Mössbauer spectroscopic study of iron oxide deposits in liver tissue from the marine mammal Dugong dugong

A sample of liver from the marine mammal Dugong dugong was found to have an iron concentration of 137 000 Μg g‑1 Fe dry weight. Histological examination of the tissue revealed dense extracellular deposits of iron-containing particles about 40 to 80 Μm in diameter. Mössbauer spectra of the sample at temperatures between 17 and 200 K show superparamagnetic behaviour with a mean superparamagnetic blocking temperature of about 67 K, with the sextet being extinguished between 160 and 200 K. The blocking temperature and spectral parameters are indicative of the goethite-like form of hemosiderin that has previously been reported in some iron-loaded thalassemic human tissues