Contribution to the penetration of radionuclides across the skin. Concentration dependence of strontium through the skin in vitro.

Toxicological studies of radionuclide passage across the skin, which represents a crucial barrier of radiation, are important for ensuring the quality of the environment. Both (137)Cs and (90)Sr are most frequently involved in radionuclide contamination of the human body. In our study, we selected (90)Sr because this radionuclide is chemically very close to the bio-element calcium. The permeation of (90)Sr from donor solution across the intact skin of 5- or 9-day-old rats (5DR, 9DR) and across stripped and split skin of the 5DR was studied. The experiments in vitro were carried out using vertical diffusion cells. Strontium chloride (SrCl(2)) was used as carrier in the donor solution in different concentrations. Liquid scintillation spectrometry was applied for radiation detection. The experiments showed that: the permeated fraction of (90)Sr(2+) was indirectly proportional to the carrier concentration in the donor solution; the stratum corneum was found to be the principal penetration barrier of strontium; and in the case of the 9DR the dominant route of strontium penetration was along the follicles.