Rodent Toxicity/Carcinogenicity Studies on Cell Phone Radio Frequency Radiation in Reverberation Chambers

Rodent Toxicity/Carcinogenicity Studies on Cell Phone Radio Frequency Radiation in Reverberation Chambers Ronald L. Melnick, Christopher Portier National Institute of Environmental Health Sciences National Institutes of Health NTP The National Toxicology Program The Department of Health and Human Services

Objective To identify potential toxic and carcinogenic effects associated with chronic exposure to modulated cell phone RFR and to characterize doseresponse relationships in laboratory animals Unrestrained animals in exposure groups of 100-200 Uniform field, exposures at least 6 hr/day Max dose: animals capable of thermoregulation

Collaborators Chamber studies at NIST, Boulder, CO Perry Wilson, John Ladbury, Galen Koepke Simulations at IT IS, Zurich Niels Kuster, Jürg Fröhlich Basic Study at IITRI David McCormick, PI Pathology and Review Independent of the NTP External Board, Other communities NIEHS - design team John Bucher, Tom Burka, Paul Foster, Jef French, Jean Harry, Denise Orzech, Joe Roycroft, Robert Sills, Greg Travlos

Reverberation Chamber Studies large shielded room with excitation antennae and paddle to create a homogeneous electromagnetic environment field exposure is from all directions, all polarizations field variations occur over time and space; average field is uniform over a large volume field distributions can be well characterized

Reverberation Chamber Feasibility Studies Cellular Telephone Frequencies (900 and 1900 MHz) Is field uniformity adversely affected when the chamber is loaded with 240 bottles containing 500 ml of a tissue simulating liquid (phantoms)? Is the SAR uniform among phantoms within a chamber? What is the effect of phantom-to-phantom proximity on SAR uniformity? What are power requirements to achieve desired SAR levels when chambers are full?

Reverberation Chamber Feasibility: Summary Total electric field uniformity (±1 SD) with no phantoms: 0.67 db at 900 MHz 0.67 db at 1900 MHz Total electric field uniformity with 255 phantoms (500 g each): 1.8-2.4 db at 900 MHz (various transmit antenna locations) 1.5-2.1 db at 1900 MHz (various transmit antenna locations) Efficiency with 255 phantoms (500 g each) 89% at 900 MHz 86% at 1900 MHz Average SAR uniformity (±1 SD) 0.75 db at 900 MHz 0.75 db at 1900 MHz

db -20-16 -12-8 -4 0

Toxicology NTP RF Studies Step 1 - architecture Step 2 - renovation Step 3 - equipment/chambers Step 4 - thermal/pilot studies Step 5 - perinatal/prechronic toxicity studies Step 6 - chronic exposure study

Animal Models Usual NTP two sexes of two rodent species usually F344 rats and B6C3F1 mice Cell phone RFR Sprague-Dawley rats (both sexes) B6C3F1 mice (both sexes)

Exposure Issues Exposure to RFR in reverberation chambers animals unrestrained and individually caged Frequencies and modulations 900 MHz, GSM & CDMA modulated signals - Rats 1900 MHz, GSM & CDMA modulated signals - Mice Power levels per frequency/modulation Thermal pilot study at SAR of 0 and 4-12 W/kg Prechronic at 0 (sham), 0.64, 1.6, 4, and? W/kg Chronic - based on prechronic results

Equipment 14 reverberation chambers 3 GSM, 3 CDMA, 1 Sham per species Possibly 21 if we need to separate male and female rats Large enough to service animals, house all of them appropriately, and provide a uniform field Shielding >100 DB Safety requirements Cleaning requirements Environmental controls Verification chamber works Monitors properly used

Exposure Issues Usual NTP inhalation studies 6 hours/day, 5 days/week Exposure chambers, not tubes Cell phone RFR 20 hours intermittent (10 min on/off) exposure/day, 5 days/week Reverberation chambers Same amplifier for both species at same dose (10 min rat, 10 min mice)

Thermal Pilot Study Usual NTP prechronic study 10 animals/species/sex/exposure level beginning at ~6 weeks of age lasting for 13 weeks Cell phone RFR study 5 pregnant rats and mice per power level per frequency/modulation beginning on GD-10 5 rats and mice per power level per frequency/modulation at ages 5 and 20 weeks 4,8,10,and 12 W/kg Implanted thermal probes (if feasible) MRI imaging of brain

Prechronic/Perinatal Study Usual NTP prechronic study 10 animals/species/sex/exposure level beginning at ~6 weeks of age lasting for 13 weeks Cell Phone RFR Study 13 dams (GD-6) per species (allows some loss) At PND 21, 20 pups per sex/species begin individual exposures for 4 weeks Blood-brain barrier leakage (10/group) Serology, special pathology, etc. Implanted thermal probes if feasible

Chronic Study: Number of animals/group NTP chronic 50 animals/species/sex/exposure level Cell phone RFR chronic 50 pregnant animals per species per power level per frequency/modulation At weaning, reduce to 105 animals per sex/species/power level/modulation for continued exposure at the same average whole body SAR Interim sacrifice at 19 weeks of age (N=5, similar age as NTP 13-week studies). Special brain pathology

Endpoints Body weights and clinical signs in all studies Core body temperature during perinatal exposure and first year of chronic Organ weights brain, liver, thymus, kidney, testis, adrenal gland, heart, lungs at end of perinatal study and at 19-week sac Complete necropsy and histopathology Perinatal: pups exposed from PND-21 to PND-49 Chronic: all interim sac and chronic exposed animals

Additional Endpoints Perinatal study Lens optical quality (focal length variability, light scatter) Serum corticosterone Blood brain barrier: permeability to 10 and 70 kd fluorescent dextrans 19-week interim sac animals Hematology Micronuclei: mouse peripheral blood, rat bone marrow cells Sperm morphology/vaginal cytology evaluation DNA strand breaks in rat and mouse brain cells Core study animals Urinalysis (16-hr samples from rats at multiple times) metabonomic profiling by HPLC-MS or 1H-NMR 6-hydroxymelatonin sulfate by radioimmunoassay

Toxicology in the 21 st Century A Road Map for the National Toxicology Program Dr. Christopher J. Portier Associate Director, National Toxicology Program National Institute of Environmental Health Sciences Department of Health and Human Services

High-Throughput Screening Develop capacity Two to five thousand agents initially Obvious toxicity targets Develop data handling tools Build a validation data set Expand as warranted Broader number of assays Broader number of agents Wider number of targeted toxicities

High-Throughput Screening Fully integrated with the NIH Molecular Libraries Initiative 10 screening centers 100 grants per year on new assays 30 grants per year on new methods 120K agents screened 1532 well format 10 plus dilutions Multiple replicates Cross-laboratory validation

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