This research addresses the potential ecotoxicity of two emerging carbonaceous materials: C 60 and biochar. The use of these materials is rapidly increasing, as well as their potential for widespread applications. Thus, information about unintended consequences associated the widespread use, incidental or accidental release, and disposal of these emerging materials is needed. The environmental impacts of C 60 , its stable water suspension (nC 60 ), and biochar are assessed here using bacteria and earthworms as model receptors. The antibacterial activity of nC 60 can be mitigated by the presence of natural organic matter as a soil constituent or dissolved in the water column. Sorption to soil might decrease the bioavailability of nC 60 and thus its toxicity to bacteria. Aqueous organic matter also may mitigate nC 60 toxicity. Pristine C 60 showed toxicity to the earthworm's reproduction and was rapidly bioaccumulated by earthworms, although to a lower extent than smaller phenanthrene molecules that are more hydrophobic; thus, the large molecular size of C 60 hinders its bioaccumulation. Less bioaccumulation occurred at higher C 60 concentration in soil, which is counterintuitive and reflects that higher C 60 concentrations that exceed the soil sorption capacity exist as larger precipitates that are less bioavailable. Earthworms avoided soils amended with high concentrations of dry biochar, and experienced significant weight loss after 28-day exposure. The avoidance response was likely to avert desiccation rather than to avoid potential toxicants (i.e., PAHs formed during biochar production by pyrolysis) or nutrient scarcity. By wetting the biochar to field capacity before exposing the worms, this adverse effect can be completely mitigated. Overall, this research provides a foundation for ecotoxicity assessment associated with exposure to C 60 or biochar, and establishes a method by which other emerging materials can be evaluated for their potential environmental impacts.

There is a growing need to develop rapid and cost-effective ecotoxicological tools for risk assessment because traditional methods examine endpoints such as mortality, which do not provide any insight into the mode of action (MOA) of the chemical. Research presented within this thesis illustrates the potential of 1H NMR-based metabolomics as a rapid and routine ecotoxicological tool that can elucidate a chemical’s MOA and also aid in the identification of metabolites of exposure. Metabolomics involves measuring the fluctuations in the endogenous metabolites of an organism within a cell, tissue, bio-fluid or whole organism in response to an external stressor. We focused on the model polycyclic aromatic hydrocarbon (PAH) phenanthrene, and the perfluoroalkyl acids (PFAAs) perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), due to their recalcitrant nature and widespread prevalence in soil environments. 1H NMR-based metabolomics analysis of the exposure of Eisenia fetida earthworms to sub-lethal phenanthrene exposure via filter paper contact tests revealed a concentration-dependent two-phased MOA: a linear correlation between the metabolic response and exposure concentration at low concentrations followed by a plateau in the responses at high concentrations. Alanine, glutamate, maltose, cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. An increased energy demand and an interruption in the conversion of succinate to fumarate in the Krebs cycle were observed due to phenanthrene exposure. Sub-lethal PFOA and PFOS exposure to E. fetida via contact tests for two days revealed heightened responses with higher PFOA and PFOS concentrations. Leucine, arginine, glutamate, maltose, and ATP were identified as potential indicators of PFOA or PFOS exposure. E. fetida responses were then investigated after exposure for two, seven and fourteen days to an artificial soil that was spiked with sub-lethal PFOS concentrations. An exposure time-dependent operation of two separate MOAs were identified. Both the contact tests and artificial soil exposure studies identified an elevation in fatty acid oxidation, a disruption in energy metabolism and biological membrane structure, and also an interruption of ATP synthesis following PFOA and PFOS exposure. This thesis illustrates the promise of NMR-based metabolomics as a routine tool for ecotoxicological assessment of contaminated sites.

Earthworms have an important role in the decomposition of organic matter, mineralization of nutrients and physical mixing of soils. Despite a large number of laboratory and greenhouse-level studies investigating how earthworms modify soil properties and promote soil fertility, we lack reliable methods to scale-up and quantify earthworm contributions to nutrient cycling at the agroecosystem level. The objective of this thesis is to determine the influence of earthworm communities on nitrogen (N) transformations in soils and to quantify their contribution to nitrogen flux through soils for soybean and maize cropping systems of Quebec. Laboratory growth rates were used to predict how earthworm growth responded to seasonal fluctuations in soil temperature and moisture. The relationships between earthworm populations, soil-N pools and annual crop production were evaluated in a field experiment. When favourable conditions occurred in 2004 (temperatures <20°C, and rainfall at least once a week), a positive relationship was found between earthworm numbers and the plant available-N, including soil mineral-N, microbial biomass-N and total-N removed in soybean grain. In 2005, soil conditions were unfavourable (temperatures > 20°C and little or no rainfall) to earthworm survival and growth, and no relationship was found between earthworm populations, soil N pools and corn production. These data permitted me to make assumptions about earthworm activity and life histories under field conditions, which were used to estimate N flux through earthworm communities with two models. The models were tested for their sensitivity to varying parameter values within the range reported in the scientific literature. During a crop growing period with favourable climate conditions, a large earthworm population (100 g fresh weight biomass m-2 or greater) is predicted to cycle as much as 120 kg N ha-1. Model predictions were very sensitive to input parameters and did not correspond to the partial N budget calculated at the site. Accurate predictions of N mineralization by earthworms require more species- and site-specific parameter values. Further investigation using stable 15N isotopes as tracers would help us to follow the N transformations and evaluate the N flux mediated by earthworms at the field scale.

There is a growing need to develop rapid and cost-effective ecotoxicological tools for risk assessment because traditional methods examine endpoints such as mortality, which do not provide any insight into the mode of action (MOA) of the chemical. Research presented within this thesis illustrates the potential of 1H NMR-based metabolomics as a rapid and routine ecotoxicological tool that can elucidate a chemical’s MOA and also aid in the identification of metabolites of exposure. Metabolomics involves measuring the fluctuations in the endogenous metabolites of an organism within a cell, tissue, bio-fluid or whole organism in response to an external stressor. We focused on the model polycyclic aromatic hydrocarbon (PAH) phenanthrene, and the perfluoroalkyl acids (PFAAs) perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), due to their recalcitrant nature and widespread prevalence in soil environments. 1H NMR-based metabolomics analysis of the exposure of Eisenia fetida earthworms to sub-lethal phenanthrene exposure via filter paper contact tests revealed a concentration-dependent two-phased MOA: a linear correlation between the metabolic response and exposure concentration at low concentrations followed by a plateau in the responses at high concentrations. Alanine, glutamate, maltose, cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. An increased energy demand and an interruption in the conversion of succinate to fumarate in the Krebs cycle were observed due to phenanthrene exposure. Sub-lethal PFOA and PFOS exposure to E. fetida via contact tests for two days revealed heightened responses with higher PFOA and PFOS concentrations. Leucine, arginine, glutamate, maltose, and ATP were identified as potential indicators of PFOA or PFOS exposure. E. fetida responses were then investigated after exposure for two, seven and fourteen days to an artificial soil that was spiked with sub-lethal PFOS concentrations. An exposure time-dependent operation of two separate MOAs were identified. Both the contact tests and artificial soil exposure studies identified an elevation in fatty acid oxidation, a disruption in energy metabolism and biological membrane structure, and also an interruption of ATP synthesis following PFOA and PFOS exposure. This thesis illustrates the promise of NMR-based metabolomics as a routine tool for ecotoxicological assessment of contaminated sites.

Earthworms are well known to increase decomposition of organic matter and release of plant available nutrients. They can also increase CO 2 and N2O fluxes from the soil by stimulating respiration, denitrification, and nitrification caused by soil microorganisms. The objective of this thesis was to examine the influence of different earthworm species and population numbers on CO2 and N2O fluxes from a corn agroecosystem. In the field study, earthworm treatments had a significant effect on CO2 fluxes, but there was no difference between CO 2 fluxes from the two species (Lumbricus terrestris L., Aporrectodea caliginosa Savigny) or from the two population levels (1x and 2x the naturally-occuring population). Also, the earthworm treatments had no significant effect on N2O fluxes. Since all treatments contained mixed species and similar population levels at the end of the study, it is likely that CO2 and N2O fluxes in the field were affected more by soil temperature and moisture fluctuations than by the earthworm treatments. The study was repeated in laboratory microcosms under environmental control. Again, earthworm treatments had a significant effect on CO2 fluxes, but not on N2O fluxes. Interestingly, the N 2O fluxes from microcosms containing L. terrestris came solely from denitrification, while the N2O fluxes from A. caliginosa microcosms were produced mostly by nitrification. It is not known why these species stimulate different groups of microorganisms that can produce N2O, and this remains to be investigated.

In this master work was researched macrofloras dynamics variation during the period of vegetation in phyto association and in the soil. Research object: the part of research was accomplished in 2003 autumn by prof. hab. dr. V. Žekonienė in her executive stationary tests in Trakų Vokė. Another part was accomplished at the stationary ground in Modžiūnai fields also not far from the Merkis near Čižiūnai, and Lazdijai and Varėna regions in the light granulemetre composition of soil. Research objective: to value by the field researches the pervasion in the agrofitocenoze in the southeast part of Lithuania in the light composition of soil macrofauna, subject to cultured species of plants and hidrotermic mode in the soil fields. Research methods: the number of earthworms was counted by dig 0,5*0,5m2 and 0,3 m deep the monoliths of soil and by counting the earthworms. According to researches the number of worms depended on species of cultured plants, influence of forecrops and hidrotermic coefficient. The best preplants were perennial grass and winter rye. At the time of researches were found strong correlation links between hydrotermic modes and the number of earthworms. Keywords: earthworms, agrofitocenose, the soil fauna.

Mining has negative impacts on the environment, and is one of the main contributors to environmental pollution. This holds a potential hazard for ecosystems surrounding mining areas and also for public health in the surrounding communities. There is therefore a need for ecotoxicological research in order to assess these possible risks and find ways to minimize the harmful effects. One way in which to assess soil vitality are soil enzymes which are produced by plants and microorganisms and will therefore be more abundant in healthy soils. Earthworms have been proven to be useful bioindicators for metal contamination of soil, as they are able to accumulate metals from their environment into their body tissue. The aim of this study was to use earthworm bioassays, neutral red retention time analysis (NRRt), enzymatic analysis and RAPD-PCR to determine the effect of mining activity on the environment. This was done by assessing the ecotoxicity of tailings collected from three different mines, viz. gold-, opencast chrome- and coal mines. The metals chosen for analyses included four (Cr, Co, Ni and Pb) of the seven (Cd, Cr, Ni, Pb, Zn, Cu, Co) environmentally important trace elements as described for South African soils. Arsenic was also chosen since it is associated with gold mine tailings. Tailings and soil were collected from three sites at each of the mines which included unrehabilitated (TDF-U) and rehabilitated (TDF-R) substrates from tailings disposal facilities (TDFs) and reference soils (RS) in close proximity to TDFs. The physical and chemical properties of these different substrates were determined in terms of pH, particle size as well as metal contents. In addition to this, they were analysed for microbial community function by means of enzymatic activity, which has been proven to be useful in evaluating contamination of soil. The enzymes analysed in this study included dehydrogenase, ßglucosidase, acid phosphatase, alkaline phosphatase and urease. Earthworms (Eisenia andrei) were exposed to different material for 28 days during which their biomass, reproduction, mortality and lysosomal membrane stability were monitored weekly. Hereafter, they were removed from the material while the cocoons were left behind for a further 56 days. The hatched and unhatched cocoons as well as the juvenile worms were then counted to determine reproduction patterns in the materials. Metal concentrations in the substrates and earthworm body tissues were compared to selected benchmarks. Results indicated that when comparing the different materials from each mine, enzymatic activity proved to be a very sensitive parameter. Enzymatic activity showed significant differences (p < 0.05) between RS, TDF-R and TDF-U materials. Biomass was not a sensitive parameter (p > 0.05) for the worms exposed to the gold and chrome mine tailings, but it was a sensitive parameter (p < 0.05) for the coal mine exposed earthworms, showing early differences between the worms from the different sites (RS, TDF-R and TDF-U). The NRR-t assay was very sensitive (p < 0.05), indicating clear differences between the worms from each investigated site. In terms of reproduction, the production of cocoons showed clear differences (p < 0.05) between the different sites and could therefore be considered a sensitive parameter. Hatching success however, was not a sensitive parameter. The reason being that there were so little cocoons produced that it is not possible to determine the correct percentage of juvenile worms hatching from, for example, only one or two cocoons. Mortality was also not a sensitive endpoint as it was only observed in the coal mine material. RAPD - PCR results indicated genetic differences between earthworms exposed to the control- and the tailings materials, indicating either DNA alterations due to possible genotoxic effects, or genetic variation between individuals of the same species. Since mine waste materials often contain complex mixtures of metals that might be toxic on their own or in combination with other factors, it is difficult to attribute any observed genotoxic effect to any of the specific metals. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012.

Mining has negative impacts on the environment, and is one of the main contributors to environmental pollution. This holds a potential hazard for ecosystems surrounding mining areas and also for public health in the surrounding communities. There is therefore a need for ecotoxicological research in order to assess these possible risks and find ways to minimize the harmful effects. One way in which to assess soil vitality are soil enzymes which are produced by plants and microorganisms and will therefore be more abundant in healthy soils. Earthworms have been proven to be useful bioindicators for metal contamination of soil, as they are able to accumulate metals from their environment into their body tissue. The aim of this study was to use earthworm bioassays, neutral red retention time analysis (NRRt), enzymatic analysis and RAPD-PCR to determine the effect of mining activity on the environment. This was done by assessing the ecotoxicity of tailings collected from three different mines, viz. gold-, opencast chrome- and coal mines. The metals chosen for analyses included four (Cr, Co, Ni and Pb) of the seven (Cd, Cr, Ni, Pb, Zn, Cu, Co) environmentally important trace elements as described for South African soils. Arsenic was also chosen since it is associated with gold mine tailings. Tailings and soil were collected from three sites at each of the mines which included unrehabilitated (TDF-U) and rehabilitated (TDF-R) substrates from tailings disposal facilities (TDFs) and reference soils (RS) in close proximity to TDFs. The physical and chemical properties of these different substrates were determined in terms of pH, particle size as well as metal contents. In addition to this, they were analysed for microbial community function by means of enzymatic activity, which has been proven to be useful in evaluating contamination of soil. The enzymes analysed in this study included dehydrogenase, ßglucosidase, acid phosphatase, alkaline phosphatase and urease. Earthworms (Eisenia andrei) were exposed to different material for 28 days during which their biomass, reproduction, mortality and lysosomal membrane stability were monitored weekly. Hereafter, they were removed from the material while the cocoons were left behind for a further 56 days. The hatched and unhatched cocoons as well as the juvenile worms were then counted to determine reproduction patterns in the materials. Metal concentrations in the substrates and earthworm body tissues were compared to selected benchmarks. Results indicated that when comparing the different materials from each mine, enzymatic activity proved to be a very sensitive parameter. Enzymatic activity showed significant differences (p < 0.05) between RS, TDF-R and TDF-U materials. Biomass was not a sensitive parameter (p > 0.05) for the worms exposed to the gold and chrome mine tailings, but it was a sensitive parameter (p < 0.05) for the coal mine exposed earthworms, showing early differences between the worms from the different sites (RS, TDF-R and TDF-U). The NRR-t assay was very sensitive (p < 0.05), indicating clear differences between the worms from each investigated site. In terms of reproduction, the production of cocoons showed clear differences (p < 0.05) between the different sites and could therefore be considered a sensitive parameter. Hatching success however, was not a sensitive parameter. The reason being that there were so little cocoons produced that it is not possible to determine the correct percentage of juvenile worms hatching from, for example, only one or two cocoons. Mortality was also not a sensitive endpoint as it was only observed in the coal mine material. RAPD - PCR results indicated genetic differences between earthworms exposed to the control- and the tailings materials, indicating either DNA alterations due to possible genotoxic effects, or genetic variation between individuals of the same species. Since mine waste materials often contain complex mixtures of metals that might be toxic on their own or in combination with other factors, it is difficult to attribute any observed genotoxic effect to any of the specific metals. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 160-168). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 160-168). Also available on the Internet.