Biological effects can be divided into two categories: ELF field effects and RF /MW field effects. ELF field effect’s concept origin from the devices used in homes and offices, power lines and transformers. RF/MW field effect’s concept origin from TV and radio transmitters, microwave owens, diathermy equipment, mobile phones and base stations.

Results of the studies done on people living near power lines:

• Changes in immune system response,
• Changes in brain and central nervous system activities,
• Changes in embryo,
• Changes in genetic mechanism,
• Increase in the statistics of depression, hallucination, headache,
• Sleeping disorders by reducing synthesis of melatonin.

Most of these effects are related to causation of cancer. In 1975 Russia reported that E-field strength should be 1-5 kV/m, USA applied this value as 9 kV/m in 1982. USA National Academy of Sciences stated that the occurrence of leukemia among children living near power lines is 1.5 times greater than others.

Studies on the effect of RF / MW radiation

Tissue Conductivity:

RF / MW radiation is mostly absorbed by kneecap, metallic implant, lens of eye, and brain.

Microwave Hearing Effect:

According to the strength and the period of exposed radiation sound can be heard as buzzing, clinking. However, it has not been found that this is a permanent effect. With experimental and epidemiological studies, it is reported that if one uses a mobile telephone for a long time in a day, then he will hear sound as pulsed and buzzing.

Effect on the Permeability of BBB (Blood Brain Barrier):

The neurovascular construct commonly known as the blood-brain barrier (BBB) functions as a differential filter that permits the selective passage of material from blood to brain. It maintains the physiochemical environment of the brain within certain narrow limits which are essential for life. Many investigators have reported studies on the effect of microwave radiation on the blood-brain barrier of experimental animals with varied results. Several authors using both high and low levels of microwave exposures have shown microwave-induced increase in BBB permeability especially increases in antibiotics. It is said that this can be lead to the treatment of viruses placed in brain.

Neurological Effects:

EM Fields having 10 W/m2 power densities causes effects on the nervous system. But, this value is above the maximum permissible limits given in the regulations of Minister of Transportation (for 900 MHz 4.5 W/m2 , for 1800 MHz 9,0 W/m2 ).

Changes in DNA Structure:

Increase in the damage of DNA structure was observed in 9 of 12 guinea pigs among, on the other hand decrease in the damage of DNA structure was observed in 5 of 9 guinea pigs among. So, experiments on this effect do not compensate each other.

In USA and England governmental and independent groups reported health effects of cell phones in their reports entitled "Mobile Phones, Base Stations and Human Health". These groups concluded "there is no human evidence of a risk of cancer resulting from exposure to radiations that arise from mobile phones. Furthermore, a biological study on possible effects on human prevention or progression, including work with experimental animals does not provide clear evidence of a risk."

On the other hand, studies on the risk of cancer and power lines showed that the occurence of leukemia among children living near power lines is 1,5 times greater than others.

Psychological and Behavioral Effects:

In both studies done by Mann & Röschke and Borberly, disorderness in sleeping was observed. In another experiment done by Wang & Lai, animals exposed to 2450 MHz having disability in learning, but this study has not repeated, yet. Also Wang & Lai has studied on long-term memory loss in the exposure to 2450 MHz and they have found positive results. All these studies done on 2450 MHz, but mobile phones work in 900 and 1800 MHz.

On people living near to power lines, it is observed an increase in the statistics of depression, hallucination, and headache.

Mobile phones' radiation effects are determined by SAR (Specific Absorption Rate). SAR (Specific Absorption Rate) is a measure of the amount of RF power absorbed in any part of the human body due to the use of equipment such as mobile phones or by human exposure close to other transmitting sources. Permissible exposure limits for SAR; 0,4 W/kg for occupational, 0,08 W/kg for public exposure.