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Immunocontraception using porcine zona pellucida (PZP) vaccines is being explored as a nonlethal method of solving the problems of locally overabundant wildlife populations. This study characterized the immunological response of captive elk (Cervus elaphus nelsoni) to PZP challenge using 18 3-yr-old cows and was conducted from 14 September 1994 to 13 December 1995. All animals were given a single PZP inoculation and 1 mo later six of these animals were randomly chosen and received a booster inoculation. Blood samples were drawn from all animals at the time of the initial inoculation and 1, 2, 4, 6, 10, and 15 mo later. Immunological response was assessed by measuring anti-PZP antibody levels in serum. All animals demonstrated a strong immune response with no evidence that the booster enhanced antibody levels. Antibody levels rose from between 0 and 4 at the time of the initial injection to peak levels of 85 to 163 within 2 to 6 mo, followed by a noticeable decline by 15 mo post-vaccination. Limited data suggest that antibody levels > 100 may be required to effect contraception. High individual variability in immune response observed in this study suggests it may be difficult to predict the proportion of animals effectively treated. Disruption of seasonal synchrony in calving also could occur if antibody levels in individuals fall below effective levels while animals are still cycling. These results indicate that immunocontraception using PZP vaccines is possible for elk. However, carefully controlled population experiments will be required in order to assess the potential and limitations for management applications of this technique.

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Monitoring mule deer (Odocoileus hemionus) on a former plutonium production site along the Columbia River at the Hanford Site, Washington (USA) revealed 27 (23%) of 116 adult males had unusually shaped, velvet-covered antlers and abnormally developed testicles. We captured 32 males to examine age-class differences and the ratio of affected to unaffected deer and determine whether affected testicles were atrophic or hypoplastic. We found testicular atrophy in most deer with velvet-covered antlers, primarily in animals older than 5 yr. Deer had marked to extreme stages of testicular atrophy, indicating permanent sterility. Decreased serum levels of testosterone and compensatory increased levels of luteininzing hormone and follicle stimulating hormone were detected in all affected males; thus, the gondopituitary hormonal pathway may have responded to abnormally low levels of testosterone in the affected animals. Brucella spp. antibodies in sera were not detected and 9 (90%) of 10 affected animals were seropositive for epizootic hemorrhagic disease virus (EHDV-2) and bluetongue virus (BTV-11) as compared to 12 (63%) of 19 unaffected animals; however, signs of other infectious diseases were not observed. Testicular degeneration generally exceeded that observed with nutritional disorders and poisons in domestic species. Also, severity of the atrophy and apparent lack of other affected tissues suggested that radiation may not be responsible. Testicular atrophy in mule deer has been reported elsewhere; however, neither prevalence has been as high nor or occurrence as well confined to a specific geographical area, as that observed at the Hanford Site. Furthermore, no physiological or age-related influences were described. Documenting the status of such variables and examining their relationships to this phenomenon is a crucial step in understanding the reproductive capacity of a wild deer population.

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In the United States, concern for human exposures to radioactivity associated with the disposal of low-level radioactive waste has resulted in a series of regulatory guides, environmental assessments, management practices, and modeling tools. A large number of radionuclide transport processes and mechanisms that may contribute to human exposure have been modeled, using computer programs to make the required calculations. The objective of our work was to evaluate the relevance of potential biological transport processes in the assessment of potential impacts at low-level waste (LLW) disposal sites. As part of this effort, we developed an order-of-magnitude estimate for potential dose to man resulting from biological transport by burrowing animals and by plant translocation at a reference low-level waste site in the arid west. We also made comparative dose-to-man estimates for a more commonly considered human intrusion exposure scenario. Parameter values for defining a reference arid LLW disposal site and biotic transport processes are based on data reported in current literature. Estimates of waste volumes for the western United States are based on information described by the U.S. Nuclear Regulatory Commission in the Draft Environmental Impact Statement in support of 10 CFR Part 61. Our estimates of the dose-to-man resulting from biotic transport are of the same order of magnitude as those resulting from a more commonly evaluated human intrusion scenario. The previously assumed lack of potential importance of biotic transport at LLW sites in earlier assessment studies is not confirmed by our findings. Our results indicate that long-term biological transport processes have the potential to influence LLW site performance, and should be carefully evaluated as part of the impact assessment process.

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Radio transmitters are a useful tool in determining the degree of use of and extent of movement from contaminated sites by highly mobile wildlife species. Programs monitoring wildlife species for environmental contaminants from localized sources can maximize the amount of information obtained from an individual animal by using radio-telemetry to ascertain residence history. The use of radio-telemetry techniques on two mobile wildlife species, mule deer (Odocoileus hemionus) and mallard ducks (Anas platyrhynchos), to document their use of and movement from low-level radionuclide contaminated waste ponds are described.

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Our sampling results indicate that raptor castings (regurgitated material containing the nondigestible remains of prey) faithfully reflect the composition of known environmental gamma-emitting radionuclides. The castings are easily obtainable and provide a way to monitor for the presence of biologically available radionuclides. Raptor castings can also provide a useful adjunct to existing monitoring programs where small mammal burrowing into buried waste may occur.

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A comparison was made between the amount of time 17 radio-collared mule deer (Odocoileus hemionus) spent near low-level waste-management ponds on the Hanford Site and the levels of radionuclides found in samples of their muscle, liver, bone and rumen contents. All deer had low, but detectable, amounts of 137Cs in their muscle, liver and rumen contents and 90Sr in their bone. Several other radionuclides were detected in the rumen samples, but were apparently not incorporated into the muscle and liver tissue. There was a positive, significant correlation between the amount of time deer spent near the waste-management ponds and the levels of 137Cs in their muscle and liver and 90Sr in their bone. The concentrations of 137Cs in rumen samples did not appear to be related to the amount of time deer spent near waste-management ponds. The variability of 137Cs in muscle was higher in those deer living near the waste-management ponds than in individuals residing in areas remote from the ponds. In general, the levels of radionuclides in Hanford Site deer appear to be reduced from that observed in the 1960s.

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A chronic feeding study using 95mTc incorporated into alfalfa and an acute study where 95mTc was amended to alfalfa showed that about 8.4% of ingested Tc was transferred to eggs. After 10 days of chronic feeding, 80% of the Tc was in yolk, 20% in albumin and less than 1% in shell and associated membranes. At necropsy, technetium concentrations in the three largest oocytes were nearly equal. The biological half-time for Tc was about one to two days in acute studies. Results from the chronic feeding study also indicated that Tc levels in albumin reach a maximum between three and five days while maximum yolk concentration is attained in about six to seven days. Albumin concentrations declined about 20-50% after Day 6.

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