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Effect of soil loading on dermal absorption efficiency from contaminated soils
1Department of Environmental Health, University of Washington, Seattle 98195, USA.
Journal of Toxicology and Environmental Health
|May 1, 1996
Summary
Soil loading significantly impacts dermal uptake of contaminants like lindane and 2,4-D. Lower soil loads (1 mg/cm2) resulted in reduced absorption, likely due to incomplete skin coverage, highlighting the need for adjusted exposure assessments.
Area of Science:
- Environmental Science
- Toxicology
- Dermatology
Background:
- Dermal exposure to soil-borne contaminants is a significant public health concern.
- Understanding the influence of soil loading on contaminant absorption is crucial for accurate risk assessment.
Purpose of the Study:
- To investigate the effect of varying soil loadings on the dermal uptake of two pesticides: lindane and 2,4-dichlorophenoxyacetic acid (2,4-D).
- To determine how soil properties influence contaminant absorption through human skin.
Main Methods:
- Utilized an in vitro evaporation/penetration apparatus with human cadaver abdominal skin.
- Assessed dermal absorption of 14C-labeled lindane and 2,4-D at soil loadings of 1, 5, and 10 mg/cm2 using soils with different organic carbon content.
Main Results:
- Mean 24-h dermal absorption varied: 0.45–2.35% for lindane and 0.18–1.64% for 2,4-D, dependent on soil load and type.
- Mass fluxes were lower at 1 mg/cm2 loading compared to 5 and 10 mg/cm2, attributed to incomplete skin coverage.
- Relative percent absorption increased as soil load decreased, though not always proportionally due to contact area and volatilization effects.
Conclusions:
- Dermal absorption of soil contaminants is influenced by soil loading and coverage.
- Laboratory data on dermal absorption require adjustments for soil loading and coverage for realistic exposure assessments.
- A standardized approach using mass transfer coefficients for dermal absorption from soil is recommended to reduce confusion.