INTERRELATION BETWEEN URINARY DELTA-AMINOLEVULINIC-ACID (ALA), SERUM ALA, AND BLOOD LEAD IN WORKERS EXPOSED TO LEAD

Using a fluorometric HPLC method, we determined delta-aminolevulinic a cid (ALA) in sera and urine samples from 16 lead workers with blood le ad levels ranging from 19 to 107 muG/100 ml. The concentration of ALA in serum correlated highly with the urinary ALA concentration (gamma=0 .957 for ALA mg/l; gamma=0.967 for ALA mg/g creatinine). The ALA conce ntrations in the serum of lead workers ranged from 11 to 151 mug/l wit h a mean of 51 mug/l. In addition, the concentrations of urinary ALA ( mg/g creatinine) and serum ALA mug/1) had a strong correlation with bl ood lead concentrations (gamma=0.838 and 0.892, respectively). These d ata indicate that the measurement of serum ALA, as well as urinary ALA , is very useful for the biological monitoring of occupational lead ex posure.