“…Almadén (central Spain), regarded as the largest geochemical anomaly of mercury on Earth, has been object of a reconnaissance survey, finding that no system (rocks, soils, sediments, waters, atmosphere, biota) in this mining district is free from strong Hg contamination (Ferrara, 1999;Ferrara et al, 1997Ferrara et al, ,1998Higueras, Oyarzun, Biester, Lillo, & Lorenzo, 2003;Higueras et al, 2006;Maserti, Ferrara, Panichi, & Storni, 1996;Sánchez et al, 2005).…”