Toxicity on human

At this point, it should also be noted that, since it is ethically impossible to test substance toxicities on humans, these are validated approximately with reference to animal experiments however, the possible effects of differences between species are a fundamental problem, and hence such validation cannot be absolute and will not necessarily predict what will happen in man [8]. 

The uranyl ion (UO ) is the most stable species, easily forms complexes, which are both well dissolved in water and represent the form present in the mammalian body [154]. It may react with biological molecules to produce cellular necrosis (cell death) and/or atrophy in the tubular walls in the kidneys, resulting in a diminished ability to filter impurities from the blood. There is no data available for long-term effects of uranium-induced developmental toxicity on humans. The information from intermediate-term studies on animals using the uranyl ion, oxides and rarely the metal [155, 156] demonstrate that DU is mutagenic and has neurotoxic properties [157]. 

Both PCE and TCE are classified in the 2A ( probably carcinogenic to humans) class by the I ARC [11]. They may cause adverse health effects via inhalation, ingestion, or dermal or eye contact. Their acute toxicity on humans is low however, high doses of exposure damage can cause reversible peripheral nerve degeneration, injury to the liver and kidneys and to the cardiovascular and gastrointestinal systems, and depression of the central nervous system, and can also lead to death. Chronic exposure can cause damage to the liver, kidneys, and nervous system. 

Granchi, D., Qapetti, G., Savarino, L., Cavedagna, D., Donati, M.E., and Pizzoferrato, A. (1996). Assessment of metal extract toxicity on human lymphocytes cultured in vitro. J. Biomed. Mater. Res. 31, 183-191. 

W. J. Hayes, Jr., and E. R. Laws, Jr., eds.. Handbook of Pesticide Toxicology, Academic Press, Inc., San Diego, Calif., 1990. Three volume set provides detailed toxicological profiles of more than 250 insecticides, herbicides, and fungicides each compound described by identity, properties, and uses toxicity to humans, laboratory animals, domestic animals, and wildlife includes comprehensive coverage of diagnosis, treatment, prevention of injury, effects on domestic animals, wildlife, and humans - ISjOOO references. 

Another dideoxypyrimidine nucleoside active against human immunodeficiency vims is 3 -azido-2/3 -dideoxyuridine [84472-85-5] (AZDU or CS-87, 64) C H N O. Since its synthesis, (167) CS-87 has been identified as a promising antiHIV agent (168) and is currentiy undergoing phase I clinical trials in patients with AIDS and AIDS-related complex. It appears to be less potent than AZT against HIV in a peripheral blood mononuclear (PBM) cell screening system and in MT-4 cell lines. This lower activity in PBM cells appears to be related to a lower affinity of CS-87 for the enzyme responsible for its initial phosphorylation (169). However, CS-87 has significantly lower toxicity on bone marrow cells than AZT (170) and penetration of the CNS as a 5 -dihydropyridine derivative. 

Many sophisticated models and correlations have been developed for consequence analysis. Millions of dollars have been spent researching the effects of exposure to toxic materials on the health of animals the effects are extrapolated to predict effects on human health. A considerable empirical database exists on the effects of fires and explosions on structures and equipment. And large, sophisticated experiments are sometimes performed to validate computer algorithms for predicting the atmospheric dispersion of toxic materials. All of these resources can be used to help predict the consequences of accidents. But, you should only perform those consequence analysis steps needed to provide the information required for decision making. 

Toxic chemicals can enter the body in various ways, in particular by swallowing, inhalation and skin absorption. Skin absorption may lead to dermatitis and this can be a most annoying complaint. Whereas some chemicals may have an almost universal effect on human beings, others may attack only a few persons. A person who has worked with a given chemical for some years may suddenly become sensitised to it and from then on be unable to withstand the slightest trace of that material in the atmosphere. He may as a result also be sensitised not only to the specific chemical that caused the initial trouble but to a host of related products. Unfortunately a number of chemicals used in the plastics industry have a tendency to be dermatitic, including certain halogenated aromatic materials, formaldehyde and aliphatic amines. 

A substance known to be so toxic to man as to afford a hazard to health during conveyance or which, in the absence of adequate data on human toxicity, is presumed to be toxic to man. 

After the use of a chemical becomes widespread, new deleterious effects on human health may be observed. In such situations, the occupational limit values will have to be modified. Usually the OELS tend to decrease when more information on the toxicity of a chemical is obtained. Knowledge of the specific features of various chemicals is thus extremely important for planning ventilation of industrial premises. It is important to be especially aware of those chemicals that may cause long-term effects without causing any acute effects. There are also compounds such as isocyanates that are extremely irritating at concentrations as low as 0.5 ppm. However, some workers may become sensitized to isothiocyanates at a concentration of 10 ppb, and therefore this has to be taken into consideration when planning the industrial ventilation. Thus, one has to plan against compounds that can cause serious health effects at concentrations at which their presence cannot be observed by the human senses, i.e., irritation or odor. 

The CESARS database contains comprehensive environmental and health information on chemicals. It provides detailed descriptions of chemical toxicity to humans, mammals, aquatic and plant life, as well as data on physical chemical properties, and environmental fate and persistence. Each record consists of chemical identification information and provides descriptive data on up to 23 topic areas, ranging from chemical properties to toxicity to environmental transport and fate. Records are in English. Available online through CCINFOline from the Canadian Centre For Occupational Health and Safety (CCOHS) and Chemical Information System (CIS) on CD-ROM through CCIN-FOdisc. 

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