Alimentary tract absorption @ S. A. IBRAHIM ET AL. 251 Table Al. (Continued) Ingested form The Rare Earths Cerium (Ce) Various ingested form A Comments 3 x 10 1x 107° Adopted value for workers Value set equal to the actinide elements, general public Revised value for the general public (chronic intakes) ICRP 1979 ICRP 1989 5x 1074 References ICRP 1996 Yttrium (Y) Various forms 1x 1074 Lanthanum (L) Chloride form, animal studies Various forms, animal studies Adopted for both acute and chronic intakes ICRP 1980, 1996; U.S. EPA 1988 1x 107 5x 1074 ICRP 1981 ICRP 1996 Praseodymium (Pr) Soluble forms Adopted for workers Revised value for the general public (chronic intakes) 3x 104 Adopted for workers, value set equal to Ce Revised value for the general public ICRP 1981 Adopted for acute and chronic intakes In normal male subjects ICRP 1980, 1995 5x 1074 The Heavy Metals Tron (Fe) Incorporated in diet FeSO, Various forms 0.10 (0.1-0.3)* ICRP 1996 Boender and Verloop 1969 Kendall et al. 1988 (NEA) 0.30 “Cautious value” based on man and animal studies, chronic intakes 0.3 Adopted value for workers (acute intakes) ICRP 1979 Adopted for the public (chronic intakes) Humanstudy, chronic intakes ICRP 1993, 1996 Adopted for acute and chronic intakes 7 human volunteers investigated, chronic intakes ICRP 1980, 1993, 1996 1x 107 Absorption in the rat Various forms, animal studies 2x 107 ICRP 1979 Soluble compounds, animal studies 1 x 10°? Adopted for workers (acute intakes) Adopted for the public (chronic intakes) Shiraishi and Ichikawa 1972 One male volunteer Animal study Adopted for acute and chronic intakes Yamagataetal. 1969 Runkle et al. 1980 ICRP 1980, 1989, 1996 Adopted for acute intakes by workers ICRP 1979; U.S. EPA 1988 Adopted for chronic intakes by the general public Adopted for acute and chronic intakes ICRP 1993, 1996 Cobalt (Co) Organic and inorganic forms Oxide and hydroxide forms Environmental (trace) levels “Co incorporated in shellfish from Sellafield plant discharge in the Irish Sea Zinc (Zn) Inorganic forms and organic incorporated in diet Incorporated in fish from the Columbia River Zirconium (Zr) Oxalate form Ruthenium (Ru) Contaminated clams Oxide form Soluble chloride, animal studies Other Radionuclides Molybdenum (Mo) Sulfide form (MoS,) All other compounds No specific information provided Bismuth (Bi) “Range of values. 0.05 0.10 0.2 0.50 0.35 (0.25—0.45)* 1 x 10°? (3 x 1077-1 x 10°77) 5x 10°? 0.05 0.80 1.0 0.05 Hunt 1998 Honstead and Brady 1967 ICRP 1989, 1996 ICRP 1980, 1996