Transport of ammonium perfluorooctanoate in environmental media near a fluoropolymer manufacturing facility

In order to understand better the pathways for transport of ammonium perfluorooctanoate (APFO) from a point source, a focused investigation of environmental media (water and soil) near a fluoropolymer manufacturing facility (Site) was undertaken. Methods were developed and validated at 2 microg kg(-1) [the limit of quantitation (LOQ)] in soil, and at 50 ng l(-1) in water. Environmental media were sampled from a public water supply well field located north of the Site, across a river. The data suggest that APFO air emissions from the Site are transported to the well field, deposited onto the soil, and then migrate downward with precipitation into the underlying aquifer.     

Metal bioaccumulation in the greater white-toothed shrew, Crocidura russula, inhabiting an abandoned pyrite mine site

Hepatic and renal concentrations of iron, magnesium, zinc, lead, copper, manganese, mercury, cadmium, molybdenum, chromium, and nickel were quantified in shrews (Crocidura russula) inhabiting a pyrite mine site in Portugal. Several morphological parameters (body weight, residual index, and relative weights) were also examined to clarify the physiological effects of pollution. Shrews from the mine showed increased bioavailability of Fe, Pb, Hg, Cd, Mo, and Ni in comparison with reference specimens. Adult shrews had the highest Cd levels while Cr and Ni concentrations diminished. Intersexual differences were found for Mo and Ni. As a consequence of metal pollution, the relative hepatic weight was higher in shrews from the mine site when compared with reference specimens. These data indicate that C. russula is a good bioindicator of metal pollution. We also evaluated the toxic effects of Pb, Hg, Cd, and Ni, because several shrews from the polluted site showed high concentrations of these metals. To approximate at the real biological impact of abandoned mines, after this first step it is necessary to associate the bioaccumulation levels and morphological effects with other physiological, ecological and genetical biomarkers.     

Effects of black carbon and montmorillonite clay on multiphasic hexachlorobenzene desorption from sediments

The desorption kinetics of hexachlorobenzene (HCB) in four freshly spiked artificial sediments were determined using a polymeric adsorbent Tenax-mediated desorption. The sediments included a standard sediment (SS) prepared as per Organisation for Economic Cooperation and Development 218 guidelines and three derived artificial sediments prepared by supplementing the SS sediment with various levels of black carbon (lamp black soot) and/or montmorillonite clay. The desorption kinetics exhibited biphasic behavior, i.e., a fast desorbing fraction followed by a slow desorbing fraction. The addition of either lamp black soot or montmorillonite clay resulted in the reduction of the fast desorbing fraction (Ffast) of HCB in three derived sediments compared with SS sediment. Both black carbon and montmorillonite clay treatment effects on the fast desorbing fraction were statistically significant for the four artificial sediments. The black carbon treatment (i.e., addition of 0.5% wt/wt lamp black soot) effect was an average reduction of Ffast by approximately 11%, whereas the montmorillonite treatment (i.e., addition of 15% wt/wt montmorillonite clay) effect was an average reduction of Ffast by approximately 17%. The presence of soot black carbon particles reduced the desorption rate of HCB in sediments since black carbon exhibits very high sorption capacity and extremely slow diffusion rate compared with those of the natural organic matter in sediment.     

Characterizing Coral Condition Using Estimates of Three-dimensional Colony Surface Area

Coral reefs provide shoreline protection, biological diversity, fishery harvests, and tourism, all values that stem from the physically-complex coral infrastructure. Stony corals (scleractinians) construct and maintain the reef through deposition of calcium carbonate. Therefore, assessment of coral reefs requires at least some measurement endpoints that reflect the biological and physical condition of stony corals. Most monitoring programs portray coral quantity as live coral cover, which is the two-dimensional proportion of coral surface to sea floor viewed from above (planar view). The absence of the third dimension, however, limits our ability to characterize coral reef value, physiology, health and sustainability. A three-dimensional (3D) approach more realistically characterizes coral structure available as community habitat and, when combined with estimates of live coral tissue, quantifies the amount of living coral available for photosynthesis, growth and reproduction. A rapid coral survey procedure that coupled 3D coral quantification with more traditional survey measurements was developed and tested in the field. The survey procedure relied on only three underwater observations – species identification, colony size, and proportion of live tissue – made on each colony in the transect. These observations generated a variety of metrics, including several based on 3D colony surface area, that are relevant to reef management.     

The interactive relationship of competitive climate and trait competitiveness with workplace attitudes,stress, and performance

There has been a considerable debate about the individual and organizational benefits of competition. Adopting a person–environment fit perspective, this research examined the influence of competition as an interaction between trait competitiveness and competitive climate. Using a sample of information technology workers, competitive climate was considered as both an individual level variable and a workgroup variable. Results show that the effect of competitive climate depended on trait competitiveness and the level at which climate was assessed for four of the outcomes assessed: job satisfaction, organizational commitment, job dedication, and supervisor‐rated task performance. In general, the effect of competitive climate was more negative for individuals lower in trait competitiveness. Competitive psychological climate was associated with greater stress regardless of the level of trait competitiveness but was not directly related to self‐rated task performance. Findings suggest that managers should be cautious in encouraging competitive climate. Copyright © 2007 John Wiley & Sons, Ltd.     

Distribution and variability of redox zones controlling spatial variability of arsenic in the Mississippi River Valley alluvial aquifer, southeastern Arkansas

Twenty one of 118 irrigation water wells in the shallow (25-30 m thick) Mississippi River Valley alluvial aquifer in the Bayou Bartholomew watershed, southeastern Arkansas had arsenic (As) concentrations (<0.5 to 77 microg/L) exceeding 10 microg/L. Sediment and groundwater samples were collected and analyzed from the sites of the highest, median, and lowest concentrations of As in groundwater in the alluvial aquifers located at Jefferson County, Arkansas. A traditional five-step sequential extraction was performed to differentiate the exchangeable, carbonate, amorphous Fe and Mn oxide, organic, and hot HNO(3)-leachable fraction of As and other compounds in sediments. The Chao reagent (0.25 M hydroxylamine hydrochloride in 0.25 M HCl) removes amorphous Fe and Mn oxides and oxyhydroxides (present as coatings on grains and amorphous minerals) by reductive dissolution and is a measure of reducible Fe and Mn in sediments. The hot HNO(3) extraction removes mostly crystalline metal oxides and all other labile forms of As. Significant total As (20%) is complexed with amorphous Fe and Mn oxides in sediments. Arsenic abundance is not significant in carbonates or organic matter. Significant (40-70 microg/kg) exchangeable As is only present at shallow depth (0-1 m below ground surface). Arsenic is positively correlated to Fe extracted by Chao reagent (r=0.83) and hot HNO(3) (r=0.85). Arsenic extracted by Chao reagent decreases significantly with depth as compared to As extracted by hot HNO(3). Fe (II)/Fe (the ratio of Fe concentration in the extracts of Chao reagent and hot HNO(3)) is positively correlated (r=0.76) to As extracted from Chao reagent. Although Fe (II)/Fe increases with depth, the relative abundance of reducible Fe decreases noticeably with depth. The amount of reducible Fe, as well as As complexed to amorphous Fe and Mn oxides and oxyhydroxides decreases with depth. Possible explanations for the decrease in reducible Fe and its complexed As with depth include historic flushing of As and Fe from hydrous ferric oxides (HFO) by microbially-mediated reductive dissolution and aging of HFO to crystalline phases. Hydrogeochemical data suggests that the groundwater in the area falls in the mildly reducing (suboxic) to relatively highly reducing (anoxic) zone, and points to reductive dissolution of HFO as the dominant As release mechanism. Spatial variability of gypsum solubility and simultaneous SO(4)(2-) reduction with co-precipitation of As and sulfide is an important limiting process controlling the concentration of As in groundwater in the area.     

Ozone uptake (flux) as it relates to ozone-induced foliar symptoms of Prunus serotina and Populus maximowiziixtrichocarpa

Field studies were conducted during 2003 and 2004 from early June to the end of August, at 20 sites of lower or higher elevation within north-central Pennsylvania, using seedlings of black cherry (Prunus serotina, Ehrh.) and ramets of hybrid poplar (Populus maximowiziixtrichocarpa). A linear model was developed to estimate the influence of local environmental conditions on stomatal conductance. The most significant factors explaining stomatal variance were tree species, air temperature, leaf vapor pressure deficit, elevation, and time of day. Overall, environmental factors explained less than 35% of the variation in stomatal conductance. Ozone did not affect gas exchange rates in either poplar or cherry. Ozone-induced foliar injury was positively correlated with cumulative ozone exposures, expressed as SUM40. Overall, the amount of foliar injury was better correlated to a flux-based approach rather than to an exposure-based approach. More severe foliar injuries were observed on plants growing at higher elevations.     

Effects of Fragmentation of Araucarian Vine Forest on Small Mammal Communities

Abstract: Habitat loss and fragmentation are major threats to the survival of forest-dependent fauna. We examined the abundance of small mammal species in forests, corridors, remnants of araucarian vine forest, and Araucaria cunninghamii plantations and pastures. None of the forest mammal species persisted following conversion of forest to pasture. Plantations supported lowered abundances of a subset of forest species that were mainly habitat generalists with respect to their occurrence in different floristic types of undisturbed native forest. Within plantations, an increased subcanopy cover was associated with a more forest-like small mammal assemblage. Species' responses to habitat fragmentation varied. The floristic habitat generalists were largely tolerant of habitat fragmentation, their abundance being similar in forests, corridors, and remnants, and were capable of persisting in remnants a few hectares in area. Floristic habitat specialists were vulnerable to habitat fragmentation and thus were abundant in continuous forest, were less abundant in corridors, and were generally absent from remnants. Species that avoid the corridor matrix and are therefore constrained to the corridor may be disadvantaged by the linearity of the habitat, consistent with the predictions of central-place foraging theory. Although small remnants and corridors provide habitat for some species, those that are more specialized in their use of undisturbed habitat types require the retention or reestablishment of large intact areas.     

Woody stem methane emission in mature wetland alder trees

Methane (CH₄) is an important greenhouse gas that is predominantly emitted to the atmosphere from anoxic wetland ecosystems. Understanding the sources and emissions of CH₄ is crucially important for climate change predictions; however, there are significant discrepancies between CH₄ source estimates derived via so-called bottom-up and top-down methods. Here we report CH₄ emission from the stems of mature wetland alder (Alnus glutinosa) trees in the UK, a common tree of northern hemisphere floodplains and wetlands. The alder stems most likely behave as conduits for soil-produced CH₄ either in the gaseous or aqueous phase, and may, therefore, help to reconcile methodological differences in the way the wetland CH₄ source is estimated.Alder tree stems emitted average peak CH₄ fluxes of 101 μg CH₄ m^?2 h^?1 (on a stem area basis) in early October, a rate that is similar to that obtained from mature Japanese ash (Fraxinus mandshurica var. japonica) in Japan and amounting to approximately 20% of the measured CH₄ flux from the soil surface. The finding suggests that trees, which occupy 60% of Earth's wetlands and are normally excluded from the measurement programmes that form the basis for bottom-up estimates of the global wetland source, could be important contributors to overall terrestrial ecosystem CH₄ flux.     

Comparison of variability in dioxin and furan data acquired using single train and simultaneous multiple train stack sampling methods

The variance of polychlorinated dibenzo-p-dioxin (PCDD; dioxin) and polychlorinated dibenzofuran (PCDF; furan) data obtained from single- and simultaneous multiple train methods was compared. Single train triplicate data were used from 4 stack tests obtained from a long dry kiln cement plant and 18 stack tests from a municipal solid waste (MSW) incinerator. Data from the American Society of Mechanical Engineers (ASME) report Reference Method Accuracy and Precision (ReMAP) (Lanier and Hendrix, 2001) were used for the simultaneous multiple samples, which accounted for 27 data points. Nineteen data points were acquired from an ASME research facility, 5 from a MSW incinerator unrelated to the single train MSW incinerator, and 3 from a lightweight aggregate kiln (LWAK). The ReMAP procedure was used to determine the relationship between the standard deviation and the concentration of the single train and simultaneous multiple train data. Results indicated that there was benefit from the use of simultaneous multiple train sampling for concentrations above 129 pg toxic equivalency (TEQ)/m³. There was no indication of benefit from the use of simultaneous multiple train sampling at concentrations below 129 pg TEQ/m³.

Implications:Precision of stack sampling data can be the difference between meeting and failing compliance limits. Generally, three dioxin/furan samples are acquired when stack sampling to meet compliance regulations. A reliable estimation of the data’s true concentration is not possible with this small amount of data. Increasing the precision decreases the chance that the acquired concentration deviates greatly from the true concentration. Facilities that use the appropriate stack sampling method will benefit by either improved data precision or minimal stack sampling expenses. The observations made suggest that facilities that are expected to have dioxin/furan concentrations above 129 pg TEQ/m³ would increase the precision of samples by using simultaneous multiple train sampling.