Spatial Variability and Source-Receptor Relations at a Street Intersection

A wind tunnel study of dispersion at a simple urban intersection comprising two perpendicular streets is described. Concentration and flow field measurement were undertaken to determine the importance of the exchange of pollutants between the streets and to investigate source-receptor relationships at the intersection. The results showed that only in a symmetrical situation were exchanges negligible and that small departures from symmetry, brought about in the experiments through an off-set in the street alignment or a change of orientation relative to the wind, were sufficient to establish significant exchanges. The results also showed that significant structure appeared in the concentration fields in the streets as a result. Examples are shown where concentrations on one side of a street are entirely due to emissions from the perpendicular street, whereas on the opposite side concentrations depend on emission upwind in the same street as the receptor. The results imply that exchanges between street systems are likely to be the norm in practice and that the consequences of such exchanges are not confined to the immediate vicinity of the intersection.     

AN EVALUATION OF PHYSICAL STREAM HABITAT ATTRIBUTES USED TO MONITOR STREAMS1

ABSTRACT: The last few decades have seen an increased reliance on the use of stream attributes to monitor stream conditions. The use of stream attributes has been criticized because of variation in how observers evaluate them, inconsistent protocol application, lack of consistent training, and the difficulty in using them to detect change caused by management activity. In this paper, we evaluate the effect of environmental heterogeneity and observer variation on the use of physical stream attributes as monitoring tools. For most stream habitat attributes evaluated, difference among streams accounted for greater than 80 percent of the total survey variation. To minimize the effect that variation among streams has on evaluating stream conditions, it may be necessary to design survey protocols and analysis that include stratification, permanent sites, and/or analysis of covariance. Although total variation was primarily due to differences among streams, observers also differed in their evaluation of stream attributes. This study suggests that if trained observers conducting a study that is designed to account for environmental heterogeneity can objectively evaluate defined stream attributes, results should prove valuable in monitoring differences in reach scale stream conditions. The failure to address any of these factors will likely lead to the failure of stream attributes as effective monitoring tools.     

Metal distribution and stability in constructed wetland sediment

The A-01 wetland treatment system (WTS) is a surface flow wetland planted with giant bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] that is designed to remove Cu and other metals from the A-01 National Pollution Discharge Elimination System (NPDES) effluent at the Savannah River Site near Aiken, SC. Copper, Zn, and Pb concentrations in water were usually reduced 60 to 80% by passage through the treatment system. The Cu concentrations in the wetland sediments increased from about 4 to 205 and 796 mg kg(-1), respectively, in the organic and floc sediment layers in cell 4A over a 5-yr period. Metal concentrations were higher in the two top layers of sediment (i.e., the floc and organic layers) than in the deeper inorganic layers. Sequential extraction was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Metal remobilization was determined by the potentially mobile fraction (PMF) and metal retention by the recalcitrant factor (RF). The PMF values were high in the floc layer but comparatively low in the organic and inorganic layers. High RF values for Cu, Zn, and Pb in the organic and inorganic layers indicated that these metals were strongly bound in the sediment. The RF values for Mn were lower than for the other elements especially in the floc layer, indicating low retention or binding capacity. Retention of contaminants was also evaluated by distribution coefficient (Kd) values. Distribution coefficient (Kd) values were lower for Cu and Zn than for Pb, indicating a smaller exchangeable fraction for Pb.     

Linking linear programming and spatial simulation models to predict landscape effects of forest management alternatives

Forest management planners require analytical tools to assess the effects of alternative strategies on the sometimes disparate benefits from forests such as timber production and wildlife habitat. We assessed the spatial patterns of alternative management strategies by linking two models that were developed for different purposes. We used a linear programming model (Spectrum) to optimize timber harvest schedules, then a simulation model (HARVEST) to project those schedules in a spatially explicit way and produce maps from which the spatial pattern of habitat could be calculated. We demonstrated the power of this approach by evaluating alternative plans developed for a national forest plan revision in Wisconsin, USA. The amount of forest interior habitat was inversely related to the amount of timber cut, and increased under the alternatives compared to the current plan. The amount of edge habitat was positively related to the amount of timber cut, and increased under all alternatives. The amount of mature northern hardwood interior and edge habitat increased for all alternatives, but mature pine habitat area varied. Mature age classes of all forest types increased, and young classes decreased under all alternatives. The average size of patches (defined by age class) generally decreased. These results are consistent with the design goals of each of the alternatives, but reveal that the spatial differences among the alternatives are modest. These complementary models are valuable for quantifying and comparing the spatial effects of alternative management strategies.     

Positive environmental effects of the coronavirus 2020 episode: a review

Environment, Development and Sustainability - The outbreak of COVID-19 has made a global catastrophic situation that caused 1,039,406 deaths out of 35,347,404 infections, and it will also cause...     

Adsorption of picloram on clays nontronite,illite and kaolinite: equilibrium and herbicide-clays surface complexes

The picloram (PCM) adsorption on nontronite, illite and kaolinite was studied at pH 3, 5 and 7. The adsorption isotherms had well-fitted to Langmuir and Freundlich models equations. The interactions of PCM with the clay mineral surfaces exhibited an anionic profile adsorption, with a decrease in adsorption when the pH increases. The PCM adsorption capacity increases in the following order: kaolinite?<?illite?<?nontronite. The X-ray diffraction (XRD) analysis of PCM-clay samples revealed that the picloram molecule does not enter into the clays basal space. The interaction of PCM with clays surface sites through nitrogen of the pyridine ring was confirmed by X-ray photoelectron spectroscopy (XPS). Due to the anionic form of PCM, the adsorption onto the external and edges surface sites of the clay minerals was proposed.     

A clash of cultures (and lawyers): Anglo Platinum and mine-affected communities in Limpopo Province,South Africa

The human rights related controversies surrounding Anglo Platinum's Mogalakwena mine in South Africa's Limpopo Province hit the world stage in 2008, attracting public scrutiny and instigating much debate in the realm of international business and human rights discussions. We provide an in-depth analysis of the controversies at Mogalakwena, and Anglo Platinum's responses. This case study contributes to ongoing debates on mining company-community relations in the context of the emerging business and human rights agenda, specifically with respect to the notion of human rights ‘due diligence’. We argue that the Mogalakwena case study illustrates the risks of companies adhering to and emphasizing the technical and logistical facets of due diligence, without sufficient attention to the relational, communicative and emergent aspects, which are closely tied to corporate culture. We highlight the complexities of company-community relationships, with particular reference to the issues of legitimate community representation and participatory decision-making, and discuss the role that organizational culture plays in exacerbating or mitigating corporate-community conflict. The case study demonstrates how legal challenges often exacerbate rather than resolve the conflicts that arise due to a clash between corporate and community cultures. We suggest the need for corporate leaders to become more conscious of this cultural dimension of effective social management, particularly when interacting with communities whose cultures are markedly different from those of business corporations.     

Qualitative impacts of Senna spectabilis on distribution of welfare: A household survey of dependent communities in Budongo Forest Reserve,Uganda

This paper presents the results of a household survey designed to qualitatively evaluate the impacts of the invasive alien species Senna spectabilis on the distribution of welfare across dependent communities in the Budongo Forest Reserve (BFR) in Uganda. The BFR is the largest forest reserve in Uganda, with globally significant conservation values. The study establishes that households in the BFR have high levels of knowledge as to its conservation values; they are aware of the invasiveness of S. spectabilis and its potential to compromise the conservation values of the BFR, and that S. spectabilis confers tangible benefits to dependent households, whose levels significantly vary with proximity to the reserve. The study concludes by evaluating strategies that are designed to manage the spread of S. spectabilis in the BFR and which consider its demonstrated socio‐economic impacts.     

Understanding the contributions of anthropogenic and biogenic sources to CO enhancements and outflow observed over North America and the western Atlantic Ocean by TES and MOPITT

We investigate the effects of anthropogenic and biogenic sources on tropospheric CO enhancements and outflow over North America and the Atlantic during July–August 2006, the 3rd warmest summer on record. The analysis is performed using the 3D Regional chEmical trAnsport Model (REAM), satellite data from TES on the Aura satellite, MOPITT on the Terra satellite and surface monitor data from the SEARCH network. The satellite measurements of CO provide insight into the location of regional CO enhancements along with the ability to resolve vertical features. Satellite and surface monitor data are used to compare with REAM, illustrating model's ability to reproduce observed CO concentrations. The REAM model used in this study features CO emissions reduced by 50% from the 1999 EPA NEI and biogenic VOC emissions scaled by EPA-observed isoprene concentrations (20% reduction). The REAM simulations show large variations in surface CO, lower tropospheric CO and column CO, which are also observed by the surface observations and satellite data. Over the US, during July–August 2006, the model estimates monthly CO production from anthropogenic sources (5.3 and 5.1 Tg CO) is generally larger than biogenic sources (4.3 and 3.5 Tg CO). However, the model shows that for very warm days, biogenic sources produce as much CO as anthropogenic sources, a result of increased biogenic production due to warmer temperatures. The satellite data show CO outflow occurs along the East Coast of the US and Canada in July and is more broadly distributed over the Atlantic in August. REAM results show the longitudinally exported CO enhancements from anthropogenic sources (3.3 and 3.9 Tg CO) are larger than biogenic sources (2.8 and 2.7 Tg CO) along the eastern boundary of REAM for July–August 2006. We show that when compared with the impacts of both sources on increasing tropospheric CO exports, the relative impacts in August are greater than in July because of preferable outflow transport.     

Assessing the hydrocarbon degrading potential of indigenous bacteria isolated from crude oil tank bottom sludge and hydrocarbon-contaminated soil of Azzawiya oil refinery,Libya

The disposal of hazardous crude oil tank bottom sludge (COTBS) represents a significant waste management burden for South Mediterranean countries. Currently, the application of biological systems (bioremediation) for the treatment of COTBS is not widely practiced in these countries. Therefore, this study aims to develop the potential for bioremediation in this region through assessment of the abilities of indigenous hydrocarbonoclastic microorganisms from Libyan Hamada COTBS for the biotreatment of Libyan COTBS-contaminated environments. Bacteria were isolated from COTBS, COTBS-contaminated soil, treated COTBS-contaminated soil, and uncontaminated soil using Bushnell Hass medium amended with Hamada crude oil (1 %) as the main carbon source. Overall, 49 bacterial phenotypes were detected, and their individual abilities to degrade Hamada crude and selected COBTS fractions (naphthalene, phenanthrene, eicosane, octadecane and hexane) were evaluated using MT2 Biolog plates. Analyses using average well colour development showed that ~90 % of bacterial isolates were capable of utilizing representative aromatic fractions compared to 51 % utilization of representative aliphatics. Interestingly, more hydrocarbonoclastic isolates were obtained from treated contaminated soils (42.9 %) than from COTBS (26.5 %) or COTBS-contaminated (30.6 %) and control (0 %) soils. Hierarchical cluster analysis (HCA) separated the isolates into two clusters with microorganisms in cluster 2 being 1.7- to 5-fold better at hydrocarbon degradation than those in cluster 1. Cluster 2 isolates belonged to the putative hydrocarbon-degrading genera; Pseudomonas, Bacillus, Arthrobacter and Brevundimonas with 57 % of these isolates being obtained from treated COTBS-contaminated soil. Overall, this study demonstrates that the potential for PAH degradation exists for the bioremediation of Hamada COTBS-contaminated environments in Libya. This represents the first report on the isolation of hydrocarbonoclastic bacteria from Libyan COTBS and COTBS-contaminated soil.