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Lead, cadmium, zinc and copper concentrations were determined in bone, kidney and liver samples of mink (Mustela vison) trapped during 1981-83 in Virginia. Ages were determined to obtain population information. The literature on delayed implantation in mink was reviewed. Lead and cadmium concentrations in all tissues were generally low. Approximately 50% of bone samples and less than 10% of kidney and liver samples had detectable lead concentrations (>1 ug/g). Mean detectable bone lead concentrations (ug/g d.w.) were 2.90 and 2.48 during 1981-82 and 1982-83, respectively. Cadmium was detected (>0.1 ug/g) in all kidney samples. Mean kidney cadmium concentrations (ug/g d.w.) were 1.21 and 1.02 in 1981-82 and 1982-3, respectively. Lead and cadmium accumulated (p < .05) with age. Cadmium concentrations were higher (p < .05) in Southwest Virginia than in other areas. Mean zinc and copper concentrations were comparable to those in other mammals and do not appear to pose any toxic threat. Bacula, femurs, radiographs of canine teeth, and cementum annuli of second premolars were examined for aging purposes. The first 3 methods were confusing in many samples, apparently due to transition from juvenile to adult characteristics. A systematic method for aging winter-trapped mink was developed. Approximately 60% of mink trapped during both seasons were juveniles. The age-specific survival rate was very low (0.292) for juveniles, increased for 2 year-olds (0.719) and then declined quickly for subsequent years. The male to female ratio was very high (approximately 3:1) probably reflecting trapping bias. / Master of Science

This study was designed to investigate potential environmental effects of stream contamination resulting from a spill by Culpeper Wood Preservers, Culpeper, Virginia. The objective was to determine the concentrations of arsenic, chromium, and copper in the sediments of streams affected by the spill and by runoff from a landfill site. The variations in metal concentrations were studied as functions of depth within the stream bed, as functions of distance from the source of contamination, and with passage of time. Sediments from several locations along the streams were extracted with Hcl and analyzed to determine metals concentrations. A microcosm experiment was conducted also to determine whether metals in the sediments would be released to the water under anaerobic conditions. Concentrations as high as 16 ppm for arsenic and 114 ppm for chromium were found in the sediment downstream of Culpeper Wood Preservers. Copper levels were not significantly higher than natural levels. Little difference was found between concentrations of shallow and deeper sediments. Downstream from the landfill site, metal concentrations were not significantly greater than natural concentrations for most sampling locations. In the microcosm experiments, chromium and copper were not released from the sediment. Arsenic concentrations in the water initially increased, then declined. The major conclusion of the study was that the metals appeared to be bound in the sediment and, except for potential releases of arsenic in anaerobic pools during low flow conditions, they should remain in the bound state. / M.S.

No periodic patterns of temporal variations in the metal levels in U. lactuca or in other seven common seaweed species from Ping Chau were observed from 1999 to 2000. Cu levels were generally negatively correlated with other metals in seaweeds. / Spore production of U. lactuca was significantly reduced by the elevation of copper and nickel levels in the seaweed samples. The reproductive frequency of U. lactuca generally increased from January and February to the maxima in March and April. Copper, nickel and nitrate levels showed significant negative correlations with these reproductive frequencies. / The metal abundance in 24 seaweeds showed the following trend: Fe > Mn, Zn > Cu, Ni, Pb, Cr > Cd. U. lactuca and Padina australis showed relatively high mean and large range values of metal levels. Principal component analysis summarized the overall metal loadings in these 24 seaweed species. The variations in Pb, Fe, Mn and Cr levels in the seaweeds varied greatly. / There were significant spatial variations of different metal levels in the extensive study of U. lactuca from various intertidal waters in Hong Kong from 1999 to 2001. In general, metal levels in U. lactuca increased from January to March or April and then dropped in the following months. No periodic patterns or temporal trends of variations of metal levels in U. lactuca were found. Different metal levels in U. lactuca were comparatively lower than those in other studies in other countries and in past studies in Hong Kong. / There were significantly differences in various metal levels in different structures of Sargassum hemiphyllum, generally decreased in the following order: receptacles > vesicles > leaves > branches. / This thesis research involves biomonitoring levels of eight metal species (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in seaweed and the effects of these metals on the reproduction of Ulva lactuca. The study started from September 1999 and ended in June 2001, covering 40 intertidal sites in Hong Kong and 24 seaweed species. Environmental data on pH, salinity and nutrient levels (ammonia, nitrite, nitrate and phosphate) in seawater from these sites were also monitored. / Wong Tai Choi Richard. / "April 2005." / Advisers: P. C. K. Cheung; P. O. Ang, Jr. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0159. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 371-401). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Thesis (MSc) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Shrews are excellent bioindicators of environmental heavy metal pollution. This is due to their diets and the high rate of consumption at which these small mammals consume their prey. Shrews feed mostly on earthworms, and earthworms accumulate high levels of heavy metals in their bodies. Biomarkers measure responses to environmental pollution in the bodies of exposed organisms. Cellular biomarkers give an indication of responses to pollutants at levels of pollutant exposure that are not yet lethal to the organism. This study was prompted by concern that the number of shrews in the Stellenbosch region was declining. For the present study, shrews (Myosorex varius and Crocidura jlavescens) from the Stellenbosch region were sampled. The levels of Cd and Pb in their bodies were analysed in order to ascertain whether or not these two heavy metals, which occur in the environment as a result of various anthropogenic activities, are present in the food chain of the shrews. In the laboratory, shrews were fed live control and metal exposed earthworms from laboratory cultures. The earthworms had been exposed to either Cd or Pb in these cultures over a number of generations. This was performed to determine whether the presence of the metals in the body of the shrews, had resulted from metal accumulation from the earthworms which were fed to the shrews. Cellular biomarkers were used to determine the cellular response to the metals and membrane integrity and DNA integrity were investigated. This was done by exposing the cells of the shrews and ofBALB/c mice to metal salt solutions of Cd, Pb and Zn in vitro. Membrane integrity was tested by cell leaching techniques viz. the LDH assay and the trypan blue assay. DNA integrity was determined by using the comet assay as a biomarker of exposure. The results of the study show that the shrews in the immediate Stellenbosch region are exposed to lower levels of Cd and even lower levels of Pb than shrews from a site 16km out of the town of Stellenbosch. The cellular responses induced by metal exposure of laboratory mice show that the metals are indeed cytotoxic and genotoxic to the cells of small mammals. Cd and Pb were found to be more cytotoxic than Zn, while Zn was more genotoxic than either CqorPb. / AFRIKAANSE OPSOMMING: Skeerbekke is uitstekende bioindikatore van swaarmetaalbesoedeling in die omgewing. Dit is as gevolg van hul dieët en die hoë koers waarteen hierdie klein soogdiere hul prooi verorber. Skeerbekke voed meestalop erdwurms, en erdwurms akkumuleer hoë vlakke van swaarmetale in hul liggaam. Biomerkers meet response as gevolg van omgewingsbesoedeling in die liggame van blootgestelde organismes. Sellulêre biomerkers gee 'n aanduiding van response op besoedelingstowwe by vlakke wat nog nie dodelik is vir die organisme nie. Die studie is aangespoor deur die bekommernis dat die getal van skeerbekkies in Stellenbosch besig is om te daal. In die studie is skeerbekke (Myosorex varius en Crocidura flavescens) van die Stellenbosch omgewing gevang en die vlakke van Cd en Pb in hul liggame gemeet om vas te stelof die twee swaarmetale, wat in die omgewing beland as gevolg van verskeie antropogeniese aktiwiteite, teenwoordig is in die voedselketting van die skeerbekke. Die skeerbekke is in die laboratorium met lewende kontrole en metaalblootgestelde erdwurms uit kulture in die laboratorium gevoer. Die erdwurms is aan Cd en Pb oor baie generasies blootgestel in hierdie kulture. Dit is gedoen om vas te stelof die teenwoordigheid van die metale in die liggame van die skeerbekke 'n oorsaak is van metaalakkumuleering as gevolg van die erdwurms waarmee hulle gevoer is. Sellulêre biomerkers is gebruik om sellulêre respons op die metale op die membraanintegriteit en DNA-integriteit vas te stel. Dit is gedoen deur die selle van skeerbekke so wel as BALB/c muise in vitro bloot te stel aan metaalsoutoplossings van Cd, Pb en Zn. Membraanintegriteit is getoets deur selmembraan permeabiliteit tegnieke nl. die LDH en tripaan blou toetse. DNA-integriteit is getoets deur die komeettoets te gebruik. Die resultate van die studie dui daarop dat die skeerbekke van Stellenbosch aan laer vlakke van Cd, en nóg laer vlakke van Pb blootgestel is as die skeerbekke van 'n perseel 16km buite die dorp. Die sellulêre response geïndusseer deur blootstelling aan metale by die laboratoriummuise het aangetoon dat die metale inderdaad skadelik is vir die selmembraan en die DNA van die selle van die muise. Cd en Pb is meer toksies vir die selmembraan as Zn, terwyl Zn weer meer toksies is vir die DNA-integriteit as Cd en Pb.

published_or_final_version / Geography / Master / Master of Philosophy

M. Tech. (Department of Biotechnology, Faculty of Engineering and Technology) Vaal University of Technology / The Klip River has suffered severe anthropogenic effects from industrial, agricultural, mining and domestic activities. As a result harmful contaminants such as heavy metals have accumulated in the river, causing microorganisms inhabiting the environment to develop mechanisms to protect them from the harmful effects of the contaminants. The current study deals with the isolation and characterization of heavy metal resistant bacteria isolated from the Klip River Catchment. Water and sediment samples were collected from 6 sites of the Klip River, and the Vaal Barrage (control). In-situ parameters, such as pH, turbidity, salinity, conductivity, temperature and dissolved oxygen were determined. Lead, iron, cadmium, nickel, zinc and copper concentrations of water were determined by atomic absorption spectroscopy. For bacterial analysis sediment and water samples were collected in sterile glass jars and bottles respectively. Heavy metal resistant bacterial isolates were screened on heavy metal constituted Luria Bertani (LB) agar. Biochemical profiles of the isolates were constructed using the API 20E® strips, antibiotic susceptibility tests were done and growth studies were carried out using spectrophotometric methods. The isolates were identified using 16SrDNA sequencing and alignment. A partial sequence of the copper resistance gene pcoA was amplified from strains Lysinibacillus sp. KR25 [KJ935917], and Escherichia coli KR29 [KJ935918]. The pcoR gene was amplified from E. coli (KR29) and the partial sequence for the chromate resistance gene chrB, was amplified from Pseudomonas sp. KR23 [KJ935916]. The gene fragments were then sequenced and translated into protein sequences. The partial protein sequences were aligned with existing copper and chromate resistance proteins in the Genbank and phylogenetic analysis was carried out. The physico-chemical properties of the translated proteins were predicted using the bioinformatics tool Expasy ProtParam Program. A homology modelling method was used for the prediction of secondary structures using SOPMA software, 3D-protein modelling was carried out using I-TASSER. Validation of the 3D structures produced was performed using Ramachandran plot analysis using MolProbity, C-score and TM-scores. Plasmid isolation was also carried out for both the wild type strains and cured derivatives and their plasmid profiles were analysed using gel electrophoresis to ascertain the presence of plasmids in the isolates. The cured derivatives were also plated on heavy metal constituted media. Antibiotic disc diffusion tests were also carried out to ascertain whether the antibiotic resistance determinants were present on the plasmid or the chromosome. The uppermost part of the Klip River had the lowest pH and thus the highest levels of heavy metal concentrations were recorded in the water samples. Turbidity, salinity and specific conductivity increased measurably at Site 4 (Henley on Klip Weir). Sixteen isolates exhibiting high iron and lead resistance (4 mM) were selected for further studies. Antibiotic susceptibility tests revealed that the isolates exhibited multi-tolerances to drugs such as Ampicillin (10 μg/ml), Amoxcyllin (10 μg/ml), Cephalothin acid (30 μg/ml), Cotrimoxazole (25 μg/ml), Neomycin (30 μg/ml), Streptomycin (10 μg/ml), Tetracycline (30 μg/ml), Tobramycin (10 μg/ml) and Vancomycin (30 μg/ml). Growth studies illustrated the effect of heavy metals on the isolates growth patterns. Cadmium and chromium inhibited the growth of most of the microorganisms. The following strains had high mean specific growth rates; KR01, KR17, and KR25, therefore these isolates have great potential for bioremediative applications. Using 16SrDNA sequencing the isolates were identified as KR01 (Aeromonas hydrophila), KR02 (Bacillus sp.), KR04 (Bacillus megaterium), KR06 (Bacillus subtilis), KR07 (Pseudomonas sp), KR17 (Proteus penneri), KR18 (Shewanella), KR19 (Aeromonas sp.), KR22 (Proteus sp.), KR23 (Pseudomonas sp.), KR25 (Lysinibacillus sp.), KR29 (Escherichia coli), KR44 (Bacillus licheniformis) and KR48 (Arthrobacter sp.). Three heavy metal resistance genes were detected from three isolates. The pcoA gene was amplified from strains Lysinibacillus sp KR25, and Escherichia coli KR29; pcoR gene from E. coli KR29 and the chrB gene, from Pseudomonas sp. KR23. The genes encoding for heavy metal resistance and antibiotic resistance were found to be located on the chromosome for both Pseudomonas sp. (KR23) and E.coli (KR29). For Lysinibacillus (KR25) the heavy metal resistance determinants are suspected to be located on a mobile genetic element which was not detected using gel electrophoresis. The translated protein sequence for pcoA_25 showed 82% homology with the copper resistant protein form Cronobacter turicensis [YP003212800.1]. Sequence comparisons between the pcoR partial protein sequence found in E. coli KR29 showed 100% homology with 36 amino acids (which was 20% of the query cover) from a transcriptional regulatory protein pcoR found in E. coli [WP014641166.1]. For the chrB partial protein sequence detected in Pseudomonas sp. (KR23), 97% of the query sequence showed 99% homology to a vitamin B12 transporter btuB in Stenotrophus sp. RIT309.

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / Polycyclic aromatic hydrocarbons (PAHs) are an alarming group of organic substances for humans and environmental organisms due to their ubiquitous presence, toxicity, and carcinogenicity. They are semi-volatile substances which result from the fusion of carbon and hydrogen atoms and constitute a large group of compounds containing two to several aromatic rings in their molecule. Natural processes and several anthropogenic activities involving complete or incomplete combustion of organic substances such as coal, fossil fuel, tobacco and other thermal processes, generally result in the release of the PAHs into the environment. However, the fate of the PAHs is of great environmental concern due to their tendency to accumulate and their persistence in different environmental matrices and their toxicity. Animal studies have revealed that an excessive exposure to PAHs can be harmful. Evidence of their carcinogenic, mutagenic, and immune-suppressive effects has been reported in the literature. In the soil environment, they have the tendency to be absorbed by plants grown on soil being contaminated by the PAHs. It is, therefore, important to evaluate their occurrence levels in different environmental matrices such as soil concentrations.

University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering