Exposure prediction

Personal exposure Predictions of exposure of occupants to airborne contaminants for risk assessment, inhaled doses, or time-integrated concentration values. 

Aquatic chemical exposure prediction tool Ecotoxicological effects Not considered... 

Boeije GM, Vanrolleghem P, Matthies M (1997) A georeferenced aquatic exposure prediction methodology for down-the-drain chemicals. Contribution to GREAT-ER 3. Water Sci Technol 36 251-258... 

Purpose Potential for effects from unintended exposure Predict and evaluate clinical findings and preclude serious hazards from clinical use... 

It may often be useful to initially conduct an exposure assessment based on worst-case assumptions, and to use default values when model calculations are applied. Such an approach can also be used in the absence of sufficiently detailed data. If the outcome of the risk characterization based on worst-case exposure assumptions is that the substance is not of concern, the risk assessment for that substance can be stopped with regard to the effect/population considered. If, in contrast, the outcome is that a substance is of concern, the assessment must, if possible, be refined using a more realistic exposure prediction in order to come to a definitive conclusion. 

Walker, S. and Griffin, S. (1998) Site-specific data confirm arsenic exposure predicted by the US Environmental Protection Agency. Environmental Health Perspectives, 106(3), 133-39. 

Other published works relevant to estimation of properties and reactivity of chemicals may be of value to the reader. A book edited by Neely and Blau (1985) (Environmental Exposure from Chemicals) is less comprehensive but has several excellent chapters on basic information, such as the one on biodegradation by Klecka. Other volumes that may be useful include The Properties of Drugs, edited by Yalkowsky et al. (1980) and Aqueous Solubility by Yalkowsky and Banerjee (1991). Chemical Exposure Predictions, edited by Calamari (1993), is somewhat different in focus but may be useful for information on exposure modeling, especially for the soil compartment. 

Calamari, D., Ed. 1993. Chemical Exposure Predictions. Lewis, Boca Raton, FL. 

Greiner, P. 1993. Ecotoxicology and environmental hazard assessment in the regulatory framework of chemical control in the EEC. In Chemical Exposure Predictions, Ed. D. Calamari, pp 205-219. Lewis, Boca Raton, FL. 

There is virtually no literature describing bioconcentration of organic compounds by wild aquatic macrophytes in spite of the facts that these plants are often the major primary producers in shallow inland waters, and are essential habitat components for both aquatic and terrestrial animals. Lockhart et al. (14) provided a regression equation describing uptake curves for a variety of organic compounds by duckweed (Lemna minor) cultures in laboratory exposures. Predictions from the regression equation agreed quite well with field observations on bioconcentration of permethrin in outdoor ponds (15). 

It is clear that an accurate exposure prediction at the landscape level requires models calibrated and validated for the landscape unit of interest and that the input parameters used have a high precision and accuracy for the area of interest (see Section 1.7 in Chapter 1). However, in a prospective risk assessment for new chemicals not yet placed on the market, chemical monitoring data are not yet available, and exposure predictions at the landscape level may be characterized by a relatively high uncertainty because the scale and intensity of the use of these chemicals are not... 

Prediction of actual exposure Prediction of actual exposure Prediction of actual effect Prediction of actual exposure... 

Prediction of actual exposure Prediction of actual exposure... 

Because the objective of an exposure assessment is to characterize both the magnitude and the reliability of exposure scenarios, planning for an uncertainty analysis is a key element of an exposure assessment. The aims of the uncertainty analysis in this context are to individually and jointly characterize and quantify the exposure prediction uncertainties resulting from each step of the analysis. In performing an uncertainty analysis, typically the main sources of uncertainties are first characterized qualitatively and then quantified using a tiered approach (see chapter 4). In general, exposure uncertainty analyses attempt to differentiate between key sources of uncertainties scenario uncertainties, model uncertainties and parameter uncertainties (for definitions, see section 3.2). 

A different approach, called a quantitative risk assessment, is used for nonthreshold effects, such as cancer. Sophisticated statistical models are used to extrapolate the experimental animal data obtained at high doses to the low exposures predicted in humans. The linearized multistage (LMS) model is frequently... 

Tischer, M. Brendendiek-Kamper, S. and Poppek, U. (2003), Evaluation of the HSE COSHH Essentials Exposure Predictive Model on the basis of BauA field studies and existing substances exposure data. Annals of Occupational Hygiene, Vol 47 No 5 pp 557-569. 

Macalady, D. L. and Schwarzenbach, R. (1993). Predictions of chemical transformation rates of organic pollutants in aquatic systems. In Chemical Exposure Prediction, ed. D. Calamari, pp. 27—46. Lewis Publishers, Inc., Boca Raton, FL. 

Vighi, M. and Di Guardo, A. (1995). Environmental distribution and fate and exposure prediction. In Pesticide Risk in Groundwater, ed. L. Bergman and M. Pugh, pp. 73-100. Lewis Publishers, Inc., Boca Raton, FL. 

Table 10.5 shows corrosion rates after 1 year of exposure predicted for difierent corrosivity classes [40]. 

Table 10.5 ISO 9223 Corrosion Rates After 1 Year of Exposure Predicted for Different Corrosivity Classes [40]...

The more general limitations of ecosystem models center on the interpretation of results. The processes occurring in a microcosm are not on the same time and spatial scales as those in the natural environment. Effects which are artifacts of the microcosm design are not always clearly distinguishable. In engineering models, these scaling effects are accounted for by the application of scaling criteria. Similar criteria need to be established for model ecosystems before environmental exposure predictions can be reliably made (707). 

Broad-Spectrum Detection Fieldable Dx Sequencing Molecular Recognition Host Response Exposure Prediction Functional Consequences... 

Information Management liMof Control Exposure Prediction... 

Distribution CR845 exhibits a low volume of distribution in humans related to its high level of solubility. Highest concentrations are found in the plasma compartment with minimal to no exposure predicted in the central nervous system (CNS) based on preclin-ical distribution analysis. CR845 has a plasma half-life of approximately 2 hours... 

These estimated parameters can be used to model the behavior of a new chemical substance. The inaccuracies inherent in deriving physical/chemical properties or fate and transport behavior from SAR, rafher fhan from reliable experimental data, will obviously affect the accuracy of exposure predictions. 

BEAT is only intended for predicted occupational exposure and not consumer exposure. Predictive consumer exposure can be determined using the CONSEXPO model developed by RIVM in the Netherlands and incorporated into EUSES (the European Uniform System for Evaluating Substances). In the USA residential SOPs have been developed for consumer use of antimicrobials and pesticides in the house. These models include ... 

McGinnity, D.F., Collington, J., Austin, R.P., and Riley, R.J. (2007) Evaluation of human pharmacokinetics, therapeutic dose and exposure predictions using marketed oral drugs. Current Drug Metabolism, 8,463-479. 

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