Radiation-induced skeletal changes were studied in beagles fed from midgestation to 1.5 yr of age diets containing SOSrC12 in equilibrium with or administered 226RaC12 in 8 semimonthly i.v. injections starting at 2,4 or 14 months of age. Skeletal changes were evaluated with a radiographic X-ray scoring system in 20 skeletal regions; each region was scored on a 0-6 scale. Skeletal changes were endosteal or periosteal cortical sclerosis and thickening (ECST, POCST), fractures, osteolytic lesions and trabecular coarsening. I n general, a lower level of skeletal changes were observed in + SOY relative to 226Ra labeled skeletons.Changes in goSr-labeled skeletons were observed for average daily ingestions larger than 1.5 pCi At 36 pCi 90Sr + goY/day diet, the highest ingested activity level in this experiment, ECST and POCST were observed in 100 and 50 % of all dogs, respectively. 226Ra induced skeletal changes were minimal for total injectivityAo = 0.53 pCi 226Ra. ECST incidence in at least one of the 20 skeletal regions was 100 %for dogs injected A, 2 9.3 pCi 2z6Ra, POCST incidence was 100 only at A, 2 83.6 pCi z26Ra. Fractures were observed at A, 2 14 pCi 226Ra. Total skeletal changes and rate of changes were analyzed as a function of $%r + and zz6Ra dose rate, dose and time. At accumulated doses of 90Sr + less than D = 7 krad, the degree and rate of skeletal changes were about the same, but for larger than 7 krad a definite dose rate dependence was observed. For equivalent doses ofradium, skeletal changes were larger at lower injected activity levels. Implications of dose rate, dose and time effects on response surface for extrapolation of experimental animal data to man are discussed. +

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The Yir body burden ingested as a constant fraction of dietary calcium in 1.5 yr goSr-goY feeding was analyzed for uptake and retention. Retention times were compared to that for a single intravenous injection of at to = 1.5 yr of age ( t ) . The uptake parameters were compared with skeletal and body growth rates. No significant differences in body weight pattern of 452 beagles were observed between the controls and gOSr-fed dogs. The retention parameters in our singly injected beagles were compared with those for 90Sr inhalation studies;no difference was observed. The average skeletal dose rate bo(t) and the time-integrated dose Do(t) were calculated from the mean body burden as a function of age and skeletal/body weight ratios. The local dose was determined by a combination of thermoluminescent dosimetry and measurement ofgoSr concentration. The local dose rate b(t) was corrected for local bone geometry and local distribution ofwSr activities. The local dose rates and dose were compared to the average skeletal dose and dose rate. The local dose to marrow at the proximal humerus was always overestimated by the average skeletal dose and dose rate. The dose rate fjo(t) overestimated the dose to hematopoietic tissue for the first 5 yr of life partially due to averaging of the higher gOSr concentration in cortical bone with the lower concentration in trabecular bones.The Do(t) overestimated D(1) at the cortical regions for all t . Autoradiographic and local measurement of 90Sr in bone revealed that a uniformly labeled skeleton (constant goSr/g of ash) was obtained in 1.5 yr of feeding. For periods t > to the fast local turnover at the proximal region relative to cortical bone produced "cold spots" and low activity regions of cancellous bone. In contrast, the injected cortical bones showed hot spot areas on a diffuse background.

3: r.w,m FOREWORDThis report is a summary of a program to develop an integrated gamma-ray spectroscopy system for use in Measurement of concentrations of radionuclides in solid samples collected near active and inactive uranium mining, milling, and fuel-processing facilities. Use of high-resolution gamma detectors allows specific quantification of the level of ground contamination. A gamma spectra of a sample of uranium mill tailings may show more than 150 individual peaks between a 40-to 1500-keV energy band. This necessitated a meticulous calibration of the system for gamma energy, efficiency, and precise knowledge of intrinsic radionuclide intensities.

This paper presents impacts of arsenic due to a steel plant operation on an agricultural and residential area. A spatial dispersion modeling of arsenic in fugitive particulates was implemented using AERMOD as a tool for analyzing the impacts of steel complex emissions in southwest of Isfahan, Iran, based on US Environmental Protection Agency (EPA) Guidelines. Evaluating the model, EPA's speciate database was used to determine the proportion of the steel plant in air pollution among other sources in the region, and values of arsenic were further compared with those obtained during an 8-h continuous monitoring at 11 downstream receptors. According to the modeling results, sampling locations of air, water, soil, rice and meat downstream the steel plant were identified and collected, and concentrations of arsenic were measured. Finally, the human health risk assessment of arsenic via inhalation, ingestion and dermal exposure was calculated. The performance evaluation of the model showed that AERMOD predictions are reliable for industrial areas, and it can provide useful information for the Environmental Impact Assessment (EIA) guidelines. The results of arsenic case study show the value of total carcinogenic risk 117 per million, while the hazard index value was found greater than one. Inhalation entry risk attributes the most, and exposure to air, water, food and soil attributes about 66%, 18%, 15% and 0.05% of total risk in the overall region, respectively. The results indicate that the high level of contamination should have high chronic non-cancer risk and medium cancer risk compared to EPA guidelines.