Table 2.

Oral Reference Dose (RfD), Upper Tolerable Daily Intake (UL) and Recommended Daily Intake (RDI) Values for Investigated Heavy Metals

Heavy metal	Cu	Fe	Ni	Mn	Zn
The oral reference dose (RfD) (mg/kg body weight/day)	0.04 [5, 40 – 42]	0.7 [5, 40 – 43]	0.02 [41, 42]	0.014 [41, 42]	0.3 [5, 40 – 43]
Upper tolerable daily intakes (UL)* (mg/day/person) for adults [41, 44]	10	45	1	11	40
Recommended daily intakes (RDI)** (mg/day/person) for men (women) [41, 44]	0.900	8 (18)	0.500	2.3 (1.8)	11 (8)

*The tolerable upper intake level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in the specified life stage group [44].