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Populations of barn swallows (Hirundo rustica) nested seasonally near the Test Reactor Area (TRA) radioactive leaching ponds on the Idaho National Engineering Laboratory (INEL). These birds utilized leaching pond arthropods as a food source and contaminated mud for nest construction and thus accumulated radioactive materials. Over 20 fission and activation products were detected in immature and adult TRA birds. The radionuclide exhibiting the highest mean concentration in adult birds was 51Cr, with 16.1 Bq g-1 (435 pCi g-1). Mean concentrations of detectable radionuclides were used to calculate internal dose rates. Approximately 72% of the total dose rate of 219 microGy d-1 (22 mrad d-1) for adult birds was due to 24Na. Swallow thyroids contained a mean 131I concentration of 3330 Bq g-1. An average dose rate to the thyroid was calculated to be 4300 microGy d-1 or 450 mGy (45 rad) for the entire breeding season. Data from LiF-700 thermoluminescent dosimeters in swallow nests indicated that average dose rates were 840 microGy d-1 for eggs and 2200 Gy d-1 for nestlings, for a total of 54 mGy (5.4 rad) during the nesting period. The breeding biology and growth rate were investigated for TRA swallows and comparison group located 15 km and 100 km away. Total mortality rates for the comparison group vs. 1976 and 1977 TRA populations were not found to be significantly (p greater than 0.9) different. Nonlinear regression was used to fit individual growth curves and estimate parameters using a logistic model. First clutch TRA swallows were found to have a significantly (p less than 0.05) lower mean growth rate compared to either the first clutch comparison group or the second clutch of TRA birds. Mean asymptotic weights achieved by immature TRA birds were also found to be significantly (p less than 0.05) lower than those achieved by comparison group birds. Both growth rate and asymptotic weights for TRA birds were within the normal range reported in the literature. The cause for the statistical difference in growth rate between the comparison group and TRA first clutch populations could not be determined.

Thyroids from mule deer (Odocoileus hemionus) were collected in New Mexico, Colorado, Wyoming and Idaho and 129I/127I atom ratios were determined. Iodine-129/127 atom ratios were significantly (P less than 0.005) different among states. Ratios in Wyoming and Idaho control thyroids were significantly (P less than 0.05) larger than ratios in New Mexico and Colorado. Fallout from past atmospheric nuclear tests at the Nevada Test Site is suggested as a possible explanation for the differences in ratios. Average 129I/127I ratios in thyroids of other large mammals collected 54 km west and 116 km northeast of the Idaho National Engineering Laboratory (INEL) in south eastern Idaho were up to 15 times those found in control thyroid samples from Idaho. Atmospheric effluents from the Idaho Chemical Processing Plant located on the INEL were likely responsible for the increased ratios in animals collected in the INEL vicinity. Although of no health consequence to the animals, 129I in deer thyroids may be a sensitive indicator of contaminants from nuclear fuel reprocessing plants and atmospheric nuclear tests or accidents.

Waterfowl were collected at radioactive leaching ponds, an adjacent sewage lagoon on the Idaho National Engineering Laboratory ( INEL ) and on nearby control areas to determine 129I / 127I (stable isotope) atom ratios in muscle tissue. Iodine-129/127 atom ratios in muscle tissue averaged about 1.6 X 10(-6) for wild waterfowl from the leaching pond, 1.6 X 10(-6) for waterfowl from the sewage pond, and 1.3 X 10(-6) for control samples. A group of wing-clipped waterfowl placed on the ponds for 2-156 days had average 129I / 127I atom ratios in muscle of 6.0 X 10(-6). Iodine-129/127 atom ratios in muscle were statistically higher (P less than 0.05) in the wing-clipped waterfowl than in control, sewage lagoon and wild waterfowl samples because of the extended period of time they spent on the ponds. Internal lifetime whole-body dose from 129I was estimated to be 1.0 X 10(-5) mrad for waterfowl from control areas and 3.0 X 10(-5) mrad for leaching pond waterfowl. The lifetime thyroid dose commitment to man consuming a wild duck from the leaching ponds was 1.3 X 10(-4) mrem. Liquid effluents disposed in the radioactive leaching ponds do not appear to cause an appreciable increase in 129I / 127I atom ratios in tissues of waterfowl using the ponds.

Thyroids were collected from rabbits on and near the Idaho National Engineering Laboratory (INEL) Site in southeastern Idaho and analyzed for 129I and stable iodine, 127I. The 129I/127I atom ratios in rabbits collected on the INEL site were larger than ratios in rabbits from a control area. Maximum 129I/127I atom ratios (9.1 x 10(-4)) occurred near the Idaho Chemical Processing Plant (ICPP). Based on rabbit thyroid concentrations, the 129I appeared to be deposited primarily in the direction of the predominant winds from the ICPP, northeast and southwest. Dose rates from the 129I to thyroids of INEL rabbits varied from 0.1 to 260 muGy/y (0.01 to 26 mrad/y). Iodine-129 atmospheric releases from the ICPP appeared to have increased the 129I/127I atom ratios on and near the INEL site.

Concentrations of 90Sr, 137Cs, 238Pu, 239+240Pu, and 241Am in deer mice tissues collected from a radioactive waste disposal area in southeastern Idaho were significantly (p less than 0.05) higher than those from a control area. The highest concentrations of Pu and Am occurred in pelts of deer mice inhabiting an area which had elevated surface and subsurface soil concentrations of these nuclides as compared to other Subsurface Disposal Area locations. Therefore, transuranic contamination in tissues likely originated from both soil depths. However, 137Cs and 90Sr in tissues likely originated from subsurface areas, since surface soils were below background concentrations for these nuclides. Based on a minimum of 6160 deer mice inhabiting the 36-ha waste disposal area over a 1-yr period, a total minimum inventory of 22.8 mu Ci radioactivity was contained in deer mice tissues. Of this estimate, 22.7 mu Ci activity was due to the radionuclides 90Sr and 137Cs. An estimated total of 8.4 mu Ci was transported from the disposal area in mice dispersing from the area. A calculated annual radionuclide inventory of 28.8 mu Ci in deer mice feces was deposited in and around the radioactive waste disposal area. Deer mice inhabiting the SDA are a mode of radionuclide uptake and transport; however, the environmental consequences of this transport mechanism are likely minimal. The results for deer mice, which make up 69% of the small mammal biomass, are discussed in relation to other small mammals within the disposal area. Other modes of transport associated with the deer mice, such as radionuclides in excavated soils associated with burrowing activities and predation, are also discussed.

Coyote fecal samples were collected near a radioactive waste leaching pond and a solid radioactive waste disposal facility and analyzed for radioactivity. Elevated concentrations of 137Cs, 90Sr and 238Pu in the samples from the liquid radioactive waste leaching area were attributed to coyotes ingesting contaminated pond water and/or small mammals. Elevated 241Am concentrations in coyote fecal samples collected around the solid radioactive waste disposal facility were due to ingestion of contaminated small mammals. Assumptions relative to the coyote use of these areas permitted an estimate of the maximum quantity of radioactivity exported and eliminated around the facilities. An annual total of 7.2, 31.4 and 1.8 microCi (90Sr, 137Cs, 238Pu, 239,240Pu, 241Am, 242Cm and 244Cm) was eliminated by coyotes within a 6.3 km radius of the solid radioactive waste disposal facility, liquid waste leaching pond, and control area, respectively. These quantities of radioactivity eliminated by coyotes were similar or less than quantities transported by other mechanisms such as waterfowl and vegetative uptake of radioactivity. Coyotes are a mode of radionuclide transport from the two radioactive waste disposal areas; however, due to the low radionuclide concentrations and low yearly radionuclide inventories in coyote fecal samples, it is doubtful that any significant environmental consequences occur as a result of this transport mechanism.

Deposition velocities and retention times were obtained for submicron aerosols of 141Ce and 13l4Cs deposited on two cool desert plant species, big sagebrush (Artemisia tridentata) and bottlebrush grass (Sitanion hystrix). Mean deposition velocities for sagebrush were 0.18 cm/s (141Ce) and 0.13 cm/s (134Cs). Mean deposition velocities for grass were 0.022 (141Ce) and 0.023 cm/s (134Cs). Species differences were significant (p less than 0.05), however, nuclide differences were not significant. The loss of activity on the vegetation consisted of two components. A rapid initial loss was found with effective half-times of approx. 1 d (1-8 d for 141Ce and 0.6 d for 134Cs) on sagebrush and approx. 2 d (2.8 d for 141Ce and 2.3 d for 134Cs) on grass. This was followed by a slower, long-term loss with effective half-times ranging from 11 d for 141Ce and 15 d for 134Cs on sagebrush to 9 d for 141 Ce and 11 d for 134Cs on grass.

(1) Radiation dose rates received by deer mice (Peromyscus maniculatus (Wagner)) and Ord's kangaroo rats (Dipodomys ordii (Woodhouse) inhabiting a solid radioactive waste disposal area and a control area in south-eastern Idaho were determined by surgically implanting lithium-floride thermoluminescent dosimeter (TLD) packets. Fifty-three percent of the 542 and 135 TLD packets implanted in deer mice and kangaroo rats, respectively, were recovered. (2) The radiation dose rates received by animals from the radioactive waste disposal area varied from 4 to 418 000 gGy day-' (0-4-42 000 mrad day-') and were significantly (P < 0.01) higher than the dose rate of 4 gGy day-' (0-4 mrad day-') received by control animals. Doses resulted primarily from radiation from buried activation and fission products and not from radionuclides in/on tissues. (3) Ninety-six percent of the waste disposal area deer mice in the autumn-winter had radiation dose rates higher than the rates of the control animals, whereas in the spring-summer 73% of the deer mice received dose rates greater than the rates of control animals. Differences in seasonal data were probably related to increased subsurface time in autumn-winter. (4) Autumn-winter dose rates received by kangaroo rats were significantly (P < 0.05) higher than spring-summer rates and were attributed to the species entering torpor beneath the soil surface during winter. (5) Conservative comparisons between the radiation dose rates received by implanted TLD packets in individual small mammals and the potential dose rates received by individual animals on the surface of the area indicated a minimum of 49 and 20% of the deer mice and kangaroo rat populations, respectively, encountered areas of buried activation and fission waste and/or contaminated soil. (6) Data obtained provided an indirect method of measuring biological intrusion into soil covers over solid low-level radioactive waste disposal areas.