Natural Radionuclides and Heavy Metal Contents in the Olive (Olea europaea L.) Groves of Northwestern Anatolia

The aim of this study is to examine the content of heavy metal (Cd, Pb, Ni, Cr, Al) and the natural radionuclide (U-238, Th-232, K-40) content of the olive groves around the highway from Aliaga to Ezine. In general, findings show that total heavy metal contents are more in the subsurface soils. In this regard, total Ni contents of the soils changed between 11-69 mg/kg. It is considered the only threatening heavy metal which exceeded 30 mg/kg critical level especially in the soils of the olive groves in Aliaga Soma, Ayvalik, Edremit and Ezine. Bergama region differed in this regard. The highest of total Pb, Cr and Cd contents in the soils of Aliaga region were found 44.59 mg/kg, 60 mg/kg and 0.81 mg/kg, respectively. These findings are found very close to the reference limit values (50, 100 and 1 mg/kg) reported by different scientists. Natural radioactivities of Ra-226, Th-232 and K-40 in the soils were also measured and found 37.45 and 410 Bq/kg respectively which were slightly above the cited limit values (Ra-226:35 Bq/kg, Th-232:30Bq/kg ve K-40:400 Bg/kg). Results in relation to olive leaves indicated that trees were not threatened by the heavy metals in the soils, only in some cases Cr (0.19-0.99 mg/kg) was found over the limit value (0.60 mg/kg). It could be concluded that this risky region with high contamination potential should be studied periodically before it is too late..