Dermal Exposure Research: Improved Methods and Models

Objective/Intended Use

This research is being conducted to improve estimates of dermal absorption methods and models to reduce uncertainty in estimates of dermal exposure that occur in a variety of human activities associated with pollutants that contaminate soil, water, and sediment.

Abstract

Estimates of dermal absorption of chemicals reported in the literature are highly variable due to the different measurement methods used. This makes it difficult to estimate dermal exposure accurately and to predict the dermal absorption of untested chemicals. This effort attempts to improve our ability to estimate dermal absorption and dermal exposure. The approach consists of collection and analysis of existing dermal absorption data submitted to the Agency. These data will be compared to published studies to standardize and validate dermal absorption methods, identify physical and chemical characteristics that govern dermal absorption. Research results will be published in the scientific literature. Citations: Spalta EW, Kissel JC, Shiraia JH and Bunge AL (2008) Dermal absorption of environmental contaminants from soil and sediment: A critical review. Journal of Exposure Science and Environmental Epidemiology: 1-30. Normal AM, Kissel JC, Shirai JH, Smith JA, Stumbaugh KL, and Bunge AL (2008) Effect of PBPK model form on interpretation of in vivo human aqueous dermal exposure trials. Toxicology Sciences. 104:210-217.

Project Status

Dermal absorption studies for several pesticides have been obtained. Two papers have been published in the scientific literature that describe use of these data to estimate dermal absorption: (1) Zendzian RP (2000) Dermal absorption of pesticides in the rat. AIHAJ 61:473-483. (2) Zendzian RP, Dellarco M, Validating in vitro dermal absorption studies: an introductory case study.in Alternative Toxicological Methods for the New Millennium. Salem H, ed. CRC Press, Boca Raton, FL p. 205-217. Studies are underway to estimate partition coefficients for highly lipophilic polutants and to investigate the use of Solid Phase Micro Extraction (SPME) chromotography to estimate dermal absorption from chemically contaminated soils. Additonal research is underway to validate dermal absorption models and to develop methods to characterize time/activity patterns with sediments.

Project Start Date

12/31/2008

Project Completion Date (Actual/Projected)

12/31/2008