1. Protistology-Zoology Unit, Biology Department, University of Pisa, Via A. Volta 4, 56126, Pisa, Italy
2. Department of Civil and Environmental Engineering, University of Florence, Via S. Marta n.3, 50139, Florence, Italy
3. CER2CO (CEntro Ricerca Reflui Conciari), Via Arginale Ovest 8, 56020, San Romano,S. Miniato, Pisa, Italy