Extensive toxicological evaluation

RfDs and RfCs are elaborated by expert committees of the US Environmental Protection Agency (EPA) on the basis of extensive toxicological evaluations, which are published in monographs. They may serve as a basis for the derivation of limit values for toxic substances in food and drinking... 

Robertson et al., 2007), prescreening animals prior to extensive toxicological evaluations, and quality control of cell media. 

DJI. Rosenblatt, Mammalian Toxicology and Toxicity to Aquatic Organisms of Four Important Types of Waterborne Munitions Pollutants—An Extensive Literature Evaluation , USAMBRDL Tech Rept No 7403 (1974) (AD 778725) 15) E.R. Hart, Subacute Toxicity... 

Discussion. Control of insects by the continuous vaporization of di-chlorvos within enclosed spaces in which persons are housed intermittently or continuously constitutes a potential threat of the absorption of significant quantities of the material dispersed as vapor in the air. Despite extensive toxicological investigation of dichlorvos, which has included observations of human beings (4,5,6,8,12,15), no work had been done to evaluate the hazard of Vapona Resin Vaporizers under actual conditions of use. The observations described in this report were designed to reveal the significance, if any, of such hazards. 

The derivation of the MRL is further complicated by the variability of the mixture s composition among wood creosote and coal tar creosote samples and the differences in mode of action of the individual components. The mixtures composition is dependent on the sources and preparation parameters of wood creosote and coal tar creosote and, as a result, the creosote components are rarely consistent in their type and concentration. Hence, toxicological evaluations of one creosote sample, for instance, are most likely inadequate for extrapolation to other creosote samples, unless their compositions are similar. An example of the composition variability among creosote samples was presented by Weyand et al. (1991). In that study, the concentrations of several PAHs were analyzed in four samples of manufactured gas plant (MGP) residue, a form of coal tar. All of the PAHs identified exhibited 2- to nearly 20-fold differences in concentration among the four samples. Benzo[a]pyrene, a component whose individual toxicity has been examined extensively, ranged from nondetectable levels (detection limit 0.3 g/kg) to 1.7, 6.4, and 3.9 g/kg of coal tar. Other studies that illustrate the variability of samples include Wrench and Britten (1975), Niemeier et al. (1988), and Emmett et al. (1981). 

Toxicological Profiles are a unique compilation of toxicological information on a given hazardous substance. Each profile reflects a comprehensive and extensive evaluation, summary, and interpretation of available toxicologic and epidemiologic information on a substance. Health care providers treating patients potentially exposed to hazardous substances will find the following information helpful for fast answers to often-asked questions. 

The process of risk evaluation for personnel working with dyes and textile chemicals has been discussed in detail [69]. The more extensive the database covering toxicological, physical, chemical and application properties of the product, the easier it is to assess the risks involved. 

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