation k = u exp (-Ea/RT)... 

Tb allium, which does not occur naturaHy in normal tissue, is not essential to mammals but does accumulate in the human body. Levels as low as 0.5 mg/100 g of tissue suggest thallium intoxication. Based on industrial experience, 0.10 mg /m of thallium in air is considered safe for a 40-h work week (37). The lethal dose for humans is not definitely known, but 1 g of absorbed thallium is considered sufficient to kHl an adult and 10 mg/kg body weight has been fatal to children. In severe cases of poisoning, death does not occur earlier than 8—10 d but most frequently in 10—12 d. Tb allium excretion is slow and prolonged. For example, tb allium is present in the feces 35 d after exposure and persists in the urine for up to three months. 

Thus the promotional index PIp is positive for promoters and negative for poisons. In the latter case the definition of PIp coincides with that of the toxicity defined by Lamy-Pitara, Bencharif and Barbier several years ago.21 In the case of pure site-blocking it is PIp=-l. Values of PI02- up to 150 and of PINas+ up to 6000 have been measured as we will see in Chapter 4. 

It is only since 1980 that in situ spectroscopic techniques have been developed to obtain identification of the adsorbed intermediates and hence of reliable reaction mechanisms. These new infrared spectroscopic in situ techniques, such as electrochemically modulated infrared reflectance spectroscopy (EMIRS), which uses a dispersive spectrometer, Fourier transform infrared reflectance spectroscopy, or a subtractively normalized interfacial Fourier transform infrared reflectance spectroscopy (SNIFTIRS), have provided definitive proof for the presence of strongly adsorbed species (mainly adsorbed carbon monoxide) acting as catalytic poisons. " " Even though this chapter is not devoted to the description of in situ infrared techniques, it is useful to briefly note the advantages and limitations of such spectroscopic methods. 

The widespread use of economic poisons has a definite impact on the animal complex on the face of the earth which provides our sustenance. Already we have seen the use of DDT for codling moth control on apples result in a relatively minor pest becoming a serious threat. The same material used as a wonder spray for fly control now fails, after a couple years of common usage, with the appearance of new, resistant strains of flies. Bees and other pollinating insects as well as helpful predators or parasites may be decimated and their important aid be lost by untimely or improper use of most of the newer insecticides. 

A sample of hops which had been treated with tetraethyl pyrophosphate showed a negative chemical analysis. The plant material was also extracted and the extract added to the drinking water of test animals and sensitive insects. The animals and insects that drank this treated water for several days showed no reaction. With the sensitive insects it would have been possible to detect even a few parts per million. In addition, there have been extensive commercial field applications of the chemical in dust and spray form to crops such as apples, pears, grapes, celery, broccoli, Brussels sprouts, and others up to within a few days of harvest there has been no detectable poison residue on any of the crops. The lack of poison residue with use of tetraethyl pyrophosphate is due to the fact that it hydrolyzes within a few hours of application, breaking down into transient nonresidual and nonpoisonous chemicals. Thus it is possible to use tetraethyl pyrophosphate well up to harvest time of food products without danger of residual poison on crops. The fact that the chemical is used in extremely small amounts is a definite advantage in respect to freedom from poison residue. 

Octamethyl pyrophosphoramide is a colorless oil, completely soluble in water, benzene, acetone, and many other common organic solvents except the paraffinic hydrocarbons. Its hydrolysis rate has not been measured, but it appears stable in the absence of alkali. In England, this systemic insecticide has been used to control aphids on hops. There it has been calculated that only a negligible quantity of the poison ultimately may find its way into the beer made from the hops. Despite calculations of this sort, the use of octamethyl pyrophosphoramide on food or fodder crops in this country is definitely not to be recommended. However, it may prove useful if properly applied to control certain insects, especially those attacking ornamental plants, such as rosebushes, and possibly on the cotton aphid and grape phylloxera. The compound has only recently been made available experimentally. 

Underpotential deposition of heavy metals on H2 evolving electrodes is a well known problem [133], The existence of a direct correlation between H2 evolution activity and metal work function, makes UPD very likely on high work function electrodes like Pt or Ni. Cathode poisoning for H2 evolution is aggravated by UPD for two reasons. First, deposition potentials of UPD metals are shifted to more anodic values (by definition), and second, UPD favors a monolayer by monolayer growth causing a complete coverage of the cathode [100]. Thus H2 evolution may be poisoned by one monolayer of cadmium for example, the reversible bulk deposition potential of which is cathodic to the H2 evolution potential. 

Much of the initial development of Gaussian modeling and definition of dispersion paramenters was done during and after World War I in addressing the problem of poison gas dispersal. These studies involved the definition of risk factors, such as exposure and dose. The next intensive development effort came during and after World War II with the nuclear weapons program. 

Case reports are available regarding lethal effects of acute exposure to arsine (Pinto et al. 1950 Morse and Setterlind 1950 Hesdorffer et al. 1986). However, no definitive quantitative exposure data accompany these reports. Signs and symptoms varied depending on the exposure situation but usually included abdominal and muscle pain, nausea and diarrhea, hematuria, and oliguria. Delayed lethality, common in arsine poisoning, varied considerably. 

Numerous cases of arsine poisoning have been reported (Elkins and Fahy 1967 DePalma 1969). However, these reports lack definitive exposure concentration data and usually lack exposure duration data as well. Some of the more recent and complete reports involving nonlethal consequences are described in the following section. These reports do not provide quantitative data suitable for AEGL derivations, but they do provide valuable insight into the nature and progression of arsine poisoning in humans. In most cases, the severity of the effects was usually sufficient to necessitate medical intervention to prevent lethality. Some of the more prominent reports and those with the best descriptive data have been summarized, but the overview is by no means exhaustive. 

Numerous case reports are available regarding the lethal and nonlethal toxicity of arsine in humans, but definitive exposure concentration or duration data are lacking. Although the case reports are of limited use for quantitative estimates of exposure limits, they do provide qualitative information about the nature of arsine poisoning in humans. Some estimated human toxicity values are available and are summarized in Table 2-3. 

Centers for Disease Control and Prevention. "Case Definition of Vesicant/Blister Agent Poisoning." Interim document, December 22,2003. 

Case Definition Arsine or Stibine Poisoning." March 4, 2005. 

Richardson etal. 1995). Some Canadian aboriginal peoples had grossly elevated blood mercury concentrations of >100 to 660 pg Hg/L, although there was no definitive diagnosis of methylmercury poisoning (Wheatley and Paradis 1995). 

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