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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23498号 / 工博第4910号 / 新制||工||1767(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 高岡 昌輝, 教授 平井 康宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Polychlorinated biphenyls (PCBs) are persistent organic pollutants, which were banned several decades ago but still exist in the environment, posing a threat to human health. Previously, joint sealants containing PCBs were used in construction. In this study, the long-term PCB-contaminated soils were from a residential area in Västerås Municipality, where the PCBs have been leaching from buildings to the soil for several years. The objective of this thesis is to investigate the feasibility of using plants to remove PCBs from the contaminated soil at a greenhouse scale, and to use a site-specific guideline model for the risk assessment of this contaminated site. After a literature review, four plant species were selected for the greenhouse cultivation including alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), horseradish (Armoracia rusticana L.) and tobacco (Nicotiana tobacum L.). The plants cultivated in the greenhouse were maintained for 92 days and then the concentrations of PCBs in the initial and remediated soils were analyzed by GC-MS. The results indicate that the selected plant species can enhance the removal of high chlorinated PCBs from soils. In the risk assessment, the contents of PCBs in soils were higher than the calculated site-specific guideline, which means it is urgent to implement measures for protecting residents’ health.

要旨ファイルを差し替え（2022-01-24） / 京都大学 / 新制・課程博士 / 博士(工学) / 甲第23492号 / 工博第4904号 / 新制||工||1766(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 高野 裕久, 教授 松井 康人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Urban, agriculture and coal mining land use/cover impacts upon aquatic habitat, toxicity and biodiversity were investigated in Leading Creek, a 388 km2 watershed in southeastern Ohio. Abandoned strip mine land (ASML) and active deep underground mines were examined along with abandoned near-surface underground mine land (AUML). The work focused on assessment of aquatic toxicity, water quality, and biodiversity through investigation of associated ecological responses for both treated and untreated AMD. Relations were examined among land use/cover, chemistry, and various ecological and toxicological endpoints. Sources of data (scale 1:24000) included Landsat5 imaging from 1988 and 1994, and directly digitized extents of underground mining activities dating to the 19th century, with more recently created strip mines. USEPA and Ohio EPA qualitative habitat scoring protocols were used. Land use/cover thresholds were established using ASML=3%, AUML=2% to 10%, Urban=3% to 5%, and Bare Soil=3%. Biodiversity was assessed using qualitative benthic macroinvertebrate taxon richness and abundance, for total and EPT groups, respectively. A better understanding of acid mine drainage (AMD) was demonstrated linking land use/cover, coal bed, sediment, and water column chemistry to aquatic ecotoxicity through examination of the origin and fate of sulfate, magnesium, iron, manganese, and zinc. Key findings in risk assessment of Leading Creek indicated that (1) abandoned near-surface underground mine lands (AUML) were associated with >90% of untreated AMD reaching Leading Creek; (2) degradation to aquatic ecology was primarily associated with water quality degradation due to AMD, not with sediment quality degradation; (3) modest habitat destruction, especially sedimentation effects, were observed for ASML>3%, and urbanization>5% in small subsheds; (4) unique chemical signatures differentiated mining techniques instream; and (5) in situ Corbicula fluminea growth rates were dependent upon drainage area. Sporadic signs of agricultural and urban impacts were indicated from acute toxicity with Ceriodaphnia dubia and chronic in situ toxicity testing with C. fluminea. Both the ecotoxicological tests were shown to be reliable indicators of AMD impact from AUML, on watershed and subwatershed scales. AMD was strongly associated with depressed biodiversity, low pH, and elevated zinc. Ecotoxicity monitoring supported interconnections found between sediment and water chemistry, land use/cover, and biodiversity. / Ph. D.