Objective: Exposure of radon and radon daughters is a potential public health problem. Isparta is known as an endemic fluorosis area due to high fluoride levels in drinking water supplies for more than 50 years. Another interesting phenomenon related with Isparta is that the indoor radon concentration is about 4.5 times higher than the average concentration value of Turkey. Although fluoride levels in drinking water supplies are regularly monitored in the province, efforts on the radon level measurements are new and not very regular. Radon is a radioactive gas. Even radon gas is known as chemically inert and does not attach to particles in air, there are some studies reporting that under rare circumstances radon can form compounds like fluorides in water. Since radon is relatively soluble in water, it can be transported into atmosphere via well water. Materials and Methods: In the present study atmospheric radon concentrations around the wells and dwellings in Yakaören and Deregümü villages, locations which are known with high fluoride concentrations in their drinking water supplies, were measured using twenty four CR-39 solid-state nuclear track detectors. Measurements were made between June and September 2010 for an 11-week period. Results: The results showed that radon concentrations ranged between 24 and 465Bq/m3 in the dwellings of Yakaören village with an average concentration of 181Bq/m3. Around the borehole in Yakaören village, atmospheric radon level was 47Bq/m3. For Deregümü village, radon concentrations in the dwellings varied between 46 and 271Bq/m3 and the average was 120Bq/m3. The average value for atmospheric radon concentration around the two wells in Deregümü village was found as 57Bq/m3. Furthermore annual effective dose equivalents for the occupants of two villages were calculated. A possible relation between radon and fluoride in water was also discussed.ÖzetAmaç: Radon ve radon ürünlerine maruz kalmak potansiyel bir halk sağlığı problemidir. İçme suyu kaynaklarındaki yüksek flor düzeyi nedeniyle Isparta, 50 yılı aşkın süredir endemik florozis bölgesi olarak bilinmektedir. Isparta'nın diğer bir özelliği de bina içi radon konsantrasyonunun Türkiye ortalamasından 4.5 kat daha fazla bir düzeyde olmasıdır. İldeki su kaynaklarındaki flor düzeyi ölçümlerinin düzenli olarak yapılmasına karşın, radon seviyelerinin ölçülmesine yönelik çalışmalar henüz yeni ve düzensizdir. Radyoaktif bir gaz olan radon kimyasal olarak inaktif olarak bilinmesine ve havadaki partiküllere bağlanamamasına rağmen, bazı nadir durumlarda sulardaki radonun florid bileşikleri oluşturabileceği yönünde çalışmalar mevcuttur. Radon sularda nispeten çözünebildiğinden, kuyu suları gibi yer altı sularından atmosfere taşınabilmektedir. Gereç ve Yöntem: Su kaynaklarındaki florun yüksek seviyelerde olduğu bilinen Yakaören ve Deregümü köylerinde yürütülen bu çalışmada, su kuyuları başındaki ve meskenlerdeki atmosferik radon düzeyleri yirmi dört adet CR-39 katıhal nükleer iz dedektörü kullanılarak belirlenmiştir. Ölçümler Haziran ve Eylül 2010 tarihleri arasında 11 haftalık bir süre boyunca yapılmıştır. Bulgular: Bu çalışma sonucunda, radon seviyelerinin Yakaören köyündeki meskenlerde 69Bq/m3 ile 465Bq/m3 arasında değiştiği ve ortalama radon konsantrasyonunun 181Bq/m3 olduğu tespit edilmiştir. Yakaören'deki sondaj kuyusu başındaki atmosferik radon düzeyinin 47Bq/m3 civarında olduğu bulunmuştur. Deregümü köyü için meskenlerdeki radon ölçümlerinin ise 46Bq/m3 ile 271Bq/m3 arasında değerler aldığı ve ortalamanın 120Bq/m3 olduğu saptanmıştır. Bu köydeki iki su kuyusu etrafında ölçülen radon konsantrasyonları ortalaması ise 57Bq/m3 olarak bulunmuştur. Ayrıca bu köylerdeki halkın radon gazı nedeniyle maruz kalacakları yıllık eşdeğer doz miktarları hesaplanmıştır. Sulardaki flor ve radon arasındaki olası ilişki tartışılmıştır.AbstractObjective: Exposure of radon and radon daughters is a potential public health problem. Isparta is known as an endemic fluorosis area due to high fluoride levels in drinking water supplies for more than 50 years. Another interesting phenomenon related with Isparta is that the indoor radon concentration is about 4.5 times higher than the average concentration value of Turkey. Although fluoride levels in drinking water supplies are regularly monitored in the province, efforts on the radon level measurements are new and not very regular. Radon is a radioactive gas. Even radon gas is known as chemically inert and does not attach to particles in air, there are some studies reporting that under rare circumstances radon can form compounds like fluorides in water. Since radon is relatively soluble in water, it can be transported into atmosphere via well water. Materials and Methods: In the present study atmospheric radon concentrations around the wells and dwellings in Yakaören and Deregümü villages, locations which are known with high fluoride concentrations in their drinking water supplies, were measured using twenty four CR-39 solid-state nuclear track detectors. Measurements were made between June and September 2010 for an 11-week period. Results: The results showed that radon concentrations ranged between 24 and 465Bq/m3 in the dwellings of Yakaören village with an average concentration of 181Bq/m3. Around the borehole in Yakaören village, atmospheric radon level was 47Bq/m3. For Deregümü village, radon concentrations in the dwellings varied between 46 and 271Bq/m3 and the average was 120Bq/m3. The average value for atmospheric radon concentration around the two wells in Deregümü village was found as 57Bq/m3. Furthermore annual effective dose equivalents for the occupants of two villages were calculated. A possible relation between radon and fluoride in water was also discussed.