Blood lead levels and erythrocyte delta-amino-levulinic acid dehydratase activity of selected population groups in Helsinki.

The levels of lead in the blood of the adult general population in Helsinki were determined during the period May 1972-June 1973. The possibility of occupational exposure to lead was scrupulously excluded.As control groups rural population groups were sampled in the commune of Pertunmaa and the communes of Haapajärvi and Pyhäjärvi. The concentrations of air-suspended particulate lead were studied during 1 year in Helsinki and Pertunmaa; the population groups were sampled from the geographical vicinity of the sampling sites. Care was taken to ensure the accuracy and precision of the analytical methods at experienced laboratories. The annual mean concentration of lead in air in Helsinki ranged from 0.43 to 1.32 mug/m3. The corresponding mean at the rural sampling site (Pertunmaa) was 0.025 mug/m3. From an international standpoint, the Pb-B levels were low. The highest mean Pb-B value in groups of the general population occurred in the rural male group (12.3 mug/100 ml); and the lowest, in the female respondents of the Pertunmaa survey (7.9 mug/100 ml). A group comprising 86 male streetsweepers from Helsinki displayed a Pb-B mean value of 13.3 mug/100 ml, and 28 traffic-directing policemen displayed a mean of 13.5 mug/100 ml, a finding indicating a slight increase in lead absorption. No effect on the Pb-B levels of traffic alone was detectalbe within the general population; thus no statistically significant differences were found between downtown and rural or suburban Pb-B levels. The observation that the Pohjois-Haaga suburbanites disclosed higher Pb-B levels. The observation that the Pohjois-Haaga suburbanites disclosed higher Pb-B levels than did other suburbanites indicates that factors other than traffic should be borne in mind in the assessment of the effect of traffic on lead absorption. The delta-amino-levulinic acid dehydratase (ALAD) assay proved useful and reliable in the discrimination between separate groups whose Pb-B levels differed to a small but measurable extent. The negative correlation between Pb-B and ALAD activity was found to prevail at a statistically significant level still at Pb-B levels of 10 mug/100 ml or lower.