Uptake of lead by humans and effect of minerals and food.

In several series of experiments, volunteers have ingested 203Pb as chloride (a) in distilled water, with or without stable Pb carriers, while fasting, (b) with varying amounts of added mineral Ca and P, (c) with hot or alcoholic beverages between normal meals, (d) in the course of meals. Also, volunteers have eaten lamb's liver and kidney into which 203Pb had been incorporated by injection into the animal before slaughter, and spinach which had taken up 203Pb from its roots. Fasting subjects absorbed 40-50% of the 203Pb, taken in distilled water, irrespective of the addition of Pb carrier up to 100 micrograms per dose. When taken with tea or coffee, uptake averaged 14% and with beer 19%. Much lower uptakes, ranging from 3 to 7%, were found when 203Pb was taken in volunteers with a meal, or incorporated in offal or vegetables which were eaten as part of a meal, or when taken with large amounts of calcium or phosphate.