Urinary nickel as bioindicator of workers' Ni exposure in a galvanizing plant in Brazil

Objectives: We measured urinary nickel (U-Ni) in ten workers (97 samples) f rom a galvanizing plant that uses nickel sulfate, and in ten control subjec ts (55 samples) to examine the association between occupational exposure to airborne Ni and Ni absorption. Methods: Samples from the exposed group were taken before and after the wor k shift on 5 successive workdays. At the same time airborne Ni (A-NI) was m easured using personal samplers. Ni levels in biological material and in th e airborne were determined by a graphite furnace atomic absorption spectrom etry validated method. In the control group the urine samples were collecte d twice a day, in the before and after the work shift? on 3 successive days , Results: Ni exposure low to moderate was detected in all the examined place s in the plant, the airborne levels varying between 2.8 and 116.7 mu g/m(3) and the urine levels, from samples taken postshift, between 3.5 and 43.2 m u g/g creatinine (mean 13.7 mu g/g creatinine). Significant differences in U-Ni creatinine were seen between the exposed and control groups (Student's t test, P less than or equal to 0.01), A significant correlation between U -Ni and A-Ni (r = 0.96; P less than or equal to 0.001) was detected. No sta tistical difference was observed in U-Ni collected from exposed workers in the 5 successive days, but significant difference was observed between pre- and postshift samples. Conclusions: Urinary nickel may be used as a reliable internal dose bioindi cator in biological monitoring of workers exposed to Ni sulfate in galvaniz ing plants regardless of the day of the workweek on which the samples are c ollected.