Aim: This prospective study was designed to the determine and discriminate the effect of radioactive ¹²⁹I in the tap water on the development of the thyroideal nodular formation in Elazığ and Bingöl areas.

Material and method: Sixty-two patients were taken into this study who were admitted to operations for nodular goitre, between March 2000 and June 2002. These patients divided into two groups, who live in Elazig referred as Group I (n=30), the other who live in Bingöl referred as Group II (n=32). β-radioactivities of the ¹²⁹I were analysed taken specimens from tap water and nodules and normal tissue of the thyroid taken from the patients using tube supported plastic scintilator and SR8 scaler/ratemeter which are sensitive for β-radiation.

Results: The mean radioactivity of the tap water of the patients take, normal thyroideal tissue and nodules were obtained to be lower in Group I than in Group II. Only tap water radioactivities were statistically significant between groups (p<0.05). Nodular tissue radioactivities were higher than normal thyroideal tissues (p<0.05) in both groups.

Conclusion: ¹²⁹I may be one of the factors caussing the noduler formation in thyroid tissue around of the Elazığ and Bingöl areas.