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Toxicological information

Exposure related observations in humans: other data

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Administrative data

Endpoint:
exposure-related observations in humans: other data
Type of information:
experimental study
Adequacy of study:
supporting study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1982

Materials and methods

Endpoint addressed:
basic toxicokinetics
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Eight adult male subjects fasted overnight and then ingested lead chloride (with 203Pb) with no minerals and with 200 mg calcium and 140 mg phosphorus. Two of the eight also ingested lead chloride with 20 mg calcium and 14 mg phosphorus, and four subjects ingested lead chloride with calcium only and with phosphorus only. Subjects fasted for 6 hours after dosing. Lead was administered with 100 ug Pb carrier in 50 ml distilled water. Further drinks of distilled water containing calcium carbonate as a fine suspension and sodium phosphate in solution were taken immediately afterwards. Uptake in the gut was measured via activity of 203Pb remaining in the body five to seven days after ingestion (measured using external gamma ray counters) and also by taking venous blood samples 24 hours after ingestion.

In a second experiment, a lamb was injected with lead chloride (with 203Pb) and six days later, the liver and kidney were cooked and served in meals including bread, peas, yogurt, and cheese to six subjects. Percentage uptake of 203Pb was measured as above. These same subjects, on another occasion, drank lead chloride in solution while eating similar meals including purchased, untreated liver or kidney.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
No details provided on test material.

Method

Ethical approval:
confirmed and informed consent free of coercion received
Details on exposure:
TYPE OF EXPOSURE: Ingestion

TYPE OF EXPOSURE MEASUREMENT: Biomonitoring (blood) / External gamma ray counters

EXPOSURE LEVELS: Levels of 203Pb ingested were not reported.

EXPOSURE PERIOD: Single exposure through drinking water or a single meal.

POSTEXPOSURE PERIOD: 24 hours or 5 to 7 days.

Results and discussion

Results:
There was a consistent decrease in uptake from about 60% with no added calcium and phosphorus to about 10% when 200 mg calcium and 140 mg phosphorus were added. In the four subjects who ingested lead with either calcium or phosphorus, lead uptake was reduced by a factor of 1.3 or 1.2 with addition of calcium or phosphorus, respectively. Both calcium and phosphorus together decreased lead uptake by a factor of 6.

There was no difference in the mean percentage uptake of 203Pb between subjects who ate liver or kidneys of the treated lamb and subjects who drank a lead solution during a meal of untreated kidney or lamb.

Applicant's summary and conclusion

Conclusions:
The authors concluded that lead in water and other drinks taken without food is likely to contribute proportionally more to uptake than lead in food.
Executive summary:

Eight adult male subjects fasted overnight and then ingested lead chloride (with 203Pb) with no minerals and with 200 mg calcium and 140 mg phosphorus. Two of the eight also ingested lead chloride with 20 mg calcium and 14 mg phosphorus, and four subjects ingested lead chloride with calcium only and with phosphorus only. Subjects fasted for 6 hours after dosing. Lead was administered with 100 ug Pb carrier in 50 ml distilled water. Further drinks of distilled water containing calcium carbonate as a fine suspension and sodium phosphate in solution were taken immediately afterwards. Uptake in the gut was measured via activity of 203Pb remaining in the body five to seven days after ingestion (measured using external gamma ray counters) and also by taking venous blood samples 24 hours after ingestion. There was a consistent decrease in uptake from about 60% with no added calcium and phosphorus to about 10% when 200 mg calcium and 140 mg phosphorus were added. In the four subjects who ingested lead with either calcium or phosphorus, lead uptake was reduced by a factor of 1.3 or 1.2 with addition of calcium or phosphorus, respectively. Both calcium and phosphorus together decreased lead uptake by a factor of 6.

In a second experiment, a lamb was injected with lead chloride (with 203Pb) and six days later, the liver and kidney were cooked and served in meals including bread, peas, yogurt, and cheese to six subjects. Percentage uptake of 203Pb was measured as above. These same subjects, on another occasion, drank lead chloride in solution while eating similar meals including purchased, untreated liver or kidney. There was no difference in the mean percentage uptake of 203Pb between subjects who ate liver or kidneys of the treated lamb and subjects who drank a lead solution during a meal of untreated kidney or lamb.

The authors concluded that lead in water and other drinks taken without food is likely to contribute proportionally more to uptake than lead in food.