BIOLOGICAL MONITORING OF EXPOSURE TO 3-CHLORO-4-FLUOROANILINE BY DETERMINATION OF A URINARY METABOLITE AND A HEMOGLOBIN ADDUCT

In two studies, involving 75 and 72 workers, potential exposure to 3-c hloro-4-fluoroaniline (CFA)) was biologically monitored by determinati on of its main urinary metabolite 2-amino-4-chloro-5-fluorophenol sulf ate (CFA-S). As this method only allows the detection of recent exposu re, analysis of CFA adducts bound to hemoglobin (Hb) was investigated as a method that allows biological monitoring of exposure to CFA over longer periods. The median CFA-S concentration in 67 samples from the first study was 0.14 mu mole/g creatinine (range <0.05 - 2.82) and in 201 samples from the second study 0.21 mu mole/g creatinine (range <0. 05 - 6.05). In addition, urine samples, collected after shifts with su pposed incidental exposure, slightly higher concentrations were measur ed: 0.27 mu mole/g creatinine (range <0.05 - 122; 18 samples) and 0.76 mu mole/g creatinine (range <0.05 - 18.5; 46 samples), respectively. The median Hb adduct concentration in 75 samples from the first study was 9 pmoles CFA/g Hb (range <5 - 640) and in 46 samples from the seco nd study 12 pmoles/g Hb (range 3 - 24). In 24 blood samples collected after incidents, a median concentration of 13 pmoles CFA/g Hb (range < 5 - 52) was found. Urinary CFA-S and Hb adducts correlated well in sam ples collected shortly after incidental exposures. However, in 25% of the operators, no CFA-S was detected during routine biological monitor ing while Hb adduct analysis showed clear evidence of exposure. This i ndicates that because of the stability of Hb adducts of CFA in blood, intermittent exposure to CFA is more reliably biologically monitored b y determination of Hb adducts of CFA than by assessment of urinary CFA -S.