Dermal absorption of chemical contaminants from soil

Abstract

Recently, Spalt et al. (1) critically reviewed the available (English language) literature describing dermal absorption from soil. The earliest entry in that review is a paper by Swiss investigators concerning oral and dermal absorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in multiple formulations including soil (2). That investigation was inspired by dioxin contamination events in Germany and Italy in the 1970s. All but one of the subsequent studies identified in the review were conducted in the United States. Given the universality of English as the language of science, this observation presumably reflects research funding priorities stemming from political attention to hazardous waste sites and other contaminated lands, and the relative importance of quantitative risk assessment in the regulatory environment in the United States, rather than mere language bias. Regardless, the total body of research is quite limited [Spalt et al. (1) found fewer than 50 distinct studies] and represents the efforts of a relatively small group of investigators. In addition to its limited scope, significant shortcomings of the extant dermal-absorption-from-soil literature include (i) a lack of uniformity of methodology, which greatly hinders systematic comparison across compounds and laboratories, (ii) frequently inadequate reporting of experimental details, and (iii) obvious flaws in some experimental approaches.