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1.
Innocent Jayawardene Marc Chenier H. David Gardner 《Journal of the Air & Waste Management Association (1995)》2014,64(9):1028-1037
This study investigates the application of the Aerosol-to-Liquid Particle Extraction System (ALPXS), which uses wet electrostatic precipitation to collect airborne particles, for multi-element indoor stationary monitoring. Optimum conditions are determined for capturing airborne particles for metal determination by inductively coupled plasma–mass spectrometry (ICP-MS), for measuring field blanks, and for calculating limits of detection (LOD) and quantification (LOQ). Due to the relatively high flow rate (300 L min?1), a sampling duration of 1 hr to 2 hr was adequate to capture airborne particle-bound metals under the investigated experimental conditions. The performance of the ALPXS during a building renovation demonstrated signal-to-noise ratios appropriate for sampling airborne particles in environments with elevated metal concentrations, such as workplace settings. The ALPXS shows promise as a research tool for providing useful information on short-term variations (transient signals) and for trapping particles into aqueous solutions where needed for subsequent characterization. As the ALPXS does not provide size-specific samples, and its efficiency at different flow rates has yet to be quantified, the ALPXS would not replace standard filter-based protocols accepted for regulatory applications (e.g., exposure measurements), but rather would provide additional information if used in conjunction with filter based methods.
ImplicationsThis study investigates the capability of the Aerosol-to-Liquid Particle Extraction System (ALPXS) for stationary sampling of airborne metals in indoor workplace environments, with subsequent analysis by ICP-MS. The high flow rate (300 L/min) permits a short sampling duration (< 2 hr). Results indicated that the ALPXS was capable of monitoring short-term changes in metal emissions during a renovation activity. This portable instrument may prove to be advantageous in occupational settings as a qualitative indicator of elevated concentrations of airborne metals at short time scales. 相似文献
2.
Management of flame retarded plastics from waste electrical and electronic equipment (WEEE) has been posing a major challenge to waste management experts because of the potential environmental contamination issues especially the formation of polybrominated-dioxins and -furans (PBDD/F) during processing. In Nigeria, large quantities of electronic waste (e-waste) are currently being managed—a significant quantity of which is imported illegally as secondhand electronics. As much as 75% of these illegal imports are never reused but are rather discarded. These waste electronic devices are mostly older equipment that contains brominated flame retardants (BFRs) such as penta-brominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) which are presently banned in Europe under the EU WEEE and RoHS Directives. Risk assessment studies found both to be persistent, bio-accumulative and toxic. The present management practices for waste plastics from WEEE in Nigeria, such as open burning and disposal at open dumps, creates potential for serious environmental pollution. This paper reviews the options in the environmentally sound management of waste plastics from electronic wastes. Options available include mechanical recycling, reprocessing into chemicals (chemical feedstock recycling) and energy recovery. The Creasolv® and Centrevap® processes, which are the outcome of the extensive research at achieving sound management of waste plastics from WEEE in Europe, are also reviewed. These are solvent-based methods of removing BFRs and they presently offer the best commercial and environmental option in the sound management of waste BFR-containing plastics. Because these developments have not been commercialized, WEEE and WEEE plastics are still being exported to developing countries. The industrial application of these processes and the development of eco-friendlier alternative flame retardants will help assure sound management of WEEE plastics. 相似文献
3.
C. Henry Obasi U. Martin Obidiegwu N. Godwin Onyeagoro O. Innocent Arukalam C. Genevive Onuegbu N. Francis Onuoha M. Chinomso Ewulonu 《Journal of Polymers and the Environment》2017,25(3):544-555
We report in this paper the transport of an aromatic solvent, xylene through palm pressed fibre filled low density polyethylene composites studied at three different temperatures (40, 60, and 80 °C) by conventional weight-gain method. The diffusion parameters were investigated with special reference to the effect of fibre content, temperature and particle size. The effect of alkali treatment on solvent uptake was also analyzed. The transport coefficients of diffusion, permeation and sorption were determined to evaluate the influence of interface bonding on transport properties. The van’t Hoff relationship was used to determine the thermodynamic parameters and was found that the estimated free energies of sorption were all positive, indicating non-spontaneity of the solubility of PPF/LDPE composites. The first order kinetic rate constant and swelling parameters were also evaluated. 相似文献
4.
Ndidzulafhi Innocent Sinthumule Tshimangadzo Ratshivhadelo Tshililo Nelwamondo 《Journal of Land Use Science》2020,15(1):11-24
ABSTRACTLand-use conflict has become a topical issue due to an increase in the number of stakeholders having incompatible interests related to particular land uses. Competing land-uses include those for conservation, irrigation, game and livestock farming, settlements and mining. These groupings of land-uses have different interests and objectives. This study aims to investigate the basis for the land-use conflict, and to get insights into how various stakeholders perceive and interpret existing conflicts. Empirical results were drawn from observation, interviews and documents collected between 2011 and 2018. The interviews were held with various stakeholders involved in land-use decisions. Qualitative data were analysed through thematic content analysis, and observations assisted with the corroboration of information collected through interviews. The study recorded four central land-use conflicts: irrigation farming with conservation; game farming with conservation; settlements/livestock farming with conservation; and mining with conservation/game farming/irrigation farming. The study also explains how local stakeholders understand these conflicts. 相似文献
5.
Edward M. Sykes Tabitha M. Innocent Ido Pen David M. Shuker Stuart A. West 《Behavioral ecology and sociobiology》2007,61(11):1751-1758
Sex allocation theory offers excellent opportunities for testing how animals adjust their behaviour in response to environmental
conditions. A major focus has been on instances of local mate competition (LMC), where female-biased broods are produced to
maximise mating opportunities for sons. However, the predictions of LMC theory can be altered if there is both local competition
for resources during development and an asymmetry between the competitive abilities of the sexes, as has been seen in animals
ranging from wasps to birds. In this paper, we test the extent to which asymmetric larval competition alters the predictions
of LMC theory in the parasitoid wasp Nasonia vitripennis. We found that the body size of both sexes was negatively correlated with the number of offspring developing within the host.
Further, we found that when faced with high levels of competition, the body size of females, but not males, was influenced
by the sex ratio of the competing offspring; females were smaller when a higher proportion of the brood was female. This asymmetric
competition should favour less biased sex ratios than are predicted by standard LMC theory. We then develop a theoretical
model that can be parameterised with our data, allowing us to determine the quantitative consequences of the observed level
of asymmetric larval competition for sex allocation. We found that although asymmetric competition selects for less biased
sex ratios, this effect is negligible compared to LMC. Furthermore, a similar conclusion is reached when we re-analyse existing
data from another parasitoid species where asymmetric larval competition has been observed; Bracon hebetor. Consequently, we suspect that asymmetric larval competition will have its greatest influence on sex ratio evolution in species
that have smaller clutches and where local mate competition is not an issue, such as birds and mammals. 相似文献
6.
Toni Lyn Morelli R. Andrew Hayes Helen F. Nahrung Thomas E. Goodwin Innocent H. Harelimana Laura J. MacDonald Patricia C. Wright 《Die Naturwissenschaften》2013,100(8):769-777
Lemurs are the most olfactory-oriented of primates, yet there is still only a basic level of understanding of what their scent marks communicate. We analyzed scent secretions from Milne-Edwards' sifakas (Propithecus edwardsi) collected in their natural habitat of Ranomafana National Park, Madagascar. We sought to test whether the scent mark could signal genetic relatedness in addition to species, sex, season, and individuality. We not only found correlations (r 2?=?0.38, P?=?0.017) between the total olfactory fingerprint and genetic relatedness but also between relatedness and specific components of the odor, despite the complex environmental signals from differences in diet and behavior in a natural setting. To the best of our knowledge, this is the first demonstration of an association between genetic relatedness and chemical communication in a wild primate population. Furthermore, we found a variety of compounds that were specific to each sex and each sampling period. This research shows that scent marks could act as a remote signal to avoid inbreeding, optimize mating opportunities, and potentially aid kin selection. 相似文献
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This paper discusses the environment as a unit under threat of negative externalities (largely climate change and air pollution) induced by the many sectors albeit with a special reference to transport, bearing in mind that transport is an economic driver. We pay particular reference to the developments in the developed nations in as much as they can provide a framework upon which Africa can draw lessons for public policy and management. While the context may be different, this review is an attempt to inform transport policy and management for environmental sustainability in Africa. The review uses case studies of South Africa, Zimbabwe, Rwanda, Nigeria, Ethiopia and Kenya. 相似文献
9.
This paper explores, explains and discusses issues around the dilemma between local conservation of natural resources (often, endangered species and habitats) and tourism needs in Africa. Often and in constitutional terms, local people have a right to exploit and use resources endowed in their local area. However, tourists often are interested in viewing the vegetation and animal resources undisturbed. Inevitably, there is an undeclared animosity of values and interests between local communities and tourists and state agencies. As a result, the dilemma is thus of governance. The purpose of this paper is to demonstrate the governance dilemma of resource utilization and tourism in Africa in a bid to create an informed stewardship framework for sustainability. This is achieved by way of case studies and narratives from Africa. As such, this paper will be a review literature on how different communities perceive tourism and derive livelihoods from their immediate environment. It also explains how the external factors influence local needs and interests. A more sustainable and operational framework that reduces friction among stakeholders is suggested. 相似文献
10.
采用氢氧化钙、碳酸钠和硫化钠处理含锌废水,在溶液pH、锌离子浓度、颗粒粒径、颗粒Zeta电位、上清液浊度和污泥体积等指标测定的基础上,结合沉淀产物表征,探讨了沉淀剂用量对锌离子去除率的影响及沉淀机理。研究结果表明,n(Ca(OH)2∶n(Zn)=1.5,去除率达到最大值99.65%,n(Na2CO3)∶n(Zn)=1.5,去除率达到最大值99.89%,n(Na2S)∶n(Zn)=2.5,去除率达到最大值99.95%。X-射线衍射和热重分析表明,氢氧化钙与废水生成的沉淀物为碳酸钙和氧化锌,碳酸钠与废水生成的沉淀物为氧化锌和碱式碳酸锌,硫化钠与废水生成的沉淀物为硫化锌,这对污泥处理处置以及回收利用有指导意义。 相似文献