Remote Sensing and Local Knowledge of Hydrocarbon Exploitation: The Case of Bovanenkovo, Yamal Peninsula, West Siberia, Russia

The capacity of satellite imagery to detect anthropogenic impacts on land cover was assessed for the Bovanenkovo gas field on the Yamal Peninsula in northwest Siberia, which contains some of the world’s largest untapped gas deposits. The region is also the homeland of nomadic Nenets reindeer herders, whose annual migration between the tree line and the northern tundra exposes them to impacts associated with exploration and production activities. These range from physical obstructions, such as roads, railways, and pipelines, to direct and indirect ecological impacts, such as changes in vegetation and hydrology. Nenets’ perceptions of their territories encompass changes in the quantity and quality of terrestrial and freshwater habitats and campsites that have been used seasonally for centuries. Industrial impacts on land cover were examined at spatial scales from very detailed to coarse. Very-high-resolution Quickbird-2 imagery revealed the most impacts, but could not detect items like trash that reduce the quality of reindeer pastures. ASTER, SPOT, and Landsat imagery were useful at the broader landscape level. A proper assessment of the overall ecological impacts of hydrocarbon exploitation requires a combination of remote sensing and detailed ground-truthing. Ideally, these efforts should combine scientific and local knowledge from both indigenous herders and non-indigenous industrial workers.L’aptitude de l’imagerie satellitaire à détecter les incidences anthropogènes sur la couverture végétale a été évaluée dans le cas du champ de gaz naturel de Bovanenkovo, dans la péninsule de Yamal située dans le nord-ouest de la Sibérie où se trouve un des plus grands gisements de gaz inexploités du monde. Les Nénètses, ou éleveurs de rennes nomades, évoluent dans cette région et leur migration annuelle entre la limite forestière et la toundra du nord les met en contact avec les travaux d’exploration et de production du gaz. Il peut s’agir d’obstructions physiques prenant la forme de routes, de chemins de fer et de pipelines ou encore, d’incidences écologiques directes et indirectes touchant notamment la végétation et l’hydrologie. Les perceptions relatives aux territoires des Nénètses concernent des changements en matière de quantité et de qualité des habitats terrestres et d’eau douce ainsi que les lieux de campement qui sont utilisés d’une saison à l’autre depuis des siècles. Les incidences industrielles sur la couverture végétale ont été examinées à diverses échelles spatiales, allant de très détaillée à grossière. Les images de très haute résolution obtenues au moyen de Quickbird-2 ont permis de révéler le plus grand nombre d’incidences, mais n’ont pas permis de détecter des éléments tels que les ordures qui avaient pour effet d’amenuiser la qualité des pâturages destinés aux rennes. Les images obtenues à partir d’ASTER, de SPOT et de Landsat ont été utiles au niveau plus vaste du paysage. L’évaluation adéquate des incidences écologiques générales découlant de l’exploitation des hydrocarbures nécessite à la fois des outils de télédétection et le recours à des sites témoins. Idéalement, ces efforts devraient faire appel tant aux connaissances scientifiques que locales, connaissances provenant des éleveurs indigènes et des travailleurs industriels non-indigènes

Development of a laser induced fluorescence technique for the analysis of organic air pollutants

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants which are of concern due to their potential human toxicity. They are formed during numerous combustion processes, including biomass burning and diesel vehicular emissions, which are of relevance in developing countries. A novel analytical screening method for atmospheric polycyclic aromatic hydrocarbons (PAHs) was developed in this study based on laser induced fluorescence (LIF) of samples on quartz multi-channel polydimethylsiloxane (PDMS) traps. A tunable dye laser with a frequency doubling crystal provided the excitation radiation, and a double monochromator with a photomultiplier tube detected emitted fluorescence. The method allowed for the rapid (<5 min), cost effective analysis of samples. Those yielding interesting results could be further analysed by direct thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS, with limits of detection of ~0.3 ng.m-3), as photodegradation was minimal (<10% over 5 min irradiation). Without any signal optimization, a LIF detection limit of ~1 ìg.m-3 was established for naphthalene using a diffusion tube (diffusion rate of 2 ng.s-1) and 292 nm excitation. Gas standards which facilitated the uniform distribution of analyte across each of the 22 PDMS tubes were provided by easily constructed diffusion tubes for naphthalene and by a gas chromatographic fraction collection method for the less volatile target PAHs. The methods developed were successfully tested in a number of applications which are of relevance to southern Africa, as emissions from sugar cane burning, household fires, diesel vehicles and industries were monitored. The LIF method allowed for the differentiation between impacted and non-impacted industrial sites, and the importance of naphthalene as an indicator for atmospheric PAHs was verified in that this PAH was the most abundant in the various applications which were investigated. The multi-channel silicone rubber traps were also evaluated theoretically and practically in the denuder configuration, in order to monitor PAHs in both the gas and particle phases, which is important in terms of human health effects. The novel LIF method developed in this study has the potential to serve as a screening tool to avoid the comprehensive and costly analysis of samples which do not contain appreciable levels of PAHs. The experimental procedure is simple and rapid, with acceptably low limits of detection, even with the initial, unoptimized optical arrangement and without extensive time-averaging. LIF also provides selectivity without the need for sample clean-up and separation processes. The LIF method could be further optimized by improving the laser energy stability, as well as by the investigation of possible time resolution techniques. As equipment cost considerations were important, it is possible that the LIF screening method could find application in a centralized environmental laboratory for the southern African region. This would facilitate the widespread monitoring of atmospheric PAHs in a cost effective manner.Thesis (PhD)--University of Pretoria, 2010.Chemistryunrestricte

Optical trapping and fluorescence control with vectorial structured light

Here we functionalized micro-scaled polymer beads with nano-scaled quantum dots and demonstrate optical trapping and tweezing, with in-situ fluorescence measurement, in an all-digital all-optical configuration. We outline the chemistry required to facilitate this, from deactivating the optical trapping environment to size, adhesion and agglomeration control. We introduce a novel holographic optical trapping set-up that leverages on vectorially structured light, allowing for the delivery of tuneable forms of light from purely scalar to purely vector, including propagation invariant flat-top beams for uniform illumination and tailored intensity gradient landscapes. Finally, we show how this has the potential to quench bleaching in a single wavelength trap by linear (spatial mode) rather than non-linear effects, advancing the nascent field of optics for chemistry.The National Research Foundation of South Africa.http://www.nature.com/scientificreportsam2023Chemistr

A review of monitoring methods for triclosan and its occurrence in aquatic environments

Triclosan is a phenyl ether with broad spectrum antimicrobial action which is employed in a great number of everyday household and personal care products including plastics, fabrics, soaps, deodorants, toothpaste, and cosmetics. There is serious concern, however, regarding this widespread use in terms of the potential environmental impacts of triclosan. Triclosan may enter the aquatic environment via numerous pathways including discharge of effluents from industries and wastewater treatment plants. To date, however, a comprehensive review of the determination of triclosan in aquatic environments has been not reported. Herein, we review the environmental concentration of triclosan in aquatic systems globally, as well as its stability and toxicity. The wide variety of monitoring methods utilized for the determination of triclosan are discussed, including those based on chromatography-mass spectrometry, electrochemistry, capillary zone electrophoresis and spectrophotometry over the last 10 years.The University of Pretoria, the Water Research Commission (grant K5-2438), the Photonics Initiative of South Africa (grant PISA-15-DIR-06) and the National Research Foundation of South Africa (grants 90720 and 93394).http://www.journals.elsevier.com/trends-in-analytical-chemistry2017-12-31hb2017Chemistr

Antiretroviral drugs in African surface waters : prevalence, analysis, and potential remediation

DATA AVAILABILITY STATEMENT : Data, associated metadata, and calculation tools are available from the corresponding author ([email protected]).Please read abstract in the article.The University of Pretoria Commonwealth Doctoral Scholarship and Rand Water.https://setac.onlinelibrary.wiley.com/journal/15528618hj2023Chemistr

Assessment of reusable graphene wool adsorbent for the simultaneous removal of selected 2–6 ringed polycyclic aromatic hydrocarbons from aqueous solution

Please read abstract in the article.https://www.tandfonline.com/loi/tent202021-09-24hj2021Chemistr

What drives reindeer management in Finland towards social and ecological tipping points?

Reindeer management (RM) in northern Fennoscandia is an example of social-ecological systems (SESs) providing social, cultural, ecological and economic values. Changing climate and pasture conditions and societal changes continue to transform the operational environment of RM. These key drivers, and resulting transformations including alternative SES states, have not been studied in detail before. Our comprehensive literature review and interviews with herders reveal that land use, climate change and governance drive the emergence of SES tipping points. The basis of successful RM depends on the quantity and quality of pastures to secure animal fitness. However, intensive forestry, extreme weather and predators constrain the availability of forage and suitable calving grounds. Maintaining RM by means of predation compensation mechanisms and regular supplementary winter feeding to adapt to changes brought about by land use and warming climate comprises an alternative system state. However, if negative impacts increase remarkably or rapidly and compensatory mechanisms become insufficient, long-term impacts on system identity, and even local collapses, are expected. Although some environmental and societal changes are perceived as pressures by herders, they can be beneficial for other livelihoods in the region. Therefore, our study raises questions for future studies on social justice, such as who has the right to decide what constitutes a desirable system state, or what collaborative efforts to maintain RM in Fennoscandia would entail. Our work is applicable also in other Arctic/sub-Arctic regions where nature-based livelihoods, such as small-scale forestry and agriculture, hunting, traditional fishing, and gathering are practiced

Influence of natural organic matter fractions on PAH sorption by stream sediments and a synthetic graphene wool adsorbent

Please read abstract in the article.The University of Pretoria Commonwealth Doctoral Scholarship, South Africa (AA), Rand Water, and the Departments of Chemistry and Physics at the University of Pretoria, South Africa.http://www.elsevier.com/locate/eti2021-10-08hj2021Chemistr

Development of a turn-on graphene quantum dot-based fluorescent probe for sensing of pyrene in water

Polycyclic aromatic hydrocarbons (PAHs) are potentially harmful pollutants that are emitted into the environment from a range of sources largely due to incomplete combustion. The potential toxicity and carcinogenic effects of these compounds warrants the development of rapid and cost-effective methods for their detection. This work reports on the synthesis and use of graphene quantum dots (GQDs) as rapid fluorescence sensors for detecting PAHs in water. The GQDs were prepared from two sources, i.e. graphene oxide (GO) and citric acid (CA) – denoted GO-GQDs and CA-GQDs, respectively. Structural and optical properties of the GQDs were studied using TEM, Raman, and fluorescence and UV-vis spectroscopy. The GQDs were then applied for detection of pyrene in environmental water samples based on a “turn-off-on” mechanism where ferric ions were used for turn-off and pyrene for turn-on of fluorescence emission. The fluorescence intensity of both GQDs was switched on linearly within the 2–10 10 6 mol L 1 range and the limits of detection were found to be 0.325 10 6 mol L 1 and 0.242 10 6 mol L 1 for GO-GQDs and CA-GQDs, respectively. Finally, the potential application of the sensor for environmental water samples was investigated using lake water and satisfactory recoveries (97–107%) were obtained. The promising results from this work demonstrate the feasibility of pursuing cheaper and greener environmental monitoring techniques.The University of Pretoria, Water Research Commission (WRC), the Photonics Initiative of South Africa and the National Research Foundation of South Africa.http://pubs.rsc.org/en/journals/journalissues/raam2021Chemistr