Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Due to homeostatic control mechanisms, bioaccumulation is not relevant to essential elements in general and to zinc in particular.

In experimental work, high BCF factors are observed at the lowest zinc exposure levels, due to the fact that organisms will concentrate zinc to satisfy internal physiological needs for the essential element. For the same reason of homeostasis, the BCF will strongly decrease when exposure concentrations increase. This results in a general negative relationship between BCF and exposure (McGeer et al 2003).

On bioaccumulation, the EU risk assessment report (ECB 2008) concluded that “secondary poisoning is considered to be not relevant in the effect assessment of zinc. Major decision points for this conclusion are the following. The accumulation of zinc, an essential element, is regulated in animals of several taxonomic groups, for example in molluscs, crustaceans, fish and mammals. In mammals, one of the two target species for secondary poisoning, both the absorption of zinc from the diet and the excretion of zinc, are regulated. This allows mammals, within certain limits, to maintain their total body zinc level (whole body homeostasis) and to maintain physiologically required levels of zinc in their various tissues, both at low and high dietary zinc intakes. The results of field studies, in which relatively small differences were found in the zinc levels of small mammals from control and polluted sites, are in accordance with the homeostatic mechanism. These data indicate that the bioaccumulation potential of zinc in both herbivorous and carnivorous mammals will be low."