New Symmetries in Crystals and Handed Structures

For over a century, the structure of materials has been described by a combination of rotations, rotation-inversions and translational symmetries. By recognizing the reversal of static structural rotations between clockwise and counterclockwise directions as a distinct symmetry operation, here we show that there are many more structural symmetries than are currently recognized in right- or left-handed handed helices, spirals, and in antidistorted structures composed equally of rotations of both handedness. For example, though a helix or spiral cannot possess conventional mirror or inversion symmetries, they can possess them in combination with the rotation reversal symmetry. Similarly, we show that many antidistorted perovskites possess twice the number of symmetry elements as conventionally identified. These new symmetries predict new forms for "roto" properties that relate to static rotations, such as rotoelectricity, piezorotation, and rotomagnetism. They also enable symmetry-based search for new phenomena, such as multiferroicity involving a coupling of spins, electric polarization and static rotations. This work is relevant to structure-property relationships in all material structures with static rotations such as minerals, polymers, proteins, and engineered structures.Comment: 15 Pages, 4 figures, 3 Tables; Fig. 2b has error

Phytoremediation of heavy metal-contaminated sites: Eco-environmental concerns, field studies, sustainability issues and future prospects

Environmental contamination due to heavy metals (HMs) is of serious ecotoxicological concern worldwide because of their increasing use at industries. Due to non-biodegradable and persistent nature, HMs cause serious soil/water pollution and severe health hazards in living beings upon exposure. HMs can be genotoxic, carcinogenic, mutagenic, and teratogenic in nature even at low concentration. They may also act as endocrine disruptors and induce developmental as well as neurological disorders and thus, their removal from our natural environment is crucial for the rehabilitation of contaminated sites. To cope with HM pollution, phytoremediation has emerged as a low-cost and eco-sustainable solution to conventional physico-chemical cleanup methods that require high capital investment and labor alter soil properties and disturb soil microflora. Phytoremediation is a green technology wherein plants and associated microbes are used to remediate HM-contaminated sites to safeguard the environment and protect public health. Hence, in view of the above, the present paper aims to examine the feasibility of phytoremediation as a sustainable remediation technology for the management of metals-contaminated sites. Therefore, this paper provides an in-depth review on both the conventional and novel phytoremediation approaches, evaluate their efficacy to remove toxic metals from our natural environment, explore current scientific progresses, field experiences and sustainability issues and revise world over trends in phytoremediation research for its wider recognition and public acceptance as a sustainable remediation technology for the management of contaminated sites in 21st century

Transport and accumulation of heavy metals in undisturbed soil columns

The podzolic soils of the Kola Peninsula, Russia, have in localised areas been highly contaminated with copper and nickel from smelting activities. Migration and retention of these metals were investigated in undisturbed soil columns irrigated with simulated background and polluted precipitation in order to study the temporal processes of retention and release within the soil. The mineral layers were strongly acidified by the contaminated precipitation. Forest floor layers demonstrated a high capacity to retain input Ni and Cu under all conditions. Mineral layers accumulated some Cu, but released Ni. In general, Ni leached through the soil faster than Cu. Since metals are strongly retained in the forest floor layer, even after reduction or cessation of inputs there may be a significant long–term risk of their leaching to deeper soil and groundwater. This risk cannot be ameliorated without remediative intervention

RESTORATION OF VEGETATION ON MINE LANDS NEAR MONCHEGORSK (MURMANSK REGION, RUSSIA)

Background. The increasing technogenic pollution actualizes the restoration of vegetation cover in many industrial regions of the planet, including the vicinity of non-ferrous metallurgy enterprises in the Kola Subarctic. The barrens podzols and abrazemes are unfavorable for plant development. The study is aimed at assessing the restoration of vegetation as a result of the mine lands remediation near the Severonickel industrial complex. Materials and methods. Remediation was carried out in 2003–2008 by two methods: chemophytostabilisation (without pretreatment of the soil) and overlapping of contaminated soils with organic matter–rich cover materials followed by liming, fertilization, seedlings planting and grass mixture sowing. The species composition and the projective cover of the vegetation, the vital status of the undergrowth, the aboveground phytomass of the ground cover and the thickness of the upper soil layer were evaluated at 11 monitoring sites taking into account spatial variation. Areas of barren lands were considered as control. For the evaluation and graphical display of the characteristic features of the vegetation variability, the principal component analysis (PCA) was used. Results. According to the state of the vegetation, the chemophytostabilisation sites only slightly differ from the control barrens sites due to adverse edaphic conditions. Planted trees and shrubs have a strongly depressed appearance and a low projective cover, and the ground cover is not restored. On remediation sites with organic matter–rich fertile layer, sparse deciduous young stands are formed with a predominance of goat willow and / or fluffy birch, with a higher level of tree vitality and species diversity, grass cover with the participation of grass and / or horsetail. The PCA revealed an objective fractioning of sites according to the vegetation condition depending on the remediation technology. Conclusions. Successful restoration of vegetation in mine lands in conditions of emissions reduction depends on the state of the soil and the technology used. Environmentally friendly and cost-effective chemophytostabilisation gives only a short-term effect that needs continuous maintenance. A more promising but expensive way to quickly restore the barren lands is to apply a constructed fertile layer to the surface of polluted soils in combination with the planting of deciduous trees and the sowing of perennial grasses

INFLUENCE OF HUMIC PREPARATIONS ON DEGRADED SOILS PROPERTIES OF TECHNOGENIC BARRENS

This research aim was testing the applicability of exogenic organic matter – extracted humic substances – for the remediation of technogenic barrens soils near Cu-Ni smelter (Kola Peninsula). In short-term laboratory experiments we studied the possibility of stabilization of heavy metals labile forms by commercial humic substances (HS) of different origin (peat humate “Flexom” and coal humate “Extra”) in comparison with HS, inoculated by microorganisms – nitrogen fixers and mycorrhizae-forming fungi and mineral fertilizers (NPK и CaCO3). Experiments were provided during 45 days after 14 days of pre-incubation under controlled conditions in climate chamber with light, temperature and humidity imitating the polar day conditions in Kola Subarctic. After experiments we evaluated changes in soil chemical properties, soil microbial community and test-culture (Deschampsia cespitosa). Peat humate application is ineffective without additional manipulations (e.g. combination with CaCO3), cooperation with biological applicants cannot be pointed out. Application of coal humate favours to metals stabilization, soil microorganism’s activation, test-culture growth. It may be effective to combine coal humate with biological applicants like mycorrhizae-forming fungi. So, coal-humates may be perspective growth-stimulator, ameliorant and detoxicant in remediation of degraded soils in conditions of polymetallic contamination