The following is the full text of physicist Dr. Bobby Leonard's statement on the effects of radiation from cellular phone towers located in Bermuda.

I am considered to be an expert on the effects of low levels of ionizing radiation. In this regard, I recently presented a paper at the June 1999 "International Conference on the Effects of low and very low doses or Ionising Radiation on Human Health'' at The University of Versailles, Paris, France.

I am currently active in research related to cancer treatment with radiation therapy at low dose rates. I am a part-time resident of Bermuda. For this reason, I have taken the time to examine the final report of the Transmission Towers in Bermuda, recently submitted by Roger Choquette, of Comgate Telemanagement Ltd.

First, I would like to address the distinction between Ionising and Non-Ionising Electro-Magnetic Radiation. Ionising Radiation, such as Gamma Rays, X-rays and Ultra-Violet Light (UV), cause the production of highly reactive free radicals, such as, plain old hydrogen peroxide, H202, that attack DNA and cause chromosome lesions in the cells. This cellular damage is frequently lethal and thus the beneficial use in killing cancer tumour cells at very high dose rates, say 7000 centiGray (equals REM for X and Gamma Rays).

At lower dose rates used in brachytherapy for cervix or prostate cancer, the necessary dose is much higher, due to the repairability of cells at lower dose rates. Just as a simple example, suppose you work in an office in Hamilton and eat your lunch in the nice surroundings of Par-la-Ville Park. Thus you are in the sunlight for 30 minutes, each work day, while having lunch, 250 days a year. As an approximation, assume your exposed skin surface receives 100 hours of ionizing UV radiation, each year at lunch, without any deleterious effects.

Now, in comparison, consider the consequences of 100 continuous hours of sunlight exposure to the same skin surfaces. You would certainly receive third-degree burns, permanent tissue scarring and maybe induce fatal skin cancer. The difference in the two scenarios is because cells have a great affinity for repair of damage at low dose rates.

Much scientific data show that within a cell, if a single DNA damage is repaired before a second occurs in the same cell on the same DNA molecule, then there can be no residual effect. The repair times for DNA damage is on the order of five to ten hours.

Other than cell killing (for Radiotherapy), Ionising Radiation can cause DNA and chromosomal mutations with the cells continuing to proliferate, but producing cancer, causing imperfect progeny. The mutating frequency is very, very low. As compared to cell killing and for radiation doses, used for example for breast mammograms, the chance of cancer induction is extremely improbable. Again, with cell killing, evidence indicates that cancerous mutations are much more likely at high dose rates where DNA double strand breaks are more likely.

The United States has about 100 nuclear power plants where thousands of workers at each plant are exposed daily to ionizing radiation -- mainly beta and gamma rays. The amount of radiation that each worker receives is carefully monitored by the US Nuclear Regulatory Commission (NRC). The occupational limit is 5 REM per year, or 1.25 REM per calendar quarter. NRC has also set limits on exposure of ionising radiation to the general public, both in terms of total annual dose and dose rate for continuous exposure. These limits have been set based on extensive radio biology research and the primary US radiation protection society (Health Physics Society) has taken an official position that an ionising dose of 5 REM per year, would not produce any deleterious effects and should be acceptable, even for general public exposure.

Just as with ionising radiation, potential non-ionizing radiation effects on humans have been extensively studied for at least 30 years, by the US Center for Devices and Radiological Health, Rockville, Maryland, telephone number, 301-443-1544. This research stems from concerns regarding non-ionising electro-magnetic exposures from microwave ovens, RF transmission towers and high voltage electric power lines. It may be worthwhile to understand the radiobiology distinction between ionising and non-ionising radiation.

Non-ionising radiations do not have enough energy to produce free radicals in the cells and thus, do not directly produce DNA and chromosome lesions and cancer. The energy of Non-Ionising Electro-Magnetic Radiations exhibit itself as increased heat within any absorbing material, such as human cells. Heat manifests itself within solids as molecular vibrations. As a simple example, when you burn your fingers on a hot stove, it is because the stove's molecules are vibrating very fast and when your fingers' make contact with the stoves' "fast'' molecules they transfer this vibration to your fingers' molecules, thus, sometimes killing the cells. However, the chance for cancerous mutations is far smaller than for Ionising Radiation. Since energy and not Ionisation causes the cell damage, units of exposure rate for Non-Ionising Radiation are milliwatt per square centimetre (energy fluence), as explained in Choquette's Bermuda RF Tower Report. The report notes that the Federal Communication Commission issues guidelines for exposure (dose) rates for occupational and general public and these are given in their tables, 1 & 2. As with NRC for Ionising Radiation, these are set based on conclusive evidence that no deleterious effects will result to humans at these levels -- period. The guidelines for general public levels are for continuous exposure at these fluences (in other words, 24 hours a day, 7 days each week) (uncontrolled areas). You can confirm this by calling the hot-line telephone number.

It is the obligation of the Ministry to provide whatever information needed by individuals of the public that want to fully understand the implications of the RF towers, but also it is the obligation of the public to educate themselves by coming to the Ministry with their questions and concerns and follow up with experts from the US Federal Communications Commission and US Center for Devices and Radiological Health. The tower issues should be addressed with truth rather than news media editorials and articles designed to create unfounded suspicion and doubt.

I feel the RF sites evaluation methods used by Comgate Telemanagement Ltd.

were well chosen. The technique of calculating the expected power densities based upon a maximum ERP of 1000 watts was a good approach by providing benchmark levels as compared to the MPE "standard'' limits. If the "inverse square'' variation with distance was used throughout the calculations low "percent of standards'' may have resulted when the emission antennas were not small "point'' sources or when there were "linear'' reflective sources as in the case of the Fort George metal walkway. The only criticism I can find of the study was the lack of knowledge of the operational status of each RF site at the time of the field surveys. It should have been possible for the Ministry of Telecommunications to bring enough pressure on the site operators to provide data on the operational output of each site at the time of the field surveys.

My suggestion to the Bermuda Ministry of Health is that they purchase perhaps two each of the survey meter and probe instruments (one each as a back-up), learn their characteristics and operating procedures, have them calibrated routinely by the US National Institute for Standards and Testing (NIST) in Gaithesburg, Maryland and randomly "spot check'' the exposure levels at the various RF sites.

Furthermore, upon request, they must be responsive to any Bermudian resident desiring to have specific general public, or occupational levels tested.

Finally, I wish to again stress that the FCC general population Maximum Permissible Exposure limits are for continuous exposure over a lifetime at their stated energy fluence levels. Further, these levels are based on the very best available scientific data accumulated over many years and set at very conservative values where no trace of deleterious health effects are evidenced. I would be happy to try to answer any individuals' questions, provided they first have tried to educate themselves (FCC Bulletin 65 is on the Internet) and provided they are not politically motivated and/or to cause unfounded fear to fellow Bermudians.

ENVIRONMENT ENV HEALTH HTH