Due to mining activities, the natural vegetation cover in Gatumba area was removed and replaced either by crops or bare wasteland with reduced available arable land. The main aim of the study was to assess the impact of the mining activities on the plant mineral uptake and the dynamics of the vegetation. The vegetation in this area under investigation was diversified and heterogeneous. Trace element concentrations in soils were similar to those in plant parts but some elements were highly concentrated in soils than in plants. According to the bioaccumulation factors of the analyzed trace elements in plant parts, two categories of plants were identified, and these are excluders and accumulators. No toxic levels of the evaluated trace elements were found in the analyzed plant samples. As a recommendation for the adaptation of plants to Gatumba mining environment, the most useful plant species for the revegetation/restitution of the technosols should be Sesbania sesban, Crotalaria dewildemaniana and Tithonia diversifolia subject to further experiments on trace elements bioaccumulation and organic matter production / Environmental Sciences / M.A. Science (Environmental Sciences)

The contamination of heavy metals in the environment is a looming concern worldwide. Egeria densa (Planch) (Submerged aquatic plant) from two ponds: Site A with co-ordinates (32º 48’22.04”S; 26°48’58.79” E) and Site B with co-ordinates (32°48’33.25”S; 26°48’33.25”S) in Alice (Eastern Cape) was evaluated for its ability to absorb heavy metals, phytochemical constituents, antimicrobial activity and ultra-structure using standard analytic procedures. Cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), and zinc (Zn) were measured in water, sediments and plant. The concentrations of these metal elements were determined with use of Inductively Coupled Plasma- Optical Emission Spectrometry (ICP-OES). In sediments, the heavy metals (mg/kg) decreased in the order of their average concentration as follows: Fe (40.320) > Zn (1.259) > Pb (0.564) > Mn (0.186) > Cu (0.037) in Pond 1 whereas in Pond 2 Fe (61.527) > Cd (0.999) > Mn (0.648) > Pb (0.586) > Zn (0.156) > Cu (0.045). The highest concentration of Fe was detected in both sites and Cu being the least. The concentrations of the metals in the plants sample (from Pond 1) were found in order of Mn > Pb > Cu > Fe whereas cadmium and zinc were not detected, while the concentration in Pond 2 decreases in order of Zn > Mn > Pb > Cd > Fe > Cu. In the water samples, concentrations of heavy metals (mg/L) decreased in the order of their average concentrations as follows: Pb (35.36) > Fe (3.07) > Mn (0.238) > Cu (0.104), both cadmium and zinc were below the limit of detection in Pond 1, whereas in Pond 2 the concentrations decreased as follows: Pb (13.033) >Fe (1.69) > Cu (0.270) > Mn (0.248) > Cd (0.004) and Zinc was not detected. Phytochemical analyses of the plant extracts revealed the presence of phenols, flavonoids, proanthocyanidin, flavonols, saponins, alkaloid and tannins in all the extracts (water, acetone and n-hexane). Both acetone and water extracts, showed high concentration of proanthocyanidin, while tannin was the lowest in acetone extract. Antimicrobial evaluation using, Gram positive (Staphylococcus aureus, Bacillus pumilus, Bacillus cereus, Streptococcus pyogenes, Enterococcus faecalis) and Gram negative (Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris and Serratia marcescens) bacteria showed negative results for all the strain, except Streptococcus pyogenes which was inhibited at MIC of 0.1 mg/ml. Scanning electron microscopy (SEM) of ultra-structure of Egeria densa, showed that certain bacteria attached to the leaf, However more work has to be done on E. densa to verify the mechanism by which it accumulates heavy metals. The study shows that E. densa has a potential of accumulating heavy metals especial Manganese in plant.

The Trinity River passes through the Dallas-Fort Worth metroplex receiving point and non-point source contaminant loadings. Lepomis spp. were collected at twelve sampling locations in the Trinity River in August 1987 and September 1988 and analyzed for organochlorine pesticides and heavy metals. Results from the study were compared to existing U.S. FDA action and tolerance levels, LC50s, and historical data. Various longitudinal trends and some concentration patterns were observed. Continual study of pesticide and metal body burdens in fish allow testing for trends, and thereby, lead to a better understanding of the distribution of contaminants in the Trinity River.

Pollution of soil by trace metals has become one of the biggest global environmental challenges resulting from anthropogenic activities, therefore, restoration of metal contaminated sites needs due attention. The use of phytoremediation technologies as nature-based solution to pollution, could support successful implementation of green economic development strategies; with economically affordable and environmentally friendly benefits. The present investigation employed an exploratory study on the phytoremediation potentials of three selected native plants; Phytolacca dodecandra (L’Herit), Adhatoda schimperiana (Hochst) and Solanum incanum L, dominating areas close to heavy metal contamination sources; in metropolitan centers of Addis Ababa. In this work, concentration of six heavy metals of interest chromium (Cr), lead (Pb), cadmium (Cd), nickel (Ni) copper (Cu) and zinc (Zn) were examined in soil and in different tissues (leaves, stems and roots) of selected plants (both seedlings and mature plants), in dry and rainy seasons using atomic absorption spectrophotometer. Efficiency of phytoremediation is discussed based on calculated values of Bio-concentration Factor (BCF), Translocation Factors (TF) and Bioaccumulation Coefficient (BAC). Phytolacca dodecandra showed BCF, TF and BAC > 1 for Zn, Pb, Ni, Cu and Cd Adhatoda schimperiana gave BCF, TF and BAC > 1 for Zn, Cu, Ni and Cr; likewise, BCF, BAC and TF values of > 1 were noted in Solanum incanum for Zn, Cu, Pb and Ni. Based on these scenarios, the three plants could be utilized for phytoextraction of contaminated soil. Conversely, BCF and BAC for Cr levels in tissues of Phytolacca dodecandra were all < 1, which indicates unsuitability for phytoremediation of Cr in contaminated soils. Besides, Adhatoda schimperiana retained Pb and Cd in their roots showing root BCF > 1, while BAC and TF < 1, which highlights its suitability for phytostabilization. Moreover, BCF, TF and BAC values of < 1 noted for Cr and Cd in Solanum incanum reveal that Solanum incanum may not be a good candidate for remediation of Cr and Cd contaminated environments. In conclusion, results from this study revealed that the selected plants can accumulate substantial amounts of the above trace metals in their tissues and can serve as prospective phytoremediators of most of these metals. Phytoextraction and phytostabilization were the main mechanisms of remediation in this study. / Environmental Sciences / Ph. D. (Environmental Sciences)

Indiana University-Purdue University Indianapolis (IUPUI) / The focus of this study was to document phosphorus (P) and metal cycling in the Eagle Creek Reservoir (ECR), located in Indianapolis, central Indiana. Eagle Creek Reservoir serves the drinking water needs of over 80,000 residents. Within the last several years, algal blooms have created stress to the local treatment facility. The objective of this study was to examine how P cycling from oxygen deprived bottom sediments affects the algal bloom productivity. As such, cores were retrieved from different water depths (7 and 16 m) from portions of the reservoir where high surficial concentrations of organic matter and P were found to occur. The dried samples were analyzed for P, sulfur, iron, barium, cadmium, copper, lead, and zinc, using a strong acid digestion technique. The samples were also analyzed for iron-bound P (Fe-P), authigenic P (A-P), detrital P (D-P), organic P (O-P), reducible iron, and reducible manganese, using a sequential extraction technique. The results from the study showed moisture contents ranged from 16 to 76% and organic matter contents ranged from 2 to 12 wt%. The dry bulk densities were determined to be between 0.27 and 1.68 g cm3. The average percentages of P in ECS-1, as determined by the sequential extraction method, were as follows: Fe-P, 66.2%; A-P, 8.1%; D-P, 4.8%; and O-P, 20.9%. The average percentages of P in ECS-3, as determined by the sequential extraction method, were as follows: Fe-P, 77.0%; A-P, 6.5%; D-P, 2.8%; and O-P, 16.7%. To determine relationships between elements, correlations were calculated. When looking as the relationships between the P fractions and reducible Fe, differences were observed between the different water depths. There was less correlation between reducible Fe and Fe-P, and between O-P and Fe-P, in ECS-3, indicating that Fe-P is more efficiently dissolved and recycled in the deep portion of ECR. The study shows that the Fe-P flux, caused by the iron redox cycle, is persistent and will continue to influence algal bloom productivity in the deeper portions of ECR.

M.Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / In the present study, the removal of Ca2+ and Mg2+ from cooling tower water using Amberlite IR120 and Amberjet 1200 was studied by the application of one factor at a time method (OFAT) and response surface modelling (RSM). The effect of operational parameters such as contact time (min), pH, dosage (mL), concentration (mg/L) and temperature (K) were investigated using central composite design. The regeneration of the Amberlite IR120 and Amberjet were also studied. The purpose of the study was to apply OFAT and RSM to investigate and optimize the ion exchange operating parameters. Furthermore, the second-order empirical model that was developed, using the analysis of variance (ANOVA), presented a sufficient correlation to the ion exchange experimental data. The optimal ion exchange operating conditions for Amberlite IR120 and Amberjet 1200 were found to be: contact time was 120 min, dosage of 150mL, initial pH level of 2, concentration of 400mg/L and temperature of 343K. Regeneration of Amberlite IR120 and Amberjet 1200 using 0.5 M NaCl stripping solution initially showed an increase in % Ca2+ and Mg2+ removal, then a decrease in subsequent cycles. The correlation coefficients (R2) of Langmuir, Freudlich and Tempkin isotherms were found to range from 0.92 to 1 and this suggest that experimental data best described the models. However correlation coefficients (R2) for Dubinin–Radushkevich (D-R) model were found to range between 0.5 to 0.8 and this means that experimental data does not fit the model. Thermodynamic functions such as entropy (Δ𝑆𝑜), enthalpy (Δ𝐻𝑜) and change of free energy (Δ𝐺𝑜) were obtained from the gradient and intercepts of straight line graphs. The positive values of ΔG° were found meaning that the adsorption is not spontaneous and positive values of ΔH° were found meaning the endothermic type of adsorption which indicate the chances of physical adsorption.The correlation coefficient (R2) values of pseudo-first-order, pseudo-second-order and intraparticle models were found to range from 0.89 to 1 on both metals as shown in table 4.4. This observation clearly indicates that pseudo-first-order, pseudo-second-order and intraparticle diffusion models best describe the experimental data in the removal Ca2+ and Mg2+ from cooling tower water.

Anthropogenic activities generate waste products that pollute the environment with bacteria and heavy metals. This research assessed pollution of the Kahwa River, Bukavu Town, DRC with cadmium and lead (HMs) and bacterial enteropathogens. A survey of businesses, households and healthcare facilities showed general use of the river to remove effluent and waste. Indicator organisms were cultured at over 200 cfu/100 ml showing faecal contamination of the river water. Antibiotic resistance was shown by enteropathogenic Vibrio cholerae and Salmonella typhi to ampicillin and cotrimoxazole with some sensitivity shown to ciprofloxacin. River water contained HMs at around 40 times the World Health Organisation limit for drinking water. The bacteria, particularly from river sediment, tolerated HMs up to a concentration of 1.5 mg/ml. The presence in the Kahwa River of antibiotic-resistant pathogens showing tolerance to HMs has serious public health implications / Environmental Management / M.Sc. (Environmental management)

Thesis (PhD) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT:Heavy metals are persistent environmental contaminants whose sources of inputs into the environment are both natural and anthropogenic. The levels of heavy metals (cadmium, copper, nickel, lead and zinc) in the False Bay intertidal zone were measured in the water, sediments and invertebrate species between August 2000 and August 2001. The results of the water and sediment analyses revealed that most pollution was associated with the northern shore of the bay between Strand and Muizenberg, where the most populated and industrial catchments occur. Significant spatial variations occurred, indicating the presence of localised contamination, while seasonal variations may be related to changes in precipitation and runoff at different times of the year. The concentrations of cadmium, nickel and lead were occasionally higher than the levels recommended by the South African Water Quality Standards. The possible sources of pollution at the different sites are also discussed. The concentrations of the five metals in the different invertebrate species (Oxystele tigrina, 0. sinensis, Choromytilus meridionalis, Patella oculus, Patiriella exigua and Tetraclita serrata) also revealed significant seasonal and spatial variations, with both the soft tissues and shells accumulating heavy metals. The barnacle T serrata from Rooiels had the highest cadmium concentration (70.67 J.lg/g dry weight), which may be related to historic pollution inputs from the military activities which took place at a weapons testing site at this site between 1987 and 1994, although no evidence was found to confirm this. The periwinkle 0. tigrina from Strand had the highest copper concentration (70.25 J.lg/g) while the limpet P. oculus from the same site had the highest nickel concentration (35.75 J.lg/g). The shells of the mussel C. meridionalis from Muizenberg had the highest concentration of lead (25.75 J.lg/g). Since cadmium occurs as a constituent of phosphate fertilisers used widely in the False Bay catchments, the effects of cadmium exposure on the different species were investigated during 14-day laboratory exposures to 200 and 400 J.lg/LCdCh. The results revealed a general pattern of tissue metal increase in the exposed organisms, followed by slight reductions after decontamination in clean seawater. The viscera and kidneys of C. meridionalis accumulated most of the dissolved cadmium. The shells of the mussels also accumulated cadmium, indicating the possible use of shells as a detoxification matrix. / AFRIKAANSE OPSOMMING:Swaarmetale is persisterende omgewingskontaminante waarvan die insetbronne beide natuurlik of van menslike oorsprong kan wees. Die kontaminasievlakke van swaarmetale (kadmium, koper, nikkel, lood en sink) in die Valsbaai tussengetysone is in die water, sedimente en invertebraatspesies bepaal vanaf Augustus 2000 tot Augustus 2001. Voorlopige resultate van die water- en sedimentontledings het getoon dat die meeste besoedeling by die noordelikke oewer van die baai voorgekom het tussen Strand and Muizenberg, waar die mees digbewoonde en ge-industrialiseerde opvangsgebiede is. Betekenisvolle ruimtelike en seisoenale variasie het in die konsentrasies van swaarmetale voorgekom, met die ruimtelike variasie wat moontlik gelokaliseerde kontaminasie aandui terwyl die seisoenale variasies weer verband mag hou met veranderings in die neerslag en afloop gedurende verskillende tye van die jaar. Die konsentrasie van kadmium, nikkel en lood was somtyds hoer as die vlakke wat deur die Suid-Afrikaanse Waterkwaliteitsstandaarde voorgestel word. Die moontlike bronne van besoedeling in die verskillende areas is ook in bespreking genoem. Die konsentrasies van die vyf swaametale in die verskillende invertebraatspesies (Oxystele tigrina, 0. sinensis, Choromytilus meridionalis, Patella oculus, Patiriella exigua and Tetraclita serrata) het ook seisoenale en ruimtelike variasies vertoon, die swaarmetale het in die sagte weefsel en skulpe van die invertebrate geakkumuleer. Die hoogste gemiddelde konsentrasie van kadmium (70.67 ).lg/g droe massa) is in die heel-liggaam monsters van die eendemossel T serrata gemeet wat by Rooiels versamel is. Die vlakke mag verband hou met die oprigting en aktiwiteite van die wapentoetsingsaanleg in die opvanggebied van die Rooiels lokaliteit tussen 1987 en 1994, maar geen bewyse daarvan is gevind nie. Die tolletjie, 0. tigrina wat in die 10kaliteit by Strand versamel is het die hoogste gemiddelde konsentrasie koper gehad 70.25 pig droe massa), terwyl die klipmossel P. oculus by dieselfde versamelpunt die hoogste konsentrasie nikkel (35.75 ).lg/gdroe massa) gehad het. Eksperimentele studies is ook uitgevoer op vier invertebraat spesies wat vir 14 dae in akwaria blootgestel is aan see-water met 200 en 400 p,g/L CdCh, en daama gedekontamineer is in skoon seewater. / The NRF and the University of Stellenbosch, for funding this study.

Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 113-120). / Abstract --- p.i / Acknowledgement --- p.iii / Table of Contents --- p.iv / List of Tables --- p.viii / List of Figures --- p.xii / Chapter CHAPTER 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Previous Heavy Metal Studies of Hong Kong Marine Waters and Sediments --- p.4 / Chapter 1.2 --- Speciation of Metals in Aquatic Environment --- p.6 / Chapter 1.2.1 --- Speciation of Metals in Water --- p.7 / Chapter 1.2.2 --- Speciation of Metals in Bottom Sediments --- p.7 / Chapter 1.3 --- AVS in Marine Sediments --- p.10 / Chapter 1.3.1 --- Formation of AVS --- p.10 / Chapter 1.3.2 --- Seasonal and Spatial Variation of AVS --- p.11 / Chapter 1.3.3 --- AVS as Mediator of Metal Toxicity --- p.13 / Chapter 1.3.4 --- Chemical Basis for AVS Sediment Normalization --- p.15 / Chapter 1.3.5 --- Analysis of Pore Water Metals --- p.17 / Chapter 1.4 --- Significance of the Research --- p.18 / Chapter 1.4.1 --- Importance of Metal Bioavailability Study in Hong Kong --- p.18 / Chapter 1.4.2 --- Importance of AVS Study in Hong Kong --- p.19 / Chapter 1.4.3 --- Approach of the Present Study --- p.21 / Chapter 1.5 --- Organization of the Thesis --- p.22 / Chapter CHAPTER 2. --- METHODOLOGY --- p.23 / Chapter 2.1 --- Study Area --- p.24 / Chapter 2.2 --- Sampling Strategy --- p.25 / Chapter 2.2.1 --- Sampling Locations --- p.25 / Chapter 2.2.2 --- Sampling Dates --- p.28 / Chapter 2.2.3 --- Sample Collection and Handling --- p.28 / Chapter 2.3 --- Sample Analysis --- p.32 / Chapter 2.3.1 --- Sediment Analysis --- p.32 / Chapter 2.3.2 --- Pore Water and Overlying Water Analysis --- p.34 / Chapter 2.3.3 --- Limitations --- p.36 / Chapter 2.4 --- Statistical Analysis --- p.39 / Chapter CHAPTER 3. --- METALS IN WATER AND BOTTOM SEDIMENTS --- p.40 / Chapter 3.1 --- Metals in the Water --- p.40 / Chapter 3.1.1 --- Variation of Metal Concentrations --- p.41 / Chapter 3.1.2 --- Metal Pollution Level of the Overlying Water --- p.42 / Chapter 3.2 --- Metals in Bottom Sediments --- p.44 / Chapter 3.2.1 --- Spatial Distribution Pattern of Heavy Metals --- p.44 / Chapter 3.2.2 --- Temporal Variation of Metal Content in the Bottom Sediments --- p.48 / Chapter 3.2.3 --- Metal Pollution Level of the Bottom Sediments --- p.49 / Chapter 3.3 --- Conclusion --- p.50 / Chapter CHAPTER 4. --- SPECIATION OF METALS IN THE OVERLYING WATER AND BOTTOM SEDIMENTS --- p.51 / Chapter 4.1 --- Speciation of Metals in the Overlying Water --- p.51 / Chapter 4.1.1 --- Concentration of Labile Metals in the Overlying Water --- p.52 / Chapter 4.1.2 --- Seasonal and Spatial Variation in the Concentration of Labile Metals in the Overlying Water --- p.54 / Chapter 4.1.3 --- Percentage of Labile Fraction in Total Metals --- p.55 / Chapter 4.2 --- Speciation of Metals in the Bottom Sediments --- p.59 / Chapter 4.2.1 --- Proportion of Various Metal Species in the Sediments --- p.60 / Chapter 4.2.2 --- Variation of the Overlying Water Properties --- p.63 / Chapter 4.2.2.1 --- Chemical Properties of the Water in the Study Area --- p.63 / Chapter 4.2.2.2 --- Seasonal Variation of Water Properties --- p.67 / Chapter 4.2.2.3 --- Stratification of the Water Column --- p.69 / Chapter 4.2.3 --- Implication of the Changes of Water Quality on Metal Remobilization --- p.73 / Chapter CHAPTER 5. --- VARIATION OF AVS AND ITS ROLE IN METAL TOXICITY MEDIATION --- p.77 / Chapter 5.1 --- Variation of AVS in the Study Area --- p.78 / Chapter 5.1.1 --- Spatial Variation of AVS --- p.78 / Chapter 5.1.2 --- Seasonal Variation of AVS --- p.81 / Chapter 5.1.3 --- Vertical Variation of AVS --- p.85 / Chapter 5.1.4 --- Effects of AVS Variation on Metal Bioavailability --- p.88 / Chapter 5.2 --- Role of AVS in Metal Toxicity Mediation --- p.91 / Chapter 5.2.1 --- SEM/AVS Molar Ratio --- p.91 / Chapter 5.2.2 --- Fraction of SEM in Total Metals of the Sediments --- p.94 / Chapter 5.2.3 --- Labile Metals in Pore Water --- p.96 / Chapter 5.2.4 --- Dissolved Sulfides in the Pore Water and Overlying Water --- p.99 / Chapter 5.3 --- Conclusion --- p.100 / Chapter CHAPTER 6. --- CONCLUSION --- p.102 / Chapter 6.1 --- Introduction --- p.102 / Chapter 6.2 --- Major Findings --- p.103 / Chapter 6.3 --- Practical Implication of the Findings --- p.108 / Chapter 6.4 --- Suggestion for Further Studies --- p.110 / Bibliography --- p.113 / Appendix A. AVS Extraction and Detection Method --- p.121 / Appendix B. Sequential Extraction Method for Metals Speciation Analysis --- p.123 / Appendix C. Instrument List for the Experiments --- p.125 / Appendix D. Monthly Total Rainfall and Mean Temperature of1995 --- p.127 / Appendix E. Analytical Results of the Overlying Water --- p.128 / Appendix F. Analytical Results of the Bottom Sediments --- p.132 / Appendix G. Analytical Results of the Pore Water --- p.136 / Appendix H. Concentration (μg/g) and Fraction (%) of Pbin Sediments --- p.140 / Appendix I. Concentration (μg/g) and Fraction (%) of Cuin Sediments --- p.142 / Appendix J. Concentration (μg/g) and Fraction (%) of Cdin Sediments --- p.144 / Appendix K. Concentration (μg/g) and Fraction (%) of Znin Sediments --- p.146 / Appendix L. Concentration (μg/g) and Fraction (%) of Niin Sediments --- p.148 / Appendix M. Fraction of Different Speciations of Metals in the Sediments --- p.150 / Appendix N. Vertical Profile of Dissolved Oxygen in the Overlying Water --- p.155 / Appendix O. Vertical Profile of Salinity in the Overlying Water --- p.159 / Appendix P. Vertical Profile of Temperature in the Overlying Water --- p.163 / Appendix Q. Vertical Profile of pH in the Overlying Water --- p.167

Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation. / Environmental Sciences / M. Sc. (Environmental Science)