Toxic chemicals hazard assessment

OECD. 2002. Co-operation on Existing Chemicals—Hazard Assessment of Perfluorooctane Sulfonate and its Salts. ENV/JM/RD(2002)17/FINAL. Robust Study Report Reference No. 8 - Early Life-Stage Toxicity Test with the Fathead Minnow Pimephales promelas), pp. 114-117. Available at http / /www.oecd.org/ env/ehs/risk-assessment/2382880.pdf (accessed March 7, 2014). 

Richardson, M.L. (ed). (1986) Toxic Hazard Assessment of Chemicals, The Royal Society of Chemistry, London. 

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... 

Two main hazards associated with chemicals are toxicity and flammability. Toxicity measurements in model species and their interpretation are largely the province of life scientists. Chemical engineers can provide assistance in helping life scientists extrapolate their resrrlts in the assessment of chemical hazards. Chemical engineers have the theoretical tools to make important contributions to modehng the transport and transformation of chemical species in the body—from the entry of species into the body to their action at the rrltimate site where they exert their toxic effect. Chemical engineers are also more likely than life scientists to appreciate... 

Barrows ME, Petrocelli SR, Macek KJ, et al. 1980. Bioconcentration and elimination of selected water pollutants by bluegill sunfish Lepomis macrochirus). In Haque R, ed. Dynamics, exposure and hazard assessment of toxic chemicals. Ann Arbor, MI Ann Arbor Science, 379-392. 

Measurement of exposure can be made by determining levels of toxic chemicals in human serum or tissue if the chemicals of concern persist in tissue or if the exposure is recent. For most situations, neither of these conditions is met. As a result, most assessments of exposure depend primarily on chemical measurements in environmental media coupled with semi-quantitative assessments of environmental pathways. However, when measurements in human tissue are possible, valuable exposure information can be obtained, subject to the same limitations cited above for environmental measurement methodology. Interpretation of tissue concentration data is dependent on knowledge of the absorption, excretion, metabolism, and tissue specificity characteristics for the chemical under study. The toxic hazard posed by a particular chemical will depend critically upon the concentration achieved at particular target organ sites. This, in turn, depends upon rates of absorption, transport, and metabolic alteration. Metabolic alterations can involve either partial inactivation of toxic material or conversion to chemicals with increased or differing toxic properties. 

Up to this point the discussion has focused on the methods of characterizing hazard at the molecular level but has not yet addressed the imderlying question of how hazards are compared so that decisions can be made about safer choices. Hazard is a relative term and therefore the difficult assignment of comparative hazard assessment must be evaluated and quantified if possible. To claim that one chemical is safe (non-toxic) and another is not is meaningless without including a description of how that decision is made. 

A Resources to identify chemicals of concern B Chemical toxicity C Exposure assessment tools D Hazard and risk assessment tools E Safer chemistry design tools... 

Alexander, M., Biodegradation of toxic chemicals in water and soil, in Dynamics, Exposure and Hazard Assessment of Toxic Chemicals, Haque, R., Ed., Ann Arbor Science, Ann Arbor, MI, 1980, pp. 179-190. 

Working groups were organized with specific responsibility to assess the utility and limits of four different methods (or tools) currently used by EPA and industry for evaluating hazards posed by toxic chemicals (1) laboratory toxicity data, (2) microcosm test data, (3) site-specific data, and (4) chemical fate and exposure model results. The Exposure Modeling Committee (3.) report presented an assessment of the current extent of field model testing and recommendations for future testing efforts. 

Mackay, D. (1981) Environmental and laboratory rates of volatilization of toxic chemicals from water. In Hazardous Assessment of Chemicals, Current Development. Volume 1, Academic Press. 

R Anliker in Toxic hazard assessment of chemicals, Ed M L Richardson (London Royal Society of Chemistry, 1986) 116. 

EPA. 1992d. Transmittal of hazard assessment of di-w-octyl phthalate. Washington, DC U.S. Environmental Protection Agency, Washington, DC. Memorandum from Lorraine Randecker, Chemical Review and Evaluation Branch, Health and Environmental Review Division, Office of Pollution Prevention and Toxics to Ken Mitchell, Toxics Release Inventory Management Staff, Economics and Technology Division, Office of Pollution Prevention and Toxics. July 15, 1992. 

Hazard assessment. A hazard assessment is required to assess the potential effects of an accidental (or intentional) release of a covered chemical/material. This RMP element generally includes performing an off-site consequence analysis (OCA) and the compilation of a five-year accident history. The OCA must include analysis of a least one worst-case scenario. It must also include one alternative release scenario for the flammables class as a whole also each covered toxic substance must have an alternative release scenario. USEPA has summarized some simplified consequence modeling... 

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