Cadmium metabolism in man

Abstract

ABSTRACT Twenty-one high frequency solderers, who had been exposed to cadmium (Cd) from a solder for periods ranging from 1 month to 18 years (median 8 months; present time-weighted average 30 nmol/m³; particle size below 1μm) had Cd levels ranging from < 10 to 440 nmol/l in blood and from < 0·5 to 27 μmol/mol creatinine in urine. Individual workers showed considerable variations in blood Cd levels with time, but less variation in urine levels. There was a statistically significant (p < 0·001) increase of Cd in urine with increasing exposure time. Four gas solderers, who had been intermittently exposed for 8-20 years (median 17 years) had Cd levels ranging from 45 to 150 nmol/l and urine levels of from 2 to 20 μmol/mol creatinine. There was no correlation between Cd levels in blood and urine during exposure. After exposure had ceased there was a considerable decay of blood Cd in most subjects. The half-time in 11 people ranged from 25 to 146 days (median 41 days). After the decay blood levels reached a steady state. Concentrations in urine did not decrease, or did so only very slowly. There was a significant increase of levels in urine (p < 0·001) with increasing post-decay levels in blood. There was also a significant increase (0·01 < p < 0·05) of excretion of ß₂-microglobulin in urine (range 1·1-18 mg/mol creatinine, median 4·7 mg/mol creatinine) measured 11-15 months after exposure had ceased, with increasing Cd levels in urine. This may indicate an effect on renal tubular function even at kidney Cd loads corresponding to Cd levels in urine of the order of as little as 10 μmol/mol creatinine.