Classification of dermal exposure modifiers and assignment of values for a risk assessment toolkit

This paper describes how default dermal exposure values can be adjusted with modifier values for specific work situations. The work presented here is supplementary to a toolkit developed for the EU RISKOFDERM project. This toolkit is intended for the assessment and management of dermal risks in small and medium sized enterprises. Potential dermal exposure (on the outer envelope of the body) is estimated with an algorithm whereby modifier values are applied multiplicatively to dermal default exposure values. These exposure modifiers with their assigned factors are intended to increase or decrease the potential (default) dermal exposure accordingly. Default estimates are modified to obtain two modified defaults: potential exposure rate to the hands and to the body. Quantitative exposure data is at present inadequate and insufficient to derive meaningful information that can be used for the selection of independent modifiers and the assignment of appropriate values. Instead, available information from the literature was considered and, in combination with expert judgement, 15 potential dermal modifiers were selected. Modifiers were classified and grouped into non-overlapping groups in order to avoid double scoring. Values were assigned to modifiers in three different exposure routes, i.e. direct contact, surface contact and deposition. Depending on the significance of a modifier, the values assigned to modifiers were weighted in equal steps on a log-scale. The values assigned to modifiers as presented in this paper are open to validation and revision once new data become available.