Air lead pollution and lead exposure of experimental animals and children in Stara Zagora town (Bulgaria)

Abstract

The air pollution with lead aerosols in Stara Zagora town was investigated at four sampling sites over a period of 6 years. Transport is the main source of air lead pollution in the town. The mean annual air lead concentrations varied from 0.06 to 0.6 μg/m3. The highest air lead levels were measured in the area of a big crossroads during the whole period. An experimental group of mice were exposed near to the crossroads and a control group was exposed in a relatively cleaner residential district for 6 months. The lead concentrations in blood, urine, bones, kidney, liver and lung investigated by atomic absorption spectrometry were significantly higher in the animals from the experimental group in comparison with the control. The lead levels in blood, urine and nails were investigated in children living and going to school in the area with high transport traffic and in a control group of children from the residential district where the control mice were exposed. The mean blood lead level estimated in the group of children exposed at the higher air lead pollution (10.28 μg/dl) slightly exceeded this estimated in the control group (9.47 μg/dl) and the standard for childhood of the Center for Disease Control and Prevention, US (10 μg/dl). It was found that 60% of children from the 'experimental' and 50% from the control group had PbB concentrations equal to or higher than the lowest limit action level. Lead levels in urine were significantly higher in the 'experimental' group as a whole, and in the 'female experimental' group of children also.