American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida. Fairfax, VA: American Industrial Hygiene Association, 2000 May; :55
Past procedures for recommending skin notations (SNs) have been criticized for being inconsistent, subjective, and poorly documented. At this time, recommending a SN relies on empirical data, the quality and relevancy of which may be highly variable. To overcome these limitations, a mathematical approach may be used which requires readily available or obtainable physical data such as molecular weight and solubility. Data from the modified "Robinson model" were compared with the calculated systemic dose received by inhalation at the occupational exposure limit (OEL), assuming 75% retention and absorption. The need for a skin notation was conservatively calculated for a skin exposure dose assuming a skin area of 360 cm2 (contact surface of both palms plus fingers) exposed for eight hours. If the ratio of dermal to inhalation dose was equal to or greater than 1, the need for a SN was suggested. The OEL SN assignments by ACGlH, NIOSH, ECETOC, and several European nations were compared to the model predictions. Although the great majority of results using this model agreed with internationally assigned SNs, some discrepancies were identified. For instance, it is estimated that the dermal-to-inhalation dose ratio for benzene (at the ACGIH TLV®) is 49:1, yet there is no assignment of a skin notation to benzene by HSE or NIOSH. On the other hand, the model predicted no need for a skin notation for 1,3-dichloropropene (ratio 0.47:1) although ACGIH, ECETOC, and NIOSH recommend a SN assignment for 1,3-dichloropropene, which ostensibly is based on a single animal LD50 experiment. In conclusion, this mathematical approach may facilitate assignment of skin notations, particularly when adequate empirical data do not exist. Although predictive approaches to assigning skin notations might have current limitations, model refinement can be improved as access to toxicological data continues.
Exposure-assessment; Mathematical-models; Skin-exposure; Exposure-limits; Standards; Quality-control; Quality-standards; Data-processing; Information-systems; Molecular-structure; Weight-factors; Absorption-rates; Inhalants; Permissible-concentration-limits; Chemical-properties; Toxic-dose; Lethal-concentrations; Lethal-dose; Analytical-models; Dermal-exposure
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida