This study tested the hypothesis that exposure to radiofrequency radiation (RFR) would affect the levels of reactive oxygen species (ROS), otherwise known as free oxygen radicals, in cells.

The authors used rat lymphocytes in their experiment. These were exposed to 930 MHz continuous wave radiation for either 5 minutes or 15 minutes at a power density of 5 W/m² (theoretical calculated SAR = 1.5 W/kg). One half of the samples were treated with ferrous chloride (FeCl) to stimulate ROS production. Four groups of cells were used in the experiment: group I, not treated with FeCl and not exposed to radiofrequency radiation (RFR);
group II, not treated with FeCl and exposed to RFR;
group III, treated with FeCl and not exposed to RFR;
and group IV, treated with FeCl and exposed to RFR.
The amount of ROS was measured using dichlorofluorescin diacetate (DCF-DA). This substance was added to the cell samples. It penetrates through the cell membrane and is altered within the cells to a derivative, DCFH. In the presence of ROS it is changed back to DCF, which is fluorescent and can be used as a marker of ROS levels. The DCF levels were measured before and after RFR exposure. FeCl was added to the appropriate groups just before exposure.

There was no difference in fluorescence between the RFR-exposed and the non-exposed cells that did not have added FeCl (groups I and II). However, in groups III and IV, where the FeCl had been added, the ROS levels were higher in group IV (the RFR-exposed group. This was the case for both the 5-minute and the 15-minute exposure.

The authors stated: "At present, we cannot offer any reasonable explanation for possible mechanisms of the observed effects".