Table 1.

Reference Doses (RfD) in (mg/kg-day) and Cancer Slope Factors (CSF) for the Pathways

Heavy Metal	Oral RfD	Dermal RfD	Inhalation RfD	Oral CSF	Dermal CSF	Inhalation CSF	References
Pb	3.60E-03	-	-	8.50E-03	-	4.20E-02	34,35
Chromium (VI)	3.00E-03	-	3.00E-05	5.00E-01	-	4.10E+01	36,34
Cobalt	2.00E-02	5.70E-06	5.70E-06	-	-	9.80E+00	36
Nickel	2.00E-02	5.60E-03	-	-	-	-	34
Copper	0.037	0.037	-	-	-	-	34,36
Zinc	3.00E-01	7.50E-02	-	-	-	-	34,36

Abbreviations: RfD, reference dose; CSF, cancer slope factor