The accumulation of essential metals in the liver is likely
linked to its role in metabolism[4]; high levels of Zn and Cu in
hepatic tissues are usually related to a natural binding proteins
such as metallothioneins (MT) [27] which act as an
essential metal store (i.e., Zn and Cu) to fulfill enzymatic and
other metabolic demands [28,29]. In the same way, Fe tends to
accumulate in hepatic tissues due to the physiological role of
the liver in blood cells and hemoglobin synthesis [27].
On the other hand, the liver also showed high levels of non-essential
metals such as Cd; this finding could be explained by the
ability of Cd to displace the normally MT-associated essential
metals in hepatic tissues [29]. Similar results of high Zn, Cu
and Cd in the liver were observed in many field studies
[4,30e33]..