Computer controlled chamber measurements for clay adherence relevant for potential dioxin exposure through skin

Abstract

A computer-controlled mechanical chamber was used to control the contact between aluminum sheet samples laden with clay, and cotton sheet samples for the measurement of mass transfer. The contact parameters of pressure (20 to 60 kPa) and time (10 to 70 sec) were varied for 160 multiple experiments of mass soil transfer. Before log transformation the average transfer for 'First Transfer' of clay particles was 34.4 ± 6.3 mg/8.97 cm(2) while that for 'Total Transfer' was 36.1 ± 6.8 mg/8.97 cm(2). Second contact, therefore, resulted in an average transfer of 1.70 ± 0.76 mg/8.97 cm(2). These values are well above adherence values measured for potting soil and sand as reported for previous experiments using the same methodologies. Based on the univariate analysis and the multiple regression analysis we were able to see some effect of parameters on the clay adherence values. The effect of pressure increases was significant for the higher levels of 50 and 60 kPa. In addition, we observed that increases in temperature were significant for 'First Transfer,' and less so for 'Total Transfer'. Past experiments using potting soil and play sand show high adherence values to human cadaver skin over cotton sample; the same scenario would be expected for clay. This data set can be used to improve estimates of dermal exposure to dioxins found in ball clays often used by artisans in the making of pottery.

Soil, Hand, and Body Adherence Measures across Four Beach Areas: Potential Influence on Exposure to Oil Spill Chemicals

“…Even though it is possible to control and assess the main factors that may affect soil adherence to skin in laboratory experiments [24][25][26][27], it is difficult to simulate real-world conditions involving serial contact events or typical activities of children in the field. To date, there have been some field studies that investigated soil-to-skin adherence factors [28][29][30][31], but measures are limited at beach settings.…”

Combined Analysis of Results on Single and Multiple Contacts: Potting Soil, Sand and Clay Transfers to Cloth for the Estimate of Soil Adherence to Human Skin

“…Temperature and relative humidity probes were used to closely monitor and record the environmental conditions in the chamber. Previous results were published for adherence experiments conducted with potting soil and sand (Ferguson et al, 2008;Ferguson et al, 2009 a, b, c) and for clay based on single contacts (Ferguson et al, 2012). Those past experiments were combined with these multiple clay experiments to look at single, multiple, and total transfers for the overlapping pressures of 20, 30, 40, and 50 kPa (60 kPa was excluded for sand and potting soil), and for 10, 30, and 50 seconds (60 seconds was excluded for sand and potting soil).…”

“…The adherence of clays, resulting from single contacts, has been previously presented in relation to artisans exposed to clays contaminated with dioxins (Ferguson, Bursac, Johnson, & Davis, 2012). Adherence studies of sand and potting soils were also previously published to provide data needed to model children's dermal exposure in and around the home (Ferguson, Bursac, Coleman, Biddle, & Johnson, 2008;Ferguson, Bursac, Coleman, Biddle, & Johnson, 2009 a, b;Ferguson, Coleman, Bursac, & Johnson, 2009c).…”

Evaluation of a robotic transfer replicator: machine parameters that affect measurements of transfer of particulates from carpet surfaces to human skin versus human skin-like surfaces

“…Many laboratories have performed experiments on the transfer of pesticides and particulates from a variety of donor surfaces to a variety of receptor materials, including human hands and fingers. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] A few of these researchers have calculated the percent transfer (amount transferred/ amount available for transfer). 1 Fewer researchers have documented transfer after multiple transfer events from the same surface.…”