Japanese experience in biological monitoring

In Japan, industrial health control is accomplished by control of the working environment, work practice management and health care. Periodical biomonitoring of workers exposed to lead and 8 popular organic solvents, including mixed solvents, became mandatory as of October 1, 1989, with an ordinance issued by the Ministry of Labor. This ordinance states that the results of measurements of lead and the 8 solvents in each work place must be classified into 3 categories, named distributions 1, 2 and 3 based on the biological level of the determinant, and then must be reported to the Labor Standards Inspection Office. Distribution 3 encompasses workers having concentration levels above the BEIs of ACGIH except for the concentration of lead in the blood. The National Federation of Industrial Health Organizations surveyed the state of biological monitoring in Japan by a questionnaire to the laboratories. The total number of cases examined in the fiscal year 1990 was about 110,000 for the biomonitoring of lead, and about 520,000 for the monitoring of urinary metabolites of the 8 organic solvents. The ratio of the number of workers in distribution 3 to that of the total workers examined was 0.4% for urinary delta aminolevulinic acid and 0.2-3.5% for the urinary metabolites of each organic solvent. Similar results were obtained from 7 major laboratories. To achieve large-scale biological monitoring in future, a method is necessary for evaluating the exposure or health risks of workers exposed to mixed organic solvents by estimating their urinary metabolites.