BLOOD-LEAD LEVELS IN SCHOOLCHILDREN FROM VELES, RELATED TO THE AMBIENT AIR POLLUTION BY LEAD

摘要

The objective of the study performed in 2001, 2003 and 2004 was to investigate and analyze the relationship between ambient air's pollution by lead and blood-lead levels in schoolchildren exposed to lead emissions in the city of Veles. The city of Veles, with its geographical position, atmospheric characteristics, urban and industrial concentration, and its improperly located the Lead and Zinc Smelter Plant upstream to the north wind opposite to the Wind Rose (north wind is dominant and dispersion of pollutants is going directly to the city), multiplied by inconvenient climate-meteorological, hydro-topographic factors has a huge and continuous air pollution problem. The Lead Smelter Plant, built in Veles in 1973, is located on the north of the city only 200-300 m away from first households. There was statistically high significant difference by Student t-test of the average annual concentration of lead in the ambient air in Veles in 2001 (x = 0.94 μg/m~3), compared to the 2003 (x = 0.22 ug/m~3) t = 4.81 p < 0.0001, and 2004 (x = 0.155 ug/m~3) t = 5.53 p < 0.0001. Registered average annual concentration of lead in the ambient air in 2001 was 89% higher than the recommended value from WHO and EL) (0.5 ug/m~3). Increased concentration of lead in the ambient air, represent high risk factor for the health of the exposed children population in the city of Veles. There was a very high significant statistical difference between the blood-lead levels in the examined schoolchildren in 2001-2002 (n = 203 with average age x = 10.06), and schoolchildren in June 2003 (n = 31, x = 16.51 μg/dl, at the 12.8 age). The difference can be explained by stop of working of the Lead Smelter Plant (20 days without emission), and biological life-time of lead into blood and soft tissues. In 2004 as a fact on stopping of ambient air emission by lead the blood-lead levels in schoolchildren have significantly dropped (n = 93, x = 7.64 μg/dl).