Toxic hazards, identification

Steroidogenesis assay using the human H295R adrenocarcinoma cell line Detects chemical effects on steroidogenesis including testosterone and estradiol production as above including gonadotrophin receptor-mediated toxicity Hazard identification and mechanistic studies... 

Hazard identification involves gathering and evaluating data on the types of health injury or disease that may be produced by a chemical and on the conditions of exposure under which injury or disease is produced. It may also involve characterization of the behavior of a chemical within the body and the interactions it undergoes with organs, cells, or even parts of cells. Hazard identification is not risk assessment. It is a scientific determination of whether observed toxic effects in one setting will occur in other settings. 

Risk characterization is defined as the integration of the data and analysis of the above three components to determine the likelihood that humans wiU. experience any of the various forms of toxicity associated with a substance. When the exposure data are not available, hypothetical risk is characterized by the integration of hazard identification and dose—response evaluation data. 

An elementary introduction to chemistry is given in Chapter 3 this serves only to provide background and for more advanced consideration reference will be necessary to specific text books, e.g. as listed in the Bibliography. A brief discussion of the relevance of physicochemical principles to hazard identification is given in Chapter 4. Relevant toxic and flammable properties, and summaries of appropriate precautions to cater for them during handling, use and disposal, are provided in Chapters 5 and 6, respectively. Reactive hazards are discussed in Chapter 7. The special problems with cryogenic materials and chemicals under pressure, typified by compressed... 

Handbook of Emergency Response to Toxic Chemical Releases HAZARDS IDENTIFICATION... 

Hazard identification, step one, means identification of new chemicals or other factors that may cause harmful health effects. Previously, novel hazards were usually observed in case studies or after accidents or other excessive exposures, usually in occupational environments. Today, thorough toxicity studies are required on all pesticides, food additives, and drugs. New chemicals also have to be studied for their potential toxic effects. Thus, earlier hazards were in most cases identified after they had caused harmful effects in humans. Today, most chemical products have been evaluated for their toxicity with experimental animals. Therefore, hazard identification has become a preventive procedure based on safety studies conducted before a chemical compound or product reaches the market, and before individuals are exposed to it. ... 

In this study detailed fault trees with probability and failure rate calculations were generated for the events (1) Fatality due to Explosion, Fire, Toxic Release or Asphyxiation at the Process Development Unit (PDU) Coal Gasification Process and (2) Loss of Availability of the PDU. The fault trees for the PDU were synthesized by Design Sciences, Inc., and then subjected to multiple reviews by Combustion Engineering. The steps involved in hazard identification and evaluation, fault tree generation, probability assessment, and design alteration are presented in the main body of this report. The fault trees, cut sets, failure rate data and unavailability calculations are included as attachments to this report. Although both safety and reliability trees have been constructed for the PDU, the verification and analysis of these trees were not completed as a result of the curtailment of the demonstration plant project. Certain items not completed for the PDU risk and reliability assessment are listed. 

Most human or environmental healtli hazards can be evaluated by dissecting tlie analysis into four parts liazard identification, dose-response assessment or hazard assessment, exposure assessment, and risk characterization. For some perceived healtli liazards, tlie risk assessment might stop with tlie first step, liazard identification, if no adverse effect is identified or if an agency elects to take regulatory action witliout furtlier analysis. Regarding liazard identification, a hazard is defined as a toxic agent or a set of conditions that luis the potential to cause adverse effects to hmnan health or tlie environment. Healtli hazard identification involves an evaluation of various forms of information in order to identify the different liaz.ards. Dose-response or toxicity assessment is required in an overall assessment responses/cffects can vary widely since all chemicals and contaminants vary in their capacity to cause adverse effects. This step frequently requires that assumptions be made to relate... 

Generally, the main pathways of exposure considered in tliis step are atmospheric surface and groundwater transport, ingestion of toxic materials that luu c passed tlu-ough the aquatic and tcncstrial food chain, and dermal absorption. Once an exposure assessment determines the quantity of a chemical with which human populations nniy come in contact, the information can be combined with toxicity data (from the hazard identification process) to estimate potential health risks." The primary purpose of an exposure assessment is to... 

In hazard identification, a hazard is a toxic agent or a set of conditions that... 

Professor Martel s book addresses specifically some of the more technical eispects of the risk assessment process, mainly in the areas of hazard identification, and of the consequence/effect analysis elements, of the overall analysis whilst where appropriate setting these aspects in the wider context. The book brings together a substantial corpus of information, drawn from a number of sources, about the toxic, flammable and explosive properties and effect (ie harm) characteristics of a wide range of chemical substances likely to be found in industry eind in the laboratory, and also addresses a spectrum of dangerous reactions of, or between, such substances which may be encountered. This approach follows the classical methodology and procedures of hazard identification, analysing material properties eind... 

Risk Assessment The scientific process of evaluating the toxic properties of a chemical and the conditions of human exposure to it, in order to ascertain the likelihood that exposed humans will be adversely affected, and to characterize the nature of the effects they may experience. It may contain some or all of the following four steps hazard identification, dose-response assessment, exposure assessment, and risk characterization. 

Scientists skilled in epidemiology, toxicology, and related disciplines collect and evaluate all of the scientific literature containing information regarding the types of toxic effect the chemical under review has been shown to produce. Toxic effects include one or more of the many manifestations of toxicity described earlier in this book. The list of adverse health effects produced by the chemical are said to constitute its toxic hazards, and the critical review and evaluation leading to the list is the hazard identification step. A discussion of the extent to which causal associations with human disease or toxic harm have been established is an important aspect of this step. 

When epidemiological evidence is limited, and insufficient to establish causation, it may remain important in the hazard identification step if it is supported by reliable animal data. Within the regulatory context, convincing animal evidence of toxicity, even in the absence of strong epidemiological evidence, or indeed any epidemiological evidence, will still be used for hazard characterization. 

Flammability properties of materials are clearly important for fire prevention but there are other properties that are also significant. There have been a number of severe fire incidents initiated by a material s reactivity properties that were previously unrecognized or unknown to the user. The development of a Materials Hazard Identification program requires knowledge of a material s toxicity and reactivity, as well as flammability. 

The purpose of the hazard identification is to evaluate the weight of evidence of adverse effects in humans based on assessment of all available data on toxicity and toxicological mode(s)... 

Thus, the hazard identification, in addition to an identification of the inherent toxicological properties (type of effects), also involves an evaluation of the nature of the observed effects, i.e. (1) whether an observed effect constitutes an adverse effect and thus results in an impairment of body function(s), and (2) whether an effect is a direct toxic effect exerted by the chemical (biologically relevant) or is due to normal unspecific reactions toward changes in the environment (homeostasis). Examples of effects, which generally are not considered as being adverse, include ... 

Selected entries from Methods in Enzymology [vol, page(s)] Types of organophosphorus inhibitors, 11,686-688 toxicity hazards, 11,688 purity and analysis, 11,688 solutions of organophosphorus compounds, 11,689 estimation of specific radioactivity of organophosphorus compounds, 11,689-690 method for estimating phosphorus content, 11,691 reactions with enzymes, 11,691 -701 [rate constants, 11,692 phosphorylation of chymotrypsin, 11, 694-696 identification of phosphoryl and phosphonyl peptides,... 

The first step in risk assessment is to gather health-related information associated with an exposure. Ideally, hazard identification starts before there is significant use of the agent. The structure of the compound is compared with that of compounds with known toxicity profiles. Cell-based studies are often performed to screen for toxicity. Finally, animal bioassays and human studies are performed to characterize and develop a toxicity profile. Multiple health-related endpoints are evaluated to determine if the compound is associated with adverse effects. Advantages of animal studies include experimental control and accurate knowledge of the dose. 

In the chemical safety report, the hazard assessment of a particular substance is based on the data set provided in the technical dossier. This contains substance-specific information on physicochemical properties as well as on toxicological and ecotoxicological hazards. One objective of the hazard assessment is the substance s hazard identification, which comprises the determination of its physicochemical and hazardous properties for the purpose of classification. Concerning human health hazards, both human and nonhuman information is taken into consideration and evaluated with respect to the classification criteria laid down in the Dangerous Substances Directive and in the CLP Regulation, respectively. However, in most cases human data do not exist, so the hazard identification has to be based on data from animal experiments. With respect to teratogenicity, this hazardous property may in principle be detected in the following toxicity studies ... 

Key words Pesticides, Prenatal toxicity study, Two-generation study. Regulatory toxicology. Hazard identification, Risk assessment... 

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