Micropollutants in Italian Kaolin: Assessment and Formation Proposal

Kaolinitic rocks can be originated in 2 different ways: from the action of volcanic fluids that altered some feldspar containing rocks, the so called primary Kaolin and secondary, showing a sedimentary formation after the weathering, erosion and transport of the primary rocks. Typical of the latter are the “ball clays”, also called “plastic clays”, that are used as main raw material in ceramics as they keep a white color after “cooking” as well as animal feed ingredients as binder and anticaking additives. Primary Kaolin, that is mainly constituted by kaolinite clay, is used in a wide amount of applications like in pottery (also in bone china if mixed with bone powder), in pharmaceutical industry as excipients and in paper industry. In the past years PCDD/Fs contained in the above rocks created serious contamination problems in different part of the world1,2,3,4. The PCDD/Fs source has been certainly recognized as non anthropogenic from their “natural pattern” but their formation model has not been uniformly accepted5,6. Recent data reported from the Italian Society of Ceramics7 shows that in Italy there are 4 mines for secondary kaolin, producing 1,000,000 tonnes/year and only one mine for “primary” kaolin producing 500,000 tonnes/year. This mine in located in Monte Sughereto, Sasso di Furbara, Rome Province. The aim of the present study was to assess the presence of organic micropollutants in the kaolinic ore and try to better understand the kaolin and micropollutants origin.