In vivo experimental data on the mobility of hazardous chemical elements from clays

Considering the increasing market demand of natural matters for healing purpose and the use of clays in pharmaceutical preparation, new aspects of clay ingestion must be regarded. In particular, the distribution of hazardous chemical elements into organs has been considered (As, Cd, Pb, Se, Te, Tl, Hg and Sb) as previous studies documented the entering of trace elements into bloodstream. Three groups of rats were fed with three different types of clays (plus normal food). Another group was fed only with conventional food and taken as a control experiment. The clays were selected according to their concentration of chemical elements, ranging from very low values to very high ones. For this purpose, a bentonite, a polymineralic marine clay and a black shale were used. The results indicate that during the 6-day trial, no macro-toxic effects were detected in the animals. Nevertheless, the trace elements content of the analysed organs (kidney, liver, heart and brain) is strictly related to the clay trace elements contents: upon increasing the clay trace elements content, the content of the organs also went up. The trace elemental distribution is not homogeneous throughout the body, but the following concentration order was observed: kidney>liver>heart>brain. Since the studies are still in an early stage, and it is not possible to generalize the results in terms of effects on human health, it is, however, clear that the use of clay products must be legally bound due to their side effects.