Biological Monitoring of a Case of Chronic Oral Exposure to Lead

Overview

The authors examined a 26-year-old woman took for a 6-month period to herb concentrate FE Femikalp, 2x2 tablets per day.This preparation contained 113 mg Pb/kg. The daily oral dose was thus 200 mg and the 6-month dose 40 000 mg Pb. This amount oflead did not produce subjective complains (with the exception of reported hair loss) and was not manifested by pathologicalfindings during the basic medical and biochemical examination (with the exception of elevated IgM). It was not sufficient for fullyexpressed development of one of the main symptoms of lead poisoning, i. e. impaited haematopoesis. There was however a certainincrease of delta-aminolaevulic acid (to 5.3 mg/mmol creatinine) and of coproporphyrin III (to 13.4 nmol/mmol creatinine) in urine.Lead exposure was however unequivocally manifested by an excessive blood level of lead at the time when the patient used thetablets (0.48 mg/l) but already one month after termination of its administration a drop of the Pb blood level (to 0.38 mg/l) wasrecorded. Very interesting were the Pb levels in hair. Hair was analyzed in its entire length (1.3 mg Pb/g), and separately the 6 cmlong exposed part of hair from the roots, comprising the 6-month use of preparation (3.5 mg Pb/g) and the remaining 15 cm longnon-exposed portion (0.3 mg Pb/g). Thus increased exposure to Pb was proved unequivocally. Although a relatively accurate(though involuntary) experiment of chronic oral Pb exposure to a know dose and with a know route of administration is involved,the results of this non-occupational exposure are relevant also for evaluation of results of preventive biological monitoring inoccupational medicine.

Key words:
Pb blood level, lead in hair, delta-aminolaevulic acid in urine, coproporphyrin III in urine