Scientists take samples from juvenile osprey for contaminant study. By FWS, 2013
The following materials document investigations of the Raleigh Field Office's Environmental Contaminants Program or those of our partners. Complete references and abstracts are available here; please contact the office directly for copies of publications, reports, or presentations.
- Drew A, Kwak T, Cope G, Augspurger T. 2015. Hierarchical Landscape Models for Endemic Unionid Mussels: Building Strategic Habitat Conservation Tools for Mussel Recovery in the South Atlantic Landscape Conservation Cooperative. Report by USGS Fish and Wildlife Cooperative Research Unit, Raleigh, NC.
- USFWS. 2014. Biological Carbon Sequestration Accomplishments Repor [Raleigh Field Office’s Sara Ward authored six sections of this report] pdf version of this report (18 KB)
- Augspurger, T. 2014. Tier 1 Preliminary Evaluation of Pollutant Sources to the Impounded Reaches of Brookford Dam and Henry River Dam on Henry Fork (Catawba River Basin), North Carolina. U.S. Fish and Wildlife Service, Ecological Services, Raleigh, NC. 20 pp.
- Augspurger T. 2014. Continuous water-quality monitoring at Lake Mattamuskeet - A foundation for national wildlife refuge water quality partnerships: Project Update, December 2014 Progress Report.
- Augspurger TP, Wang N, Kunz JL, Ingersoll CG. 2014. Pollutant Sensitivity of the Endangered Tar River Spinymussel as Assessed by Single Chemical and Effluent Toxicity Tests. U.S. Fish and Wildlife Service, Ecological Services, Raleigh, NC pdf version of this report (1.6 MB)
- Augspurger, T. and S. Ward. 2012. Tier 1 Evaluation of Pollutant Sources to the Impounded Reach of Clifton 2 Mill Dam, Pacolet River, Spartanburg County, South Carolina. U.S. Fish and Wildlife Service, Ecological Services, Raleigh, NC. 39 pp. + appendice pdf version of this report (4 MB)
- Augspurger, T. 2012. Milburnie Dam Tier 2 Sediment Sampling and Evaluation Report. U.S. Fish and Wildlife Service, Ecological Services, Raleigh, NC. Summary of this report (125 kb) pdf version of this report (7.7 MB)
- U.S. Fish and Wildlife Service. 2010. Benefits of wetland hydrology restoration in historically ditched and drained peatlands: Carbon sequestration implications of the Pocosin Lakes National Wildlife Refuge cooperative restoration project, January 2010 Update. Raleigh Field Office, Raleigh, NC. Summary of this report (476 kb) pdf version of this report (1.2 MB)
- Augspurger TP. 2009. Sediment Pollutant Evaluation at Priority Dam Removal Sites in North Carolina. Final Report: Off-Refuge Contaminant Study 4F38, U.S. Fish and Wildlife Service, Raleigh, NC. pdf version of this report (771 Kb)
- Augspurger, T.P. and S.E. Ward. 2008. Tier 1 Preliminary Evaluation of Pollutant Sources to the Impounded Reaches of Five Dams in the Neuse River Basin, North Carolina. U.S. Fish and Wildlife Service, Raleigh, NC. pdf version of this report (3.4 MB)
- Ward, SE. 2008. Assessment of Potential Toxicity and Aquatic Community Impacts Associated with Membrane and Ion Exchange Water Treatment Facility Effluents in Coastal North Carolina. Final Report. U.S. Fish and Wildlife Service, Raleigh, NC. Summary of this report (200 kb) pdf version of this report (2.4 MB)
- Augspurger TP. 2008. Avian Vacuolar Myelinopathy in the Southeast: An Ecoepidemiological Assessment with Emphasis on Lake Surf, North Carolina. Final Report: Off-Refuge Contaminant Study 4F33, U.S. Fish and Wildlife Service, Raleigh, NC pdf version of this report (330 kb)
- Ward, SE. 2008. Site-Specific Fish Tissue Mercury at Four Eastern North Carolina National Wildlife Refuges. Final Report. U.S. Fish and Wildlife Service. USFWS, Raleigh, NC. Summary of this report (150kb)
- pdf version of this report (1.5MB)
- Augspurger, T.P., C.G. Ingersoll, N.E. Kemble, J.L. Kunz and S.E. Ward. 2007. Sediment Quality within the Impounded Reaches of Cape Fear River Locks and Dams. U.S. Fish and Wildlife Service and U.S. Geological Survey. USFWS, Raleigh, NC. Summary of this report (90kb) pdf version of this report (4.3MB)
- Ward, S., D. Shea and G. Cope. 2005. Development of a Standardized Process for Ranking and Prioritizing Contaminants in the Contaminant Assessment Process, U.S. Fish Wildl. Serv., Raleigh, NC. 143 pp. Summary of this report (640kb) pdf version of this report (890kb)
- U.S. Fish and Wildlife Service. 2004. Sediment Contaminants at Dillsboro Reservoir: Report on Site Assessment and Sediment Analyses. U.S. Fish and Wildl. Serv., Raleigh, NC. 28 pp. pdf version of this report (3.6MB)
- Abstract: Potential removal of Dillsboro Dam, located on the Tuckasegee River near Sylva (Jackson County), North Carolina, has caused some concern for the potential mobilization of sediment-associated contaminants accumulated behind the dam in Dillsboro Reservoir. We used the framework of the U.S. Environmental Protection Agency / U.S. Army Corps of Engineers technical guidance manual on disposal of dredged material in inland waters to evaluate this issue. A tier 1 review of existing information indicated no major pollutant sources or contaminant concerns upstream of the dam. The review also indicated that sediments within the reservoir might have low potential to accumulate contaminants from a physical standpoint, being comprised primarily of sand and gravel. Finally, it appears that watershed land uses upstream and downstream of the reservoir are similar and that any mobilized sediments from behind the dam may merely subject downstream areas to the same sources of contaminants to which they have been historically exposed. While no major concerns were noted in the review of existing information, new data were collected to support management decisions (tier 2). Six sediment samples from within the reservoir and four samples downstream were collected in June 2003 and analyzed for elemental contaminants. None of the sediment samples from within the reservoir or downstream exceeded probable effects concentration screening values, indicating no obvious concern. Over 80 percent of the sediment sample results were also less than threshold effects screening values, indicating they are unlikely of toxicological significance. Slightly less than 20 percent of the sample results fell between the screening values and they were further evaluated by comparing their magnitude to the geometric mean of the screening values. Only two values (both for nickel) exceeded the geometric mean of the screening values. The highest nickel concentration (41.5 ug/g dry weight) was from a downstream sediment sample near Dillsboro gage, and the average of the four downstream samples (27.4 ug/g dry weight) exceeded the average concentration of the six samples collected within the reservoir (21.8 ug/g dry weight). Accordingly, the nickel concentrations behind the dam should not be a concern relative to movement downstream where concentrations are slightly higher. Our review of existing data and an on-site assessment (tier 1) and results of sediment chemistry (tier 2) indicated no significant sediment contamination. This assessment is limited to the toxicological properties of the sediments evaluated. It does not address the potential physical impacts of sediment mobilization.
- Howard, A.K. 2003. Influence of instream physical habitat and water quality on the survival and occurrence of the endangered Cape Fear shiner. Masters Thesis. North Carolina State University, Department of Zoology, Raleigh, NC. 133 pp. Abstract not available in electronic format. pdf version of this document (950 KB)
- Winger, P.V. and P.J. Lasier. 2002. Alligator River National Wildlife Refuge: Potential Impacts from Dare County Landfills. Final Report, USGS Patuxent Wildlife Research Center, Warnell School of Forest Resources, University of Georgia, Athens, GA.
- Abstract: Surface runoff or leachate from two landfills (East Lake Landfill and the Dare County Construction and Demolition Debris Landfill) have the potential to impact fish and wildlife resources associated with Alligator River National Wildlife Refuge, Dare and Hyde Counties, North Carolina. Sediments were collected in March 2000 from 14 locations in canals down-gradient from the landfills for laboratory assessment of sediment quality. Sediments were analyzed for metal (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, Zn) and organic contaminants (PAHs and organochlorine pesticides). Chronic toxicity of the sediments was determined using 28-day static-renewal exposures with Hyalella azteca (Crustacea: Amphipoda) with survival and growth as the test endpoints. Acute toxicity was evaluated using static 96-hour exposures of H. azteca to sediment pore water. Sediments from four locations were selected for a 28-day bioaccumulation study with Lumbriculus variegatus (freshwater oligochaete) based on the toxicity evaluation. Solid-phase sediments were not acutely toxic to H. azteca, but length was significantly reduced in sediments from five locations. Pore waters from sediments collected at four locations were acutely toxic to H. azteca. Bioaccumulation studies exhibited uptake of several metals and PAHs, demonstrating the availability of these contaminants to the biota. Residue analyses of the sediments showed that several metals and PAHs exceeded sediment quality guidelines, and pore water concentrations of several metals exceeded water quality criteria for the protection of aquatic wildlife. These data demonstrate that runoff or leachate from the landfills have reduced sediment quality and have the potential to adversely affect resident fish and wildlife resources associated with Alligator River National Wildlife Refuge. Efforts to reduce, eliminate or isolate surface and subsurface discharge from these landfills may be desirable for the protection of wildlife resources associated with Alligator River National Wildlife Refuge.
- Kwak, T.J., W.G. Cope and A.K. Howard. 2002. Restoration of Cape Fear Shiner populations in North Carolina: Assessment of habitat suitability. U.S. Geological Survey-North Carolina Cooperative Wildlife Research Unit and North Carlina State University-Department of Environmental and Molecular Toxicology, Raleigh, NC. 90 pp. Abstract not available in electronic format
- Beeman, D.K. and T. Augspurger. 1996. Dioxins and furans in wood duck eggs from the lower Roanoke River, North Carolina. U.S. Fish Wildl. Serv., Raleigh, NC. 27 pp.
- Abstract: In the springs of 1992 and 1993 ten clutches of wood duck eggs were collected from the lower Roanoke River below a kraft process pulp paper mill that had historically bleached with molecular chlorine. In addition, one clutch was collected from Pocosin Lakes National Wildlife Refuge (PLNWR), a site with no known history of dioxin contamination. Embryos only, with no yolk sacs, and a limited number of companion yolk sacs were analyzed for the seventeen 2,3,7,8-substituted polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) isomer was found in all eggs sampled from the Roanoke River (0.32 to 26.6 pg/g wet weight) but was not detected in the sample from PLNWR (‹0.15 pg/g). The 2,3,7,8-tetrachlorinated dibenzofuran (2,3,7,8-TCDF) isomer was detected in all samples from the Roanoke River (0.92 to 393 pg/g) as well as the sample from PLNWR (1.6 pg/g). We calculated 2,3,7,8-TCDD equivalencies (TEQs) using the international toxicity equivalency factors (I-TEFs). TEQs were calculated for embryos and yolk sacs; a regression curve was derived to predict yolk sac TEQs in the samples for which only embryos were analyzed. Total TEQs approximated for two whole eggs (22 and 82 pg/g) were within a range reported in the literature as deleterious to wood ducks (20-50 pg/g). Liver monooxygenase activities of three dealkylases, benzyloxyresorufin-O-dealkylase (BROD), ethoxyresorufin-O-dealkylase (EROD), and methoxyresorufin-O-dealkylase (MROD), were induced in some clutches for the Roanoke River but not in all clutches. The hatching success of two nests were below 75%, the remainder ranged from 75 to 100%. Three clutches had 10-day survival rates below 75%, the others ranged from 75 to 100%. No relationship was found between hatching success or survivorship and PCDD/PCDF burdens. One embryo had multiple deformities including being a conjoined twin, a bill deformity and exencephaly. Although the deformities observed are consistent with those that can be caused by dioxin, available data do not indicate that dioxins were a causative factor. Data indicate that enticing wood ducks to nest boxes within two kilometers downstream of the mill may not be prudent. The areal extent of habitat adjacent to the mill where concentrations of PCDDs and PCDFs may cause eggs to exceed reproductive effects levels should be determined along with a characterization of the diversity and abundance of waterfowl and other avian species at risk in the immediate vicinity.
- Varela, V.W. and T. Augspurger. 1996. Cholinesterase activity as a devise for biomonitoring pesticide exposure in the freshwater mussel Elliptio complanata. U.S. Fish Wildl. Serv., Raleigh, NC. 26 pp.
- Abstract. A die-off of freshwater mussels in 1990, attributed to anticholinesterase pesticide contamination of a North Carolina stream, has led the National Biological Service and the U. S. Fish and Wildlife Service to explore the development of biomonitoring programs using cholinesterase activity to assess the threat of anticholinesterase pesticides to freshwater mussels. However, background information such as "normal" cholinesterase activities and basic biochemical properties of the cholinesterases present in mussels is extremely limited. Early attempts to identify baseline cholinesterase activities for field-collected eastern elliptio (Elliptio complanata) have been plagued by high levels of variation in activities measured in mussels exposed to the same environmental conditions. The objectives of this study were two-fold: 1) to elucidate and reduce this variability through the characterization of the cholinesterases involved and the refinement of assay protocols, and 2) to continue for a second year the biomonitoring of cholinesterase activities in E. complanata in the area of the Tar River basin, North Carolina, where the die-off occurred. Enzyme characterization studies discovered that cholinesterase activities in crude homogenates of adductor muscle demonstrated inhibition with increasing substrate concentrations, preferred acetylthiocholine as a substrate over butyryl- and propionylthiocholine, and was not significantly inhibited by a specific butyrylcholinesterase inhibitor, suggesting that the predominately active enzyme in adductor muscle tissue is acetylcholinesterase. Minor improvements to the assay protocols did not lower the overall variation in activities of field samples. Coefficients of variation for each collection event still ranged from 24.12% to 65.46%. However, despite the large intra-site variation in ChE activities, the Hilliardston collection site, located near the 1990 die-off site, did reveal a significantly (p < 0.05) lower average cholinesterase activity (94.41 ± 46.05 moles substrate hydrolyzed/min/g protein) than the Berea reference site (141.20 ± 58.36 moles substrate/min/g protein). Evidence was insufficient to conclude that the decrease in cholinesterase activity at the die-off site was due to anticholinesterase agents. It is suggested that the variation in cholinesterase activities is mainly influenced by characteristics of the individual rather than measured water quality parameters. These characteristics are discussed along with recommendations for improving the biomonitoring program.
- Augspurger, T. and K. Looney. 1995. Mercury in Lake Mattamuskeet osprey and largemouth bass, Mattamuskeet National Wildlife Refuge, Hyde County, North Carolina. U.S. Fish Wildl. Serv., Raleigh, NC. 19 pp.
- Abstract. In 1990 and 1991, five dead pre-fledging ospreys (Pandion haliaetus) from nests on Lake Mattamuskeet were analyzed for mercury. Liver mercury ranged from 0.91 to 2.8 ppm-wet weight; although not at avian hazard levels, these concentrations appear moderately elevated in comparison to published values. Mercury in four osprey eggs analyzed in 1992 ranged from 0.09 to 0.27 ppm-ww (adjusted to fresh wet weight). These levels are also below those thought to adversely affect avian reproduction but are at the high end of the range of mercury concentrations reported for osprey eggs throughout the United States. Osprey egg mercury concentrations should be re-evaluated in a larger sample of eggs to obtain a better estimation of mercury burdens and establish a foundation for future mercury monitoring at the Refuge. Eighteen largemouth bass (Micropterus salmoides) collected in 1992 and analyzed whole contained mercury at concentrations from 0.12 to 0.51 ppm-ww (geometric mean 0.29 ppm-ww). Mercury in the five largemouth bass fillets analyzed in 1992 ranged from 0.19 to 0.64 ppm-ww (geometric mean 0.38 ppm-ww). None of the fillets exceeded the Food and Drug Administration action level for mercury in food of 1.0 ppm-ww. Largemouth bass data are compared to previous Lake Mattamuskeet collections and recommendations for additional monitoring are discussed.
- Benkert, K. and T. Augspurger. 1994. Draft baseline environmental contaminants survey of biota and sediment from Pee Dee National Wildlife Refuge, Anson and Richmond Counties, North Carolina. U.S. Fish Wildl. Serv., Raleigh, NC. 18 pp.
- Abstract. Sediment, fish, mussels and turtles were collected from the impoundments on, and streams feeding, Pee Dee National Wildlife Refuge in 1989 to determine baseline contaminant levels. Sediment elemental contaminants, oil and grease, and aliphatic and aromatic hydrocarbons were generally at background levels, but there were indications of lead and zinc accumulation in impoundment sediments. The maximum levels of these heavy metals in Refuge impoundments, 23 µg/g-dry weight Pb and 65 µg/g-dry weight Zn, were not of toxicological significance. However, potential long-term heavy metal enrichment in the impoundments fed by the Pee Dee River should be recognized as warranting increased sampling effort in future Refuge monitoring. Elemental contaminants, organochlorine pesticides, and aliphatic and aromatic hydrocarbons in representative fish, shellfish, and turtles were detected at low levels characteristic of background contamination. Mercury concentrations in Refuge fish ranged from 0.04 to 0.42 µg/g-wet weight and were well below the U.S. Food and Drug Administration action level of 1.0 µg/g currently used by North Carolina for protection of human health. Only the concentrations of lead (0.98 to 1.1 µg/g-wet weight) and mercury (0.75 to 2.1 µg/g-wet weight) in the livers of two turtles were of concern; these may represent enrichment, but the lack of additional samples limits interpretation. Organochlorine contamination was low in six whole brown bullheads (Ictalurus nebulosus), a single spotted sucker (Minytrema melanops), and a single longnose gar (Lepisosteus osseus) with only the gar exceeding 1984 national averages for organochlorines in fish. Organochlorines should be deleted from future Refuge monitoring in favor of increasing the number of samples to be analyzed for heavy metals. The data sets developed for freshwater mussels and brown bullheads are the most robust; these fauna and sediments should be the focus of future monitoring efforts.
- Benkert, K. and T. Augspurger. 1994. Draft baseline environmental contaminants survey of biota and sediment from Cedar Island National Wildlife Refuge, Carteret County, North Carolina. U.S. Fish Wildl. Serv., Raleigh, NC. 16 pp.
- Abstract. Sediment, fish, and clams were collected from the embayments around Cedar Island National Wildlife Refuge in 1989 to determine baseline contaminant levels and provide the foundation for future monitoring of the Refuge. Geometric mean concentrations, in µg/g-dry weight, of As (3.9), Cd (‹0.1), Cr (20), Cu (5.4), Pb (8.6), Ni (6.3), Hg (0.06), Se (0.44), Zn (21.3), and total polycyclic aromatic hydrocarbons (PAHs) (0.13) in eight sediment samples were generally below sediment screening values for biological effects. Organochlorine pesticides and total polychlorinated biphenyls (PCBs) were below detection limits of 0.01 to 0.05 µg/g-wet weight in all sediments. Organochlorines were also below detection limits in three composite samples of hard clam (Mercenaria mercenaria). Concentrations of elemental contaminants and PAHs and aliphatic hydrocarbons were characteristic of background conditions. Elemental contaminants and organochlorine pesticides in representative predatory and bottom-feeding fish were at background levels. Average mercury concentrations in Refuge fish ranged from to 0.05 µg/g-wet weight in Atlantic croaker (Micropogon undulatus) to 0.15 µg/g-wet weight in bluefish (Potatomus saltatrix), and were well below the U.S. Food and Drug Administration action level of 1.0 µg/g currently used by North Carolina for protection of human health. The absence of organochlorine pesticides and PCBs above detection limit in all sediments and hard clams indicates organochlorines should be deleted from future Refuge monitoring. The low concentrations of p,p-DDE, total PCBs, and trans nonachlor in bluefish and Atlantic menhaden (Brevoortia tyrranus), when considered with the discontinued use of these compounds in the U.S., also support a move from further monitoring of organochlorines in favor of increasing the number of samples to be analyzed for heavy metals and hydrocarbons.
- Wicker, A.M. 1994. Contaminant assessment of fish, rangia clams and sediments in the lower Pamlico River, North Carolina. U.S. Fish and Wildlife Service, Ecological Services, Raleigh, NC. 16 pp.
- Abstract. Samples of sediment, rangia clams (Rangia cuneata), gizzard shad (Dorosoma cepedianum), and longnose gar (Lepisosteus osseus) were collected from five sites in the lower Pamlico River and analyzed for elemental contaminants, organochlorines, aliphatic hydrocarbons, and polynuclear aromatic hydrocarbons. Most sample concentrations were either beneath the detection limit or too low to be associated with biological impacts. However, sediment sample concentrations of cadmium and fluoride were observed at levels that could be associated with biological impacts at one of the sites which was located near the discharge from a large phosphate mining operation.
- Benkert, K. and T. Augspurger. 1992. Draft environmental contaminant impacts of highway runoff on freshwater mussels, Swift Creek, Nash County, North Carolina. U.S. Fish Wildl. Serv., Raleigh, NC. 15 pp.
- Abstract: Sediments and freshwater mussels, Elliptio complanata, were collected upstream and downstream of the Interstate 95 (I-95) crossing of Swift Creek, Nash County, North Carolina in 1990 to identify contaminants present near highway stream crossings and to assess the impacts of highway runoff waters on freshwater mussels. Sediments were analyzed for twelve elemental contaminants, oil and grease, petroleum hydrocarbons, and polycyclic aromatic hydrocarbons (PAHs). Composite samples of the soft tissues from mussels were analyzed for elemental contaminants, petroleum hydrocarbons, and PAHs. Total aliphatic hydrocarbons, total PAHs, oil and grease, arsenic, lead, selenium, chromium, copper, iron, manganese, nickel and zinc were elevated in sediments collected downstream of I-95 relative to upstream reference samples. All of these contaminants except nickel, chromium, and total PAHs were significantly (p‹0.05) elevated. Average concentrations of sediment oil and grease (1060 ppm-dry weight), arsenic (3.02 ppm), lead (26.0 ppm), iron (19900 ppm), and chromium (36.5 ppm) downstream of I-95 exceeded or approached U.S. Environmental Protection Agency or National Oceanic and Atmospheric Administration sediment quality screening guidelines for contaminated sediments and biological effects. Total aliphatic hydrocarbons, lead, and mercury were elevated in mussels collected downstream of I-95 relative to upstream reference samples; all other analytes were higher in the reference mussels. Although elevated, average concentrations of lead and mercury in mussels downstream of I-95 appear to be of minimal toxicological significance. Total aliphatic hydrocarbons (average 0.70 ppm-wet weight; maximum 1.19 ppm) were over 20 times greater in mussels downstream of I-95 relative to upstream reference specimens; levels in downstream mussels indicate chronic low level aliphatic hydrocarbon pollution. Because of the fast depuration rate of aliphatic hydrocarbons, levels well above those identified in this study may be present in mussels receiving highway runoff following rainfall. The overall small number of samples, differing sizes of mussels from the study area and reference site, and composition of sediments from these two areas may mask or exaggerate differences in contaminant burdens up- and downstream of I-95. However, it appears from this initial reconnaissance that highway crossings of important freshwater mussel habitat are a source of sediment contamination that could lead to low level mussel contamination and stress. Recommendations for additional study include sampling a larger number of mussels and sediments for a select group of the contaminants detected in this work, and analyzing stormwater runoff and receiving water collected during storms. These studies should incorporate analysis of sediment total organic carbon and grain size, and target similar sized mussels above and below bridges, to aid in interpretation of contaminant residues.
- Looney, K.T. and T. Augspurger. 1992. Mercury and other elemental contaminant residues in largemouth bass from Mattamuskeet National Wildlife Refuge. Raleigh Field Office, Raleigh, N.C. 7 pp.
- Abstract. Largemouth bass (Micropterus salmoides) were collected from Lake Mattamuskeet in 1990 and analyzed for elemental contaminants as part of on-going refuge monitoring. Five wholebody samples and five fillets were analyzed for mercury, arsenic, selenium, lead, cadmium, chromium, copper, iron, nickel, and zinc. Largemouth bass were targeted for collection because they are known to be a major food source for Lake Mattamuskeet's breeding population of ospreys. Wholebody mercury concentrations ranged from 0.25 to 0.65 parts per million wet weight (ppm-ww) with a mean concentration of 0.46 ppm-ww. Dietary levels of mercury as low as 0.1 ppm-ww are known to cause adverse reproductive impacts in sensitive avian species; concentrations detected in this study may hence be of concern for avian productivity. Mercury levels in fillets averaged 0.95 ppm-ww, and exceeded the Food and Drug Administration action level of 1 ppm-ww in two samples (1.14 and 1.16 ppm-ww). Concentrations of other elemental contaminants were consistent with background levels for the region and do not appear to be of toxicological significance.
- Benkert, K. 1992. Contaminant assessment of biota and sediments in the Albemarle-Pamlico Region. U.S. Fish and Wildlife Service, Ecological Services, Raleigh, NC. 57 pp. Abstract not available in electronic format
- Benkert, K. 1990. Limnological assessment of Lake Mattamuskeet and Pungo Lake in relation to metal residues in biota and sediments. U.S. Fish and Wildlife Service, North Carolina Field Office, Raleigh, NC. 73 pp. Abstract not available in electronic format