Lead does not participate in any metabolic process in humans. Nevertheless, it is the most important non ferrous metal in industry since ancient times. This fact promoted a huge and extensive environmental contamination, allowing for an excessive input of lead by humans through ingestion and inhalation. In this review it is discussed aspects of kinetics and toxicity of lead in its inorganic form, being the most important chemical form presenting in occupational and general environment. As a metal, lead does not suffer biotransformation as other toxic substances. Its metabolism is limited to a complex kinetics of distribution and excretion which depends on its chemical speciation, determining the redox potential, rates of ionization and protein binding; crossing of blood brain and placental barriers; rates of tissue accumulation and renal excretion. Adults absorb 10% after lead ingestion, contrasting with children that can absorb 50%. Lead is distributed rapidly and easily through all tissues, including brain, crossing placental barrier and being secreted in maternal milk. Elimination half lifes can be very different according to the body compartment as follows: for blood = 15 to 30 days (in children under low doses of exposure = 10 to 12 months); soft tissues in general = 60 days; trabecular bone = 90 to 120 days; cortical bone with stable deposits = 25 to 30 years. Lead presents toxic action in the central and peripheral nervous system, renal and hemopoietic systems, by toxic mechanisms that are discussed in the paper.423268276Patterson, C., Ericson, J., Manea-Krichten, M., Shirahata, H., Natural skeletal levels of lead in Homo sapiens sapiens uncontaminated by technological lead (1991) Sci Total Environ, 107, pp. 205-236Paoliello MMB, De Capitani EM. Chumbo. In: Azevedo AA, M. CAA, eds. Metais - Gerenciamento da Toxicidade São Paulo: Atheneu-Intertox2003:353-98Leggett, R.W., An age-specific kinetic model of lead metabolism in humans (1993) Environ Health Perspect, 101, pp. 598-616Shäfer, S.G., Dawes, R.L.F., Elsenhans, B., Forth, W.K.S., Metals Toxicology, pp. 755-804. , Marquardt H, Schafer SG, McCellan R, Welsch F, eds, San Diego: Academic Press;Carrington, C.D., Bolger, P.M., An assessment of the hazards of lead in food (1992) Regul Toxicol Pharmacol, 16, pp. 265-272Toxicologic Profile for Lead - Update Statement (1999) Registry, p. 587. , ATSDR, USDoHHS-PHS-AfTSaD, ed. Atlanta;Davies, D.J., Thornton, I., Watt, J.M., Lead intake and blood lead in two-year-old U.K. urban children (1990) Sci Total Environ, 90, pp. 13-29Nadig, R.J., Treatment of lead poisoning (1990) Jama, 263, pp. 2181-2182Rabinowitz, M.B., Wetherill, G.W., Kopple, J.D., Kinetic analysis of lead metabolism in healthy humans (1976) J Clin Invest, 58, pp. 260-270Gulson, B.L., Jameson, C.W., Mahaffey, K.R., Mizon, K.J., Korsch, M.J., Vimpani, G., Pregnancy increases mobilization of lead from maternal skeleton (1997) J Lab Clin Med, 130, pp. 51-62Bellinger, D., Leviton, A., Waternaux, C., Needleman, H., Rabinowitz, M., Longitudinal analyses of prenatal and postnatal lead exposure and early cognitive development (1987) N Engl J Med, 316, pp. 1037-1043Silbergeld EK. Lead in bone: implications for toxicology during pregnancy and lactation. Environ Health Perspect 1991;91:63-70Ong, C.N., Phoon, W.O., Law, H.Y., Tye, C.Y., Lim, H.H., Concentrations of lead in maternal blood, cord blood, and breast milk (1985) Arch Dis Child, 60, pp. 756-759Gulson, B.L., Jameson, C.W., Mahaffey, K.R., Relationships of lead in breast milk to lead in blood, urine, and diet of the infant and mother (1998) Environ Health Perspect, 106, pp. 667-674Koyashiki, G.A.K., (2008) Níveis de chumbo em leite e sangue de doadores de banco de leite em município do Sul do Brasil, , Mestrado, Londrina: Universidade Estadual de Londrina;Barry, P.S., A comparison of concentrations of lead in human tissues (1975) Br J Ind Med, 32, pp. 119-139Kosnett, M., Becker, C., Osterloh, J., Kelly, T., Pasta, D., Factors influencing bone lead concentration in a suburban community assessed by noninvasive K X-ray fluorescence (1994) J Am Med Assoc, 271, pp. 197-203Smith, D.R., Osterloh, J.D., Flegal, A.R., Use of endogenous, stable lead isotopes to determine release of lead from the skeleton (1996) Environ Health Perspect, 104, pp. 60-66Kehoe, R.A., The metabolism of lead in man in health and disease. I. The normal metabolism of lead (1961) J R Inst Public Health, 24, pp. 81-97Alessio, L., Lead, F.V., (1983) Human biological monitoring of indutrial chemicals series, p. 188. , Alessio L, Berlin A, Roi R, Boni M, eds, Brussels, Luxembourg: Commission of The European Communities;Henretig FM. Lead. In: Goldfrank LR, ed. Goldfrank's Toxicologic Emergencies. New York: McGraw-Hill2002:1200-27Lauwerys, R., Buchet, J.P., Roels, H., Berlin, A., Smeets, J., Intercomparison program of lead, mercury, and cadmium analysis in blood, urine, and aqueous solutions (1975) Clin Chem, 21, pp. 551-557Holness, D., Nethercott, J., Acute lead intoxication in a group of demolition workers (1988) Appl Ind Hyg, 3, pp. 338-341Feldman, R.G., (1999) Occupational and Environmental Neurotoxicology, , Philadelphia: Lippincott-Raven;Matte, T., Figueroa, J., Burr, G., al e. Lead exposure among leadacid battery workers in Jamaica (1989) Am J Ind Med, 16, pp. 167-177Marino, P., Franzblau, A., Lilis, R., al e. Acute lead poisoning in construction workers: The failure of current protective standards (1989) Arch Environ Health, 44, pp. 140-145Lilis, R., Fischbein, A., Diamond, S., Lead effects among secondary lead smelter workers with blood lead levels below 80 mcg/100ml (1977) Arch Environ Health, pp. 256-266Dahlgren, J., Abdominal pain in lead workers (1978) Arch Environ Health, pp. 156-159Spivey, G., Brown, C., Baloh, R., Subclinical effects of chronic increased lead absorption: A prospective study (1979) J Occup Med, 21, pp. 423-429Cullen, M., Robins, J., Eskenazi, B., Adult inorganic lead intoxication: Presentation of 31 new cases and a review of recent advances in the literature (1983) Medicine, 62, pp. 221-247(1992) Oxford Textbook of Clinical Nephrology, , Cameron S, Davison AM, Grunfeld J-P, Kerr D, Ritz E, eds, Oxford: Oxford, Oxford University Press;Woods, J.S., Hematopoietic system (1995) Metal Toxicology, pp. 287-304. , Goyer RA, Klaassen C, Waalkes M, eds, San Diego: Academic Press;CDC. Preventing lead poisoning in young children - a statement by the Centers for Disease Control - Oct 1991: USDHHSPHS-CDCP1991Lansdown, R., Yule, W., Urbanowicz, M.A., Hunter, J., The relationship between blood-lead concentrations, intelligence, attainment and behaviour in a school population: The second London study (1986) Int Arch Occup Environ Health, 57, pp. 225-235Fulton, M., Raab, G., Thomson, G., Laxen, D., Hunter, R., Hepburn, W., Influence of blood lead on the ability and attainment of children in Edinburgh (1987) Lancet, 1, pp. 1221-1226Winneke, G., Brockhaus, A., Ewers, U., Kramer, U., Neuf, M., Results from the European multicenter study on lead neurotoxicity in children: Implications for risk assessment (1990) Neurotoxicol Teratol, 12, pp. 553-559Needleman, H.L., Lead at low dose and the behavior of children (1983) Acta Psychiatr Scand Suppl, 303, pp. 26-37Needleman, H.L., Gatsonis, C.A., Low-level lead exposure and the IQ of children. A meta-analysis of modern studies (1990) Jama, 263, pp. 673-678Haenninen, H., Hernberg, S., Mantere, P., Vesanto, R., Jalkanen, M., Psychological performance of subjects with low exposure to lead (1978) J Occup Med, 20, pp. 683-689Hogstedt, C., Hane, M., Agrell, A., Bodin, L., Neuropsychological test results and symptoms among workers with well-de fined long-term exposure to lead (1983) Br J Ind Med, 40, pp. 99-105Batuman, V., Maesaka, J.K., Haddad, B., Tepper, E., Landy, E., Wedeen, R.P., The role of lead in gout nephropathy (1981) N Engl J Med, 304, pp. 520-523Batuman, V., Lead nephropathy, gout, and hypertension (1993) Am J Med Sci, 305, pp. 241-247Emmerson, B.T., Chronic lead nephrompathy: The diagnostic use of calcium EDTA and the association with gout (1963) Aust Ann Med, 12, pp. 310-324Bennet, W., Lead nephropathy (1985) Kidney Int, 28, pp. 212-220Wedeen, R.P., Malik, D.K., Batuman, V., Detection and treatment of occupational lead nephropathy (1979) Arch Intern Med, 139, pp. 53-57Tuppurainen, M., Wagar, G., Kurppa, K., Thyroid function as assessed by routine laboratory tests of workers with longterm lead exposure (1988) Scand J Work Environ Health, 14, pp. 175-180Gennart, J.P., Buchet, J.P., Roels, H., Ghyselen, P., Ceulemans, E., Lauwerys, R., Fertility of male workers exposed to cadmium, lead, or manganese (1992) Am J Epidemiol, 135, pp. 1208-1219Siegel, M., Forsyth, B., Siegel, L., Cullen, M.R., The effect of lead on thyroid function in children (1989) Environ Res, 49, pp. 190-196Huseman, C.A., Varma, M.M., Angle, C.R., Neuroendocrine effects of toxic and low blood lead levels in children (1992) Pediatrics, 90, pp. 186-189Rosen, J.F., Chesney, R.W., Hamstra, A., DeLuca, H.F., Mahaffey, K.R., Reduction in 1,25-dihydroxyvitamin D in children with increased lead absorption (1980) N Engl J Med, 302, pp. 1128-1131Koo, W.W., Succop, P.A., Bornschein, R.L., Serum vitamin D metabolites and bone mineralization in young children with chronic low to moderate lead exposure (1991) Pediatrics, 87, pp. 680-687Alexander, B.H., Checkoway, H., van Netten, C., Semen quality of men employed at a lead smelter (1996) Occup Environ Med, 53, pp. 411-416Lin, S., Hwang, S.A., Marshall, E.G., Stone, R., Chen, J., Fertility rates among lead workers and professional bus drivers: A comparative study (1996) Ann Epidemiol, 6, pp. 201-208Telisman, S., Cvitkovic, P., Jurasovic, J., Pizent, A., Gavella, M., Rocic, B., Semen quality and reproductive endocrine function in relation to biomarkers of lead, cadmium, zinc, and copper in men (2000) Environ Health Perspect, 108, pp. 45-53Hu, H., Knowledge of diagnosis and reproductive history among survivors of childhood plumbism (1991) Am J Public Health, 81, pp. 1070-1072McMichael, A.J., Vimpani, G.V., Robertson, E.F., Baghurst, P.A., Clark, P.D., The Port Pirie cohort study: Maternal blood lead and pregnancy outcome (1986) J Epidemiol Community Health, 40, pp. 18-25Baghurst, P.A., Robertson, E.F., McMichael, A.J., Vimpani, G.V., Wigg, N.R., Roberts, R.R., The Port Pirie Cohort Study: Lead effects on pregnancy outcome and early childhood development (1987) Neurotoxicology, 8, pp. 395-401Ernhart, C.B., Wolf, A.W., Kennard, M.J., Erhard, P., Filipovich, H.F., Sokol, R.J., Intrauterine exposure to low levels of lead: The status of the neonate (1986) Arch Environ Health, 41, pp. 287-291Needleman, H.L., Rabinowitz, M., Leviton, A., Linn, S., Schoenbaum, S., The relationship between prenatal exposure to lead and congenital anomalies (1984) Jama, 251, pp. 2956-2959