The stability of hydrogen peroxide (H2O2) is a critical factor for the brightening of mechanical pulps. Inorganic ions, including Fe, Mn and Cu catalytically decompose H2O2. These troublesome metals promote the rapid transformation of H2O2 to nonselective hydroxyl radicals that degrade the cellulose fibres and decrease yields. / The interaction of aqueous metal•complexes with magnesium metal (Mg°) or bimetallic mixtures of magnesium with either palladium (Pd°/Mg°) or silver (Ag°/Mg°) were optimized to remove metals (Mn, Cu and Fe) from solution with concomitant release of the complexing reagent. The analyte metals were removed by both cementation on the surfaces of the excess Mg° and by precipitation as hydroxides. Overall, the reactions were rapid (3 or 10 min) and very efficient. The accelerators (Ag or Pd) were deposited on the surfaces of the Mg°. In a separate study, the excess of Mg° could be reused to mediate more metals removal without apparent loss of reactivity. Among the other iminodiacetate analogs (CDTA, MEDTA, EGTA, HEDTA, DPTA and MTBE), the EGTA and HEDTA proved to be possible substitutes for both efficient metal removal of Mn, Cu and Fe from solution and efficient release of chelating reagent. The measurement of particle size, performed by laser granulometry, demonstrated that smaller particles of precipitate were generated from metal-EDTA complexes by reaction with NaOH than by reaction with Pd°/Mg° bimetallic mixture. If the suspensions of particles were analyzed in the absence of ultrasound, the particles became aggregated into large flocs (up to 150 mum3 ). The reactivity of the bimetallic mixtures was exploited to remove Cu, Mn, Fe, Zn and Al that had been initially chelated with EDTA or DTPA from a thermomechanical pulp (TMP). After 15 min, the metals had been removed efficiently with the bimetallic mixtures. The EDTA released from the TMP filtrate could be recycled efficiently for a total of three cycles. On the other hand, the DTPA was not released as efficiently. Measurements of turbidity and chemical oxygen demand (COD) indicated no appreciable difference between the pulp samples with either chelating reagent. Residual H2O2 and ISO brightness measurements indicated no apparent differences among pulps that had been treated wi

<p>The aim of the study was to quantify the extent of inorganic chemical pollution of the Franschhoek River and draw relationships between contaminants in water, sediment and plants. The invasive Acacia mearnsii and Salix babylonica and indigenous Brabejum stellatifolium species were chosen as biomonitors due to their wide spread distribution along the river and their apparent ability to accumulate heavy metals. The sites chosen allowed for comparison of the river quality upstream with that of the river further down stream as it meandered through residential, agricultural and recreational areas, until it joined with the Berg River further downstream. The general aim of the study was to assess the degree of inorganic pollution in the Franschhoek River to evaluate its contribution to pollution of the Berg River, of which it is an important tributary. Also understanding the sources of the pollution would contribute to the ability to reduce pollution.</p>

As pollution becomes an ever-increasing threat to the global environment pressure is being placed upon industry to "clean-up" its act, both in terms of reducing the possibility of new pollution and cleaning up already contaminated areas. It was with this in mind that Amplats embarked on a phytoremediation project to decontaminate nickel-polluted soils at one of their mine sites in Rustenburg, using the nickel hyperaccumulating plant, Berkheya coddii, which is endemic to the serpentine areas near Barberton, Mpumalanga. Besides the applied aspects pertaining to the development of the phytoremediation process we were also interested in more academic aspects concerning the transport and storage of nickel within the plant tissues. In order that the progress of nickel could be followed through the plant, a radio-tracer of ⁶³nickel was placed in the soil and its movement within the plant followed by analysing the plant material, at set intervals, using a liquid scintillation counter. From these studies it was found that the nickel appeared to be transported from the roots to the leaves of the plant via the xylem. It appeared that the nickel was not confined to the leaf to which it was initially transported and so movement of nickel within the phloem also appears to occur in B. coddii. As nickel is generally toxic to most plants, hyperaccumulators contain elements that nullify the toxic effect of nickel. In the case of Berkheya coddii it is thought that the accumulated nickel is bound to malate to form a harmless nickel complex. With this in mind an assay for L-malic acid was developed in order that any effect on L-malic acid, caused by growing Berkheya coddii on soils containing various concentrations of nickel, could be determined. This method also enabled comparisons of L-malic acid concentrations to be made between hyperaccumulators and non-hyperaccumulators of various plant species. From the L-malic acid comparisons it was found that the nickel concentration within soils affected the levels of L-malic acid within B. coddii and that the levels of L-malic acid within B. coddii were greater than that of a closely related non-hyperaccumulator, suggesting that L-malic acid is indeed involved in the hyperaccumulation mechanism within B. coddii. B. coddii was chosen as the tool in nickel phytoremediation at Rustenburg Base Metal Refineries as it was found to accumulate up to 2.5% nickel in the dry biomass, it grows rapidly and has a large above-ground biomass with a well developed root system, and it is perennial and so does not need to be planted each season. Earlier work had shown that the nickel levels in the roots were comparatively low (up to 0.3% nickel in the dry material) and thus, for ease of harvesting and to ensure the continued vegetative growth of the plant on the planted sites, it was decided that the leaves and stems of the plants would be harvested at the end of each growing season. The plant was also found to accumulate low levels (0.006 - 0.3 %) of precious metals, including platinum, palladium and rhodium, within its above ground biomass, making it attractive for the remediation of certain soils that contain low levels of these metals. Before B. coddii could be introduced to the Rustenburg area a comparison of the climatic and soil conditions of Barberton, the area to which B. coddii is endemic, and Rustenburg needed to be made to ensure that the plant would be able to survive the new conditions. These comparisons showed that Rustenburg receives on average, 484 mm less rain per year than Barberton, indicating that irrigation was required when the Rustenburg sites were planted out with B. coddii, in order to reduce water stress. Rustenburg was also found to be, on average, 4.6°C warmer than Barberton, but as B. coddii growth responds to wet/dry seasons, as opposed to hot/cold seasons, it was not felt that this temperature difference would have a negative effect on the growth of the plants. The soil comparisons showed the contaminated Rustenburg sites to be serpentine-like in nature, with respect to Barberton, again giving confidence that the plant would adapt to the conditions occurring at the contaminated sites. However, to ensure optimal growth, nutrient experiments were also performed on B. coddii to ascertain the ideal macronutrient concentrations required, without inhibiting nickel uptake. These trials indicated that the individual addition of 250 mg/l ammonium nitrate, 600 mg/l calcium phosphate, 2 000 mg/l calcium chloride, 600 mg/l potassium chloride and 250 mg/l magnesium sulphate enhanced plant growth and nickel uptake, suggesting that, for phytoremediation purposes, these nutrients should be added to the medium in which the plants are growing. The growth-cycle of naturally occurring B. coddii plants in Barberton was also studied in order that seedlings could be germinated, in greenhouses, at the correct time of year so that the plants could be sown as the naturally occurring plants were germinating. From this information the seeds of the plants could be collected at the correct time of year and the above ground biomass harvested when the nickel concentrations were at their highest. It was found that the plants began to germinate as the first rains fell, which was generally at the beginning of September, and plant maturity was reached at about five months, after which flowers were produced. Seeds were produced from the flowers and these matured and were wind-dispersed one month to six weeks after full bloom, usually during February. The plants then started to die back and dry out and dormancy was reached about nine months after germination, generally in about mid- to late- May. It was found that the nickel concentration was at its highest about one month after the plants had begun to dry out and thus it was decided that the above ground biomass would usually be harvested at the end of April each season, in order to achieve maximum nickel recovery. Finally, in order that the plant's potential for use in phytoremediation could be fully assessed, field trials at the contaminated sites in Rustenburg were performed. Germination procedures were developed for the mass production of B. coddii and it was found that, although fully formed plants could be propagated in tissue culture, it was cheaper and faster to germinate the seeds in speedling trays, containing a zeolite germination mix, in greenhouses. It was also found that the seeds had a low germination rate, due to dehydration of the embryos and thus, in order to obtain the number of plants required, four to five times the amount of seeds needed to be sown. The two-month-old seedlings were transferred to potting bags, containing a mixture of potting soil and RBMR soil, and grown up in the greenhouse for a further three months. This growth period allowed B. coddii to adapt to the RBMR soil and also ensured that the plants were relatively healthy when transplanted into three prepared sites at RBMR. The plants were allowed to grow for the entire season after which the above ground biomass, comprising the leaves and stems, was harvested, dried and then ashed in an ashing vessel designed by the author, with the help of Mr K Ehlers. The ashed material was acid-leached with aqua regia in order that the base metals (mainly nickel) and precious metals could be removed from the silicates and carbonised material. The acid solution was then neutralised, causing the base metals (mainly nickel) and precious metals to be precipitated. This precipitate was then smelted with a flux in order that nickel buttons could be formed. Thus, from all the phytoremediation trials it was found that this process is highly successful in employing B. coddii for the clean-up of nickel-contaminated sites. This constitutes the first time that such a complete phytoremediation process has ever been successfully developed with B. coddii as the phytoremediation tool. It also appears to be the first time that phytoremediation has been performed "commercially" to produce a saleable metal product. The success of this project has stimulated Amplats to continue with, and expand it, to include more studies on phytoremediation as well as in the biomining of certain areas containing very low levels of precious metals which, with conventional techniques, were previously not worth mining. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

In this thesis, the uptake kinetics of Cd by the liverwort D. hirsuta and the moss A. androgynum were investigated. In preliminary experiments, the toxicity of Cd to the bryophytes was investigated by characterising the effects of Cd on photosynthesis and K loss. Experiments were carried out to explain the existence of variation between different collections observed in uptake kinetics in the liverwort D. hirsuta. Photosynthesis in D. hirsuta was more sensitive to Cd than photosynthesis in A. androgynum. The sensitivity was directly related to intracellular Cd concentrations. D. hirsuta accumulated considerably higher concentration of intracellular Cd than A. androgynum. Cd caused intracellular K loss in D. hirsuta but not in A. androgynum. Extracellular Cd uptake was rapid and independent of metabolism. Intracellular Cd uptake as a function of Cd concentrations followed Michael is-Menten kinetics. Intracellular Cd uptake in D. hirsuta was affected by age of the plant, K pretreatment and the site where plants were collected. The moss A. androgynum displayed Cd uptake acclimation when uptake was measured at low temperatures. The results indicated that uptake kinetics could be affected by seasonal variation. Tolerance of Cd in the moss A. androgynum could be induced by pretreating the plants with low concentrations. The moss possibly excludes Cd from the cytoplasm and thus reduces the concentration of Cd in the cytoplasm to below toxic level. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

The production of 1,2-Dichloroethane (1,2-DCA) exceeds 5.44 billion kg per year, and is higher than that of any other industrial halogenated chemical. Improper disposal practices or accidental spills of this compound have made it a common contaminant of soil and groundwater. 1,2-DCA has been classified as a priority pollutant by the Environmental Protection Agency owing to its toxicity, persistence and bioaccumulation in the environment. It has also been shown to have mutagenic and potential carcinogenic effects on animals and humans. Bioremediation is emerging as a promising technology for the clean-up of sites contaminated with chlorinated hydrocarbons. However, sites co-contaminated with heavy metals and 1,2-DCA may pose a greater challenge for bioremediation, as the former pollutant could inhibit the activities of microbes involved in bioremediation. Therefore, this study was undertaken to quantitatively assess the effects of heavy metals on 1,2-DCA biodegradation and to investigate the use of biostimulation, bioaugmentation, dual bioaugmentation, and biosorption for remediation of water co-contaminated with 1,2-DCA and heavy metals in microcosms. The combined effect of 1,2-DCA and the respective heavy metals on the microbial population and diversity was also investigated. The minimum inhibitory concentrations (MICs) and concentrations of the heavy metals (arsenic, cadmium, mercury and lead) that caused half-life doubling (HLDs) of 1,2-DCA as well as the degradation rate coefficient (k1) and half-life (t1/2) of 1,2-DCA were measured in two different wastewater types. An increase in heavy metal concentration from 0.01–0.3 mM, resulted in a progressive increase in the t1/2 and relative t1/2 and a decrease in k1. The MICs and HLDs of the heavy metals were found to vary, depending on the heavy metals and wastewater type. In addition, the presence of heavy metals was shown to inhibit 1,2-DCA biodegradation in a dose-dependent manner, with the following order of decreasing inhibitory effect: Hg2+ > As3+ > Cd2+ > Pb2+. For the bioremediation experimental set-up, 150 ml wastewater was spiked with 1,2-DCA (2.5 mM) and the respective heavy metal in air-tight serum bottles (Wheaton). The bottles were biostimulated, bioaugmented, dual-bioaugmented or undergoing biosorption. The microcosms were incubated at 25 °C and the 1,2-DCA concentration was measured weekly. Co-contaminated water undergoing biostimulation, bioaugmentation and, in particular, dual bioaugmentation were observed to exhibit higher degradation of 1,2-DCA in the presence of the heavy metal, compared to co-contaminated water receiving none of the treatments. Dual bioaugmentation, proved to be most effective, resulting in up to 60% increase in 1,2-DCA degradation after 4 weeks, followed by bioaugmentation (55%) and biostimulation (51%). In addition, an increase in the total number of 1,2-DCA degrading bacterial population was observed in the bioaugmentated microcosms compared to those biostimulated, which corresponds to an increased 1,2-DCA degradation observed in the bioaugmentated co-contaminated microcosms. Dominant bacterial strains obtained from the co-contaminated microcosms were identified as members of the genera, Burkholderia, Pseudomonas, Bacillus, Enterobacter and Bradyrhizobiaceae, that have been previously reported to degrade 1,2-DCA and other chlorinated compounds. Some of these isolates also belong to genera that have been previously shown to be resistant to heavy metals. PCR-DGGE analysis revealed variations in microbial diversity over time in the different co-contaminated microcosms, whereby the number of bands was reduced, the intensity of certain bands increased, and new bands appeared. Agricultural biosorbents (AB) were found to adsorb heavy metals effectively when utilized at a concentration of 2.5%, with the level of biosorption found to be dependent on the type of AB as well on the type of heavy metal present. OP proved to be the most efficient biosorbent for the heavy metals tested, followed by CNF, and corn cobs (CC) least efficient; therefore CC was not used in further bioremediation experiments. Both orange peel (OP) and coconut fibre (CNF) were found to be excellent at removing heavy metals from co-contaminated microcosms, with OP removing 14.59, 74.79, 60.79 and 87.53% of As3+, Cd 2+, Hg2+ and Pb2+, respectively, while 10.03, 40.29, 68.47 and 70.00% of As3+, Cd2+, Hg2+ and Pb2+, respectively, was adsorbed by CNF. Consequently, a higher degradation of 1,2-DCA was observed in the presence of OP and CNF, compared to the untreated control. It can be concluded that the remediation approaches utilized in this study proved effective in the bioremediation of water co-contaminated with 1,2-DCA and heavy metals and may provide the foundation for new and innovative treatment strategies for co-contaminated sites. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Two enzymatic systems from the lactic acid bacterium Oenococcus oeni, isolated from wine, have been studied. The first one is the H+-ATPase for which the activity was characterized under various conditions of growth. The activity gradually increased by l.6 to 1.9-fold upon inoculation at pH 3.5. The H+-ATPase activity did not vary significantly in function of the growth rate or with and without malic acid. However, acidification of the medium in the absence of malic acid induced the activity by 1.5 to 2.2-fold depending on the initial pH. The partially cloned H+-ATPase genes shared high homologies with those from other bacterial F0F1-ATPases. A mRNA of about 7 kb was detected by Northern blot and its size suggests that the genetic organization of O. oeni atp operon is similar to most F0F 1-ATPases. Furthermore, the amount of atp mRNA was shown to increase in acidic conditions. O. oeni H +-ATPase activity was pH-inducible and regulation of the expression seems to occur at the level of mRNA synthesis. Thus, the results confirmed the proposed role of the H+-ATPase in acid tolerance in O. oeni. / The second system studied was a chromosome-encoded P-type ATPase (CopB) and its putative transcriptional regulator (CopR). The copB gene encodes a protein showing great similarities with other Cu2+-ATPases of the CPx-type family of heavy-metal ATPases like Enterococcus hirae copB. Another gene (copR) was found 250 bp upstream of copB and displays great similarities with proteins of the MecI/BlaI family of transcriptional regulators, including En. hirae CopY repressor. O. oeni was shown to be highly resistant to copper and growth occurred in up to 30 mM CuSO4. Northern blot analyses indicated that the amount of copB mRNA increased upon a 0.2 to 4.0 mM copper stress suggesting that expression of the enzyme might be regulated at the level of mRNA synthesis. Whether CopR is involved in this regulation remains to be determined, but the results suggest that copRB genes might be involved in copper resistance in O. oeni.

Baigiamajame magistro darbe nagrinėjamas sunkiųjų metalų (toliau – SM) keliamas pavojus biotinei ir abiotinei aplinkai, vertinamas eksperimento aktualumas, užsienio šalių bei Lietuvos patirtis šioje srityje. Darbo tikslas – nustatyti SM (Cu, Zn, Ni, Cr, Pb, Cd, Pb) mišinio kaupimosi dėsningumus atlantinių lašišų Salmo salar L. audiniuose (inkstuose, žiaunose, raumenyse, kepenyse) eksperimentinėmis sąlygomis. Gauti rezultatai palyginami su ankstesniųjų metų tyrimų duomenimis, kur analogiškomis bandymo sąlygomis buvo tirtos penkios žuvų rūšys. Nustatyta, kad skirtingos žuvų rūšys skirtingai kaupia SM audiniuose. Lašišoje SM kaupėsi tokia mažėjančia seka: raumenys > žiaunos > inkstai > kepenys. Nustatyti Ni DLK viršijimai raumenyse ir žiaunose, o Pb leistinas kiekis viršytas net 3 audiniuose: raumenyse, žiaunose ir kepenyse. Parengto matematinio modeliavimo rezultatai parodė, kad SM kaupimasis lašišų audiniuose yra specifinis metalui ir audiniui, t. y., skirtingi audiniai parodė skirtingą gebėjimą kaupti SM. Darbo pabaigoje pateikiamos išvados ir rekomendacijos. Darbą sudaro 6 dalys: įvadas, literatūros apžvalga, metodikos aprašymas ir rezultatų analizė, matematinis modeliavimas, išvados ir rekomendacijos, literatūros sąrašas. Darbo apimtis – 90 p., 48 iliustr., 16 lent., 73 bibliografiniai šaltiniai. / The final master thesis discusses potential risks of heavy metals (hereinafter referred to as HM) to theLeopoldas biotic and abiotic environment, relevance of the experimental investigation, Raimondas Idzelis experience of Lithuania and foreign countries in this field. Aim of the work is to evaluate the accumulation patterns of heavy metal mixture (Cu, Zn, Ni, Cr, Pb, Cd) in the tissues of Atlantic salmon Salmo salar L. (kidneys, gills, muscles, liver) in experimental conditions. Results of the work are compared with previous studies, where five species were investigated in the same conditions. It was found that different species accumulate different amounts of HM in the tissues. Salmon accumulate HM in the following descending order: muscles > gills > kidneys > liver. Maximum permissible amount of Ni was exceeded in muscles and gills, while amount of Pb was exceeded even in the three tissues: muscles, gills and liver. Results of the mathematical model showed that the HM accumulation in salmon is specific for metal and for tissue, i.e. different tissues showed a different ability to accumulate HM. At the end of the work general conclusions and recommendations are presented. Structure: introduction, review of literary sources, description of methodology and analysis of results, mathematical modelling, conclusions and recommendations, references. Thesis consists of: 90 p., 48 pictures, 16 tables, 73 bibliographical entries.

Heavy metals can serve as a significant component of pollution in watersheds. In this study, ICP-MS analysis was used to determine the heavy metal content (Cd, Cr, Cu, Mn, Pb, and U) in water and sediment of three different Costa Rican watersheds: the Tarcoles River, the Terciopelo Creek, and the Cacao Creek. While the metal content of each the Terciopelo Creek and Cacao Creek was expected to be lower than that of the Tarcoles River, the results showed that this held true only for Cr and Pb. Elevated levels of the other four metals (Cd, Cu, Mn, and U) in the Terciopelo and Cacao Creeks are likely due to natural, lithogenic origin instead of anthropogenic input.

Pollution from industrial sources, such as leather tanneries, jewelry factories, car batteries, and construction refuse, has been linked to increased concentrations of toxic heavy metals in rivers in Costa Rica. This study focused on the concentrations of arsenic, cadmium, chromium, copper, nickel, and lead in sediment and water in Rio Baru, Costa Rica, which has not been previously studied. The concentrations in Rio Baru were compared to two controls and the Environmental Protection Agency toxicity limits to determine pollution levels. Inductively coupled plasma mass spectrometry was utilized to determine the concentrations of heavy metals in water and sediment samples from Rio Baru, Terciopelo, and Rio Tarcoles. Watershed analysis for Rio Baru was expected to reveal mostly agricultural sources of contaminants. Rio Baru was predicted to have levels of inorganic heavy metals between Rio Tarcoles and Terciopelo, with Tarcoles containing the highest levels. As, Cr, and Ni in Rio Baru were between unpolluted levels in Terciopelo and polluted levels in Rio Tarcoles, but Rio Baru had lower concentrations of Cu and Pb than both Rio Tarcoles and Terciopelo. Analysis of watersheds determined that Rio Baru’s watershed contained intermediate ratios of human development and agricultural sources of pollution. Further comparisons of watershed size with total dissolved sediment levels found a positive linear relationship, indicating a portion of differences in heavy metal concentrations were due to watershed sizes. Concentrations of heavy metals in Rio Baru’s water were below toxic limits for drinking water and placed Rio Baru within “good” sediment levels for As, Cd, Cr, Ni, and Pb. As geochemistry and proximity to industrial sources was not accounted for in methodology, further research would be necessary for determination of natural concentrations of heavy metals in Rio Baru.

With rapidly urbanizing societies, waste management needs attention. In 2008, EUs Waste Framework Directive (WFD) set new concepts, like reducing usage of natural materials. Thus, the interest for alternative materials increased. In Skellefteå, since the 1970’s, iron sand has often substituted natural gravel in road construction. But, today stricter regulations might forbid iron sand for further use. The issue is whether leachate from iron sand causes heavy metal pollution or not. This thesis tried to provide more knowledge into iron sand’s environmental impact. In order to investigate this, a sediment sample (&lt;53 cm deep) collected in Inre-viken, a lake 50m from a road with iron sand, were analyzed for Zn, Pb and Cu concentrations. Enrichment factor (EF), national benchmarks, and reference data were used to evaluate anthropogenic impact and age-determine the sediment. The results showed: (1) Inre-viken has elevated heavy metal levels compared to pre-industrial levels, with highest Cu (133 mg/kg) and Zn(204 mg/kg) concentrations found in the surface layer. (2) Zn and Cu showed an increase between 41-0 cm depth (1970-2015), but only Cu reaches high concentrations, while Zn and Pb range between low to very low concentrations. (3) The metal enrichment is low compared to the reference lake. The findings show that there are elevated levels in Inre-viken compared to pre-industrial levels. However, identifying the main source of pollution is difficult, because many pollution sources exist in the area. To determine if iron sand is the culprit, further studies are necessary.