[Stimulation for sebum excretion of PCDDs, PCDFs and coplanar PCBs on bathing ceramic sand bath]

We previously reported that high risk environmental contaminants such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (PCBs) are excreted not only in feces but also in the sebum of the face and body in both normal subjects and Yusho patients. A combination of administration of rice bran fiber and cholestyramine increased fecal excretion of PCDFs and PCBs. In the present study, we stimulated excretion of these compounds in sebum using a ceramic sand bath, a kind of sand bath using small ceramic balls (3.5 mm diameter) instead of natural sand. Five normal volunteers participated in this experiment. Sebum eliminated from the body on bathing ceramic sand bath was collected and weighed and then concentrations of the compounds interest in the sebum were determined. We also examined the effects varying the bath conditions such as temperature of sand, length of bathing time and frequency of taking bath on the amounts of the compounds in the eliminated sebum. The results can be summarized as follows: 1. The average amount of sebum per one bath eliminated from the body during the ceramic sand bath was 0.252 g, and those of PCDDs, PCDFs and coplanar PCBs in it were 2.2, 2.0 and 2.2 pg of TEQ (2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent quantity). It was considered that the amounts of these compounds corresponded to between one quarter and third of those eliminated through the sebum in a day. On the other hand, 0.05 g of the sebum was collected from the face during the bath, included 0.39, 0.39 and 0.59 pg TEQ for PCDDs, PCDFs and coplanar PCBs, respectively. 2. As the number of bathing times a day increased, the amount of sebum per bath gradually decreased. However, we could not determine the influence of the conditions of the bath such as temperature and time.