Estimating oil spill characteristics from oil heads in scattered monitoring wells

The results are presented of a comparison of four different methods of interpolating observed hydrocarbon depths in monitoring wells, as well as a comparison of different methods of selecting sampling points for interpolation. The results provide criteria for selecting one interpolation method over another, under different scenarios. The methods analyzed are: (1) inverse-distance weighting; (2) punctual kriging; (3) minimum surface curvature; and (4) Akima's quintic polynomial.     

Lesion Scoring in Field Vole Teeth: Application to the Biological Monitoring of Environmental Fluoride Contamination

The relationship between fluoride-induced lesions, measured using an incremental scoring system, and fluoride concentration was investigated in the teeth of the field vole (Microtus agrestis). Both the magnitude of lesion score and the severity of observed lesions in both incisor and molar teeth was correlated with the respective tissue fluoride concentration. This relationship was observed not only in animals trapped from sites contaminated by industrial fluorides, but also those bred and maintained under laboratory conditions and consuming fluoride in either diet or drinking water. Although some variation occurred between field and laboratory animals as to the mean fluoride concentrations in the incisor or molar for each specific lesion score, this may result in part from differences in the nature of the assimilable fluoride in laboratory diets compared to those consumed by wild animals. The practical application of the relationship between dental lesion score and tissue fluoride concentration to monitoring environmental fluoride contamination is discussed. Because the incisor and molar teeth of the field voles are open-rooted and grow throughout life, they are sensitive to even minor temporal changes in fluoride concentration in tissue fluids and blood and, by inference, in the diet and the environment. Therefore, assessment of visual lesions in the dentition of wild-caught field voles may provide the basis of a scheme to monitor the magnitude and effects of environmental fluoride contamination on populations of wild and domestic mammals. The development of non-destructive methods to allow the repeated examination of the teeth of captured field voles, and hence the dynamic monitoring of environmental fluoride contamination, is also considered.     

Shark recreational fisheries: Status,challenges, and research needs

For centuries, the primary manner in which humans have interacted with sharks has been fishing. A combination of their slow-growing nature and high use-values have resulted in population declines for many species around the world, and to date the vast majority of fisheries-related work on sharks has focused on the commercial sector. Shark recreational fishing remains an overlooked area of research despite the fact that these practices are popular globally and could present challenges to their populations. Here we provide a topical overview of shark recreational fisheries, highlighting their history and current status. While recreational fishing can provide conservation benefits under certain circumstances, we focus our discourse on the relatively understudied, potentially detrimental impacts these activities may have on shark physiology, behavior, and fitness. We took this angle given the realized but potentially underestimated significance of recreational fishing for shark conservation management plans and stock assessments, in hopes of creating a dialogue around sustainability. We also present a series of broad and focused research questions and underpin areas of future research need to assist with the development of this emergent area of research.     

Bisphenol A in human placental and fetal liver tissues collected from Greater Montreal area (Quebec) during 1998-2008

In this study, the presence of bisphenol A (BPA) in human placental and fetal liver samples collected from 1998 to 2008 was investigated to provide a more detailed analysis of the transfer of BPA across the placenta and fetal exposure to BPA. The average concentrations in placental samples were 12.6 ng g⁻¹ for free BPA, 17.2 ng g⁻¹ for BPA-glu, and 30.2 ng g⁻¹ for total BPA. The highest concentrations in placental samples were 165 ng g⁻¹ for free BPA, 178 ng g⁻¹ for BPA-glu, and 280 ng g⁻¹ for total BPA. Samples with higher levels of BPA-glu had higher levels of free BPA in general. Fetal age was observed to have a significant effect on BPA-glu levels in placental samples, but not on free or total BPA. The percentages of free BPA relative to total BPA for the placental samples varied considerably from 4.2% to 100%, suggesting that the ability of maternal liver and/or the placenta to conjugate BPA is highly variable during early to mid-gestation. The average concentrations in fetal liver samples were 9.02 ng g⁻¹ for free BPA, 19.1 ng g⁻¹ for BPA-glu, and 25.8 ng g⁻¹ for total BPA. The highest concentrations in fetal liver samples were 37.7 ng g⁻¹ for free BPA, 93.9 ng g⁻¹ for BPA-glu, and 123 ng g⁻¹ for total BPA. The percentages of free BPA level relative to total BPA for all fetal liver samples varied from 12.4% to 99.1%, indicating extensive variability in the ability of the human feto-placental unit to glucuronidate BPA.     

Dwelling in the biosphere: exploring an embodied human–environment connection in resilience thinking

Resilience has emerged as a prominent paradigm for interpreting and shaping human–environment connections in the context of global environmental change. Resilience emphasizes dynamic spatial and temporal change in social–ecological systems where humans are inextricably interwoven with the environment. While influential, resilience thinking has been critiqued for an under-theorized framing of socio-cultural dynamics. In this paper, we examine how the resilience concepts of planetary boundaries and reconnecting to the biosphere frame human–environment connection in terms of mental representations and biophysical realities. We argue that focusing solely on mental reconnection limits further integration between the social and the ecological, thus countering a foundational commitment in resilience thinking to social–ecological interconnectedness. To address this susceptibility we use Tim Ingold’s ‘dwelling perspective’ to outline an embodied form of human–environment (re)connection. Through dwelling, connections are not solely produced in the mind, but through the ongoing interactivity of mind, body and environment through time. Using this perspective, we position the biosphere as an assemblage that is constantly in the making through the active cohabitation of humans and nonhumans. To illustrate insights that may emerge from this perspective we bring an embodied connection to earth stewardship, given its growing popularity for forging local to global sustainability transformations.     

Distribution of antimony in contaminated grassland: 1--Vegetation and soils

Antimony concentrations in surface soils were found to decrease with increasing distance from an antimony smelter. This pattern was also found in moss bags exposed in the same area. At three sites close to the smelter, antimony concentrations in soil and vegetation were much higher than at a rural control site and published background levels. Maximum soil and plant concentrations on a dry weight basis of 1489 mg kg(-1) and 336 mg kg(-1), respectively, were found, compared to background levels of <1 mg kg(-1). Field exposure of grass in pots of uncontaminated soil and a laboratory experiment using soils from near the smelter suggested that the antimony in vegetation was largely due to continued aerial deposition and not to uptake from soil.     

Developing a framework to assess costs and benefits of Health Impact Assessment

This paper presents some early thinking as to how the costs and benefits of HIA might be assessed. After considering previous work it uses a comprehensive HIA in Dulwich, SE London as a case study to highlight the possibilities and difficulties of collecting necessary data on costs and benefits. It then sets a context for developing a cost–benefit framework for analysis. The framework is viewed alongside the major types of economic evaluation. The paper concludes with a review of outstanding issues and considers how evidence on cost and benefit might make a difference in the application of HIA.     

Topographical imaging as a means of monitoring biodegradation of poly(hydroxyalkanoate) films

Poly(hydroxyalkanoates) (PHAs) are a class of bacterially-derived polymers that are naturally biodegradable through the action of extracellular depolymerase enzymes secreted by a number of different bacteria and fungi. In this paper we describe the development of topographical imaging protocols (by both scanning electron microscopy; SEM, and confocal microscopy; CM) as a means of monitoring the biodegradation of solution cast films of poly(3-hydroxybutanoate-co-3-hydroxyhexanoate) (P3HB/3HHx) and medium-chain-length (mcl-) PHA. Pseudomonas lemoignei and Comamonas P37C were used as sources for PHA depolymerase enzymes as these bacteria are known to degrade at least one of the polymers in question. SEM revealed the bacterial colonization of the film surfaces while CM permitted the comparative assessment of the roughness of the film surfaces upon exposure to the two bacterial strains. By dividing the total surface area of the film (A′) by the total area of the scan (A) it was possible to monitor biodegradation by observing differences in the topography of the film surface. Prior to inoculation, P3HB/3HHx films had an A′/A ratio of 1.06. A 24-h incubation with P. lemoignei increased the A′/A ratio to 1.47 while a 48- and 120-h incubation with Comamonas resulted in A′/A ratios of 1.16 and 1.33, respectively. These increases in the A′/A ratios over time demonstrated an increase in the irregularity of the film surface, indicative of PHA polymer breakdown. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

COVERING BOTTOM SEDIMENTS AS A LAKE RESTORATION TECHNIQUE1

ABSTRACT: Sediment covering to control macrophytes and sediment nutrient release is reviewed. It is concluded that fly ash application to control sediment phosphorus release presents more dangers to the lake than benefits and should not be used. Polyethylene sheeting has not had long term effectiveness due to macrophyte regrowth on its surface. PVC-coated fiberglass screen is expensive but nontoxic and appears to give long term macrophyte control. Similar results may be obtained with spun-bonded polypropylene. Sand, clay, and sheeting to retard nutrient release have received insufficient attention.