Raccoons as Potential Vectors of Radionuclide Contamination to Human Food Chains from a Nuclear Industrial Site Author(s): Karen F. Gaines, Christine G. Lord, C. Shane Boring, I. Lehr Brisbin, Jr., Michael Gochfeld, Joanna Burger Source: The Journal of Wildlife Management, Vol. 64, No. 1 (Jan., 2000), pp. 199-208 Published by: Allen Press Stable URL: http://www.jstor.org/stable/3802991 Accessed: 07/12/2010 14:25 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=acg. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact firstname.lastname@example.org. Allen Press is collaborating with JSTOR to digitize, preserve and extend access to The Journal of Wildlife Management. http://www.jstor.org RACCOONS POTENTIAL AS OF VECTORS RADIONUCLIDE TO CONTAMINATIONHUMANFOODCHAINS A FROM NUCLEAR SITE INDUSTRIAL F. KAREN GAINES,' SavannahRiverEcologyLaboratory, P.O. DrawerE, AikenSC 29802, USA and and CHRISTINE LORD,Nelson BiologicalLaboratories Environmental Occupational G. HealthSciences Institute, Rutgers Piscataway,NJ 08855, USA University, C. SHANEBORING, and and Nelson BiologicalLaboratories Environmental Occupational HealthSciences Institute, Rutgers Piscataway,NJ 08855, USA and SavannahRiverEcologyLaboratory, University, P.O. DrawerE, AikenSC 29802, USA i. LEHR BRISBIN, SavannahRiverEcologyLaboratory, JR., P.O. DrawerE, AikenSC 29802, USA MICHAEL GOCHFELD, and Environmental Occupational HealthSciences Institute, Piscataway,NJ 08855, RutgersUniversity, USA JOANNABURGER,Nelson BiologicalLaboratories and and Environmental Occupational HealthSciences Institute, Rutgers Piscataway,NJ 08855, USA University, Abstract: Although the raccoon (Procyon lotor) is commonly harvested and consumed throughout the south- eastern United States, little is known regarding the fate and effects of environmental pollutants to this species, and the potential for it to act as a contaminant vector to humans or other predators. Muscle and liver tissues were collected from 76 raccoons from locations on and near the Department of Energy's Savannah River Site (SRS) in South Carolina and analyzed for radiocesium (137Cs).Raccoons were trapped from areas near a former reactor cooling reservoir known to be contaminated from former nuclear production activities, a stream drain- age system also known to have received 137Cs contamination from low level releases, and 4 on-site reference areas that have been unimpacted by nuclear production activities. Raccoons from 3 hunting areas 3-15 km of SRS were used as off-site reference samples. 137Cs levels differed between the 3 treatment groups (contami- nated, on-site reference, off-site reference) for both muscle and liver tissues. Muscle and liver samples from raccoons from on-site reference areas were higher in 1'37Cs than those from off-site reference animals. 137Cs in raccoon tissues from contaminated habitats exceeded levels in the pooled reference animals. The 2 contam- inated areas differed in 137Cstissue levels. Only 1 of 20 raccoons from contaminated sites on the SRS exceeded the European Economic Community (EEC) limit for 137Cs in edible muscle tissue of 0.6 Bq 137Cs/g fresh- weight edible muscle. Further, none of the raccoons from the on-site reference areas exceeded EEC limits for muscle. It is unlikely that the hunting public faces any significant risk from exposure to raccoons from the SRS. Although some raccoons might stray off the SRS which is closed to public access, most of the heavily contaminated areas are not adjacent to the edges of the site, decreasing the potential for off-site movement of contaminated animals. MANAGEMENT JOURNALOF WILDLIFE 64(1):199-208 Key words: contaminant transport, Procyon lotor, radiocesium, raccoon, risk assessment, Savannah River Site, South Carolina. Understanding the fate and effects of envi- trial and aquatic food chains (Lotze and Ander- ronmental pollutants is an important concern, son 1979, Khan et al. 1995); (2) their ability and particularly when wildlife may act as vectors of proclivity to travel extended distances (Glueck contamination to the food chain of humans or et al. 1988, Walker and Sunquist 1997, Gehrt other predators. The raccoon has seldom been and Fritzell 1998); and (3) a propensity to uti- considered in this regard, although it is com- lize human-altered habitats in combination with monly harvested and consumed throughout the an ability to move freely in and out of toxic southeastern United States (South Carolina De- waste sites (Hoffmann and Gottschang 1977, partment of Natural Resources 1996a,b). Sev- Clark et al. 1989, Khan et al. 1995). eral characteristics of raccoons make them po- Numerous studies of the chemical cycling tential agents of contaminant movement and and kinetics of 137Cshave provided insight into its environmental behavior and potential biolog- dispersal including: (1) a broadly omnivorous diet which includes components of both terres- ical uptake by game species (Brisbin 1991, Col- well et al. 1996, Peters and Brisbin 1996). Ra- diocesium has a moderately long physical half- 1 E-mail: email@example.com life (30.2 yr) and thus can persist for prolonged 199 200 IN * RADIOCESIUM RACCOONS Gaines et al. J. Wildl. Manage. 64(1):2000 periods in contaminated habitats. However, the South Carolina biological half-life of 137Csfor many species can be considerably shorter. We found no studies concerning the biological half-life of 137Cs in raccoons. It has been documented that the bi- ological half-life in the gray fox (Urocyon ciner- Georgia eoargenteus) is around 30 days, which compares closely with that of the pig, both of which are •0 0 Io omnivorous species like the raccoon (Jenkins et al. 1969). Further, it has been shown that spe- LEGEND cies having similar '37Cs biological half-lives = Reservoirs E SRS Delta could have different 137Cs ecological half-lives /V SRS RiverDrainage 0 UpperThree Runs depending on characteristics of the contaminat- 0 Pond B ed habitats (Brisbin 1991). Since 137Cs accu- 0 CarolinaBay 0 Ash Basins mulates in edible muscle tissue (Narayanyan 0 Steel Creek 0 Beech Island and Eapen 1971, Brisbin and Smith 1975, Pot- 0 Jackson ter et al. 1989), it can enter the human food o CreekPlantation R Former reactor nuclearproduction chain when hunters near such sites consume 5 0 5 10 Kilometers contaminated meat. Many radionuclide studies have focused on of Fig. 1. Map of the U.S. Department Energy'sSavannah RiverSite showingwetlandsand riverdrainagesystems. Cap- highly mobile avian species because they can ital letters ("R")indicatethe locationsof formernuclearpro- rapidly transport accumulated radionuclides ductionreactors,some of whichare knownto have served as over long distances to the hunting public. past sources of radiocesium releases (see text). Studying the potential for game mammals to ac- cumulate 137Cs and serve as a direct vector to nated stream floodplain. Our final objective was the hunting public is warranted because of lim- to estimate the relative health risks to humans ited home ranges (e.g., vs. migratory game from consumption of raccoons at observed birds) and long-term exposure. To explore this, 137Cs levels in edible muscle tissue. This work we examined 137Cs levels in muscle and liver was part of a larger study on the part of the tissues of raccoons inhabiting areas within and Consortium for Risk Evaluation with Stakehold- surrounding the SRS, a former nuclear produc- er Participation (CRESP) and the Savannah tion and research facility in South Carolina. We River Ecology Laboratory to develop bioindi- chose raccoons because of their potential to cators of both human and ecological health. serve as an indicator species for monitoring con- taminant uptake and transport. Additionally, life STUDYAREA history of raccoons and other furbearers have The SRS is a 778 km2 former nuclear pro- been studied on the SRS since 1954, 2 years duction and current research facility located in after closure of the site to public access (Kinard west-central South Carolina (33.10N, 81.3?W; 1964, Wood and Odum 1964, Jenkins et al. Fig. 1) that was closed to public access in 1952. 1969). Raccoons are commonly hunted in the In 1972, the entire SRS was designated as the vicinity of the SRS (Cothran et al. 1991) and nation's first National Environmental Research may either be consumed by hunters or given Park to provide tracts of land where the effects away or sold to the local public (South Carolina of human impacts upon the environment could Department of Natural Resources 1996a) be studied (Davis and Janacek 1997). Workman The first objective of this study was to com- and McLeod (1990) provide a detailed descrip- pare the levels of 137Csin the liver and muscle tion of the terrestrial and aquatic habitats of the of raccoons living in (1) sites known to be con- SRS. Raccoons were collected from 6 locations taminated by '37Cs on the SRS, (2) SRS sites on the SRS, 4 of which have not been directly that had no history of 137Cscontamination from impacted by 137Cs-contamination from the SRS nuclear activities, and (3) habitats outside of the (Fig. 1). Raccoons from SRS areas known to SRS boundaries. The second objective was to have been directly contaminated by 137Cs re- compare 137Cslevels in raccoons residing in dif- leases were collected from an 87-ha former re- ferent habitats on the SRS, to include a contam- actor cooling reservoir (Pond B) and a disturbed inated reactor cooling reservoir and a contami- stream flood plain (Steel Creek). Both of these J. Wildl. Manage. 64(1):2000 RADIOCESIUM RACCOONS * Gaines et al. IN 201 systems have been intensely studied with regard imately 15 km northwest of SRS (Beech Island), to the bioaccumulation of 137Csin resident flora and an area approximately 3 km from the south- and fauna (Brisbin et al. 1974a,b; Evans et al. ern SRS boundary (Creek Plantation). All 3 1983; Gladden et al. 1985; Brisbin et al. 1989; hunting areas are part of the bottomland hard- Whicker et al. 1990; Kennamer et al. 1993, wood floodplain ecosystem of the Savannah Riv- 1998). Pond B received cooling water discharg- er, which extends into the SRS along the site's es from the SRS R-Reactor (shut down in 1964) southwestern border. that were contaminated with 137Csfrom leaking reactor fuel elements. Peak introductions of METHODS 137Cs occurred during 1963 and 1964 and RaccoonTrapping Sampling and amounted to 5.7 x 1012 becquerels (Bq) of Raccoons (n = 52) were collected on SRS 137Cs (Ashley and Zeigler 1980). The Steel between December 1996 and June 1997 from Creek watershed drains into an inundated riv- 2 137Cs-contaminated sites (n = 21) and 3 ref- erine swamp delta that is contiguous to the Sa- erence sites (n = 31). Raccoons were collected vannah River. Two production reactors dis- using baited traps (T. Fox, manufacturer, Bates- charged effluents into Steel Creek containing burg South Carolina, USA) set in the afternoon cooling water mixed with purge water from ba- and checked the following morning. Raccoons sins used to store irradiated reactor fuel and were transported to the laboratory, euthanized, target assemblies. From 1954 through 1978, ap- and dissected immediately. On the SRS we only proximately 1.06 x 1013 Bq 137Cs that leaked used male raccoons for this study to control for from defective experimental fuel assemblies possible variation due to sex and to prevent re- were discharged into Steel Creek via this purge moving pregnant females or females with young water (Ashley and Zeigler 1980). from the population. Off-site reference rac- Two of the 4 sites on the SRS that were not coons (n = 24) were collected during the state- directly contaminated by plant operations wide hunting season between January and Feb- (hereafter "reference") were Carolina bays (Dry ruary 1997 and frozen individually in labeled Bay and Rainbow Bay; Fig. 1), which are nat- plastic bags until dissection. Since it was not ural elliptical depressions that vary in size and possible to determine the sex of the raccoon in the degree to which they retain water (Shar- while hunting, females were included (n = 9). itz and Gibbons 1982, Ross 1987). The third These females were used within our analyses reference site on the SRS was an undisturbed because 137Cs levels in tissues from these rac- natural stream flood plain system (Upper Three coons were not different from the males col- Runs-Tinker Creek area). Upper Three Runs lected from the same sites (Wilcoxon 2-sample Creek (UTR) has been used previously as a test: Z = -1.68, P = 0.09). We removed livers standard reference for comparing other upper (10-20 g) and gastrocnemius muscles (10-20 g) coastal plain stream areas of the southeastern and froze tissues in scintillation vials for later United States. The fourth reference site on the 137Cs analyses. We followed an animal welfare SRS was a coal-fired power plant (D-Area ba- protocol approved by the University of Georgia sins), which discharges sluiced fly and bottom Institutional Animal Care and Use Committee ash into a series of open settling basins. Past (A960205) and Rutgers University (97-017). investigations of the D-Area basins, and nearby Beaver Dam Creek, have found enrichment of Determinations 137CS water, sediments, and biota with Al, As, Cd, Cr, We determined 137Cscount rates of wet mus- Cu, Fe, Hg, Mn, Ni, Se, and Zn (Cherry and cle and liver tissues using a Packard Auto-Gam- Gutherie 1977, Evans and Giesy 1978, Alberts ma A5530 counting system (Packard Instru- et al. 1985, Sandhu et al. 1993, McCloskey and ment, Meriden, Connecticut, USA) with a 7.62- Newman 1995, Rowe et al. 1996). However, no cm thallium-activated Nal crystal of through- direct 137Cs contamination from SRS activities hole design with a counting window of 550-760 has occurred at this location. keV. Accuracy of the instrument was assessed Raccoons were also collected from nearby by calibrating it prior to every counting se- public hunting grounds to serve as an off-site quence using a certified calibration standard. reference group (Fig. 1). These sites included Counting time per sample was 60 min for sam- an area located approximately 8 km west-north- ples from contaminated areas and 500 min for west of SRS (Jackson), an area located approx- samples from reference areas. Counting times 202 IN * RADIOCESIUM RACCOONS Gaines et al. J. Wildl. Manage. 64(1):2000 for each group were based upon preliminary an- 0.8 alyses of the sample count rate for all on-site reference samples and sample masses, relative oi to resultant minimal detectable concentrations (MDC). To estimate tissue wet mass 137Cscon- f 0.7 I centrations (Bq/g), we first adjusted sample O: . .. H... . .C.n.p ..L.n.(EEC) gross count rates for background count rates. We then compared the adjusted count rates of . 0 samples to similarly adjusted count rates of aqueous standards approximating the sample geometry and containing known quantities of SRSREFERENCE OFF 137Cs. Background count rates were recorded SRSCONTATED REER~EINCE following every third sample. This also provided in Fig. 2. Concentrations radiocesium raccoontissues col- of a measure to assure the precision of the instru- lected between December1996 and June 1997 fromthe U.S. ment over the analysis period. Count rates of Department Energy'sSavannahRiverSite and offsitepublic of hunting lines representranges,boxes represent areas. Vertical standards were determined daily for samples 25%-75% quartilelimits,and horizontallines indicatemedi- counted for 60 min and twice a week for sam- ans. For both muscle and liver, the SRS reference tissues were significantlyhigherthan the off-sitetissues (P < 0.05). ples run for 500 min. Standard count times cor- Tissues fromthe contaminated were significantly site different responded to count times of samples to which fromthe pooled (SRS and offsite)referencesites (P < 0.05). they would be compared. The MDC's were cal- The bold horizontalline represents the limitfor radiocesium culated following procedures described by Cur- contamination meatforhumanconsumption of (European Eco- nomicCommunity 1986), and numbersindicatesample sizes. rie (1968). Statistical Analyses roni corrections were performed when appro- We first examined 1'37Csdistributions using priate. Kolomogorov-D statistics (PROC UNIVARI- ATE, v.6.12; SAS Institute 1988). Tests of hy- RESULTS potheses that these data were random samples Those samples below their individual MDC from normal distributions and tests of homo- ranged from 0.01-0.10 Bq/g wet tissue mass for geneity of variances were all rejected (P < 0.05) this study. Radiocesium concentrations of all even after efforts to transform the data failed. off-site raccoon liver tissues and 96% of off-site Therefore, we used Kruskal-Wallis tests (chi- muscle tissues were below their respective square approximation; PROC NPAR1WAY, MDC's. However, 58% of liver and 72% of mus- v.6.12; SAS Institute 1988) to test for overall cle tissues from on-site reference areas con- differences among the 3 test groups (on-site tained 137Cs levels above their MDC's. All liver contaminated, on-site reference, and off-site and muscle tissues from on-site contaminated reference). Wilcoxon 2-Sample tests (Z approx- areas contained 137Cslevels above their MDC's. imation; PROC NPAR1WAY, v.6.12; SAS Insti- Radiocesium levels differed among the 3 test tute 1988) were used to determine significant groups (contaminated, on-site reference, off- differences between on-site and off-site refer- site reference) for both muscle (Kruskal-Wallis ence groups and for differences between areas ANOVA: X22 = 43.90, P = 0.0001) and liver affected by plant operations vs. all other areas. (Kruskal-Wallis ANOVA: X22 = 44.81, P = This test was also used to determine differences 0.0001; Fig. 2). Radiocesium levels differed be- between habitats for the 2 on-site contaminated tween on-site and off-site reference groups for areas (Steel Creek vs. Pond B). Negative values both muscle (Wilcoxon 2-sample test: Z = for 137Cs concentrations occasionally resulted -4.23, P = 0.0001) and liver (Wilcoxon 2-sam- from sample count rates that were below back- ple test, Z = -2.69, P = 0.0071; Fig. 2), with ground. These negative and positive values on-site reference areas showing higher levels of which fell below their respective MDC's were contamination in both tissues. Radiocesium lev- not censored from the data analysis since to do els were significantly higher in raccoons col- so would bias the overall variance and could lected from contaminated areas than those col- bias the analysis (Gilbert and Kinnison 1981, lected from pooled reference areas (on-site and Newman et al. 1989). All statistical tests were off-site) for both muscle (Wilcoxon 2-sample considered significant at P 0.05 and Bonfer- test: Z = 6.36, P = 0.0001) and liver (Wilcoxon - IN * RADIOCESIUM RACCOONS Gaines et al. 203 J. Wildl. Manage. 64(1):2000 Table1. Concentrationsradiocesium wetmass)inraccoon of (Bq/g tissuescollected December andJune1997 between 1996 2 from contaminated on theU.S.Department Energy's areas of SavannahRiver Both Site. and differed < 0.05) muscle liver (P between 2 contaminated the areas. Pond B Steel Creek Tissue n i Median Range n Median Range Muscle 9 0.367 0.314 0.171-0.851 11 0.144 0.146 0.040-0.272 Liver 10 0.301 0.233 0.066-0.841 11 0.117 0.105 0.032-0.279 2-sample test, Z = 6.35, P = 0.0001; Fig. 2). such as 137Csare prevalent in the soils and sub- Finally, raccoons from the 2 contaminated areas surface sediments on and around SRS (Strom (Steel Creek and Pond B) differed in 137Cslev- and Kaback 1992, Seaman et al. 1996). Further, els for both muscle (Wilcoxon2-sample test, Z there is an inverse relationship between con- = 3.34, P = 0.0008) and liver (Wilcoxon 2-sam- centration of available potassium in soil and up- ple test, Z = 2.71, P = 0.0067; Table 1), with take of 137Cs (Nishita et al. 1960) since plants Pond B being the highest in both cases. growing in potassium-deficient soils take up the available '37Cs as a potassium substitute (Has- DISCUSSION elow et al. 1989, Looney et al. 1990, Haselow Animalsinhabitingon-site areasthat received 1990). Soils from the on-site reference areas direct contamination from SRS activities were where raccoons showed higher tissue 137Cscon- an order of magnitude higher and showed high- centrations (e.g. UTR) were predominantly er levels of variance in 137Cs than those from sandy and would tend to leach potassium and the combined reference groups. Thus, raccoon be less likely to bind 137Cs cations. Conversely, foraging habits and resource utilization may be areas with soils of higher organic matter and sufficiently limited to allow them to reflect dif- high clay content (e.g., off-site areas such as ferences in habitat contamination patterns at Jackson) may tend to bind cations such as 137Cs these spatial scales. However, 137Cslevels in the especially if the clays are illitic in nature (Co- on-site reference group were also significantly mans and Hockley 1991). This in turn would higher than raccoons from the off-site reference make 137Cs less bioavailable. group. This suggests that even in areas that have Radiocesium differences in these reference not been directly subjected to 137Cs releases, raccoon populations may also be explained by some SRS raccoons are still being exposed and home range size, with on-site raccoons possibly accumulate more 137Cs than off-site popula- feeding on some occasions in contaminated ar- tions. Seasonal differences in raccoon diets eas. Trap-recapture studies in the early 1960's and-or overall fallout levels of 137Csover time on the SRS indicated that male raccoons trav- might have contributed to differences in 137Cs eled 1.4 km between trap sites (Cunningham levels between the 2 reference groups. Studies 1962), which would make it possible for SRS on the SRS have shown seasonal differences raccoons to reside within uncontaminated ref- based on these factors (fall-winter vs. spring- erence areas and yet still forage in some con- summer) in white-tailed deer (Odocoileus vir- taminated areas. ginianus; Rabon 1968) and in feral hogs (Sus Because raccoons may move long distances Scrofa; Stribling et al. 1986). Differences may (up to 4.3 km; Walker and Sunquist 1997), it is also occurred because off-site raccoons were possible for raccoons to leave contaminated ar- collected in late winter while on-site reference eas and move to off-site areas using the flood- raccoons were collected late winter to early plain corridor. Raccoon tissues obtained from spring. off-site locations were very low in 137Cs, sug- Differences in 137Cs between the 2 reference gesting that sampled individuals from these groups may also be due, at least in part, to the populations were not residing in 137Cs-contam- nature of the geology and associated soil types inated areas on the SRS. The risk of transport between on-site and off-site foraging areas (Ta- of 137Cs from the SRS to off-site locations by ble 2). Soils with higher clay content may tend raccoons would probably be higher for raccoons to bind available 137Cs, depending on mineral- inhabiting the Savannah River floodplain system ogy, thus making it less bioavailable. Such clays than for those associated with the contaminated with a high affinity for poorly hydrated cations reservoirs, since the former represent large con- Table 2. Concentration radiocesium(Bq/g wet mass) in raccoon muscle tissue collected fromreference locationson the U.S. Department of o publichuntingareas near the SRS. Physiographic and province(Workman McLoed1990), general soil types, and theirdescriptions(Rogers 1 Physiographic Location n Median Minimum Maximum province General soil type On-site reference Upper Three Runs Creek 12 0.053 0.011 0.123 Sandhill Blanton-Lakebed Association Somewhat drained are sandy Troup-Pickney--Lucy Associ- Well draine ation have a sa some are flooding. Carolina Bays 6 0.050 0.074 0.018 Upper coastal Blanton-Lakebed Association See above. Plain Fuquay-Blanton-Dothan As- Well draine sociation soils that Rembert-Hornsville Associa- Poorly drai tion that have D-area Ash Basin 13 0.019 0 0.058 Upper Coastal Rembert-Hornsville Associa- See above. Plain tion Chastain-Tawcaw-Shellbluff Poorly drai Association drained s and are Off-site reference Beech Island 8 0.005 -0.040 0.037 Upper Coastal Shellbluff-Chewacla-Johnston Well draine Plain poorly dr loamy th Jackson 14 0.005 -0.014 0.037 Upper Coastal Bethera-Ogeechee-Angie Poorly drai Plain soils that es. Creek Plantation 2 0.011 0.010 0.012 Upper Coastal Blanton-Fuquay--Lakeland Nearly leve Plain Associations a sandy s excessivel out. IN * Gaines et al. RADIOCESIUMRACCOONS 205 J. Wildl. Manage.64(1):2000 tiguous areas of suitable habitat that lead off- sumption pattern and the median 137Cslevel in site. the raccoon muscle (0.182 Bq 137Cs/g) from Raccoon tissues from the Pond B reservoir contaminated sites, a hunter could consume no area contained significantly higher 137Cs con- more than 18 meals of SRS raccoon meat per centrations than those from the Steel Creek year (or 6.43 kg of meat per year), without ex- Delta-Savannah River floodplain area. Our data ceeding the U.S. Food and Drug Administra- suggest that 137Csmay be more bioavailable to tion's and U.S. Environmental Protection Agen- raccoons in the Pond B reservoir system than cy's most conservative action level of a 1 x 10-6 the Steel Creek floodplain of SRS, even though excess lifetime cancer risk (Rodricks 1992; see the latter originally received larger inputs of this Kennamer et al. 1998 for calculations). Further, contaminant (Ashley and Zeigler 1980). This muscle of only 1 of 20 raccoons from contami- finding is consistent with previous studies ex- nated sites on the SRS exceeded the EEC limit amining 137Cs in wood duck (Aix sponsa) eggs of 0.60 Bq 137Cs/g (EEC 1986) and no muscle from the same 2 areas (Kennamer et al. 1993, samples of raccoons from the reference areas 1995). The longer retention of the original 137Cs on SRS or off-site exceeded the EEC limit. released to Pond B vs. that to Steel Creek (Bris- Public hunting is allowed on the Crackerneck bin 1991), together with the seasonal remobili- Wildlife Management Area (WMA) adjacent to zation of 137Csfrom sediments to the water col- the SRS, but access is limited to only 30 days a umn in the hypolimnion in Pond B (Alberts et year, during the daylight hours (Sanchez and al. 1979, 1987; Whicker et al. 1990), could ac- Burger 1998). Most hunters use Crackerneck count for its longer persistence in the biota of WMA for white-tailed deer, and not raccoons the Pond B area. because night hunting is not allowed. Although some raccoons might move off SRS, most of the IMPLICATIONS MANAGEMENT heavily contaminated areas are not adjacent to Raccoons are trapped for their fur and hunt- the borders of the site or in the Savannah River ed for both sport and food in South Carolina. swamp, with the exception of the Steel Creek Raccoons accounted for 20% of the state's total delta, thus limiting the potential for off-site 1995-96 commercial fur harvest (South Caro- movement of contaminated animals. Thus, as lina Department of Natural Resources 1996a). long as public access for the hunting of raccoons Raccoon hunting is a growing sport, among is restricted from the on-site contaminated ar- both young and experienced hunters, with par- eas sampled in this study, it is unlikely that the ticipation in raccoon field trials nearly doubling consumption of 137Cs-contaminated meat pre- in the last 10 years (South Carolina Department sents any meaningful health concern for the of Natural Resources 1996b). Despite the in- hunting public in the vicinity of SRS. Further, crease in sport hunting for raccoons, there are long-term studies on SRS addressing issues of few data on the consumption of this species by ecological half-life in several game species have the public. In South Carolina, the raccoon hunt- indicated that there have been long-term de- ing season is usually from mid-September to creases in 137Cs body burdens as this isotope mid-March, with no bag or possession limit. undergoes physical decay (Brisbin 1991, Brisbin Thus, a diligent hunter who enjoyed the sport and Kennamer 2000). However, these studies of raccoon hunting and ate the meat could le- have also shown that disturbances can further gally consume as much raccoon meat as desired. remobilize this contaminant, thus increasing its A survey of attendees at a sportsmen's exposi- bioavailability and making it difficult to model tion in Columbia, South Carolina in 1998 re- its effective ecological half-life. vealed that nearly 10% of those interviewed said The consumption of contaminated raccoon they ate raccoon, with an average serving size meat would be only 1 possible route of human equivalent to 350 g (J. Burger, unpublished exposure. Any comprehensive risk assessment data). Those who ate raccoon averaged only 1 should also include estimates of the risk from meal per year, with a maximum of 12 meals per other contaminants in all hunted species. Such year. It is likely however that few people in low- a comprehensive risk estimate should also esti- er economic strata attended this event, and mate external exposure to gamma radiation therefore subsistence hunters who might con- from contaminated sediments and particulate sume raccoons more frequently may have been inhalation while hunting or otherwise residing underrepresented. Based on the above con- within contaminated areas (Whicker et al. 206 * RADIOCESIUM RACCOONS Gaines et al. IN J. Wildl. Manage. 64(1):2000 1993). Although the different forms of contam- S. K. WOODS. 1974a. Patterns of radiocesium in inants may vary by species and between sites, the sediments of a stream channel contaminated studies as reported here can serve as a model by production reactor effluents. Health Physics 27: 19-27. for ways in which data for contaminant burdens , D. D. BRESHEARS, L. BROWN,M. LADD, K. can be used to provide general estimates of the M. H. SMITH, M. W. SMITH, AND A. L. TOWNS. health risks that would be associated with the 1989. Relationships between levels of radioces- ium in components of terrestrial and aquatic food consumpti"n of game by the hunting public. webs of a contaminated streambed and floodplain community. Journal of Applied Ecology 26:173- ACKNOWLEDGMENTS 182. AND R. A. KENNAMER.2000. Long-term We thankW. L. Stephens, Jr.for contributing , studies of radionuclide contamination of migra- to the experimental design of this study and for tory waterfowl at the Savannah River Site: impli- his expertise and contribution in the field. Com- cations for habitat management and nuclear ments by E. L. Peters, R. A. Kennamer, Buddy waste site. Studies in Avian Biology 1999: In Baker, B. D. Goldstein, C. Powers, T. E. Phil- press. , AND M. H. SMITH. 1975. Radiocesium con- lippi, J. M. Novak, and 2 anonymous reviewers centrations in whole-body homogenates and sev- helped improve the manuscript. We also ac- eral body compartments of naturally contaminat- knowledge J. M. Novak for his statistical con- ed white-tailed deer. Pages 542-556 in J. B. Gen- sultation. We thank C. S. Romanek and J. C. try and M. H. Smith, editors. Mineral cycling in Seaman for advice concerning geology and soil southeastern ecosystems. National Technical In- formation Service, Springfield, Virginia, USA. geochemistry. This project was funded through M. A. STATON, E. PINDER, III, AND R. A. J. 1, Financial Assistance Award DE-FC09-96SR185464 GEIGER. 1974b. Radiocesium concentrations of from the U.S. Department of Energy to the snakes from contaminated and non-contaminated habitats of the AEC Savannah River Plant. Cop- University of Georgia Research Foundation and eia 1974:501-506. by the Consortium for Risk Evaluation with CHERRY, D. S., AND R. K. GUTHERIE. 1977. Toxic Stakeholder Participation (funded through the metals in surface waters from coal ash. 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