Evaluating dermal exposure hazards for assignment of skin notations.
Authors
Chen-C; Boeniger-M; Ahlers-H; Demchuk-E
Source
American Industrial Hygiene Conference and Exposition, May 10-15, 2003, Dallas, Texas. Fairfax, VA: American Industrial Hygiene Association, 2003 May; :69
Abstract
Skin notations (SNs) provide a warning of the health hazards from dermal exposures to the chemicals. However, their use as a preventive mechanism is limited, as the SNs are often assigned using inconsistent criteria. A mathematical algorithm was developed to quantitatively characterize the potentials of skin absorption and consequent toxicity arising from chemical exposures. In this algorithm, the time-dependent biological uptake of a chemical through skin (skin dose) is calculated and compared to the dose absorbed via inhalation (inhalation dose). The inhalation dose represents a critical body-burden level and is estimated from the reference 8-hr TWA air concentration (RAC), taken as either the NIOSH REL or the inhalation LC50. The ratio of skin dose to inhalation dose (SI ratio) is then determined to evaluate the dermal toxicity potential of the chemical. To examine the consistency of the proposed algorithm, we evaluated its performance on 108 chemical substances assigned with NIOSH SNs and known to cause systemic toxicity. For 61 chemicals the SI ratio was greater than one when the REL was used as the RAC, and for 45 of these chemicals the ratio exceeded one within 2 hours of simulated exposure. In comparison, the compounds with SI ratios > 1 are more hydrophilic (log Kow = 0.7+/-1.5) than those with SI ratios < I (log Kow = 3.5+/-2.0). For 21 chemicals the ratio was also estimated using the LC50 as the RAC. The SI ratios estimated by LC50 values were correlated, whereas the SI ratios estimated against RELs were not, probably because of the subjectivity and range of considerations introduced when developing these criteria. The findings of this research suggest that the described algorithm provides a parallel analysis to objective toxicity data and may serve as a mechanism for systematic assignment of SNs.
Keywords
Dermatitis; Exposure-levels; Health-hazards; Quantitative-analysis; Skin-absorption; Inhalation-studies; Chemical-properties; Models; Dermal-exposure; Dermal-absorption
NIOSH Division
DSHEFS; HELD; EID
Priority Area
Disease and Injury: Allergic and Irritant Dermatitis
Source Name
American Industrial Hygiene Conference and Exposition, May 10-15, 2003, Dallas, Texas
