National Exposure Research Laboratory NERL

Lake Park, NC, United States

National Exposure Research Laboratory NERL

Lake Park, NC, United States
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Gabriel M.C.,National Exposure Research Laboratory NERL | Howard N.,University of Florida | Osborne T.Z.,University of Florida | Osborne T.Z.,Whitney Laboratory for Marine Bioscience
Environmental Management | Year: 2014

Few published studies present data on relationships between fish mercury and surface or pore water sulfate concentrations, particularly on an ecosystem-wide basis. Resource managers can use these relationships to identify the sulfate conditions that contain fish with health-concerning total mercury (THg) levels and to evaluate the role of sulfate in methyl-mercury (MeHg) production. In this study, we derived relationships between THg in three fish trophic levels (mosquitofish, sunfish, and age-1 large-mouth bass) and surface water sulfate from 1998 to 2009 for multiple stations across the Everglades Protection Area (EPA). Results show the relationship between sulfate and fish THg in each fish type is nonlinear and largely skewed, similar to the relationship between MeHg production and sulfate concentration in peatland sediment pore water identified by other researchers. Peak fish THg levels occurred in ∼ 1 to 12 mg/L sulfate conditions. There was significant variability in the fish THg data, and there were several instances of high-fish THg levels in high-sulfate conditions (>30 mg/L). Health-concerning fish THg levels were present in all surface water sulfate conditions; however, most of these levels occurred in 1-20 mg/L sulfate. The data in this study, including recent studies, show consistent and identifiable areas of high- and low-fish THg across the spectrum of surface water sulfate concentration, therefore, applying an ecosystem-wide sulfur strategy may be an effective management approach as it would significantly reduce MeHg risk in the EPA. © The Author(s) 2014.


Moser W.E.,Smithsonian Institution | Klemm D.J.,National Exposure Research Laboratory NERL | Phillips A.J.,City University of New York | Phillips A.J.,American Museum of Natural History | And 5 more authors.
Comparative Parasitology | Year: 2011

Philobdella gracilis Moore, 1901 (Macrobdellidae: Hirudinida) is reported from Arkansas and Oklahoma for the first time. Specimens were collected in creeks and ponds. The Mississippi drainage distribution of P. gracilis and eastern distribution Philobdella floridana were confirmed by reexamination of museum specimens. © 2011 The Helminthological Society of Washington.


Barzyk T.M.,National Exposure Research Laboratory NERL | White B.M.,U.S. EPA Office of Research and Development | Millard M.,U.S. EPA Region 5 | Martin M.,U.S. EPA Region 5 | And 5 more authors.
Environmental Justice | Year: 2011

Environmental justice (EJ) indicators, including a number of parameters ranging from pollutant concentrations to socio-economic status, were compiled for three case study locations that have a documented history of EJ issues. Instead of consolidating the 14 EJ indicators into a single metric, they are displayed separately to facilitate comparisons at four different spatial scales to allow characterization of local, city, county, and state environmental conditions. This methodology provides a broader assessment of EJ, conveyed more as a neighborhood story than as an associative relationship. Information and measurements for these EJ indicators were downloaded from national and local sources of publicly available, Web-based information. There are different motivations for conducting EJ assessments, but this approach provides an overview of the conditions for a given community so that a range of options can be considered to inform and support the EJ decision-making process. © Copyright 2011, Mary Ann Liebert, Inc.


McAllister C.T.,Eastern Oklahoma State College | Moser W.E.,Smithsonian Institution | Klemm D.J.,National Exposure Research Laboratory NERL
Comparative Parasitology | Year: 2011

One of 4 (25%) white crappie, Pomoxis annularis, specimens from the Ouachita River, Dallas County, Arkansas, was found to be infested with 8 glossiphoniid leeches, Actinobdella inequiannulata Moore, 1901. Leeches were removed from within the operculum on gills and gill arches. This leech is generally thought to be uncommon but has been reported previously, mainly on members of the family Catostomidae from 21 states of the United States and 5 provinces of Canada. We report a new host record and the first report of A. inequiannulata from Arkansas. © 2011 The Helminthological Society of Washington.


Wickham J.D.,National Exposure Research Laboratory NERL | Wade T.G.,National Exposure Research Laboratory NERL | Riitters K.H.,USFS
Global Ecology and Biogeography | Year: 2013

Because of the low albedo of forests and other biophysical factors, most scenario-based climate modelling studies indicate that removal of temperate forest will promote cooling, indicating that temperate forests are a source of heat relative to other classes of land cover. Our objective was to test the hypothesis that US temperate forests reduce surface temperatures. Location: The continental United States. Methods: Ordinary least squares regression was used to develop relationships between forest extent and surface temperature. Forest extent was derived from the 900m2 2001 National Land Cover Database (NLCD 2001) and surface temperature data were from the MODIS 1 km2 8-day composite (MYD11A2). Forest-surface temperature relationships were developed for winter, spring, summer, autumn and annually using 5 years of MODIS land surface temperature data (2007-11) across six spatial scales (1, 4, 9, 16, 25 and 36 km2). Regression models controlled for the effects of elevation, aspect and latitude (by constraining the regressions within a 1° range). Results: We did not find any significant positive slopes in regressions of average annual surface temperatures versus the proportion of forest, indicating that forests are not a source of heat relative to other types of land cover. We found that surface temperatures declined as the proportion of forest increased for spring, summer, autumn and annually. The forest-surface temperature relationship was also scale dependent in that spatially extensive forests produced cooler surface temperatures than forests that were dominant only locally. Main conclusions: Our results are not consistent with most scenario-based climate modelling studies. Because of their warming potential, the value of temperate afforestation as a potential climate change mitigation strategy is unclear. Our results indicate that temperate afforestation is a climate change mitigation strategy that should be implemented to promote spatially extensive forests. Copyright © 2013 Blackwell Publishing.

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