The PTWI is an estimate of the amount
of a chemical with no intended function that
can be ingested weekly over a lifetime without appreciable health risk (WHO 1989).
The original PTWI for Cd was set at
400–500 µg/person/week (WHO 1989), but it
was later revised to 7 µg/kg body weight/week
(WHO 1993). In its latest assessment, the
WHO adjusted the tolerable intake of Cd to
25 µg/kg body weight/month (62 µg/day for
a 70-kg person) (WHO 2010). However, the
EFSA (2011) established a tolerable intake of
2.5 µg/kg body weight/week (25 µg/day for
a 70-kg person). In addition, the WHO set a
U-Cd level of 5.24 µg/g creatinine as a threshold to protect against kidney damage, whereas
the EFSA set a U-Cd threshold of 1 µg/g creatinine. Mortensen et al. (2011) reported that
Cd exposures in the United States resulted in
U-Cd concentrations of > 1 µg/g creatinine
in 4.8% of nonsmoking adults and 20.8%
of smokers