Raccoon (Procyon lotor) Harvesting on and near the U.S. Department of Energy’s Savannah River Site

Understanding the toxicodynamics of wildlife populations in contaminated ecosystems is one of the greatest challenges in ecotoxicology today. The goal is to manage these populations to minimize risk to ecosystem integrity as well as human health. Ecological risk assessments (ERAs) in the United States are designed to meet the regulatory mandates of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Resource Conservation and Recovery Act. According to the U.S. Environmental Protection Agency, an ERA evaluates the potential adverse effects that human activities have on the \u27 ora and fauna that de( ne an ecosystem (U.S. Environmental Protection Agency 1997). When conducted for a particular geographic location, the ERA process can be used to identify vulnerable and valued resources, prioritize data collection, and link human activities with their potential effects. Risk assessment results provide a common framework for comparing different management options, thus enabling decision makers and the public to make better informed decisions about the management of ecological resources. The ERA uses available toxicological and ecological information to estimate the occurrence of a speci( ed undesired ecological event or end point. The types of end points targeted for investigation depend on the objectives and the constraints imposed upon the risk assessment process (Newman and Strojan 1998) based on all of the relevant stakeholders; therefore, multiple endpoints at different scales may be necessary but are not commonly used (Gaines et al. 2004). In this case, the stakeholders are the public who live near and hunt on and near the Department of Energy’s (DOE) Savannah River Site (SRS; ( gure 4.1). To date, there is a dearth of knowledge concerning how environmental risk can be managed at the population level when using wildlife as endpoint (receptor) species

Oral Microbial Biofilm Stimulation of Epithelial Cell Responses

Oral bacterial biofilms trigger chronic inflammatory responses in the host that can result in the tissue destructive events of periodontitis. However, the characteristics of the capacity of specific host cell types to respond to these biofilms remain ill-defined. This report describes the use of a novel model of bacterial biofilms to stimulate oral epithelial cells and profile select cytokines and chemokines that contribute to the local inflammatory environment in the periodontium. Monoinfection biofilms were developed with Streptococcus sanguinis, Streptococcus oralis, Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis on rigid gas-permeable contact lenses. Biofilms, as well as planktonic cultures of these same bacterial species, were incubated under anaerobic conditions with a human oral epithelial cell line, OKF4, for up to 24 h. Gro-1α, IL1α, IL-6, IL-8, TGFα, Fractalkine, MIP-1α, and IP-10 were shown to be produced in response to a range of the planktonic or biofilm forms of these species. P. gingivalis biofilms significantly inhibited the production of all of these cytokines and chemokines, except MIP-1α. Generally, the biofilms of all species inhibited Gro-1α, TGFα, and Fractalkine production, while F. nucleatum biofilms stimulated significant increases in IL-1α, IL-6, IL-8, and IP-10. A. naeslundii biofilms induced elevated levels of IL-6, IL-8 and IP-10. The oral streptococcal species in biofilms or planktonic forms were poor stimulants for any of these mediators from the epithelial cells. The results of these studies demonstrate that oral bacteria in biofilms elicit a substantially different profile of responses compared to planktonic bacteria of the same species. Moreover, certain oral species are highly stimulatory when in biofilms and interact with host cell receptors to trigger pathways of responses that appear quite divergent from individual bacteria

Toxicodynamic modeling of 137Cs to estimate white-tailed deer background levels for the Department of Energy\u27s Savannah River Site

The U.S. Department of Energy\u27s (USDOE) Savannah River Site (SRS) is a former nuclear weapon material production and current research facility adjacent to the Savannah River in South Carolina, USA. The purpose of this study was to determine the background radiocesium (137Cs) body burden (e.g., from global fallout) for white-tailed deer (Odocoileus virginianus) inhabiting the SRS. To differentiate what the background burden is for the SRS versus 137Cs obtained from SRS nuclear activities, data were analyzed spatially, temporally and compared to other off-site hunting areas near the SRS. The specific objectives of this study were: to compare SRS and offsite deer herds based on time and space; to interpret comparisons based on how data were collected as well as the effect of environmental and anthropogenic influences; to determine what the ecological half-life/decay rate is for 137Cs in the SRS deer herd; and to give a recommendation to what should be considered the background 137Cs level in the SRS deer herd. Based on the available information and analyses, it is recommended that the determination of what is considered background for the SRS deer herd be derived from data collected from the SRS deer herd itself and not offsite collections for a variety of reasons. Offsite data show extreme variability most likely due to environmental factors such as soil type and land-use patterns (e.g., forest, agriculture, residential activities). This can be seen fromresultswhere samples from offsite military bases (Fort Jackson and Fort Stewart) without anthropogenic 137Cs sources were much higher than both the SRS and a nearby (Sandhills) study site. Moreover, deer from private hunting grounds have the potential to be baited with corn, thus artificially lowering their 137Cs body burdens compared to other freeranging deer. Additionally, sample size for offsite collections were not robust enough to calculate a temporal decay curve with an upper confidence level to determine if the herds are following predicted radioactive decay rates like the SRS or if the variability is due to those points described above. Using mean yearly values, the ecological half-life for 137Cs body burdens for SRS white-tailed deer was determined to be 28.79 years— very close to the 30.2 years physical half-life

A Spatially Explicit Model to Predict Radiocesium Body Burdens of White- Tailed Deer on the U.S. Department of Energy\u27s Savannah River Site

We developed a spatially explicit exposure model to interpolate and predict radiocesium (137Cs) body burdens found in white-tailed deer (Odocoileus virginianus) on the U.S. Department of Energy’s (USDOE) Savannah River Site (SRS) to gain insight into and differentiate between the main contributing sources of this radionuclide for use in harvest management strategies that focus on minimizing human risk. Hunting has been allowed from permanent stands as a mechanism to manage the deer herd since 1965. All animals are monitored in the field for gross beta and gamma activity levels, providing a spatially explicit dataset. The models described here use the relative locations of the hunt-stands to predict 137Cs exposure distributions. We used kriging to create an interpolation surface using average white-tailed deer body burdens. Cross-validations of the kriged surfaces differentiated between sources of 137Cs and where deer reside on the SRS. The kriged surfaces, coupled with additional regression analyses, provide a comprehensive assessment of deer’s 137Cs body burdens with predictive capability that quantifies the scale at which such investigations can be conducted. Although the models are local in scale, the methods presented here can be used as a template for other large areas that are being monitored for radioactive fallout

Toxicodynamic modeling of 137Cs to estimate white-tailed deer background levels for the Department of Energy\u27s Savannah River Site

The U.S. Department of Energy\u27s (USDOE) Savannah River Site (SRS) is a former nuclear weapon material production and current research facility adjacent to the Savannah River in South Carolina, USA. The purpose of this study was to determine the background radiocesium (137Cs) body burden (e.g., from global fallout) for white-tailed deer (Odocoileus virginianus) inhabiting the SRS. To differentiate what the background burden is for the SRS versus 137Cs obtained from SRS nuclear activities, data were analyzed spatially, temporally and compared to other off-site hunting areas near the SRS. The specific objectives of this study were: to compare SRS and offsite deer herds based on time and space; to interpret comparisons based on how data were collected as well as the effect of environmental and anthropogenic influences; to determine what the ecological half-life/decay rate is for 137Cs in the SRS deer herd; and to give a recommendation to what should be considered the background 137Cs level in the SRS deer herd. Based on the available information and analyses, it is recommended that the determination of what is considered background for the SRS deer herd be derived from data collected from the SRS deer herd itself and not offsite collections for a variety of reasons. Offsite data show extreme variability most likely due to environmental factors such as soil type and land-use patterns (e.g., forest, agriculture, residential activities). This can be seen fromresultswhere samples from offsite military bases (Fort Jackson and Fort Stewart) without anthropogenic 137Cs sources were much higher than both the SRS and a nearby (Sandhills) study site. Moreover, deer from private hunting grounds have the potential to be baited with corn, thus artificially lowering their 137Cs body burdens compared to other freeranging deer. Additionally, sample size for offsite collections were not robust enough to calculate a temporal decay curve with an upper confidence level to determine if the herds are following predicted radioactive decay rates like the SRS or if the variability is due to those points described above. Using mean yearly values, the ecological half-life for 137Cs body burdens for SRS white-tailed deer was determined to be 28.79 years— very close to the 30.2 years physical half-life

DNA Double-Strand Breakage as an Endpoint to Examine Metal and Radionuclide Exposure Effects to Water Snakes on a Nuclear Industrial Site

This study examined metal levels (especially U and Ni) in the tail tissues of water snakes from contaminated (Tim’s Branch) and reference areas on the Department of Energy’s Savannah River Site (SRS). Home ranges of snakes were quantified to determine the ratio of the habitat that they use in relation to the contaminated areas to better estimate exposure Compared to conventional methods that do not. The exposure assessment indicated that water snakes in the contaminated areas could expect U exposure at 3–4 orders of magnitude greater than the Agency for Toxic Substances and Disease Registry’sMinimum Risk Level (MRL) from ingestion of amphibians and fish. Ni and U, in addition to Se, Mn, and Cu, were related to increased DNA double-strand breakage (DDSB) in water snakes.We report burdens for each metal individually, but the results of the DDSB indicated that these metals did not behave independently, but as a suite. If we did not have a secondary endpoint (DDSB), we might have assumed from the exposure predictions and tissue burden analyses that U was the sole metal of concern to water snakes in Tim’s Branch. These data also imply that these toxicants do not biomagnify at the spatial and temporal scale of this study

Trophic dynamics of U, Ni, Hg and other contaminants of potential concern on the Department of Energy’s Savannah River Site

The Department of Energy’s Savannah River Site is a former nuclear weapon material production and current research facility located in South Carolina, USA. Wastewater discharges from a fuel and nuclear reactor target manufacturing facility released depleted and natural U, as well as other metals into the Tims Branch- Steed Pond water system. We investigated the current dynamics of this system for the purposes of environmental monitoring and assessment by examining metal concentrations, bioavailability, and trophic transfer of contaminants in seven ponds. Biofilm, detritus, and Anuran and Anisopteran larvae were collected and analyzed for stable isotopes (δ15N, δ13C) and contaminants of potential concern (COPC) with a focus on Ni, U, and Hg, to examine metal mobility. Highest levels of Ni and U were found in biofilms U (147 and 332 mg kg−1 DW, respectively), while highest Hg levels were found in tadpoles (1.1 mg kg−1 DW). We found intraspecific biomagnification of COPCs as expressed through stable isotope analysis. Biofilms were the best indicators for contamination and Anuran larvae with the digestive tract removed were the best indicators of the specific bioavailability of the focal metals. Monitoring data showed that baseline δ15N values differed between ponds, but within a pond, values were stable throughout tadpole Gosner stage, strengthening the case to use this species for monitoring purposes. It is likely that there still is risk to ecosystem integrity as COPC metals are being assimilated into lower trophic organisms and even low levels of this mixture has shown to produce deleterious effects to some wildlife species

The Clapper Rail as an Indicator Species of Estuarine Marsh Health

Clapper Rails (Rallus longirostris) can potentially serve as an indicator species of estuarinemarsh health because of their strong site fi delity and predictable diet consisting predominantly of benthic organisms. These feeding habits increase the likelihood of individuals accumulating signifi - cant amounts of contaminants associated with coastal sediments. Moreover, since Clapper Rails are threatened in most of their western range, additional study of the effects of potential toxins on these birds is essential to conservation programs for this species. Here we present techniques (DNA strand breakage, eggshell structure, and human-consumption risk) that can be used to quantify detrimental effects to Clapper Rails exposed to multiple contaminants in disturbed ecosystems as well as humans who may eat them. Adult birds collected near a site contaminated with polychlorinated biphenyls (PCBs) and metals in Brunswick, Georgia had a high degree of strand breakage, while those collected from a nearby reference area had no strand breakage. Although, results showed that eggshell integrity was compromised in eggs from the contaminated sites, these results were more diffuse, reemphasizing that multiple endpoints should be used in ecological assessments. This study also shows that techniques such as eggshell integrity on hatched eggs and DNA strand breakage in adults can be used as non-lethal mechanisms to monitor the population health of more threatened populations such as those in the western US. We also present results from human-based risk assessment for PCBs as a third toxicological endpoint, since these species are hunted and consumed by the public in the southeastern US. Using standard human-risk thresholds, we show a potential risk to hunters who consume Clapper Rails shot near the contaminated site from PCBs because of the additional lifetime cancer risk associated with that consumption

The Clapper Rail as an Indicator Species of Estuarine Marsh Health

Clapper Rails (Rallus longirostris) can potentially serve as an indicator species of estuarinemarsh health because of their strong site fi delity and predictable diet consisting predominantly of benthic organisms. These feeding habits increase the likelihood of individuals accumulating signifi - cant amounts of contaminants associated with coastal sediments. Moreover, since Clapper Rails are threatened in most of their western range, additional study of the effects of potential toxins on these birds is essential to conservation programs for this species. Here we present techniques (DNA strand breakage, eggshell structure, and human-consumption risk) that can be used to quantify detrimental effects to Clapper Rails exposed to multiple contaminants in disturbed ecosystems as well as humans who may eat them. Adult birds collected near a site contaminated with polychlorinated biphenyls (PCBs) and metals in Brunswick, Georgia had a high degree of strand breakage, while those collected from a nearby reference area had no strand breakage. Although, results showed that eggshell integrity was compromised in eggs from the contaminated sites, these results were more diffuse, reemphasizing that multiple endpoints should be used in ecological assessments. This study also shows that techniques such as eggshell integrity on hatched eggs and DNA strand breakage in adults can be used as non-lethal mechanisms to monitor the population health of more threatened populations such as those in the western US. We also present results from human-based risk assessment for PCBs as a third toxicological endpoint, since these species are hunted and consumed by the public in the southeastern US. Using standard human-risk thresholds, we show a potential risk to hunters who consume Clapper Rails shot near the contaminated site from PCBs because of the additional lifetime cancer risk associated with that consumption

Clapper rails as indicators of mercury and PCB bioavailability in a Georgia saltmarsh system

Clapper rails (Rallus longirostris) were used as an indicator species of estuarine marsh habitat quality because of their strong site fidelity and predictable diet consisting of mostly benthic organisms. Mercury (Hg) and the polychlorinated biphenyl (PCB) Aroclor 1268 concentrations were determined for sediments, crabs, as well as clapper rail adults and chicks collected from salt marshes associated with the LCP Superfund site in Brunswick, Georgia. Home ranges were established for adult rails, and sediment and crab samples were taken from each individual’s range. The study was designed to minimize the spatial variability associated with trophic transfer studies by choosing an endpoint species with a potentially small home range and specifically sampling its foraging range. The mean home range for clapper rails was 1.2 ha with a median of 0.28 ha. Concentrations of Hg and Aroclor 1268 were shown to increase with each trophic level. Transfer factors between media followed the same pattern for both contaminants with the highest between fiddler crabs and clapper rail liver. Hg and PCB transfer factors were similar between sediment to fiddler crab and fiddler crab to muscle, however the PCB transfer factor from fiddler crabs to liver was over twice as large as for Hg. PCB congener profiles did not significantly differ between media types