Actual status of measurement of blood concentration of lead, urinary concentration of delta-aminolevulinic acid and urinary concentration of metabolites of organic solvents entrusted to occupational health organizations

Abstract

In Japan "the Regulation on the Prevention of Lead Poisoning" and "the Regulation on the Prevention of Organic Solvent Poisoning" were partially amended in 1989 to introduce biological monitoring in the special medical examinations of workers exposed to lead and 8 organic solvents (toluene, xylene, styrene, N,N-dimethylformamide, n-hexane, tetrachloroethylene, 1,1,1-trichloroethane, trichloroethylene). Since many companies entrust these medical examinations to the Occupational Health Organizations (OHOs), a survey of OHOs which collect blood and urine samples for biological monitoring was made in August 1992, to ascertain the actual status of their activities from April of 1991 to March of 1992. The following findings were obtained through this survey. 1) One hundred and eighty-six OHOs collected 129,996 blood samples to measure the concentration of lead, and the median number of samples collected per organization was 356. 2) Thirty-nine OHOs (21.0%; Group A) measured all samples in their own laboratories. The number of samples measured was 55,462 (42.7%). However, 133 OHOs (71.5%; Group B) entrusted the measurement of all samples to registered laboratories. 3) The median number of samples collected by OHOs in Group A was 1,121, and the median number of Group B was 211. 4) One hundred and eighty-three OHOs collected 126,915 urine samples to measure the concentration of delta-aminolevulinic acid and the median number of samples collected per organization was 358. 5) The blood samples as well as the urine samples were divided into three groups according to the levels of lead or delta-aminolevulinic acid concentration. The concentration is relatively low in Group 1 and relatively high in Group 3. The cut-off values for this classification are legally set in the Regulation on the Prevention of Lead Poisoning. The frequency of each group was as follows: lead (Group 1; 93.8%, Group 2; 4.9%, Group 3; 1.3%), delta-aminolevulinic acid (Group 1; 96.8%, Group 2; 3.1%, Group 3; 0.2%).(ABSTRACT TRUNCATED AT 250 WORDS)