Preliminary Results of a Survey of Lead Levels in Human Liver Tissue

Abstract

Lead and compounds containing lead are widespread throughout the environment. Aside from specific instances of occupational exposure (for example, workers in smelters, radiator repair shops, battery manufacturing plants), there are several routes by which the general population is exposed to lead. Humans are exposed to trace quantities of lead on a daily basis through inhalation of air, consumption of drinking water, and inigestion of food. Children, who tend to have increased hand-to-mouth activity, ingest larger quantities of lead-containing dust and dirt than adults. Although direct contact is made daily with dust, dirt, and painted surfaces containing lead, very little lead is adsorbed through the skin.Lead generally enters the body via the lungs or gastrointestinal tract and subsequently enters the bloodstream. It has been estimated that young children absorb 42% of the lead that reaches the gastrointestinal tract as compared to the 5 to 15% absorbed by adults (Goyer 1991). Children also tend to retain a much higher proportion of absorbed lead than adults, typically greater than 30% versus less than 5%, respectively. Most of the lead which is stored by the body is found in bone and teeth. Lead which is not stored by the body is eliminated in urine and feces.

Scientific Opinion on Lead in Food

“…The relative distribution of lead in soft tissues, in both males and females, expressed in terms of liver tissue concentration ratios, was: liver, 1.0 (approximately 1 µg/g wet weight); kidney cortex, 0.8; kidney medulla, 0.5; pancreas, 0.4; ovary, 0.4; spleen, 0.3; prostate, 0.2; adrenal gland, 0.2; brain, 0.1; fat, 0.1; testis, 0.08; heart, 0.07; and skeletal muscle, 0.05 (Barry, 1975;Gross et al, 1975). In contrast to lead in bone, which accumulates lead with continued exposure in adulthood, concentrations in soft tissues (e.g., liver and kidney) are relatively constant in adults (Barry, 1975;Treble and Thompson, 1997), reflecting faster turnover of lead in these tissues.…”

Characterizing Golden Eagle Risk to Lead and Anticoagulant Rodenticide Exposure: A Review

“…The relative distribution of lead in soft tissues, in males and females, expressed in terms of tissue:liver concentration ratios, were: liver, 1.0 (approximately 1 μg/g wet weight); kidney cortex, 0.8; kidney medulla, 0.5; pancreas, 0.4; ovary, 0.4; spleen, 0.3; (Barry 1975;Gross et al 1975). In contrast to lead in bone, which accumulates lead with continued exposure in adulthood, concentrations in soft tissues (e.g., liver and kidney) are relatively constant in adults (Barry 1975;Treble and Thompson 1997), reflecting a faster turnover of lead in soft tissue, relative to bone.…”

Toxicological profile for lead

“…expressed in terms of tissue:liver concentration ratios, were: liver, 1.0 (approximately 1 μg/g wet weight); kidney cortex, 0.8; kidney medulla, 0.5; pancreas, 0.4; ovary, 0.4; spleen, 0.3; prostate, 0.2; adrenal gland, 0.2; brain, 0.1; fat, 0.1; testis, 0.08; heart, 0.07; and skeletal muscle, 0.05 (Barry 1975;Gross et al 1975). In contrast to Pb in bone, which accumulates Pb with continued exposure in adulthood, concentrations in soft tissues (e.g., liver and kidney) are relatively constant in adults (Barry 1975;Treble and Thompson 1997), reflecting a faster turnover of Pb in soft tissue, relative to bone.…”