Characteristics and potential pedogenetic processes of a Technosol developing on iron industry deposits

Abstract

Technosols include soils dominated or strongly influenced by human-made materials. Similarly to natural soils, technogenic parent materials submitted to environmental factors undergo weathering and transformation processes. But the pedogenesis of the Technosols remains little known. With this aim in view, a Technosol developing on purely technogenic materials resulting from iron industry was thoroughly characterized in order to discuss pedogenetic evolution of this Technosol using knowledge about pedogenesis of natural soils. Materials and methods:The studied site was a former settling pond, where mainly sludge generated by wet cleaning of blast-furnace fumes was dumped until probably in the mid-20 th century. Thereafter the pond has been colonized by vegetation and is covered by a diversified forest. The soil was composed of contrasted layers. A 20 cm organic layer has developed at the surface. Samples were collected in the first two meters which are under root influence.Elemental composition, agronomic parameters, mineralogy as well as physical and hydraulic properties of the soil materials were characterized.

Fly ash as a permeable cap for tailings management: pedogenesis in bauxite residue tailings

“…This is a common problem for the classification of Technosols in industrial areas where several tailings or waste types are co-disposed into the same storage facility (Huot et al 2013(Huot et al , 2014Séré et al 2010). The use of a novel prefix qualifier, ordic, would improve the clarity of the Technosol classification at sites with multilayered spolic profiles by allowing each spolic layer to be described separately, in parentheses, in order of sequence below the surface.…”

A Technosol as archives of organic matter related to past industrial activities

“…Main mechanisms contributing to OM stabilization in temperate soils are i) selective preservation due to OM recalcitrance in initial phases of decomposition, ii) spatial inaccessibility of OM against decomposer organisms due to occlusion, intercalation, hydrophobicity and encapsulation and iii) stabilization by interaction with mineral surfaces (Fe-, Al-, Mn-oxides, phyllosilicates) and metal ions (Lützow et al, 2006). Physical and hydraulic properties (high porosity, high water retention capacity and semipermeable behavior at saturation) of these finely divided materials (Huot et al, 2013) could explain the low OM degradation rate and limited and/or slow vertical transfers. Porosity was dominated by capillary pores, with a significant part potentially occupied by pores of diameter lower than 0.2 µm, which is considered to be the limiting size for access by bacteria (Lützow et al, 2006).…”

“…This former settling pond has been evolving under the influence of climatic and biologic factors for at least 50 years. In relation to its composition as well as its chemical and physical properties, the soil developing on this material can be classified as a Spolic Technosol (Calcaric, Laxic, Hydric, Thixotropic, Andic, Toxic) according to WRB (IUSS Working Group WRB, 2006) (Huot et al, 2013). The analyses of mineralogy and soil structure at different scales, combined with the knowledge of industrial operations have evidenced deposition cycles along the profile as well as early processes of mineral transformation and solute transfer.…”

Assessment of Environmental Indicators on the Topolithosequence with a Particular Reference to Soil Developmemt in South Sulawesi, Indonesia

“…The presence of highly reactive mineral phases, such as low periodic order Mn oxides or allophone-like minerals, with high contents of carbonates is rarely in the natural environment and may suggest an important potential for pedogenic evaluation, which could be directed by the balance between the weathering processes of these phases [17] and [18].…”