Existing Default Values and Recommendations for Exposure Assessment

A Nordic Exposure Group Project 2011

image of Existing Default Values and Recommendations for Exposure Assessment

Default values are often used in exposure assessments e.g. in modelling because of lack of actually measured data. The quality of the exposure assessment outcome is therefore heavily dependent on the validity and representativeness this input data. Today the used default factors consist of a wide range of more or less well-documented values originating from many different sources. The purpose of this report is to give an overview and to evaluate exposure factors that are currently used by the authorities and industry in the exposure assessments for both adults (occupational and consumer exposure) and children in relation to REACH. Another important purpose of the report is to contribute towards a further harmonisation of exposure factors by giving recommendations of most valid and representative defaults. These recommendations can be used besides REACH also in biocide's and plant protection product's exposure assessments. The exposure default values were collected from the relevant European sources (ECHA, Consexpo, EUSES, Biocide TNsG, ECETOC, ExpoFacts) as well as from WHO and US-EPA. The following key default factors selected to the evaluation: body weight, body surface area, inhalation rate, soil and dust ingestion, drinking water, food intake, non-dietary ingestion factors, lifetime expectancy, activity factors and consumer products



Lifetime Expectancy

The length of an individual’s life is an important factor to consider when evaluating cancer risk because the dose estimate is averaged over an individual’s lifetime. Since the averaging time is found in the denominator of the dose equation, a shorter lifetime would result in a higher potential risk estimate, and conversely, a longer life expectancy would produce a lower potential risk estimate. (US-EPA, 2009).


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