Toxicity pathway, risk assessment based

Bhattacharya S et al (2011) Toxicity testing in the 21 century defining new risk assessment approaches based on perturbation of intracellular toxicity pathways. PLoS One 6(6) e20887... 

A physiologically based pharmacokinetic model for predicting ethylene dibromide kinetics and consequent toxicity, based on in-vitro metabolic parameters of rodents and humans and on the use of scaling factors, has been presented (Ploemen et al., 1997). Its most important prediction is that the GST pathway is significantly active even at low ethylene dibromide concentrations, which has important implications for risk assessment. 

The National Academy of Sciences put together a symposium entitled "Toxicity Pathway-Based Risk Assessment Preparing for Paradigm Change." Presentations... 

Toxicity Pathway-Based Risk Assessment. Current risk assessment strategies are challenged by issues related to species extrapolation, dose extra-... 

Application of the HRF increases the transparency of delineation of the relative degrees of nncertainty associated with various options for considraation in assessment of risk for impacted populations. HRFs are also instrumental in acquiring transparency on critical data gaps that will further reduce uncertainty. They force distinction of choices made on the basis of science policy versns those that are science jndgment related, inclnding reliance on default, based on the erroneous premise that it is always health-protective (Meek and Doull 2009). They focus on early events in a toxicity pathway through relation of early perturbations to apical endpoints in frameworks designed to systematically address (a) consideration of key events in modes of action and (b) their snbseqnent implications for dose-response in risk assessment [see, for example. Meek (2008)]. 

Toxicity-Pathway-Based Risk Assessment Preparing for Paradigm Change (2010) The Use of Title 42 Authority at the U. S. Environmental Protection Agency (2010) Review of the Environmental Protection Agency s Draft IRIS Assessment of Tetrachloroethylene (2010)... 

Health assessments are based on factors such as the nature, concentration, toxicity, and extent of contamination at a site the existence of potential pathways for human exposure community health concerns the size and nature of the community likely to be exposed relevant community-specific, past and current, health outcome data and any other information available to ATSDR that is relevant to a determination of potential risks to public health. 

Fate studies identify the type of compounds and their exposure concentration at different points in the ecosystem and the organism(s) at greatest risk of exposure. The toxicant released into the environment can reach humans through a number of pathways (Figure 11.10). Although greatest immediate attention should be paid to human health, ultimate human welfare may depend on the overall quality of the ecosystem. Future environmental hazard assessment should be based on comparative toxicology. 

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