The genotoxic properties of geothermal wastewaters investigated with plant test systems

-63- SUMMARY Since geothennal waters are in contact with minerals for a long period under high temperature and high pressure conditions, they have almost always element concentrations above limit values in respect of environment and human health. In this study, Vicia faba micronucleus test and chromosomal aberration test were used to investigate the genotoxic effects of geothermal waters. Büyük Menderes Basin was selected as the study area. Water samples were collected from 3 locality. First sample was collected from Kızıldere Geothermal Power Plant (SKS), second sample collected from Büyük Menderes River where the wastewater of the same plant is discharged (SKO). The last sample was collected from Alangüllü Thermal Plant which is located in Germencik. Sampling was repeated three times; rainy period (2003 May), dry period (2003 September) and winter period (2003 December). Vicia faba seeds were germinated with water samples. For the Vicia faba micronucleus test, 1000 cells per slide were examined and °/00 Micronucleus and Pollution Indices were calculated. Ratios of chromosomal aberrations and the mitotic index for each root were also calculated. In all sample groups it was observed that chromosomal aberrations and micronucleus frequencies were increased significantly, whereas mitotic indexes were decreased significantly when compared with control. Periodical differences were observed in SKS samples for micronucleus frequency, chromosomal aberrations and mitotic index, but in other sample groups there was not any periodical difference. Micronucleus frequency and the ratio of the chromosomal aberrations were highest in the samples of Alangüllü Thermal Plant. Results of this study showed that, the wastewaters arise from the geothermal resources which are located within Büyük Menderes Basin have cytotoxic and genotoxic potentials.