Lead Level in Blood of Japanese in Relation to Environmental Concentration of Lead

Abstract

In view of the changes in exposure of the Japanese to atmospheric lead in recent decades, it seems important to reconsider the normal lead level in the blood of the Japanese in relation to the environ mental concentration of lead. The lead levels in the blood of 361 people were determined by the dithizone method, and atmospheric lead was measured either by the atomic-absorption method for samples collected by a high volume air sampler or by the impinger and dithizone method for workers in printing offices.1. In Fukuoka City, the effect of atmospheric lead from gasoline engine emission on the blood lead level was studied in 45 people (m: 21, f: 24) living for over three years beside a congested intersection and in 55 people (m: 28, f: 27) living in a residential area away from the intersection. The atmospheric lead levels were 5.65-1.33μg/m3 along the roadside, and less than 1.0μg/m3 in the residential section. The arithmetic mean lead levels in the blood of men and women near the intersection were 14.9μg/100g and 10.0μg/100g and in the residential section 12.1μg/100g and 10.6μg/100g, respectively. The difference of the geometric mean lead levels in both groups was not significant.2. In Ishigaki Island of Okinawa, the atmospheric lead concentration was less than 1.0μg/m3, and the average concentration of lead in the blood was 18.8 and 14.4μg/100g in 28 men and 28 women.3. At 3 printing offices, the average concentration of atmospheric lead was less than 1.5μg/m3, but a relatively high lead level of 30μg/m3 was detected near the melting bath. Lead concentrations in the blood of 155 workers (m: 141, f: 11) were determined, and the highest mean blood lead level in 3 printing offices was 15.9μg/100g in 122 workers in “C” printing office.4. In a basement parking area where about 1, 500 cars park in a day, the atmospheric lead levels of the working room were less than 2.0μg/m3 and the mean lead levels in the blood were 19.9μg/100g in 10 men and 15.8μg/100g in 5 women in the fee collector's room, 16.6μg/100g in 7 men's driver, 9.7μg/100g in 9 men and 14.1μg/100g in 3 women in the main office.5. In a room where workers were soldering radio parts, 0.30-5.81μg/m3 of lead was detected, the average concentration of lead at 10 places being 2.1μg/m3. The mean blood lead level of 8 women who were soldering radio parts was 15.7μg/100g and that of the control group was 15.4μg/100g.6. The lead levels in daily foods collected by 10 families in Fukuoka City ranged from 39.6 to 182.4μg/day.7. The average blood lead levels and 95% fiducial limits obtained from the basis of the theoretical log-normal distribution curve were 12.4μg/100g and 40.9μg/100g in 249 men, 11.1μg/100g and 28.8μg/100g in 112 women, 12.0μg/100g and 36.1μg/100g in a total of 361 people respectively.