According to scientific research published on Wednesday, the soaring radioactivity levels measured in the Negev Desert and in the Arava valley are caused by natural radioactive elements such as uranium and radon gas.
But Professor Avner Vengosh, who co-authored the study by Ben Gurion University, dismissed any relation between the abnormal findings and the nearby nuclear plant of Dimona, also in southern Israel.
"This phenomena has spread throughout the area," he said, referring to Jordan and Egypt's Sinai desert.
"We discovered concentrations of radium reaching up to 10 times the normal average in (Israel's) water table," he added.
Officials in the environment ministry have advised local fish farmers not to use the water for fear it will contaminate fish destined for human consumption.
The agriculture ministry insisted however that no contaminated fish had been found in the area.