Variations of nickel in plasma and urine during the work period.

One of the basic problems in monitoring exposure of nickel refining workers has been the unclear correlation between plasma nickel, urine nickel, and airborne nickel during the eight-hour work period or throughout the 24-hour day. In previous studies the authors have demonstrated the value of biological sampling in an occupational health program in the nickel processing industry. Whether a single plasma or single urine sample is an adequate gauge of exposure or whether 24-hour urine specimens or a three-day average plasma level are more accurate indices remained to be determined. The purpose of this paper is to report the results of studies of diurnal variations which affect the significance of single biological samples. In addition, data gathered on the correlation of plasma and urine nickel levels with soluble and insoluble nickel compounds in the atmosphere are presented.