Geochemical transformation of soil cover in copper–molybdenum mining areas (Erdenet,Mongolia)

Purpose

The aim of the present study is to evaluate geochemical transformation of soil cover in the territory of Erdenet (Mongolia) and to assess the environmental risk associated with soil cover contamination. The objectives of the present study included: (1) the determination of heavy metals (HMs) and metalloids contents in surface horizons of background and urban soils and the assessment of geochemical transformation of the city’s soil cover; (2) the identification of elements’ associations and patterns of their spatial distribution in the soil cover of the city; (3) the assessment of environmental hazard, related to contamination of soils with complexes of HMs and metalloids.

Materials and methods

Soil–geochemical survey was conducted by the authors in the summer periods of 2010 and 2011. In total, 225 samples, including 32 backgrounds, were collected. Bulk contents of HMs and metalloids in soil samples were analyzed by mass-spectral method with inductively coupled plasma at All-Russian Research Institute of Mineral Raw Materials (Moscow) using Elan-6100 and Optima-4300 devices (Perkin Elmer, USA).

Results and discussion

Mo, Cu, and Se appeared to be the priority pollutants nearly in all land-use zones. The maximum accumulation of Mo, Cu, Se, As, Sb, and W is restricted to the industrial area where total pollution index of soils (Zc) equals 74.8. Three technogenic associations of elements, derived mainly from petrochemical features of Erdenet ore field and characterized by similar spatial distribution within the city, are identified. Environmental assessment of surface soil horizon geochemistry in Erdenet showed that 1/5 of its area has dangerous and extremely dangerous levels of soil pollution.

Conclusions

Experience of the environmental–geochemical assessment of soil cover in the impact zone of mining enterprises could be useful for other fields of the non-ferrous metals with high lithological–geochemical heterogeneity of the territory. It suggests the need of accounting for the geological diversity and specific features of metallogeny of an area. Geochemical indices local enrichment factor/local depletion factor should be calculated against the individual background values for each soil-forming rock. Such approach allows more accurate assessment of the degree of technogenic geochemical transformation of soils and the environmental hazard of pollution.

     

Potential for improving bioavailable zinc in wheat grain (Triticum species) through plant breeding

A "whole-body" radioassay procedure was used to assess retention and absorption by rats of Zn in mature kernels of whole grain wheat harvested from 28 genotypes (Triticum spp.) grown in nutrient solution supplied with 2 microM ZnSO4 radiolabeled with 65Zn. Grain-Zn concentration differed among genotypes and ranged from 33 to 149 microg g(-1) of dry weight (DW); similarly, grain-Fe concentration varied approximately 4-fold, from 80 to 368 microg g(-1) of DW. Concentrations of Zn and Fe in the grain were positively correlated. Therefore, selecting genotypes high in grain-Zn also tends to increase grain-Fe concentration. Concentrations of myo-inositolhexaphosphate (phytate) in the wheat grain varied from 8.6 to 26.1 micromol g(-1) of DW. Grain intrinsically labeled with 65Zn was incorporated into test meals fed to Zn-depleted rats. All rats readily ate the test meals, so that Zn intake varied directly with grain-Zn concentration. As determined by the percentage of 65Zn absorbed from the test meal, the bioavailability to rats of Zn in the wheat genotypes ranged from about 60 to 82%. The amount of bioavailable Zn (micrograms) in the grain was positively correlated to the amount of Zn accumulated in the grain. There was a significant negative correlation between grain-phytate levels and percentage of Zn absorbed from the wheat grain, but the effect was not large. These results demonstrate that concentrations of Zn in whole-wheat grain, as well as amounts of bioavailable Zn in the grain, can be increased significantly by using traditional plant-breeding programs to select genotypes with high grain-Zn levels. Increasing the amount of Zn in wheat grain through plant-breeding contrivances may contribute significantly to improving the Zn status of individuals dependent on whole grain wheat as a staple food.     

Influence of cytokinins on in vitro morphogenesis in root cultures of Centaurium erythraea—Valuable medicinal plant

The purpose of this work was to acquire more information on the capacity of in vitro grown Centaurium erythraea Gillib. normal and hairy root cultures to simultaneously regenerate adventitious buds and to evaluate the variations induced on regeneration response by treatments with six cytokinins. Explants from normal and hairy root cultures were cultured on half-strength MS medium (1/2 MS) with kinetin (KIN), N⁶-benzylaminopurine (BA), 6-γ,γ-dimethylallylaminopurine (2IP), N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU), 1-Phenyl-3-(1,2,3-thiadiazol-5-yl)urea (TDZ) and 6-[4-Hydroxy-3-methyl-but-2-enylamino]purine (ZEA), used alone in six different concentrations. The average number of adventitious buds per explant was promoted by all of cytokinin treatments. Urea-type cytokinins, TDZ and CPPU were more effective for the induction the morphogenesis of adventitious buds than adenine-type cytokinins. We found that the 1.0 μM CPPU induced the largest number (25.6, 18.2, respectively) of adventitious buds in normal and hairy root culture. TDZ-supplemented media induced highest number of adventitious buds (24.2) from normal root explant, but from hairy root explant average number of buds is lower (20.5). Regenerated shoots were excised and placed on 1/2 MS medium without hormone. The rooted plantlets were successfully acclimatized in greenhouse conditions.     

Editorial

Skadar Lake, a large, shallow, subtropical lake on the Albanian frontier in south-western Yugoslavia, supports a commercial fishery which annually yields nearly a thousand metric tons. Examination of catch statistics plus documentation of increasing effort during 1947 through 1973 reveals a declining catch per unit of effort. Water quality has not changed since 1952. However, changes in gear, effort, and exploitation have apparently caused major shifts in species composition and size of the catch. Rapid technological changes in gear coupled with potential environmental degradation may lead to decreased stocks and over-exploitation. Only by instituting a comprehensive management programme, within the context of international cooperation and sound ecological information, can a high sustained yield be maintained and over-exploitation of commercially important fish stocks in Skadar Lake be presented.     

Eighty-year review of the evolution of landscape ecology: from a spatial planning perspective

Landscape Ecology - Sustainable spatial development requires the establishment of a balance between rational land use and the protection of nature, ecosystems and biodiversity on various spatial...     

Dependence of the common carp (Cyprinus carpio L.) fatty acid profile on diet composition in a semi‐intensive farming system: tissue and time variability

Increasing the amount of n‐3 PUFA in carp meat is one of the most important tasks in enhancing its overall quality. However, the relative influence of supplemental feed and natural feed on the FA profile of cultivated carp flesh is not well documented, making it difficult to choose the most efficient strategy. Carp diet composition and diet and flesh fatty acid profiles were simultaneously followed in order to determine the influence of pelleted feed compared to natural feed on fatty acid profiles of carp tissues. Pelleted feed clearly dominated over zooplankton and Chironomidae in the carp diet, producing carp tissue fatty acid profiles closely resembling those of pelleted feed. However, increase in the abundance of zooplankton over the course of the investigation resulting in concomitant increase of its proportion in feed bulk was in strong positive correlation with increase in n‐3 HUFA in the dorsal muscle. n‐3 PUFA enrichment of supplemental feed could be the dominant mechanism in production of carp meat rich in n‐3 PUFA. However, even a small increase in natural feed availability could significantly change the diet of common carp and result in considerable improvement of meat quality with regard to n‐3 HUFA content.     

The Effect of Thermal Treatment Method on Fatty Acid Composition in Northern Pike (Esox lucius) Fillets

The aim of the present study was to investigate the effect of thermal treatment methods, such as microwave cooking, steaming, and shallow pan-frying on fatty acids composition in northern pike fillets. All methods of thermal treatment increased fat content in the fillets. Microwave cooking decreased the proportion of saturated fatty acids and increased the proportion of total, n-3, and n-6 polyunsaturated fatty acids as compared with fresh fillets. Steam cooking did not affect the proportion of saturated, monounsaturated, and polyunsaturated fatty acids, whereas pan-frying significantly increased the proportion of monounsaturated and n-6 polyunsaturated fatty acids. All cooked fillets, regardless of the thermal treatment used, had acceptable n–6/n–3 ratio; however, microwave cooking enabled fish products to obtain more beneficial n-6/n-3 ratio than frying. Due to high polyunsaturated fatty acids content and low n-6/n-3 ratio, microwave cooking may be recommended for preparing wild pike fillets in households.