Thesis (M.S.)--University of Toledo, 2005. / Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Biology." Includes bibliographical references (leaves 54-61).

No description available.

No description available.

No description available.

A creosote treatment facility was active during the 1950’s and 1960’s at a railroad tie yard site. In 1990, creosote contamination was discovered along a creek bank at the site. Phytoremediation was selected as the remedial technology and hybrid poplar trees were planted at the site in 1997. A research project was designed to: 1) characterize the site through collection of soil and ground water samples; 2) assess phytoremediation effects of 3 grasses, clover, fescue and rye, in creosote-contaminated surface soils; 3) perform assessment of the hybrid poplar tree phytoremediation system; 4) develop a hybrid poplar tree evapotranspiration model. This thesis is focused on the first and second items on the research agenda. Soil and ground water samples were collected and analyzed for 6 polycyclic aromatic hydrocarbons (PAHs), acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene and chrysene. Site characterization revealed multiple creosote sources. Areal subsurface bedrock DNAPL distribution, approximately 6500 ft², was much greater than previously reported. Total PAHs (Σ 6 PAHs) in the soil and ground water ranged from below detection limits (BDL) to 8,276 mg/kg and BDL to 1.58 mg/L, respectively. Aqueous phase PAHs should be available for hybrid poplar tree and microbial uptake. Dissolution and diffusion of PAH constituents from the free product phase to the aqueous and soil phases contaminated both matrices. PAH cosolvency effects were also evident. The presence of more soluble PAHs in the aqueous phase enhanced the solubility of two hydrophobic PAHs, chrysene and benzo(b)fluoranthene. Phytoremediation effects of fescue, rye, and clover grasses were assessed in creosote-contaminated surface soils. Over the 9 month period, clover grass growth was very poor. Clover data was not used in comparative analyses. Rye and fescue grasses exhibited acceptable growth. In planted and control (unplanted-amended) plots, acenaphthene, fluorene, phenanthrene, fluoranthene, and pyrene soil concentrations were reduced 72, 50, 73, 55 and 49 percent, respectively. Chrysene reduction was not statistically significant. During the first 4 months of the study, dry site conditions limited grass growth and subsurface biological activity. The site received approximately 16 inches of precipitation during the last 3 months of the study, including multiple, intense precipitation events. The subsurface was saturated for prolonged periods of time and oxygen transfer to indigenous microorganisms was likely limited. The root structures of fescue and rye grasses were neither dense nor complex enough to promote phytoremediation effects. PAH reductions were generally greater for constituents with higher aqueous solubilities. It is thought that PAH losses were primarily due to solubilization and/or microbial uptake. / Master of Science

Numerous soils have been contaminated by radiocaesium (Cs) as a result of nuclear weapon testing and accidents at nuclear power-plant facilities. Management of the areas, which have been exposed to either intense or diffuse Cs pollution, has therefore become a major environmental concern. Strategies orientated toward the use of plants and microorganisms, or both in combination, have been proposed in the recent years as potential players in removing or stabilizing Cs in contaminated soils. Among these microorganisms, arbuscular mycorrhizal (AM) fungi are of particular interest due to their unique position at the soil/root interface and their recognized role in element transport and immobilization. In the recent years, contradictory results have been published on the impact of AM fungi on Cs accumulation by plants, failing to ascertain whether AM fungi could effectively transport this radionuclide to their host. Therefore, the objective of this work was to determine the role of AM fungi in plant Cs acquisition and accumulation. Using in vitro compartmented systems, we unambiguously demonstrated that AM fungi could transport Cs to their host, while its accumulation within the extraradical mycelium was rather limited. Our results also suggested that AM fungi could have an effect on Cs distribution within their host. Indeed, it appeared that AM fungi could potentially limit the translocation of Cs from roots to shoot. However, if the results obtained during this research project have shown that AM fungi could influence the acquisition and accumulation of Cs by plants, their capacity to take part in phytoremediation strategies remains questionable and would need additional investigations. In particular, attention should be focused on the mechanisms behind Cs transport by AM fungi, their influence on Cs root to shoot translocation and the subsequent validation of the findings obtained to in situ conditions.

In this study,we used mangrove phytoremediation ecotechniques to treat polycyclic aromtic hydrocarbons (pyrene) contaminated soil. First, we compared the four species of mangroves in Taiwan, Kandelia candel Druce, Rhizophora stylosa Griff, Avicennia marina Vierh and Lumnitzera racemosa Willd, inoculated by endomycorrhizae in no contaminated soils. According to the experimental results, the four species of mangroves could be colonized by Glomus aggregatum and Glomus mosseae. In colonization rate and colonization intensity, Glomus aggregatum were found higher than those of Glomus mosseae. For the degradation efficiencies of pyrene in soils, according to the experimental results, we found that the Lumnitzera racemosa Willd exhibited best growing conditions among the four species. The degradation rates for all tests systems pyrene were measured above 90% . In accordance with passed study, the species of Kandelia candel Druce presented effective efficiencics for pyrene degradation. The speacis of Lumnitzera racemosa Willd and Kandelia candel Druce were planted in the artifical pyrene contaminated soils, which were incubated in a greenhouse , while the control systems without vegetation were used for comparison. After 90 days of incubation, the experimental result showed that the soils planted with Lumnitzera racemosa Willd and Kandelia candel Druce were found able to enhance the microbial and dehydrogenase activities. The addition of Glomus aggregatum could help plants to prevent from the stress of pyrene. The addition of salinity into the siols was a pressure for mangroves so the mangroves, incoculated by endomycorrhizae showed stronger dependence on mycorrhizal fungi than those in the siols of no salinity. In salty siol, mangroves exhibited high effective degradation rates for pyrene. In the siols for the illumination groups, the pyrene degradation rates for all test systems were measured about 85%. The siols for the dark groups showed that the average pyrene degradation rates were about 70%.

There is no abstract available for this thesis. / Department of Natural Resources and Environmental Management

Thesis (M. S. in Environmental Engineering)--Vanderbilt University, Dec. 2008. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 23, 2007) Includes bibliographical references (p. 54-57).