Tissue, age, and sex distribution of thallium in shrews from Doñana, a protected area in SW Spain.

In 1998, the protected area of Doñana, an important natural region in SW Europe, was affected with great amount of acidic waters and sludge from a pyrite mine loaded with toxic metals such as thallium (Tl). Since this ecological catastrophe, several studies have addressed the effects of this pollution on the flora and fauna in this protected area. However, in contrast to other non-essential metals, scarce information on Tl was available after this disaster, especially in terrestrial environments. This study reported a 3- and 10-fold increase in Tl in liver and kidneys, respectively, of the greater white-toothed shrew, Crocidura russula, in the polluted site in comparison with reference animals. Kidneys showed the highest concentrations of this metal in the polluted site, whereas both organs analysed have similar concentrations in the reference site. Although no significant age-dependent variation was found, adults had higher concentrations than juveniles. Moreover, females showed higher concentrations than males. These results demonstrate the high entrance and transfer of Tl in terrestrial food-chains. To the best of my knowledge, these data constitute the first measurements of Tl in mammals from the protected area of Doñana and are among the few available for insectivorous mammals.