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Development of analytical methods for the speciation of arsenic in the marine environmentMomplaisir, Georges-Marie January 1995 (has links)
No description available.
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The environmental impacts of land claim-discarded settlement development in Mamahule, Polokwane Local Municipality of Limpopo ProvinceMathabatha, Lotty Elizabeth January 2013 (has links)
Thesis ( M.Dev.) -- University of Limpopo, 2013 / Environmental impacts from a land claim-discarded settlement development are positive, negative and cumulative by nature, within the broad scope of environmental impacts there has been much focus on the physical environment neglecting the socio economic and other political factors of the environment. This study presents from a total environmental perspective the investigation of the environmental impacts of land claim-discarded settlement development in Mamahule ga-Matsaung.
Both primary and secondary sources of data were used for the purposes of this study. The study used the non-probability purposive sampling for the entire targeted population. The study used both thick descriptions and qualitative techniques to analyse the collected data. Thick descriptions were used to explain the environmental impacts of various temporal phases as well as processes settlement development and land claim, while quantitative (Leopold matrix and Cost Benefit Analysis) were used to evaluate environmental impacts and economic valuations of the land claim and the settlement development.
The study shows that the Environmental Impact Assessment should be conducted prior the development of any settlement to avoid multiple negative environmental impacts on the environment. The study also highlights the impact that land claim has on development activities and the way in which settlement development can delay the process of a land claim. The study arrived to a conclusions that both settlement development and land claim impacted differently on the environment. / National Research Foundation (NRF) Scholarship
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The bioavailability of trace metals to soil invertebrates in urban contaminated soils /Kennette, Debra. January 1997 (has links)
No description available.
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Interfacial Reactions and Transport Behaviors of CO₂ and Emerging Contaminants for the Investigation of Water-Energy-Environment (WEE) NexusChoi, Soyoung January 2024 (has links)
Since the Industrial Revolution, human society has rapidly developed and flourished. Meanwhile, some interconnected side effects, particularly in realms of water, energy, food and environment, are tackling the sustainability of society. These grand challenges are intricately interconnected, underscoring the importance of addressing these problems through the lens of the water-energy-environment (WEE) nexus, which emphasizes the interlinkages between these sectors.
For instance, the unprecedented scale of CO₂ has accumulated in the atmosphere, and it has accelerated global warming and the chained environmental problems, such as droughts and floods. This insecurity for water resources has encouraged water recycling. At the same time, a new class of anthropogenic contaminants, including pharmaceutical and personal care products (PPCP), heavy metals, herbicides or pesticides, and per-fluoroalkyl substances (PFAS), have been accumulated in natural water bodies.
These contaminants are called emerging contaminants, and these can potentially cause severe problems in ecology and human health. Thus, this thesis aimed to tackle these multifaceted issues by investigating the interfacial chemistries between the natural or engineered solids and aqueous phases, particularly in the context of in-situ carbon mineralization and water remediation.To mitigate climate change, we should not only reduce CO₂ emissions but also remove the previously emitted CO₂ from the air. In-situ carbon mineralization is a critical technology to meet the agenda of carbon dioxide removal from the air (CDR) as the potential capacity and offer a thermodynamically downhill reaction to store CO₂ permanently in solid form.
During the in-situ carbon mineralization, water plays a pivotal role in the interactions at Rock-H₂O-CO₂ interfaces. However, the kinetics and mechanisms of interfacial reactions in the mineral-aqueous phases with various compositions still need to be fully understood. Additionally, in-situ carbon mineralization demands substantial water usage; therefore, addressing water security become imperative. However, during the water usage and recycling process, the accumulation of ions, including heavy metals, and the spreading of organic pollutants can intensify the concerns about water security.
Thus, this thesis’s objectives are to focus on a fundamental understanding of reaction kinetics and mechanisms occurring at the interested interfaces to address these challenges. At the mineral-aqueous phase for in-situ carbon mineralization, the effect of parameters, such as temperature, pH, and mineralogy has been assessed for mineral dissolution in the aqueous phase, and both basalt and peridotite were investigated. Related to the dissolution kinetics, this thesis discussed the frameworks for determining the dissolution rate, which can affect our understanding of experimental results. The dissolution studies exploring the effect of various parameters related to the in-situ carbon mineralization provided valuable insights into the reactivity of feedstock and morphological alterations that can be utilized for reactive-transportation modeling. Also, the experiment results may suggest the system boundary to engineer the geological CO₂ storage process.
Also, carbonation behaviors were studied in terms of direct carbonation and nucleation. For the direct carbonation, olivine mineral and peridotite rock retrieved from a potential CO₂ storage site were tested, and the effects of parameters including pH, additives, and temperature were discussed. During the in-situ carbon mineralization, dissolved cations and dissolved CO₂ can be nucleated and precipitated on the different types of mineral surfaces. Therefore, this study investigated the interfacial interactions with different types of mineral surfaces and containing ions in the aqueous phase. These studies provide the fundamental understanding of the thermodynamics and kinetics of carbonation during in-situ carbon mineralization.
Lastly, this study explored the kinetics and mechanisms of adsorption at adsorbent–emerging contaminant containing fluid interfaces in regard to water remediation and recycling. In this study, biochar from waste streams and MOFs with different modifications were used for the strategical development of adsorbents, while spectroscopic analysis methods were adopted to elucidate the mechanisms. Also, the effect of coexisting ions or reusability was discussed. Further, the results and insights from this investigation can be utilized for developing future generations of adsorbents and designing the remediation process.
Consequently, through understanding the various regimes of interfaces, this study may contribute to the advancement of strategic approaches for addressing the complex challenges within the WEE nexus, particularly related to sustainable in-situ carbon mineralization.
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Ecotoxicological studies of shipping operational oily wastes in Hong Kong.January 1999 (has links)
Lai Ho-yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 104-122). / Abstracts in English and Chinese. / ACKNOWLEDGEMENT --- p.I / ABSTRACT (ENGLISH) --- p.II / ABSTRACT (CHINESE) --- p.IV / TABLE OF CONTENT --- p.VI / LIST OF FIGURES --- p.IX / LIST OF TABLES --- p.V / INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Sources of oil pollution --- p.1 / Chapter 1.3 --- Composition of oil --- p.4 / Chapter 1.4 --- Fate of oil in the environment --- p.6 / Chapter 1.5 --- Toxic effect of oil on marine ecosystem --- p.8 / Chapter 1.5.1 --- Acute toxicity --- p.8 / Chapter 1.5.2 --- Chronic toxicity --- p.9 / Chapter 1.5.3 --- Carcinogenicity of oil --- p.11 / Chapter 1.6 --- The origins of ecotoxicology --- p.12 / Chapter 1.7 --- Need for ecotoxicity tests --- p.13 / Chapter 1.8 --- Testings in ecotoxicology --- p.15 / OBJECTIVES --- p.17 / MATERIALS AND METHODS --- p.18 / Chapter 1. --- Collection of oily wastes samples --- p.18 / Chapter 2. --- Preparation of samples --- p.18 / Chapter 2.1 --- Water-soluble fraction --- p.19 / Chapter 2.2 --- Polycyclic aromatic hydrocarbon fraction --- p.20 / Chapter 2.2.1 --- Supercritical fluid extraction --- p.20 / Chapter 2.2.2 --- Silica gel chromatography --- p.22 / Chapter 2.2.3 --- Sample concentration --- p.22 / Chapter 3. --- Chemical analyses of oily wastes --- p.26 / Chapter 3.1 --- Determination of heavy metal concentration in oily waste samples --- p.26 / Chapter 3.1.1 --- Nitric acid-perchloric acid digestion --- p.26 / Chapter 3.1.2 --- Inductively coupled plasma-emission spectrometric analysis --- p.26 / Chapter 3.2 --- Determination of polycyclic aromatic hydrocarbon concentration in oily waste samples --- p.28 / Chapter 3.2.1 --- Determination of polycyclic aromatic hydrocarbon concentration in water- soluble fraction --- p.28 / Chapter a. --- Liquid-liquid extraction --- p.28 / Chapter b. --- Gas chromatography-mass spectrometric analysis of water-soluble fraction --- p.29 / Chapter 3.2.2 --- Determination of polycyclic aromatic hydrocarbon concentration in crude oily waste samples --- p.32 / Chapter a. --- Supercritical fluid extraction and silica gel column chromatography --- p.32 / Chapter b. --- Gas chromatography-mass spectrometric analysis of polycyclic aromatic hydrocarbon fraction --- p.33 / Chapter 4 --- ecotoxicological studies of oily wastes --- p.34 / Chapter 4.1 --- Toxicity tests and sample preparation --- p.34 / Chapter 4.2 --- Ecotoxicological studies of water soluble fraction --- p.34 / Chapter 4.2.1 --- "Growth inhibition test on a marine alga, Chlorella pyrenoidosa CU-2" --- p.34 / Chapter 4.2.2 --- "Survival test on a marine amphipod, Elasmopus rapax" --- p.39 / Chapter 4.2.3 --- "Survival test on a marine fish, Ambassis gymnocephalus" --- p.41 / Chapter 4.2.4 --- Microtox® test --- p.43 / Chapter 4.3. --- Ecotoxicological studies of polycyclic aromatic hydrocarbon fraction --- p.45 / Chapter 4.3.1 --- "Growth inhibition test on a marine alga, Chlorella pyrenoidosa CU-2" --- p.45 / Chapter 4.3.2 --- "Survival test on a amphipod, Parhyale plumulosa" --- p.45 / Chapter 4.3.3 --- "Survival test on the fish, Sparus sarba" --- p.47 / Chapter 4.3.4 --- Microtox® test --- p.49 / Chapter 5. --- Statistical analyses of chemical and ecotoxicological analyses --- p.50 / RESULTS --- p.51 / Chapter 1. --- Chemical analyses of oily wastes --- p.51 / Chapter 1.1 --- Inductively coupled plasma-emission spectrometric analysis --- p.51 / Chapter 1.1.1 --- Heavy metal concentration in crude oily wastes --- p.51 / Chapter 1.1.2 --- Heavy metal concentration in water-soluble fraction --- p.51 / Chapter 1.1.3 --- Heavy metal concentration in ploy cyclic aromatic hydrocarbon fraction --- p.54 / Chapter 1.2 --- Gas chromatography- mass spectrometry analysis --- p.54 / Chapter 1.2.1 --- Polycyclic aromatic hydrocarbon concentration in crude oily wastes --- p.54 / Chapter 1.2.2 --- Polycyclic aromatic hydrocarbons concentration in water-soluble fraction --- p.59 / Chapter 1.2.3 --- Polycyclic aromatic hydrocarbons concentration in polycyclic aromatic hydrocarbon fraction --- p.61 / Chapter 2. --- Ecotoxicological studies of oily wastes --- p.63 / Chapter 2.1 --- Ecotoxicological studies of water-souble fraction --- p.63 / Chapter 2.1.1 --- Growth inhibition test on Chlorella pyrenoidosa CU-2 --- p.63 / Chapter 2.1.2 --- Survival test on Elasmopous rapax --- p.63 / Chapter 2.1.3 --- Survival test on Ambassis gymnocephalus --- p.67 / Chapter 2.1.4 --- Microtox® test --- p.67 / Chapter 2.2 --- Ecotoxicological studies of polycyclic aromatic hydrocarbon fraction --- p.70 / Chapter 2.2.1 --- Growth inhibition test on Chlorella pyrenoidosa CU-2 --- p.70 / Chapter 2.2.2 --- Survival test on Parhyale plumulosa --- p.70 / Chapter 2.2.3 --- Survival test on Sparus sarba --- p.74 / Chapter 2.2.4 --- Microtox® test --- p.74 / Chapter 3. --- Statistical analyses of chemical and ecotoxicological studies --- p.77 / Chapter 3.1 --- Statistical analyses of studies on water-soluble fraction --- p.77 / Chapter 3.1.1 --- Correlation between heavy metal concentration in water-soluble fraction and toxicity tests --- p.77 / Chapter 3.1.2 --- Correlation between concentration of total polycyclic aromatic hydrocarbon in water-soluble fraction and toxicity tests --- p.80 / Chapter 3.1.3 --- Correlation among acute toxicity tests --- p.80 / Chapter 3.2 --- Statistical analyses of polycyclic aromatic hydrocarbon fraction --- p.84 / Chapter 3.2.1 --- Correlation between heavy metal level and toxicity tests --- p.84 / Chapter 3.2.2 --- Correlation between total polycyclic aromatic hydrocarbon concentration in polycyclic aromatic hydrocarbon fraction and toxicity tests --- p.84 / Chapter 3.2.3 --- Correlation between four acute toxicity tests --- p.88 / DISCUSSION --- p.91 / Chapter 1 --- Chemical analyses of oily wastes --- p.91 / Chapter 1.1 --- Inductively coupled plasma-emission spectrometric analysis --- p.91 / Chapter 1.2 --- Gas chromatography-mass spectrometry analysis --- p.93 / Chapter 2. --- ecotoxicological studies of oily wastes --- p.95 / Chapter 2.1 --- Growth inhibition test on Chlorella pyrenoidosa CU-2 --- p.95 / Chapter 2.2 --- Survival tests on Elasmopus rapax and Parhyale plumulosa --- p.96 / Chapter 2.3 --- Survival test on Ambassis gymnocephalus and Sparus sarba --- p.97 / Chapter 2.4 --- Microtox® test --- p.98 / Chapter 3 --- Statistical analyses of chemical and ecotoxicological analyses --- p.99 / Chapter 4. --- statistical analyses between acute toxicity tests --- p.101 / CONCLUSION --- p.102 / REFERENCES --- p.104
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Impacts of road traffic on the environment of Hong Kong. / CUHK electronic theses & dissertations collectionJanuary 1998 (has links)
by Luk Shiu-fai. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 234-240). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.
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Differential exposure of the urban population to vehicular air pollution in Hong Kong.January 2011 (has links)
Fan, Xiaopeng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 101-108). / Abstracts in English and Chinese. / LIST OF FIGURES --- p.viii / LIST OF TABLES --- p.x / LIST OF ABBREVIATIONS --- p.xi / Chapter Chapter One - --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Hong Kong as a Case Study --- p.4 / Chapter 1.3 --- Research Objectives --- p.6 / Chapter 1.4 --- Significance of the Research --- p.7 / Chapter Chapter Two - --- LITERATURE REVIEW --- p.9 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.1.1 --- Origin of environmental justice --- p.9 / Chapter 2.1.2 --- Concept --- p.10 / Chapter 2.2 --- Review of environmental inequality studies --- p.12 / Chapter 2.2.1 --- The siting of hazardous waste treatment storage or disposal facilities --- p.12 / Chapter 2.2.2 --- Release of toxics from industries and facilities --- p.13 / Chapter 2.2.3 --- Population exposure to noise and air pollution --- p.15 / Chapter 2.2.3.1 --- Noise --- p.15 / Chapter 2.2.3.2 --- Air pollution --- p.16 / Chapter 2.2.4 --- Dissimilarity of the findings --- p.20 / Chapter 2.3 --- Research methodology --- p.21 / Chapter 2.3.1 --- Environmental indicators and parameters --- p.21 / Chapter 2.3.2 --- Pollution exposure assessment method --- p.22 / Chapter 2.3.3 --- Choice of socioeconomic indicators --- p.24 / Chapter 2.3.3.1 --- Demographic and socioeconomic indicators --- p.24 / Chapter 2.3.3.2 --- Source of socioeconomic data --- p.26 / Chapter 2.3.4 --- Study unit --- p.26 / Chapter 2.3.5 --- Analytical methods --- p.29 / Chapter 2.4 --- Factors contributing to inequality --- p.29 / Chapter 2.5 --- Summary --- p.31 / Chapter Chapter Three - --- RESEARCH METHODOLOGY --- p.33 / Chapter 3.1 --- Research Framework --- p.33 / Chapter 3.2 --- Study Unit and Sampling Strategy --- p.34 / Chapter 3.2.1 --- Study unit used in other studies --- p.35 / Chapter 3.2.2 --- Study unit --- p.35 / Chapter 3.2.3 --- Sampling Method --- p.37 / Chapter 3.3 --- Air pollution exposure assessment --- p.39 / Chapter 3.3.1 --- Assessment method --- p.40 / Chapter 3.3.2 --- Calculation of emission inventory --- p.42 / Chapter 3.3.2.1 --- Emission factors estimated by EMFAC-HK model --- p.42 / Chapter 3.3.2.2 --- Vehicular emission inventory --- p.44 / Chapter 3.3.3 --- Simulation by air pollution dispersion model --- p.44 / Chapter 3.3.3.1 --- IMMISnet Model --- p.44 / Chapter 3.3.3.2 --- Data requirement of MMISn e t Model --- p.45 / Chapter 3.3.3.3 --- Output ofIMMISnet Model --- p.49 / Chapter 3.4 --- Population socioeconomic indicators --- p.51 / Chapter 3.5 --- Analytical method --- p.53 / Chapter 3.6 --- Summary --- p.53 / Chapter Chapter Four - --- FINDINGS AND DISCUSSION --- p.55 / Chapter 4.1 --- Pollution Exposure Assessment --- p.55 / Chapter 4.2 --- The differential exposure of different age and SDI groups --- p.60 / Chapter 4.2.1 --- The selection of socioeconomic indicators --- p.60 / Chapter 4.2.2 --- Decile analysis --- p.64 / Chapter 4.2.2.1 --- Differential exposure based on age groups --- p.64 / Chapter 4.2.2.2 --- Differential exposure based on SDI groups --- p.71 / Chapter 4.3 --- Regression Analysis --- p.75 / Chapter 4.3.1 --- Pearson's correlation analysis --- p.75 / Chapter 4.3.2 --- Stepwise regression analysis --- p.81 / Chapter 4.4 --- Discussion --- p.87 / Chapter Chapter Five - --- CONCLUSION --- p.90 / Chapter 5.1 --- Introduction --- p.90 / Chapter 5.2 --- Summary of Findings --- p.90 / Chapter 5.3 --- Limitation of the study --- p.92 / Chapter 5.4 --- Recommendations for further study --- p.93 / APPENDIX --- p.94 / REFERENCES --- p.101
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Waste handling practices in the South African high-throughput poultry abattoirsMolapo, Ntahli Ashley January 2009 (has links)
Thesis (M. Tech.) - Central University of Technology, Free State, 2009 / The production of poultry meat at abattoirs implies a tremendous amount of organic matter that requires environmentally and biologically safe disposal or utilisation. As a result, waste management is a concern in poultry abattoirs worldwide. Problems with proper storage, handling, management and utilisation of by-products have come to the forefront in planning, establishing and operating of poultry abattoirs.
The rationale for this study centres on the need for the review of poultry abattoir waste management practices, by-product production and environmental implication at South African high-throughput abattoirs. The need for this review stems from the rapid growth of the poultry industry over the past ten years. The industry has responded to this growing demand with larger and faster processing lines and more employees. This has led to the generation of high loads of waste material associated with negative environmental impacts. Poultry waste is of great concern as it plays a major role in environmental affairs over and above the present crisis with waste in South Africa, especially in rural and peri-urban areas.
The primary objectives of the study were to identify the existing waste management practices in relation to the sources, type of waste material generated, and the methods of handling (collection, storage and disposal) as well as to ascertain whether there is any in-house treatment methods practised. In addition, to identify any environmental impacts resulting from waste management practices.
To obtain data, site visits were conducted countrywide and abattoir personnel were interviewed through a questionnaire, in detail about the operation and waste management practices of their respective abattoirs. Their experiences in the industry regarding waste management were determined as well. From a total of thirty-four registered and operating high-throughput poultry abattoirs, twenty-six (76.4%) were visited.
Huge amounts of wastes are generated at South Africa high-throughput poultry abattoirs, and these amongst others includes blood, feathers, feet, intestines, trimmed meat off-cuts, faecal matter, condemned chickens and waste-water. Waste handling practices varies according to abattoir preferences. Different collection facilities are used for different types of waste, 50 - 750_ containers and blood troughs are used for blood (table 4.5), crates, wheelie bins, conveyors, black rubbish bags for feathers (table 4.6).
Waste is either stored at the dirty area of the abattoir or in an open space next to the abattoir under strict supervision prior to disposal or by-product processing. Since not all abattoirs dispose off generated waste, some abattoirs have by-products processing facilities either on site or outside abattoir premises. Examples of by-products produced (table 4.3) include poultry (carcass) meal, feather meal, poultry oil and blood meal. Disposal methods used differs from burial, rendering, land application, municipal landfill, collection by farmers (animal feeding), burning, composting depending on waste type. It should however be noted that some of disposal method used are not legally approved in South Africa although legally permitted in other international countries as per literature review.
Three environmental implications were identified by the respondents included in the study (table 4.14) and these included air pollution, water pollution and land/soil pollution.
Recommendations are made to encourage the safe disposal of abattoir waste, minimisation of environmental implications and to limit the methods of disposal to those that are internationally permitted and suggested.
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Incorporation of the environment as a phase organiser in the foundation phase : a case studyKhosa, Hlekani Lucia 11 1900 (has links)
This study investigates the incorporation of Environmental Education as a phase
organiser in learning programmes in the Foundation Phase by educators as
recommended by Curriculum 2005. A literature review indicates the role which
Environmental Education plays in society. It presents a feasible strategy for changing
attitudes to the environment. It is interdisciplinary and holistic, relevant, practical and
focuses on learners and learning. It can improve the quality of life of all by enabling
people to utilise resources, make informed decisions, apply and transfer knowledge,
thereby empowering others. An empirical investigation adopted a qualitative research
approach. Participants in a case study from primary schools in the Malamulele area,
Northern Province, as well as two specialists were purposefully selected. Multiple
methods of data collection, such as observation. and in-depth Interviews based on
questionnaires, were used. Photographs and relevant documents complemented the
data gathering. Finally, recommendations based on the findings were made. / Educational Studies / M.Ed. (Environmental Education)
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Cellular responses to Cd, Pb and Zn in shrews (Myosorex varius and Crocidura flavescens) and BALB/c miceChapman, Aletia Ann 12 1900 (has links)
Thesis (MSc) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Shrews are excellent bioindicators of environmental heavy metal pollution. This is
due to their diets and the high rate of consumption at which these small mammals consume
their prey. Shrews feed mostly on earthworms, and earthworms accumulate high levels of
heavy metals in their bodies. Biomarkers measure responses to environmental pollution in the
bodies of exposed organisms. Cellular biomarkers give an indication of responses to
pollutants at levels of pollutant exposure that are not yet lethal to the organism.
This study was prompted by concern that the number of shrews in the Stellenbosch
region was declining. For the present study, shrews (Myosorex varius and Crocidura
jlavescens) from the Stellenbosch region were sampled. The levels of Cd and Pb in their
bodies were analysed in order to ascertain whether or not these two heavy metals, which
occur in the environment as a result of various anthropogenic activities, are present in the
food chain of the shrews. In the laboratory, shrews were fed live control and metal exposed
earthworms from laboratory cultures. The earthworms had been exposed to either Cd or Pb in
these cultures over a number of generations. This was performed to determine whether the
presence of the metals in the body of the shrews, had resulted from metal accumulation from
the earthworms which were fed to the shrews. Cellular biomarkers were used to determine
the cellular response to the metals and membrane integrity and DNA integrity were
investigated. This was done by exposing the cells of the shrews and ofBALB/c mice to metal
salt solutions of Cd, Pb and Zn in vitro. Membrane integrity was tested by cell leaching
techniques viz. the LDH assay and the trypan blue assay. DNA integrity was determined by
using the comet assay as a biomarker of exposure.
The results of the study show that the shrews in the immediate Stellenbosch region are
exposed to lower levels of Cd and even lower levels of Pb than shrews from a site 16km out
of the town of Stellenbosch. The cellular responses induced by metal exposure of laboratory
mice show that the metals are indeed cytotoxic and genotoxic to the cells of small mammals.
Cd and Pb were found to be more cytotoxic than Zn, while Zn was more genotoxic than either
CqorPb. / AFRIKAANSE OPSOMMING: Skeerbekke is uitstekende bioindikatore van swaarmetaalbesoedeling in die
omgewing. Dit is as gevolg van hul dieët en die hoë koers waarteen hierdie klein soogdiere
hul prooi verorber. Skeerbekke voed meestalop erdwurms, en erdwurms akkumuleer hoë
vlakke van swaarmetale in hul liggaam. Biomerkers meet response as gevolg van
omgewingsbesoedeling in die liggame van blootgestelde organismes. Sellulêre biomerkers
gee 'n aanduiding van response op besoedelingstowwe by vlakke wat nog nie dodelik is vir
die organisme nie.
Die studie is aangespoor deur die bekommernis dat die getal van skeerbekkies in
Stellenbosch besig is om te daal. In die studie is skeerbekke (Myosorex varius en Crocidura
flavescens) van die Stellenbosch omgewing gevang en die vlakke van Cd en Pb in hul
liggame gemeet om vas te stelof die twee swaarmetale, wat in die omgewing beland as
gevolg van verskeie antropogeniese aktiwiteite, teenwoordig is in die voedselketting van die
skeerbekke. Die skeerbekke is in die laboratorium met lewende kontrole en
metaalblootgestelde erdwurms uit kulture in die laboratorium gevoer. Die erdwurms is aan
Cd en Pb oor baie generasies blootgestel in hierdie kulture. Dit is gedoen om vas te stelof die
teenwoordigheid van die metale in die liggame van die skeerbekke 'n oorsaak is van metaalakkumuleering
as gevolg van die erdwurms waarmee hulle gevoer is. Sellulêre biomerkers is
gebruik om sellulêre respons op die metale op die membraanintegriteit en DNA-integriteit vas
te stel. Dit is gedoen deur die selle van skeerbekke so wel as BALB/c muise in vitro bloot te
stel aan metaalsoutoplossings van Cd, Pb en Zn. Membraanintegriteit is getoets deur selmembraan
permeabiliteit tegnieke nl. die LDH en tripaan blou toetse. DNA-integriteit is
getoets deur die komeettoets te gebruik.
Die resultate van die studie dui daarop dat die skeerbekke van Stellenbosch aan laer
vlakke van Cd, en nóg laer vlakke van Pb blootgestel is as die skeerbekke van 'n perseel
16km buite die dorp. Die sellulêre response geïndusseer deur blootstelling aan metale by die
laboratoriummuise het aangetoon dat die metale inderdaad skadelik is vir die selmembraan en
die DNA van die selle van die muise. Cd en Pb is meer toksies vir die selmembraan as Zn,
terwyl Zn weer meer toksies is vir die DNA-integriteit as Cd en Pb.
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