Vanessa Angela Jackson

Bio: Vanessa Angela Jackson is an academic researcher from Cape Peninsula University of Technology. The author has contributed to research in topics: Water quality & Freundlich equation. The author has an hindex of 12, co-authored 19 publications receiving 482 citations.

Polycyclic Aromatic Hydrocarbons: A Critical Review of Environmental Occurrence and Bioremediation.

Abstract: The degree of polycyclic aromatic hydrocarbon contamination of environmental matrices has increased over the last several years due to increase in industrial activities Interest has surrounded the occurrence and distribution of polycyclic aromatic hydrocarbons for many decades because they pose a serious threat to the health of humans and ecosystems The importance of the need for sustainable abatement strategies to alleviate contamination therefore cannot be overemphasised, as daily human activities continue to create pollution from polycyclic aromatic hydrocarbons and impact the natural environment Globally, attempts have been made to design treatment schemes for the remediation and restoration of contaminated sites Several techniques and technologies have been proposed and tested over time, the majority of which have significant limitations This has necessitated research into environmentally friendly and cost-effective clean-up techniques Bioremediation is an appealing option that has been extensively researched and adopted as it has been proven to be relatively cost-effective, environmentally friendly and is publicly accepted In this review, the physicochemical properties of some priority polycyclic aromatic hydrocarbons, as well as the pathways and mechanisms through which they enter the soil, river systems, drinking water, groundwater and food are succinctly examined Their effects on human health, other living organisms, the aquatic ecosystem, as well as soil microbiota are also elucidated The persistence and bioavailability of polycyclic aromatic hydrocarbons are discussed as well, as they are important factors that influence the rate, efficiency and overall success of remediation Bioremediation (aerobic and anaerobic), use of biosurfactants and bioreactors, as well as the roles of biofilms in the biological treatment of polycyclic aromatic hydrocarbons are also explored

Comparison of microbial contamination at various sites along the Plankenburg: and Diep Rivers, Western Cape , South Africa

Abstract: This study was aimed at investigating and comparing the microbial contamination levels at various sites in the Plankenburg and Diep Rivers in the Western Cape, South Africa. Sampling of sites along the Plankenburg River started in June 2004 and continued for a period of 1 year until June 2005. Sampling of the Diep River sites started in March 2005 and continued for a period of 9 months until November 2005. Faecal coliform (FC) and E. coli (EC) counts were determined by means of the most probable number (MPN) technique, the number of culturable cells were determined using the heterotrophic plate count (HPC) technique and total microbial counts were evaluated by Flow cytometric analysis (FCM). The highest microbial counts for the Plankenburg River were observed at Site B where the highest MPN, FC, E. coli and total FCM counts of 9.2 x 106 (Week 14), 3.5 x 106 (Week 39) and 3.5 x 106 micro-organisms/100 m. (Week 39) and 2.1 x 108 micro-organisms/m. (Weeks 1 and 39) respectively, were recorded. The highest HPC recorded for the Plankenburg River was 7.9 x 106 micro-organisms/100 m. (Week 44, Site A). Site B is situated close to an informal settlement where waste effluents from stormwater drainage pipes enter the river system. In addition, other possible contamination sources included agricultural (Site A) and industrial (Site C) areas bordering the Plankenburg River. The highest total MPN, FC and E. coli counts in the Diep River were 5.4 x 106 (Week 23) and 1.6 x 106 micro-organisms/100 m. (FC and E. coli, respectively (both in Week 23)), recorded at Site B. The highest HPC and total FCM counts of 1.7 x 107 micro-organisms/100 m. (Week 14) and 2.5 x 109 micro-organisms/m. (Week 23), respectively, were also recorded at Site B. This site was identified as the most contaminated site along the Diep River and served as an accumulation point for waste effluents from the residential and industrial areas, which included paint and machine manufacturers. Other sources situated along the Diep River included storage and maintenance facilities for steel containers, a wastewater treatment plant and an oil-refinery. Most of the bacterial counts obtained for the Plankenburg and Diep Rivers exceeded the accepted maximum limit for river water for most of the sampling period.

Investigation into the metal contamination of the Plankenburg and Diep Rivers, Western Cape

Abstract: Metal contamination in the Plankenburg and Diep Rivers (Western Cape) was investigated over a 12 and 9 month period, respectively. Aluminium (Al), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn) concentrations were determined using the nitric acid digestion method and analysed by inductively coupled plasma atomic emission spectrometry (ICP-AES). For both rivers the Al and Fe concentrations were higher than that for all the other metals analysed for in sediment and water samples. The highest concentrations recorded in the Plankenburg River were 13.6 mgE.-1 (water . Week 18, Site B) and 15 018 mgEkg-1 (sediment . Week 1, Site C) for Al, and 48 mgE.-1 (water . Week 43, Site A) and 14 363.8 mgEkg-1 (sediment . Week 1, Site A) for Fe. The highest concentrations recorded in the Diep River were 4 mgE.-1 (water . Week 1, Site A) and 19 179 mgEkg-1 (sediment . Week 1, Site C) for Al, and 513 mgE.-1 (water . Week 27, Site A) and 106 379.5 mgEkg-1 (sediment . Week 9, Site C) for Fe. For most of the metals analysed the concentrations were higher than the recommended water quality guidelines as stipulated by the Department of Water Affairs and Forestry, the Canadian Council for the Ministers of the Environment and the accepted eworld averagef. Point sources of pollution could not be conclusively identified, but runoff from both industrial and residential areas could have contributed to the increased concentrations. Metal concentrations should be routinely monitored and the guidelines should be updated and revised based on the current state of the rivers and pollution sources.

Preparation and characterisation of activated carbon from Vitis vinifera leaf litter and its adsorption performance for aqueous phenanthrene

Abstract: The adsorption of phenanthrene onto activated carbons produced from Vitisvinifera leaf litter (a waste plant biomass) was investigated in this study. Zinc chloride (ZnCl2) and phosphoric acid (H3PO4) were utilised as activating agents in producing the activated carbons. The characterisation of the activated carbons was achieved with Fourier transform infrared spectroscopy (for surface functional groups), scanning electron microscopy (for surface morphology) and Brunauer–Emmett–Teller (BET) (for surface area determination). The adsorption of phenanthrene onto the activated carbons was optimised in terms of solution pH, adsorbent dosage, initial concentration of adsorbate solution and contact time. Experimental results showed that H3PO4 modified activated carbon gave better yield (up to 58.40%) relative to ZnCl2 modified activated carbon (only up to 47.08%). Meanwhile, surface characterisation showed that ZnCl2 modification resulted in higher BET surface area (up to 616.60 m2/g) and total pore volume (up to 0.289 cm3/g) relative to BET surface area of up to 295.49 m2/g and total pore volume of up to 0.185 cm3/g obtained from H3PO4 modified activated carbons. Adsorption equilibrium data fitted well into Freundlich isotherm model relative to other applied isotherm models, with maximum Kf value of 1.27 for ZnCl2 modified activated carbon and 1.16 Kf value for H3PO4 modified activated carbon. The maximum adsorption capacity for ZnCl2 and H3PO4 activated carbons for the removal of phenanthrene were 94.12 and 89.13 mg/g, respectively. Kinetic studies revealed that dynamic equilibrium was reached at 80 min contact time. Experimental data fitted best into the Elovich kinetic model relative to other kinetic models, based on the correlation coefficient (R2) values obtained from kinetic studies. Chemisorption was deduced as a major phenanthrene removal pathway from aqueous solution and the physicochemical characteristics of the adsorbents have major influence on phenanthrene removal efficiencies.

Polycyclic Aromatic Hydrocarbons

Abstract: Polycyclic Hydrocarbons Vol. 1. Pp. xxvi + 487. 126S. (With a chapter on carcinogenesis by Regina Schoental.) Vol. 2. Pp. lvii + 487. 140s. By E. Clar. (London and New York: Academic Press; Berlin: Springer-Verlag, 1964.)

Recent Advances in Microbial Metal Bioaccumulation

Abstract: Removal of hazardous metals through biological means has received considerable attention in the last few decades. Nevertheless, only a fraction of these studies employed growing microbial cells that harbor multiple mechanisms of metal sequestration and thus may hold greater metal uptake capacities. The authors summarize the studies concerning response of growing cells to metals toxicity in terms of growth rate, biomass production, and morphological/structural adaptations along with latest reports involving genomics and proteomics approach. The studies indicate bright potential of metal resistant strains or strains with hormesis phenomenon for field application. In the second part of the review they focuses on the effect of nutritional conditions and process parameters on metal removal capacities and the performance in simultaneous removal of multiple pollutants. Reports demonstrating effective treatment of actual industrial effluents using growing cells have been summarized. With ample evidence available ...

Assessment of Trace Metals Contamination of Surface Water and Sediment: A Case Study of Mvudi River, South Africa

Abstract: Trace metals contamination of rivers and sediments remains a global threat to biodiversity and humans. This study was carried out to assess the variation pattern in trace metals contamination in Mvudi River water and sediments for the period of January–June 2014. Metal concentrations were analyzed using an inductively-coupled plasma optical emission spectrometer after nitric acid digestion. A compliance study for the water samples was performed using the guidelines of the Department of Water Affairs and Forestry (DWAF) of South Africa and the World Health Organization (WHO). The National Oceanic and Atmospheric Administration (NOAA) sediment quality guidelines for marine and estuarine sediments and the Canadian Council of Ministers of the Environment sediment guidelines (CCME) for freshwater sediments were used to determine the possible toxic effects of the metals on aquatic organisms. pH (7.2–7.7) and conductivity (10.5–16.1 mS/m) values complied with DWAF and WHO standards for domestic water use. Turbidity values in nephelometric turbidity units (NTU) were in the range of 1.9–429 and exceeded the guideline values. The monthly average levels of trace metals in the water and sediments of Mvudi River were in the range of: Al (1.01–9.644 mg/L and 4296–5557 mg/kg), Cd (0.0003–0.002 mg/L and from below the detection limit to 2.19 mg/kg), Cr (0.015–0.357 mg/L and 44.23–149.52 mg/kg), Cu (0.024–0.185 mg/L and 13.22–1027 mg/kg), Fe (0.702–2.645 mg/L and 3840–6982 mg/kg), Mn (0.081–0.521 mg/L and 279–1638 mg/kg), Pb (0.002–0.042 mg/L and 1.775-4.157 mg/kg) and Zn (0.031–0.261 mg/L and 14.481–39.88 mg/kg). The average concentrations of Al, Cr, Fe, Mn and Pb in the water samples exceeded the recommended guidelines of DWAF and WHO for domestic water use. High concentrations of Al and Fe were determined in the sediment samples. Generally, the concentrations of Cd, Cr and Cu in the sediments exceeded the corresponding effect range low (ERL) values in the sediment quality guidelines and could have adverse effects on aquatic organisms in Mvudi River.