Introduction: Lead is a constant poisonous metal used frequency in daily life and identifying this element as a neurological poison comes back to 2000 years ago before Christ. Lead compound are used in various industries. The main sources of pollution with lead are paints dusts, drinking water, the parent's job environment, water and foods. The different studies showed the prevalence of lead poisoning varies about 8-20%. As there is lack of information about lead poisoning in children in Semnan city, thus this study was performed.
Materials and Methods: This is a descriptive cross-sectional study. Sampling on 320 students was done randomly in two areas in Semnan city. 6 ml blood was taken from each student, 5 ml was sent to atomic energy organization in Tehran in order to determine the blood lead by atomic absorption (Spect AA.20), and then the rest of the blood (1ml) was sent to Pastur laboratory in Semnan to perform completed blood count (CBC) and differentiation. The data were analyzed in descriptive statistics in the form of table and graphs. To test the hypothesis the regression were used in level 5%.
Results: 78.8% of the children had lead poisoning (Pb>10 g/dl). In 5% of them toxic levels of lead was observed (Pb>20 g/dl). There was no relation between lead concentration in blood with age, gender, parent's job, residential area, grade average, RBC level, painting and reconstruction of home, but there was a relation between lead with Hct, MCV, RDW, MCHC and the years in which houses have been made (P<0.05).
Conclusion: In this study, lead poisoning is higher than the other studies but toxic level of Semnan is necessary.