Environmental Science - Toxicology - Lead Bioavailability

Lead Bioavailability

Summary of Estimates of Gastrointestinal Absorption of
Lead in Children and Adults

Study	Lead Dose (mg)	% Lead Absorption (subjects, estimates)		Study Design (dosing, absorption, estimation methodology, subjects)
Study	Lead Dose (mg)	Fed	Fasted
Children
Alexander et al. (1974)	9 + 4 (per kg/day)	53 (11,11)	--	Dietary lead; lead intake minus fecal excretion; healthy children; mean age (+SD) 33 + 33 m, range 3-98 m.
Barltrop and Strehlow (1977)	6 + 4 (per kg/day)	-43 + 149 (29, 29)	--	Dietary lead; absorption lead intake minus fecal excretion; hospitalized children; mean age (+SD) 3 + 44 m, range 0.7-137 m.
Ziegler et al. (1978)	9 + 5 (per kg/day)	26 + 55 (12, 89)	--	Dietary lead; lead intake minus fecal excretion; healthy children; mean age (+SD) 7.8 + 5.2 , range 0.5 - 24.5 m. Absorption was 40% + 22 at lead intakes greater than 4.3 mg/kg/day and mean intake (+SD) 12 + 4 mg/kg/day.
Adults
Blake (1976)	NA	21.1 + 16.9 (10, 11)		Tracer dose in water without carrier 2 hours after a meal; 4-day whole-body retention of tracer.
Blake et al. (1983)	220	--	69.5 + 3.9 (3, 3)	Tracer dose with lead chloride carrier either cooked in food; 4-day whole-body retention of tracer.
Graziano et al. (1996)	250 (per 70 kg)	--	70 + 18 (6)	Lead in sherry after an overnight fast and 5 hours preceding a meal; blood lead kinetics after oral or i.v. dose.
Heard and Chamberlain (1982)	100	3.0 + 1.0 (6, 6)	63.3 + 1.7 (8, 8)	Tracer dose in water with carrier (compound not reported) given with a meal or after an overnight fast and 6 hours preceding a meal; 5-7-day whole-body retention of tracer.
Hursh and Suomela (1968)	NA	8.5 + 7.4 (3, 3)		Tracer dose in beer without carrier 1-2 hours after a meal; 24-hour urinary excretion of tracer after oral or i.v. dose.
James et al. (1985)	55	3.5 + 2.9 (10, 10)	61.3 + 8.7 (23, 23)	Tracer dose in water as lead acetate carrier at the mid-point of a meal or on the 12^th hour of a 19-hour fast; 7-day whole-body retention of tracer
Maddaloni et al. (1998)	250 (per 70 kg)	2.5 + 1.7 (6, 6)	26.2 + 8.1 (6, 6)	Lead in 70-100 mg soil immediately after a meal or after an overnight fast and 5 hours preceding a meal; blood lead kinetics after oral or i.v. dose.
Rabinowitz et al. (1980)	144-221	8.2 + 2.8 (5, 13)	35 + 13 (5, 9)	Tracer dose in water as lead nitrate, cysteine or sulfide carrier (form did not affect absorption) at mid-point of meal or on the 9^th hour of a 16-hr fast; modeling of kinetics of blood lead and fecal lead excretion.
Watson et al. (1986)	NA	10.0 + 2.4 (9,9)	--	Three tracer doses as lead chloride at midpoint of consecutive meals; 7-day or 12-day whole-body retention of tracer compared to retention after an i.v. dose.

References
Alexander, F.W., Clayton, B.E. and Delves, H.T. Mineral and Trace-metal Balances in Children Receiving Normal and Synthetic Diets, Quarterly Journal of Medicine, New Series, 93:89-111, 1974.

Barltrop, D. and Strehlow, D. The Absorption of Lead by Children, Proceedings of Trace Element Metabolism in Man and Animals, 3, July 1977, pp.332-334. Technische Universitat Munchen, Freising, Germany, 1977.

Blake, K.C.H., Absorption of 203Pb from Gastrointestinal Tract of Man, Environmental Research, 11:1-4, 1976.

Blake, K.C.H., Barbezat, G.O. and Mann, M. Effect of Dietary Constituents on the Gastrointestinal Absorption of 203Pb in Man, Environmental Research, 30:182-187, 1983.

Graziano, J.H., Blum, C.B., LoIacano, N.J., Slavkovich, V., Manton, W.I., Pond, S., Moore, M.R. A human in vivo model for the determination of lead bioavailability using stable isotope dilution. Environmental Health Perspectives, 104: 176-179, 1996.

James, H.M., Milburn, M.E. and Blair, J.A., Effects of Meals and Meal Times on Uptake of Lead from the Gastrointestinal Tract of Humans, Human Toxicology, 4:401-407, 1985.

Heard, M.J. and Chamberlain, A.C., Effect of Minerals and Food on Uptake of Lead from the Gastrointestinal Tract in Humans, Human Toxicology, 1:411-445, 1982.

Hursh, J.B., Suomela, J. Absorption of 212Pb from the gastrointestinal tract of man. Acta Radiolgica: Therapy, Physics, Biology, 7: 108-120, 1968.

Maddaloni, M., LoIacono, N., Manton, W., Blum, C., Drexler, J. and Graziano, J. Bioavailability of soil-borne lead in adults by stable isotope dilution. Environmental Health Perspectives, 106: 1589-1594, 1998.

Rabinowitz, M.B., Koppel, J.D. and Wetherill, G.W. Effect of Food Intake on Fasting Gastrointestinal Lead Absorption in Humans, American Journal of Clinical Nutrition, 33:1784-1788, 1980.

Watson., W.S., Morrsion, J., Bethel, M.I.F., Baldwin, N.M., Lyon, D.T.B., Dobson, H., Moore, M. R. and Hume., R. Food iron and lead absorption in humans. American Journal of Clinical Nutrition, 44: 248-256, 1986.

Ziegler, E.E., Edwards, B.B., Jensen, R.L., Mahaffey, K.R. and Foman, S.J., Absorption and Retention of Lead by Infants, Pediatric Research, 12:29-34, 1978.