Zinc (mostly in the form of zinc oxide) is added to pig feeds as a
‘cure-all’ for scour and in some countries can be given to pigs of
b10 kg liveweight without a veterinary prescription (Nicholson et
al., 1999). There are traces of Cd in zinc oxide. As shown, additives
given to pigs had higher concentrations of Cd (ZnO: 45.9 mg Cd kg − 1;
Zn (1): 133 mg Cd kg − 1; Zn (2): 48.7 mg Cd kg − 1) (Table 5). Estimated Cd addition rates represent an important source of this metal
to agricultural soils, although Cd is usually thought of as being
added mainly via atmospheric deposition and phosphate fertilizer
use (Nicholson et al., 1998)