The effect of different types of sanitation facilities on soil contamination with geohelminth eggs and the associated risk factors were assessed in three informal settlements in Durban, South Africa. Adult members of 30 households in each settlement were interviewed to determine their knowledge, attitudes and perceptions on risk factors associated with geohelminth transmission. Two hundred soil samples were collected in each study settlement from areas considered potential sources of infection such as houses, pathways, sanitation facilities and washing areas. Of the total 600 soil samples collected, 190 (32%) were positive for geohelminth eggs with the eggs of Ascaris lumbricoides, Trichuris trichiura and Taenia spp. being recovered. Quarry Road West, where open defaecation was the most common (80%), sanitation coverage the lowest (11%) and lack of knowledge on geohelminth transmission high (97%), showed the highest levels of soil contamination (mean = 102.55eggs/100g). Stool samples were also collected from 135 children aged 1-16 years living in the three study areas. Children were found to be infected with A. lumbricoides and T. trichiura with prevalences of 33.4 and 6.5%, respectively and corresponding geometric mean intensities of 5.6 and 0.87eggs/g faeces. Some children (9.6%) also harboured dual infections. No hookworm or tapeworm infections were recorded. The results show a direct link between high levels of soil contamination and increased prevalence and infection rates. Indiscriminate defaecation by community members is recognised as the main contributing factor of geohelminth eggs in soil. The type and the number of toilets provided to a community greatly influence the success of a sanitation facility. In order to effectively control geohelminth transmission, health education and antihelminthic treatment need to accompany sanitation programmes in these areas. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

The original aims of this project were to investigate the potential for phytoremediation, with emphasis on metal accumulation, of three contrasting industrial processing wastes. These were tailings material (PT) from the decommissioned Pering Pb/Zn Mine (Reivilo, North West Province, South Africa (SA)), smelter slag (SS) from the Samancor Mnsmelter (Meyerton, Gauteng, SA) and electro-winning waste (EW) from MMC (Nelspruit, Mpumalanga, SA). It became evident, however, early in the project, that the use of metal hyperaccumulating plants was not a viable technology for these wastes. The project objectives were thus adapted to investigate alternative remedial technologies. The use of endemic and adapted grass species was investigated to revegetate the PT. In addition, chemically-enhanced phytoremediation was investigated to induce metal hyperaccumulation by grasses grown in the PT (Part 1). Revegetation of the SS and EW were not considered feasible, thus land disposal of these two Mn-rich processing wastes was investigated (Part 2). Part 1 - Revegetation of tailings from Pering Mine The PT was found to be alkaline (pH > 8.0), and consisted mainly of finely crushed dolomite. It was generally nutrient poor with high amounts of readily extractable Zn. It also had a very high P-sorption capacity. Seven grass species (Andropogon eucomus Nees; Cenchrus ciliaris L.; Cymbopogon plurinodis Stapf ex Burtt Davy; Digitaria eriantha Steud; Eragrostis superba Peyr; Eragrostis tef (Zucc.) Trotter and Fingeruthia africana Lehm) were grown in PT treated with different rates of inorganic fertiliser under glasshouse conditions. The fertiliser was applied at rates equivalent to 100 kg N, 150 kg P and 100 kg K ha-1 (full), half the full rate (half) and no fertiliser (0). Seed of C. ciliaris, C. plurinodis, D. eriantha, E. superba and F. africana were collected from Pering Mine. Seed of A. eucomus was collected from the tailings dam of an abandoned chrysotile asbestos mine. These were germinated in seedling trays and replanted into the pots. A commercial variety of E. tef was tested, but due to poor survival this species was subsequently excluded. The foliage and root biomass of the grasses and concentrations of Ca, Cu, Fe, K, Mg, Mn, Pb and Zn in the foliage were determined. The yield of all the grasses increased with an increase in fertiliser rate, with a significant species by fertiliser interaction (p = 0.002). The highest yield was measured for C ciliaris, followed by D. eriantha (4.02 and 3.43 g porI, respectively), at the full fertiliser application rate. Cymbopogon plurinodis was the third highest yielding species, while the yields of E. superba and F. africana were similar. There were positive linear correlations between foliage yield and fertiliser application rate for all grasses. The root biomass of the grasses also increased with an increase in fertiliser application rate. The interaction between grass species and fertiliser level had a non-significant (p = 0.085) effect on the yield of grasses, though there were significant individual effects of species (p < 0.001) and fertiliser (p < 0.001). Digitaria eriantha had the highest root biomass at each fertiliser application rate, followed by C plurinodis and C ciliaris. Similarly to foliage yield, there were positive linear correlations between root biomass and fertiliser application level. Positive, linear correlations were found between foliage yield and root biomass, though the strength of these varied. The weakest correlation was found for D. eriantha (R2 = 0.42) but this was attributed to a moderately high variance in foliage yield and roots becoming potbound. Generally, nutrient concentrations were within adequacy ranges reported in the literature, except for P concentrations. This was attributed to the high P-sorption capacity of the PT. Zinc concentrations were higher than the recommended range for grasses, and also increased with an increase in fertiliser application rate. This was attributed to the high available Zn concentrations in the PT and improved growth of the grasses at higher fertiliser application rates. It was recommended that C ciliaris and D. eriantha be used for revegetation due to high biomass production and that E. superba be used because of rapid growth rate and high self-propagation potential. Both C plurinodis and F. africana can also be used but are slower to establish, while A. eucomus was not a suitable species for revegetation of the PT. Inorganic fertiliser improved the growth of all these species and is recommended for the initial establishment of the grasses. An experiment was conducted to investigate the potential of inducing metal hyperaccumulation in three grass species (C ciliaris, D. eriantha and E. superba) grown in the PT. Grasses were grown in fertilised tailings for six weeks, then either ethylenediaminetetraacetic acid (EDTA) or diethylentriaminepentaacetic acid (DTPA) was added to the pots at rates of 0, 0.25, 0.5, 1 and 2 g kg-I. Grasses were allowed to grow for an additional week before harvesting. The concentrations of Cu, Pb and Zn were determined in the foliage. The interactive effect of species and chelating agent on the uptake of Cu was marginally significant (p = 0.042) and non-significant for Pb and Zn (p = 0.14 and 0.73, respectively). While the addition of the chelating agents resulted in an increase in Pb uptake by the grasses, it did not induce metal hyperaccumulation in the grasses. This was attributed to the ineffectiveness of the chelating agents in the PT in the presence of competing base cations (mainly Ca). The use of this technology was not recommended. Part 2 - Land disposal of Mn-rich processing wastes Chemical characterisation of the SS showed that it was an alkaline (pH > 9.5), Mn-rich silicate (glaucochroite), that generally·had low amounts of soluble and readily extractable metals. Acidic extractants removed high amounts of Mn, Ca and Mg, attributed to the dissolution of the silicate mineral. The EW was highly saline (saturated paste EC = 6 780 mS m,l) with a near-neutral pH. It had high amounts of soluble Mu, NHt+, S, Mg, Ca and Co. The primary minerals were magnetite, jacobsite (MnFe204) and gypsum. The effect of SS and EW on selected chemical properties of six soils was investigated by means of an incubation experiment, and their effect on the yield and element uptake by ryegrass was investigated in selected soils under glasshouse conditions. Five A-horizons (Bonheim (Ba), Hutton (Hu), lnanda (la), Shortlands (Sd) and Valsrivier (Va» and an Ehorizon (Longlands (Lo» were treated with SS at rates of 30, 60, 120,240 and 480 g kg'l and EW at rates of20, 40,80,160 and 320 g kg'l. Soils were incubated at field capacity at 24 QC and sampled periodically over 252 days. The soil pH, both immediately and over time, increased, while exchangeable acidity decreased after the addition of SS to the soils. The pH at the high rates of SS tended to be very high (about 8). The electrical conductivity (EC) of the soils also increased with an increase in SS application rates and over time. The most marked changes tended to occur in the more acidic soils (e.g. la). In the soils treated with EW, there was generally an increase in the pH of the acid soils (e.g. la) while in the more alkaline soils the pH tended to decrease (e.g. Va), immediately after waste application. There was a general decrease in pH over time, with a concurrent increase in exchangeable acidity, due to nitrification processes. The EC of all the soils increased sharply with an increase in EW application rate, attributed to the very saline nature of the EW. Water-soluble Mn concentrations in the soils treated with SS tended to be below measurable limits, except in the acid la. Iron concentrations decreased with an increase in SS application rate and over time for all soils. The water-soluble concentrations of Mn, Ca, Mg and S increased sharply with an increase in EW application rate in all soils. There was also a general increase in Mn concentrations over time. Iron concentrations tended to be low in the EW-treated soils, while Co concentrations increased as EW application rate increased. Exchangeable (EX, 0.05 M CaCh-extractable) concentrations of Fe, Co, Cu, Zn and Ni were low in the SS-treated soils. The concentrations of EX-Mn tended to increase with an increase in SS application rate in the la soil, but generally decreased in the other soils. There was also a decrease over time, attributed to the high pH leading to immobilisation of Mn. The EX-metal concentrations of the EW-treated soils were generally low, except for Mn. The concentrations of EX-Mn increased sharply as EW application rate increased. The contribution of EX-Mn was calculated to range from 209 to 3 340 mg Mn for EW rates of 20 to 320 g kg-I, respectively. In the Lo soil the expected amount of Mn was extracted at the different EW application rates. In the other soils the EX-Mn concentrations were typically higher than expected. This was attributed primarily to the dissolution ofMn from the EW due to the interaction between soil organic matter and the EW. There was generally an increase in EX-Mn concentrations over time, attributed to the decrease in pH of the soils treated with EW. The above-ground biomass production of ryegrass grown in Lo and Hu soils treated with SS increased at low application rates, but decreased again at the highest rates. The reduction in yield was attributed to an increase in soil pH leading to trace nutrient deficiencies. At the lower SS application rates, nutrient concentrations of the ryegrass tended to be within typical adequate ranges reported in the literature. Of concern was the elevated Mn concentration in the ryegrass foliage, though no toxicity symptoms were seen. This was attributed to the dissolution of the silicate mineral due to soil acidification processes and the possible ameliorating effect of high Ca and Si concentrations on Mn toxicity. The growth of ryegrass was generally poor in the Hu soil treated with EW and it did not survive beyond germination in the Lo soil treated with EW. In the Hu soil plants grew well in the 20 and 40 g kg-I EW treatments, but died at the higher rates. In both cases mortality was thought to be due to the high salinity that resulted in toxicity and osmotic stress in the newly germinated seedlings. The improved growth at the lower rates ofEW, in the Hu soil, was attributed mainly to increased N availability. The concentrations of Mn in the foliage were elevated in the soils treated with EW. A pot experiment was conducted to test the effect of applying either humic acid (HA) or compost (at a rate of 20 g kg-I) with lime (at rates of 0, 5 and 10 Mg ha-I) on the growth and nutrient uptake of ryegrass grown in the Hu soil treated with EW at rates of 0, 10, 20 and 40 g kg-I. A basal P-fertiliser was also applied in this experiment. The highest yields were measured in the treatments receiving either HA or compost at the highest application rate ofEW. The addition oflime did not improve the yield of the HA treatments, but did in the compost treatments. Generally, nutrient concentrations were adequate. The Mn concentrations were markedly lower than expected, and this was attributed to the formation of insoluble Mn-P compounds due to the addition of fertiliser. The effect of either HA or compost on Mn concentrations was not marked, but lime reduced Mn uptake. A leaching column experiment showed that, generally, the Mn was not readily leached through a simulated soil profile, though the addition of compost may enhance mobility. There was also evidence to indicate an increase in salinity and that Co concentrations of the leachate may be a problem. These data suggest that soil organic matter may be a very important factor in determining the release of Mn from the wastes, notably the EW. The land disposal of the SS and EW was not recommended at the rates investigated here, as both showed the potential for Mn accumulation in above-ground foliage, even at low application rates, while high application rates negatively impacted on plant growth. It appears that P-compounds may be beneficial in reducing Mn availability in the EW, but further testing is required. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

La major conscienciació actual dels problemes de pol·lució que acompanyen les pèrdues de N del sòl cap a l'atmosfera ha reorientat les investigacions cap a un coneixement més profund dels processos implicats en les emissions dels compostos nitrogenats que comporten un major perjudici des d'un punt de vista ecològic així com els seus principals factors reguladors. La creixent preocupació per l'increment de la concentració atmosfèrica de N2O és deguda a les seves interaccions amb la fotoquímica atmosfèrica i el balanç de radiació de la Terra ja que intervé en la destrucció de la capa estratosfèrica d'ozó, contribueix a l'efecte hivernacle i participa de la pluja àcida. Es considera que els sòls són la principal font de N2O atmosfèric. Al voltant del 90% d'aquestes emissions són d'origen biòtic; els principals processos implicats són la desnitrificació i la nitrificació. L'emissió del N2O produït a través d'aquests dos processos es caracteritza pels diferents nivells de regulació que presenta ja que depèn de la taxa dels processos, de la proporció de N canalitzada per cada procés cap a la producció de N2O i del seu consum dins el mateix sòl el qual està relacionat amb les dificultats en el transport cap a l'atmosfera. Això comporta una gran dificultat a l'hora d'aprofundir en el coneixement de les emissions de N2O del sòl cap a l'atmosfera i de la seva regulació. El desconeixement dels nivells d'emissió de N2O i de la importància de la desnitrificació així com de la seva regulació tant en sòls agrícoles com naturals de les nostres contrades és el principal punt de partida dels objectius d'aquest treball. / The current increased awareness of pollution problems that accompany the loss of soil N to the atmosphere has reoriented research towards a deeper understanding of the processes involved in emissions of nitrogen compounds that lead to greater damage from an ecological point of view as well as their regulatory factors. The growing concern over the increased atmospheric concentration of N2O is due to their interactions with atmospheric photochemistry and radiation balance of Earth as it participates in the destruction of the stratospheric ozone layer, the greenhouse effect and in acid rain. It is considered that the soils are the main source of atmospheric N2O. Around 90% of these emissions are of biotic origin, the main processes involved are nitrification and denitrification. The emissions of N2O produced via these two processes are characterized by different levels of regulation, as it depends on the rate of processes, the proportion of N channeled by each process to N2O production and consumption within the same soil which is related to difficulties in transport to the atmosphere. This entails a great difficulty to deepen the knowledge of soil N2O emissions to the atmosphere and its regulation. The ignorance of N2O emission levels and the importance of denitrification as well as their regulation in both natural and agricultural soils is the main starting point of the objectives of this work.

Effective agricultural planning and environmental monitoring requires basic soil information. However, analyzing soil properties by conventional methods is often expensive and time consuming. In addition, these analyses result in chemical residues, which may be environmentally hazardous. In recent decades near-infrared diffuse reflectance spectroscopy (400-2500 nm) has been shown to be a viable alternative for rapidly analyzing soil properties. Information needs to be mathematically extracted from the spectra in order to correlate them with soil properties, and multivariate statistics are often used to calibrate soil prediction models.However, soils evaluated by the mid-IR region (4000 to 400 cm-1) warrants new studies. The primary aim of this study was to investigate the feasibility to use soil spectral data and chemometrics methods to predict soil properties, in order to reduce the number of conventional soil analyses. The understanding of the relationships between spectral characteristics and the physic-chemical properties of soils were evaluated in three different studies with soils of: (i) spectral library (Chapter 1), (ii) amazonian region (Chapter 2), (iii) soils contaminated with heavy metals and tannery sludge (Chapter 3).It was possible to identify regions of the vis-NIR and mid-IR spectra that showed absorption features due to water, iron oxides, and clay minerals. In Chapter 1 the predicted models for clay and soil organic matter showed high accuracy. It reflects the influence of the direct spectral responses of these properties in the NIR. The division of the large library into smaller subsets based on variation in the spectra characteristics was the best alternative to quantify soil attributes in tropical soils by Partial Least Square regressions. Another alternative would be to use Boosted regression trees for the whole library. In Chapter 2, the mid-IR predicted models outperformed the vis-NIR. Comparison of the interpolation results revealed that the predictions of the PLS regression (mid-IR and vis-NIR) adequately reproduced the spatial pattern of the properties evaluated, especially soil organic carbon and cation exchange capacity and, had the ability to predict the soil properties of unknown samples from a different geographical location. In Chapter 3, the metals adsorption to soil constituents caused expressive changes in soil spectral curves, showing spectral differentiation between highly contaminated soil and soils that are relatively contaminant-free. The results indicate that the Cr pseudo-total content can be predicted by spectroscopy reflectance with both sensors data. Fe and Mn also can be predicted accuratley by vis-NIR. The vis-NIR models outperformed the mid-IR. Besides these results, the vis-NIR instrument has less complicated sample and can be used directly in the field using portable spectrorradiometers. / Para o planejamento agrícola e o monitoramento ambiental são necessárias informações sobre os solos. As análises de solos realizadas através de métodos convencionais em laboratório são normalmente caras e demoradas. Além disso, geram resíduos químicos que caso não sejam dispostos e/ou tratados adequadamente, podem contaminar o ambiente. Nas últimas décadas a espectroscopia de reflectância difusa na região do visível e infravermelho próximo (vis-NIR, 400-2500 nm) do espectroeletromagnético tem se mostrado uma alternativa viável para analisar atributos de solo de maneira rápida. Para tanto, a informação espectral é matematicamente extraída do espectro e métodos multivariados são usados afim de correlacioná-la com as propriedades do solo. Entretanto, ainda são poucos estudos de solos em que a espectroscopia de reflectância na região do infravermelho médio (mid-IR, 4000-400 cm-1) foi usada. Objetivaram-se com este trabalho investigar a viabilidade da utilização de dados espectrais vis-NIR e mid-IR de solos e métodos quimiométricos para predizer as propriedades dos mesmos, a fim de reduzir o número de análises convencionais de terra. As relações existentes entre características espectrais e propriedades físico-químicas de solos tropicais foram avaliadas em três estudos distintos com solos (i) de uma biblioteca espectral (Capítulo 1), (ii) da região amazônica (Capítulo 2) e, (iii) contaminados com metais pesados e lodo de curtume (Capítulo 3). Foi possível identificar faixas espectrais nas regiões do vis-NIR e mid-IR relacionadas às feições de absorção características da água, óxidos de ferro e minerais de argila. No capítulo 1 os modelos de predição vis-NIR de argila e matéria orgânica do solo apresentaram elevada acurácia. Isto reflete a influência direta destas propriedades do solo na sua resposta espectral. A divisão da biblioteca espectral em subgrupos menores baseada nas características espectrais foi eficiente na quantificação de atributos de solos tropicais. Outra alternativa foi usar o método de regressão de árvores para o conjunto total de dados. No capítulo 2, os modelos de predição mid-IR foram mais precisos que os vis-NIR. Os modelos de carbono orgânico do solo e capacidade de troca catiônica obtidos pela regressão pelo método dos mínimos quadrados parciais permitiram a reprodução do padrão espacial destas propriedades na área estudada (r > 0.81); e puderam ser aplicados em uma área geográfica diferente, em amostras de solos desconhecidas. No capítulo 3, a adsorção de metais em constituintes dos solos provocou mudanças nas curvas espectrais dos mesmos, mostrando diferenças entre solos altamente contaminados por metais pesados e solos livres de contaminação. Os teores de Cr (semi-total) no solo pode ser predito através da espectroscopia de reflectância vis-NIR-mid-IR e regressão por mínimos quadrados parciais. Fe e Mn também foram preditos com acurácia usando dados vis-NIR. Em geral, os modelos de predição vis- NIR de metais pesados foram mais precisos que o mid-IR. A vantagem da utilização do sensor vis-NIR está no preparo mais simples de amostras e na possibilidade de utilizá-lo diretamente no campo.

Gold mining in the Witwatersrand Basin of South Africa has resulted in soil contamination due to the lack of sufficient environmental management plans for the tailings dumps and remnant footprints. Tailings reclamation as a strategy of reducing pollution in the Central Rand, for instance, has resulted in contamination of water systems by acid mine drainage (AMD). After removal of the tailings dumps, remnant material is left over on the tailings footprints and these contain significant amounts of pollutants that were initially in the tailings. Heavy rainfall during summer dissolves primary minerals and later in the dry season, secondary minerals are precipitated as efflorescent crusts on and nearby tailings dumps as well as footprints due to high evaporation. The efflorescent crusts can redissolve when it rains and form acidic, metal and sulphate-rich solutions due to their soluble characteristics. This study aimed to characterise tailings footprints in areas targeted for human settlements and office spaces to assess their potential to release left over toxic elements such arsenic (As), lead (Pb), copper (Cu) and zinc (Zn). The approach to the study involved characterisation of oxidised and unoxidised tailings material and secondary precipitates on both tailings dumps and footprints. This involved determining the mineralogical composition using Powder X-ray Diffraction (PXRD). Dissolution and leaching studies were also conducted on the material followed by determination of constituent elements using inductively coupled plasma optical emission spectroscopy (ICP-OES) and sulphates using ion chromatography (IC). The leaching solutions used included rainwater; dilute sulphuric acid at pH of 3.0 (a common leachate in such acidic soils); as well as plant exudates such as oxalic and citric acids. The leachate solutions were used to correlate the mineralogical composition of secondary precipitates and tailings footprints. Potential implications on humans following any accidental ingestion of the tailings or contaminated soils were assessed using gastric juices. The ecological risk factors and risk index together with the model to evaluate daily intake and different pathways to humans were used to assess the toxicity caused by exposure to contaminants in the materials. The experimental work was augmented by computer simulations based on geochemical modelling (using the PHREEQC geochemical modelling code) to determine the speciation of elements (and thus their potential lability and bioavailability), dissolution and formation of secondary mineral precipitates in the tailings dumps and footprints. The findings of the PXRD study showed that the mineralogy of the tailings and footprints was dominated by quartz (SiO2) and some minor minerals such as pyrite (FeS2), pyrophyllite (Al2Si4O10(OH)2), chlorite (Mg,Fe)3(Si,Al)4O10), mica (K(Mg,Fe)3 AlSi3O10(F,OH)2) while that of secondary precipitates was dominated by jarosite (KFe3+ 3(OH)6 (SO4)2), goethite (FeOOH), melanterite (FeSO4.7H2O) and gypsum (CaSO4.2H2O). Minerals obtained for the secondary precipitates were corroborated by geochemical modelling. Leaching results using rainwater with pH ranges from 3.5 to 3.9 showed that trace elements are released very slowly from tailings dumps and footprints and in small concentrations during rainy seasons as follows: As (1.5 mg/L-4.5 mg/L), Pb (3.5 mg/L-5.5 mg/L), Cu (4 mg/L-4.8 mg/L) and Zn (23 mg/L-44 mg/L). The release and mobility of Cu, Pb, Zn and As occurs quite markedly when secondary precipitates dissolve, making the immediate impacted environment unfavourable for plant growth and any habits in the vicinity. This was substantiated by simulated dissolutions and assessment of the resulting elemental speciation that pointed to the elements being distributed in bioavailable forms, implying potential uptake by plants (such as vegetables that may be cultivated on such impacted soils). The model was used to evaluate the daily intake and different exposure pathways and the results showed that children may daily intake 48.4 mg kg-1 day-1 and adults‟ 32.8 mg kg-1 day-1 . After 5 years (1825 days) of exposure more harm may be experienced and findings shows that kids are the most victims on these contaminated sites compared to adults. Both children and adults may absorb low levels of these toxic elements daily and after long time of exposure it may cause disease like cancer in their body which may lead to death. Pathways may be through inhalation and accidentally ingesting tailings soil that contain toxic elements. Drawing from the above findings, it will be important that tailings footprints that have been earmarked as land for development (residential or office space) be thoroughly assessed for potential release of toxic elements and high levels of acidity. Further reclamation aimed at reducing these hazards can then be implemented. / College of Agriculture and Environmental Sciences / M. Sc. (Environmental Science)

Lebanon is situated in a Mediterranean semi-arid region rich in hydraulic resources but strongly under the impact of anthropogenic pressure, mainly after the industrial boost in the last 50 years. In this thesis our research is devoted to the study of water resources and the assessment of soil pollution in two contrasting watersheds that may resemble similar regions in the world. Rivers act as a collective funnel of contaminants derived from rock weathering, industrial, agricultural and urban practices. Thus we focus our study on the two main contrasting watersheds in Lebanon: an industrially dominated watershed located northwest of the country on the Mediterranean coast (Al Jouz basin), and a rural historically agricultural watershed that lies in the continental valley between the two mountainous chains (Litani basin). Geochemical analysis coupled to multi-isotopic applications was used as tools to investigate the collective influence of land-use cover, geomorphological processes, topography, soil type, geology, geography, orography, climate, and hydrological variability on drainage basin evolution. A two-year sampling strategy was followed (2011-2013) to collect not only water samples at various depths in the reservoir and in the piezometers, but also sediments (lacustrine, riverine and coastal) and soils (surficial and cores) to cover seasonal variations (rainy, first flush and dry seasons) in both studied areas. The results highlight the entire mechanism of characterization, origin, and partitioning between the dissolved and particulate phases of pollutants. Furthermore, the environmental implication of the Qaraaoun reservoir was assessed by emphasizing water hydrodynamics and its interaction with the watershed. Characterizing industrial and agricultural pollution allows the understanding of metal behavior and the prediction of its fate, in association with the environmental receiving media in semi-arid and Mediterranean areas. This work was the first to trace pollution sources and to reconstruct the metal fluxes in two of the most environmentally significant watersheds in the country. Stable and radioactive Pb isotopes were used in addition to 137Cs to study the geomorphological influence and the chronology of the environmental stress exerted by the factory and the dam on basin ecology. Moreover, the nature of the Qaraaoun reservoir and the internal hydrological dynamics were explored using stable hydrogen and oxygen isotopes to delineate the reservoir water layers and its fast response to meteorological and hydrodynamic changes in the watersheds, and to demonstrate its strong hydrological connectivity with groundwater. Reservoir water balance was made, indicating groundwater influx into the reservoir which was reported for the first time. The water hydrodynamics was also assessed using a box model, which in its role can be used to evaluate the reservoir water balance and hydro-project functionality and to establish the basis for water sustainability in the long term. This work has yielded a better understanding of biogeochemical processes under different environmental conditions. The treated issues in this thesis will provide a foundation for future hydropower projects and allow one to draw a road-map for national management plans, and to raise the alert for remediation processes and management methods to preserve the environment and resource sustainability, and ultimately the wellbeing of the local population.<p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Les travaux entrepris au cours de cette thèse visaient à répondre à des questions fondamentales sur la biologie évolutive des plantes adaptées aux sols contaminés par des métaux lourds. À travers une approche comparative de populations métallicoles (M :sur sols métallifères) et non métallicoles (NM :sur sol normal) de l’espèce modèle Thlaspi caerulescens, cette thèse avait donc pour objectif général d’appréhender l’adaptation aux habitats métallifères d’une manière plus globale que par le seul trait de tolérance aux métaux. Nous avons donc cherché à mettre en évidence les différences de stratégie de vie entre les populations M et NM. Nous avons également estimé le coût de l’adaptation à l’environnement métallifère. Enfin, nous avons porté une attention particulière au rôle que pouvait jouer la plasticité dans l’adaptation à l’environnement métallifère. Cette plasticité a été considérée au niveau des traits d’histoire de vie et du système racinaire. <p>Trois expériences ont étudié les variations des traits d’histoire de vie des populations M et NM: (1) une culture en conditions contrôlées des populations sur un gradient de concentrations en Zn, (2) une expérience de transplantation réciproque in situ de populations M et NM et (3) un suivi démographique dans les populations M et NM. Enfin, une quatrième expérience (4) visait à évaluer les variations entre populations M et NM d’un trait particulier :la plasticité du système racinaire en réponse à une distribution hétérogène des métaux dans le sol. <p>Nos résultats montrent que les plantes M ont, en moyenne, des cycles de vie plus courts que les plantes NM (exp. 1, 3). Par ailleurs, les populations M sont capables de modifier leur stratégie de reproduction en fonction des teneurs en métaux dans le sol ou du site de transplantation (métallifère vs. non métallifère). Que ce soit sur des substrats non contaminés en Zn (exp. 1) ou sur des sites non métallifères (exp. 2), les plantes M produisent autant de graines au cours de leur vie que les plantes NM. Ces résultats suggèrent l’absence d’un coût adaptatif fort chez les plantes M. In situ (exp. 3), nous avons mis en évidence un effet structurant de l’hétérogénéité spatiale des sites métallifères sur les stratégies de vie des plantes M. Enfin, les plantes M ont exprimé une plasticité plus élevée du comportement d’exploration racinaire que les plantes NM (exp. 4). <p>L’existence de stratégies de vie plastiques, l’homéostasie de la fitness sur une large gamme de concentrations en Zn, ainsi que le faible coût adaptatif mis en évidence chez les populations M suggèrent que ces populations sont plus aptes à fonder de nouvelles populations que les populations NM. Nos résultats ont également clairement démontré que les populations M sont caractérisées par une plasticité plus élevée que les populations NM (génotype généraliste). Cette plasticité concerne à la fois les stratégies de vie et les mécanismes d’exploration racinaire. Cette plasticité élevée des plantes M a très probablement évolué en réponse à l’hétérogénéité spatiale des sites métallifères La sélection de génotypes généralistes sur les sites métallifères est une piste de recherche qui mérite, à présent, d’être approfondie chez les autres espèces colonisant les sites métallifères. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Abandoned non-reclaimed marl mine dumps of the cement factory in the Novorossiysk industrial agglomeration (NW Caucasus, Russia) are hazardous because of fugitive dust emissions, erosion and possible occurrence of a debris-flow disaster. Having high sorption capacity, dust accumulates pollutants contained in the atmospheric air and subsequently precipitates on the topsoil. Soil and plant sampling and chemical analysis (> 200 specimens) revealed the geochemical anomalies of Pb, Zn, Cu, Ba and Sr. Land zoning based on accumulated environmental damage indicators and the debris-flow technical risk was performed to assess environmental threats. The designed mine dump reclamation includes soil stabilisation by application of geosynthetic cover, hydro-seeding of soil improvers and seeds of herbaceous plants on the slopes, and anti-erosion plantation of cades and smoke trees at subhorizontal surfaces.

Thesis (M.Sc. Agriculture. (Soil Science)) -- University of Limpopo, 2022 / The constant growth experienced by the coffee industry has led to the high-volume production of coffee waste worldwide. One of the main coffee wastes is spent coffee ground (SCG), a residue obtained after the ground coffee beans are treated under pressure. The present study was aimed to investigate the utilization of SCG to amend soil physicochemical properties. This study was conducted at Greenhouse Biotechnologies Research Centre of Excellence, University of Limpopo, South Africa, where the effect of various rates of SCG concentration in volume percentage (vol%) was tested for a period of nine months. The spent coffee ground residue was collected from four restaurants at Haenertsburg, and the application rates were 0, 5, 10, 20, 30, 50 vol%. To evaluate the change in soil physicochemical properties overtime, the incubation period was divided into four test periods namely T1 was after a month, T3 after 3 months, T6 after 6 months, and T9 after 9 months. Physicochemical properties including nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), total organic carbon (TOC), cadmium (Cd), copper (Cu), nickel (Ni), zinc (Zn), and lead (Pb), pH, electrical conductivity (EC), C:N ratio, large macroaggregates (LM), small macroaggregates (sM), microaggregates (m), unaggregated silt and clay (s+c), mean weight diameter (MWD) and soil moisture content (SMC) were quantified at the end of each test period. Results revealed that the interaction between incubation periods and various SCG application rates significantly (p<0.05) increased pHw, EC, MWD, LM, base cations and significantly decreased TOC, heavy metals, SMC, m, and sM. Spent coffee ground increased pHw and EC of the soil at all application rates and reached a maximum of 7.8 units at T6 in treatment SCG-5 and 202.30 S/cm at T9 in treatment SCG-50 above the control respectively. Total organic carbon increased by 548% above control in the highest treatment (SCG-50) at T1, but, however, started declining from T3 in all treatments across the incubation period. SCG’s highest application rates (SCG-20 to SCG-50) reduced the soil Cd toxicity (threshold of >2 mg/kg), but however, also reduced the availability of micronutrients (Cu and Zn) during the incubation period. At T9, Mg, Ca, K, and P increased from mean values of 55.9 to 77.9, 40.9 to 62.2, 77.4 to 112, and 22.0 to 30.0 mg/Kg above control in treatments with high application rates. LM increased whilst sM, and m decreased across the incubation period in all treatments. MWD increased by 46% at T1 and reached its maximum of 56% at T6 in treatment SCG-50 above control. Additionally, there was a positive relationship between LM and MWD. Soil moisture content however increased to 60.26% at T1 in treatment SCG-50 and decreased from T3 across the incubation period. Spent coffee ground has the potential to be used as a liming material, a chelating agent, and for water management in semi-arid areas. It retains and cycles nutrients and improves soil structure through aggregation. However, research should be done in field conditions to access the effectiveness of this residue. / NRF

En av de vanligaste föroreningarna i mark och grundvatten är aromatiska kolvä- ten såsom bensen, toluen, etylbensen och xylener. Dessa härstammar från ex. ben- sin och har läckt ut till omgivande miljö från drivmedelsanläggningar. I stället för schaktning och bortforsling av de förorenade jordmassorna som mest förekom- mande ex situ-saneringsmetod behövs mer forskning kring in situ-saneringsmetoder där föroreningen alltså kan angripas på plats. I denna rapport undersöks förhöjd biologisk nedbrytning genom att redogöra för de önskvärda (bio)kemiska reak- tionerna i marken, de parametrar som styr den biologiska nedbrytningen samt huruvida dessa parametrars inverkan har kunnat påvisas i tre stycken fallstu- dier där in situ-sanering utförts vid drivmedelsanläggningar. Studien kommer fram till ett antal primära (ursprungliga) variabler såsom föroreningen i fråga, jordtätheten och klimatet, samt ett antal sekundära (förändringsbara) variabler såsom oxidationsmedlet, mikroorganismerna, näringsämnena och markvattnet. Dessa presenterades sedan i en schematisk skiss som visar hur de växelverkar med parametrarna för optimal biologisk nedbrytning, vilka visade sig ha vissa optimala värden. Dessa konstaterades vara föroreningshalten (&lt;5-10 viktprocent torr jord), pH-värdet (6-9), temperaturen (20-35◦C), vattenmättnaden (40-80%), syrehalten (&gt; 2 500 viktprocent kolväten), C:N:P-kvoten (100:10:1) samt koncent- rationen mikroorganismer (&gt; 103 CFU/ml). När de olika parametrarnas inverkan  i fallstudierna undersöktes kunde slutsatsen dras att det skulle behövas ytterliga- re data och mätningar vid varje sanering för att kunna garantera att parametrarna varit inom sina respektive optimala värden. / One of the many goals for a sustainable living and a healthy environment is the reduction of toxic substances in soil and groundwater. Within this ambit, one of the most common pollutants is aromatic hydrocarbons such as benzene, tolue- ne, ethylbenzene and xylenes (BTEX) which are spread from e.g. filling stations for fuel as they are constituents of petrol. These are volatile and can constitute a risk for humans and the environment as they percolate through the soil and groundwater resources as well as can exfiltrate from the ground to surrounding buildings and pollute the indoor air. Once these pollutants are present in the soil, the site needs to be remediated, something which is mainly done ex situ by exca- vating the polluted masses to be sent to a treatment facility. An alternative to this is in situ remediation where the pollution can be treated without being excavated and thus having a smaller impact on the environment.  In this report, one of these techniques called enhanced biodegradation was studied, which implies the application of oxidisers to faciliate microbial activities. It investigated (1) how this remediation technique works and what (bio)chemical reactions are desired in the soil; (2) what are the principal parameters that enable this remediation process and how do they interact with the surrounding factors, and (3) whether the impact of these parameters can be estimated in three case studies where this technique has been used. The three case studies were filling stations located in Sweden, having similar pollutants and geology, and two diffe- rent oxidisers had been used.  The study resulted in the identification of a number of primary (initial) varia- bles such as the pollutant characteristics, the soil density and the climate; as well as a number of secodnary (modifiable) variables such as the oxidiser, microorga- nisms, nutrients and soil moisture. These were then presented in a scheme which shows how their interactions with the parameters for optimal biodegradation. Each parameter was found to have a certain optimum such as the concentration of hydrocarbons (&lt;5-10 mass percent of the dry soil) , pH value (6-9), tempe- rature (20-35◦C), soil water saturation (40-80%), oxygen concentration (&gt; 2,500 mass percent of the hydrocarbons), C:N:P ratio (100:10:1) as well as concentration of microorganisms (&gt; 103 CFU/ml). A negative correlation could be identified between the soil density and the oxygen concentration in the soil, as well as a po- sitive correlation between the soil water saturation in the and the soil moisture, alternatively additional water via irrigation. The impact of each parameter in the case studies of in situ remediation was assessed and the it could be concluded that they would need additional data and measurements for most parameters in order to guarantee that they are within the respective optima.