Applied geo-ecology is advocated as a new academic field for ecological conservation and sustainable land use.
For the ecological conservation, some academic fields such as eco-technology and revegetation technology have already existed. These fields are interdisciplinary sciences of ecology or botany and technology, especially civil engineering. Whereas, geo-ecology (landscape ecology), which belongs to scientific field, has not been well known until now.
Geo-ecology is developed as a specialized field in geography, which treats relationship between the ecosystem and the topographical or geological condition. Recently, geo-ecology or landscape ecology occupy the attention of the field of civil engineering. However, the systematization of applied geo-ecology has to be done by engineering geologists.
The understanding of geo-environments and those change are our strong point and role. Ecological conservation requires the collaboration of many fields not only ecology but also geomorphology, geography, pedology, hydrology, civil engineering. Engineering geology has a suitable position for managing the collaboration because engineering geology originally connects with these all fields closely. Engineering geologists have to consider the methods of investigation, analysis, evaluation, and countermeasure for ecological conservation or sustainable land use more seriously. Engineering geology would be left alone in the environmental field if we do not establish new technology in collaboration with other fields.

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Water pollution in surface and ground water caused by the inflow of acid water that enriched in heavy metals becomes serious environmental problems around the mining areas the excavation sites where the chemical resolution of sulfide minerals such as pyrite occurs. The Hakkouda Tunnel in northern Honshu passes near the mine area, so it is feared that water pollution around this tunnel occur due to acid water generated from sulfide-containing rocks as muck.
To establish the evaluating method regarding exudation of acid water from rocks, we examined the batch leaching test, the magnetic susceptibility and the chemical composition for the rocks distributed in this tunnel. For all rock types distributed in this tunnel, the rocks that can exude the acid water are rich in sulfur and poor in CaO, and the SO₄^2- contents of elution water increase according to the rise of the sulfur contents in rocks. Therefore it is assumed that the sulfuric acid is liquated out by resolution of sulfide such as pyrite. The Ca-containing minerals in mudstones such as calcite and plagioclase will be decomposed continuously, and these minerals will counteract on the sulfuric acidic water. This processes are estimated by the relationship between SO₄^2- contents, Ca²⁺ contents and pH in elution water. In the case of volcanic rocks, as the magnetic susceptibility become lower the sulfur content of rocks become larger and the pH of elution water become lower.
From these results, it becomes clear that the exudation of acid water from rocks distributed in the mining area can be evaluated by the four indices as follows. (1) the magnetic susceptibility that is applied only volcanic rocks, (2) the pH value after one hour in batch leaching test, (3) the sulfur contents and (4) the S/Ca mol ratio for only mudstones.

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In order to manage issues concerning groundwater environment often created by construction of underground facilities, it is important to understand the hydro-geological features and potential transport pathways including fractures and matrices of bedrock. In this paper, the authors present the result of a field survey conducted in Tertiary sedimentary rock area with the aim of developing the exploration method for modeling hydrogeological structures and transport pathways. The results of this study can be summarized as follows:
·Fractures can be divided into several groups based on their features, orientations, fracturing ages and others.
·The specific fracture groups play a primary role in groundwater flow.
·Rock matrices of sandstone and mudstone conduct small amount groundwater flow.
Based on these results, a conceptual model of the water conducting features is discussed.

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Development during the past few decades has irrevocably damaged coastal ecosystems, and ongoing projects threaten to further disrupt the environment. A Tokyo Bay restoration project must harness the area's natural ability to recover from environmental damage. The recovery is accomplished through three mechanisms: sea-water exchange, sedimentation, and biological production.
The reclamation projects had also created more intractable problems. The Bay floor surrounding reclaimed land is scarred with deep trenches where the earth was dredged up to build the artificial islands. Hydrogen sulfide released from water stagnating in these trenches created toxic blue tides that threatened to exterminate life in the Bay. The Bay restoration project could include filling such trenches, measures which would prevent the blue tide and help keep the Bay waters moving.
Sedimentation is the Bay's second method of self-purification. The average molecule of water remains in the bay for about a month and a half. Heavy metals found in sewage are settling into the bay bottom before they can be drawn out to sea; as sediment, they are rendered effectively harmless. Sedimentation is useless, however, against pollutants which remain suspended or dissolved in the bay water. Phosphorous, a chemical indicator of water pollution, dissolves and decomposes easily. So do nitrogen-incorporating nutrient salts. They stay in the bay nearly as long as the water in which they are dissolved, and are easily reintroduced into the ecosystem.
Tokyo Bay's tidal flats and shallow waters yielded over 100, 000tons of seaweed and clams annually. The latter fed on plankton brought by tidal currents from spring to early fall; seaweed thrived in the nutrient salt-rich environment from fall to winter. The ecosystem of the tidal flats thus functioned to purify the Bay's water by processing organic substances year-round. When reclamation projects were built on the tidal flats and seaweed beds which had hosted this seasonal ecosystem, they disrupted the food cycle and wiped out 50% of the fish catch. The disappearance of the tidal flats also meant an end to their ability to purify the Bay.
The coast is the interface between land and sea-its ecosystem has developed over thousands of years. Coastal restoration projects must be designed to work with the powerful cleaning system of the Bay itself if they are to assist truly sustainable development.

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The leaching of potentially toxic elements or the generation of acidity often creates significant environmental pollution. Silica micro encapsulation using a silica solution, which was produced from diatomaceous earth of organic origin, is examined to prevent the release of harmful elements. This new approach has a long span of effectiveness because silica is chemically stable and leach-resistant. The surface of specimens taken from the overflow of the Matsuo sulfur mine was coated with the silica solution adjusted to various pHs at room temperature. Microanalyses by EPMA (electron probe microanalyzer) were performed on the specimens pre-treatment and post-treatment into higher pH, to certify the amorphous silica on the surface of harmful particles.
The results of leaching tests showed high performance remediation in the specimens, that is, iron and arsenic contents leached from specimens coated into the silica solutions at the pH value of 9 or 11, were less than 10ppm and 0.1ppm respectively, below the environmental quality standard, while those from the untreated specimens were about 280ppm and 6ppm, respectively.

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