extrapolation of toxicity data in risk assessment

...  not in   present  REP/TEF  studies  evaluated   Mixtures of  PCDDs,  PCDFs  and  DL-­‐PCBs    s*ll  a  health risk?   One  order of  magnitude  decline in  background  human   exposure  since ...  intake   situa*ons  (TEFs  based  largely  on  uptake  studies)   Applica'on  these  ‘intake  or  inges'on’  TEFs  has  limited  toxicological   relevance  and  use  for risk assessment of ...  A  Global  Foodborne  Burden of  Disease?  WHO-­‐FERG In  prep   Es*ma*on of  number of  W-­‐Europe  children  exceeding   the  TDI  significantly  (<  10x) in  period  2005-­‐2010   M ...

Ngày tải lên: 16/04/2015, 08:52

... by issuing a strategic plan for evaluating the toxicity of chemicals that included three goals: identifying toxicity pathways and using them in screening, using toxicity pathways in risk assessment, ... president of the National Academy of Engineering The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions ... important in environmental responses but might be playing a prominent role in defining disease outcomes Dioxin: Evaluation of Pathways at the Molecular Level Alvaro Puga, of the University of Cincinnati...

Ngày tải lên: 16/03/2014, 14:20

... the opposite side of that coin is that it also represents serious risk Finding and maintaining a balance between the benthat it also represents serious risk Finding and maintaining a balance between ... ethical inquiry What value people place on benefiting from a loss of control of their data (letting others use it in novel, innovative, and beneficial ways) versus the risk of that data being used in ... benefits of big -data innovations Unfavorable perceptions and bad press affect the bottom line Even the perception of unethical data handling creates a risk of negative consequences, diminishing internal...

Ngày tải lên: 31/03/2014, 12:20

... Practical Example of Risk Assessment Risk Assessment to Phycotoxins in a Recreational Shellfish Harvesters Subpopulation Contamination data are often left-censored because of the limits of detection ... unavailability of SPX ARfD value explained by the lack of quantitative data on acute oral toxicity by this phycotoxin However, only in order to have an idea of the order of magnitude of the margin of exposure, ... EFSA Panel on Contaminants in the Food Chain (CONTAM); Scientific Opinion on marine biotoxins in shellfish Cyclic imines (spirolides, gymnodimines, pinnatoxins and pteriatoxins) The EFSA Journal,...

Ngày tải lên: 28/06/2014, 10:20

... results of ecological modeling As these kinds of models are used more in risk assessment, evaluating the kinds of errors that can be made and developing modeling approaches for avoiding such ... Decision-Making Lev R Ginzburg and H Resit Akỗakaya Training and Education Applying Existing Ecological Models Integrating Existing Models Developing New, Case-Specific Models Investment Trade-offs ... ecological models in the context of ecological risk assessment in the next section THE PROCESS OF ECOLOGICAL MODELING FOR CHEMICAL RISK ASSESSMENT The U.S EPA (1992) defined ecological risk assessment...

Ngày tải lên: 11/08/2014, 09:21

... it Relevance — HIGH — Possible endpoints include expected population size (age- or stage-specific), risk of decline, risk of extinction, and expected crossing time (the time at which the population ... estimating two matrices — one with toxins and one without toxins) Obtaining estimates of all such parameters can often be quite difficult However, model parameters are intuitive and can be interpreted ... and extinction risk In RAMAS Ecotoxicology, a model of population dynamics and toxicant kinetics can be constructed and linked to bioassay data Using this program, a modeler can import data from...

Ngày tải lên: 11/08/2014, 09:21

... results include risk of extinction, risk of decline, time to extinction, time to decline, expected abundance, and expected variation in abundance The model has several parameters (e.g., carrying ... extinction risk and recolonization probability) require observations of locally extinct patches (defined as suitable habitats in which the species of interest is absent) Treatment of Uncertainty ... structure of the models allows all available and relevant demographic data to be used Model assumptions are generally realistic Relevance — HIGH — The results include risk of extinction, risk of decline,...

Ngày tải lên: 11/08/2014, 09:21

... modeling incorporating the effects of toxic chemicals Software for population and food-web modeling Software for food-web modeling incorporating the effects of toxic chemicals Reference Internet ... of all of the species involved, the concentration of chemicals in all species, and the concentration of chemicals in the environment All of these endpoints are useful in an ecotoxicological assessment ... Relevance — HIGH — Potential endpoints include the expected population size of any population in the model, risk of decline, risk of extinction, and expected crossing time (the time at which the...

Ngày tải lên: 11/08/2014, 09:21

... LEEM was initiated by the International Joint Commission to aid in anticipating the effects of declining nutrient loading, invasion of zebra mussels, loading of toxic organic contaminants on ... are relevant to ecological risk assessment The examination of direct and indirect effects of stressors (e.g., entrainment) is of high interest in ecological risk assessment Although the model does ... the value of integrated models in predicting long-term effects of contaminant exposure is limited by key limitations in food-web modeling rather than in the representation of contaminant fate...

Ngày tải lên: 11/08/2014, 09:21

... capabilities include forecasting vegetative structure, assessing wildlife habitat, analyzing fire hazard, determining forest health risk, and monitoring ecological processes Using a parallel processing ... nonlinear regression of the natural logarithm of the number of species against time In the model, changes in species number are described relative to variations in the probability of extinction ... throughout the U.S., including assessments of disturbances by fire and insects (see USDA 1999 for examples) risk assessment of toxic chemicals in terrestrial systems, further development of landscape...

Ngày tải lên: 11/08/2014, 09:21

... recycling in the benthic food web The kinds of data inputs needed for ERSEM include annual cycles of monthly mean (or median) values together with ranges of variability, time series of river input ... paired in all probable combinations, excluding pairs whose combined areas are larger than the largest single patch in the database On the basis of these combinations, a series of SLOSS indices ... modeling, CEL HYBRID does for ecosystem modeling (Nestler 2001, pers comm.) The modeling strategy inherent in CEL HYBRID has subtle problems in maintaining conservation when any sources or sinks...

Ngày tải lên: 11/08/2014, 09:21

... future abundance, risk of decline in abundance, risk of extinction, time to extinction, time to decline, harvested biomass, as well as measures of uncertainty about these endpoints Highly recommended ... abundance, risk of decline in abundance, risk of extinction, time to extinction, time to decline, harvested biomass Has high realism, relevance, and flexibility and can be used for risk assessment ... decline of a specified size Has minimum data requirements for any population-level, risk- analytic model; can include effects of density dependence or omit them in a conservative assessment; can integrate...

Ngày tải lên: 11/08/2014, 09:21

... as a result of training, increasing investments can be focused on application of existing models Over time, the increased knowledge from applying models allows integration of existing models and ... INVESTMENT TRADE-OFFS Investments in enhancing the use of ecological models in environmental decision-making involve three trade-offs represented by the diamond-shaped boxes in Figure 14.1 (Ginzburg and ... availability) Collecting the appropriate data Analyzing data to estimate model parameters Incorporating variability and uncertainty Presenting model results APPLYING EXISTING ECOLOGICAL MODELS...

Ngày tải lên: 11/08/2014, 09:21

... approach for addressing many risk assessment issues (Ferson et al 1996; Barnthouse 1998) Indeed, incorporation of simple, scalar population modeling into screening-level ecological risk assessments could ... results of such assessments; in some cases, they could help to avoid unnecessary expenditures on a higher-tier risk assessment Examined over a hierarchical spectrum of endpoints, modeling of populations ... effects of toxicants are explicitly represented • Developing software and guidance for use of stochastic scalar abundance models in ecological risk assessments of toxic chemicals • Integrating metapopulation...

Ngày tải lên: 11/08/2014, 09:21

... Ferson, 1997): Interval risk decline is the probability of a population declining by as much as a given percentage of its initial value at any time during the simulation Interval extinction risk is ... (geographic information system) software that combines a database and mapping capability; often used in spatially explicit modeling growth rate the rate of change of population abundance Depending ... Springer-Verlag, Berlin Mineau, P., B.T Collins, and A Baril 1996 On the use of scaling factors to improve interspecies extrapolation of acute toxicity in birds Regul Toxicol Pharmacol 24:2429 Minns, C.K.,...

Ngày tải lên: 11/08/2014, 09:21

... the problem of missing data in the field of HRQL and lung transplantation, and secondly to compare results from different methods of analysis in a data- set where missing data occur in order to ... investigation Irrespective of the reasons for, and the magnitude of the missing data problem, two methods of analyzing data are commonly performed in studies regarding the effects of lung transplantation ... covered a long period of follow-up, it included different types of missing data, and depending on the period of follow-up, there was a rather substantial amount of missing assessments Patients...

Ngày tải lên: 12/08/2014, 18:22

... the amount of L-argininosuccinate in the cell (Figure 1) There are probably many ways the cell can handle extra amounts of L-argininosuccinate One of them is to increase the efficiency of its utilization ... the increased level of ASL expression The ASL overexpression will speed up Largininosuccinate transformation into fumarate and arginine Thus, even if two genes are not directly involved in regulatory ... packages available, such as Ingenuity Pathway Analysis software [38], which transforms a list of genes into a set of networks according to internal database information of gene pairwise relationships...

Ngày tải lên: 14/08/2014, 21:20

... Schneider et al Data types Toxicity (in vivo and in vitro) and ecotoxicity (acute and chronic) data Ecotoxicity data Ecotoxicity (both acute and chronic) data Toxicity data (both in vivo and in vitro) ... much of the research done within the field of ecotoxicology and risk assessment is financed through tax payer’s money and to not find a way for use of this data in risk assessments would be an inefficient ... approach can include checklists or even pre-defined evaluation criteria A major advantage of using a structured way of evaluating data is increased transparency and predictability of the risk assessment...

Ngày tải lên: 21/06/2014, 03:20

... and Ventura F (2001) Monitoring of pesticides in drinking and related waters in NE Spain with a multiresidue SPE-GC-MS method including an estimation of the uncertainty of the analytical results, ... 30 40 50 60 Incubation time (min) Fig - Formation of MPP metabolites by CYP3A4 up to an incubation time of 60 The molarity of MPP (10 M) at the beginning of the reaction was defined as 100% ... careful monitoring of MPP oxides in drinking water is required to evaluate the acute toxicity of MPP because human population could be exposed to MPP oxon sulfone through the drinking water and...

Ngày tải lên: 05/09/2013, 10:15

... As described above deterministic risk assessments rely on single-point estimates of multiple input parameters to define exposure Current risk assessments use a mixture of average and upper bound ... underestimating risk and to ensure protection of human health or environmental quality The appropriate level of conservatism in risk assessments is the subject of continued debate in setting regulatory ... variability and uncertainty in risk A tiered approach to PRA is recommended for Superfund sites, beginning with a point-estimate analysis or deterministic risk assessment, progressing to PRA as needed...

Ngày tải lên: 14/02/2014, 03:20