Mobility of heavy metals associated with the natural weathering of coal mine spoils.

Knowledge of chemical mobility of heavy metals is fundamental to understanding their toxicity, bioavailability, and geochemical behavior. In this paper, two different methods, i.e. mineralogical means and sequential extractions, were employed to analyze the total contents, existing states, and chemical forms of heavy metals in coal mine spoils. The results demonstrate that the mobility of heavy metals in coal mine spoils depends not only on their existing states and the stability of their host minerals but also on the properties of the coal mine spoils. In the process of coal mine spoils-water interaction, sulfides that contain heavy metals first break down and release metals, which are then adsorbed and complexed by the iron oxyhydroxide colloid resulting from pyrite oxidization and organic matter. During the natural weathering of coal mine spoils, only a small fraction of these metals are released to the environment, and most of them still remains in the residual material.

Environmental influences on landslide activity : Almora Bypass, Kumaun Lesser Himalaya

Landslides are self-organizing and self-referenced systems. The conditions which lead to their emergence along Himalayan highways are not the same as those which their subsequent evolution. Landslides originate at sites which differ from average conditions by having significantly higher, steeper roadcuts, carved into steeper hillsides, with more finely bedded but less steeply dipping rocks, and fewer trees upslope. The system exhibits independence (autopoiesis) from its environment. Additionally, landslides dominated by rock-mechanical processes tend to produce lower angle outfalls from higher, north-facting, roadcuts than those dominated by soil-mechanical processes which are associated with greater dephts of below-soil regolith. However, the outfall volumes produced by the landdslides of different type are similar. These findings are generated from statistical (correlation/T-test/stepwise discriminant) analyses of data produced by a field survery of average environmental conditions, and the morphometry and environmental contexts of 88 landslides, on 7.6 km of the Almora Bypass (AU)