A Proposal for Calculating Occupational Exposure Limits for Volatile Organic Compounds Acting as Sensory Irritants on the Basis of Their Physicochemical Properties

A common biological effect of exposure to workplace chemicals is sensory irritation. The ACGIH threshold limit values (TLVs) are developed based on data derived from industrial settings as well as experimental human and animal studies. Considering the limited amount of human data and the tendency to reduce the volume of animal testing, there is a need for an alternative method to assess sensory irritation. Nasal pungency involves transfer of a compound through the mucosa into the receptor area. This environment is inhomogeneous, being partly a hydrophobic lipid-like and hydrophilic aqueous-like area. A general equation has been developed that seems satisfactory for explaining the transfer of volatile organic compounds (VOCs) from the gaseous phase to biophases, making it possible to calculate the nasal pungency threshold (NPT). The obtained correlation between log 1/NPT and log TLV for 71 VOCs, which is based exclusively on their irritant properties, indicates that for the compounds that act through a nonreactive mechanism (alcohols, ketones, esters, ethers, aromatic and aliphatic hydrocarbons, amides) the relationship between these values differs from that calculated for compounds that act through a reactive mechanism (aldehydes, allyl compounds, aliphatic amines, benzyl halides, carboxylic acids, acrylates, and mercaptans). The correlation coefficient for nonreactive VOCs is very high (n ) 46, r ) 0.89), and it appears that the regression equation (log TLV ) -0.422 log 1/NPT + 0.309) could be used to predict occupational exposure limits (OELs) for this group of compounds. Regarding reactive VOCs, the correlation coefficient is considerably lower (n ) 25, r ) 0.32), which implies that some kind of correction for their reactivity would have to be applied to calculation.

Authors: Jakubowski, Marek; Czerczak, Slawomir ;Journal of Occupational and Environmental Hygiene 2010, 7(7), 429-434 (Eng) ;