Remediation of metal-contaminated mine tailings by the application of organic and mineral amendments

Purpose Tailings are generally characterized by severe physicochemical conditions that limit the establishment of vegetation. The present study aimed to select suitable combinations of organo-mineral amendments to improve the physicochemical, biochemical, and biological properties of spolic technosols, highly contaminated with metals. Materials and methods Several substrates were prepared by mixing mine tailings (MT) of an abandoned mining area with non-contaminated agricultural soil (anthrosol), green waste compost, lime, and rock phosphate at different rates: S1 - 50% of MT + 50% of agricultural soil; S2 - S1 + 3% of lime (CaCO3); S3 - S1 + 6% of rock phosphate; S4 - S1 + 10% of compost; S5 - S1 + 10% of compost + 3% of lime; S6 - S1 + 10% of compost + 6% of rock phosphate. Untreated MT and agricultural soil were analyzed immediately, and 8 months after incorporating the amendments. Results and discussion Heterotrophic microorganisms were not recovered from untreated MT due to the highly acidic pH and available metal concentrations. However, the addition of organo-mineral amendments ameliorated the tailings' characteristics by increasing pH, conductivity, total organic carbon, and available P levels. Moreover, after 8 months, heterotrophic microorganisms were recovered from those substrates and dehydrogenase activity was enhanced. The incorporation of agricultural soil and green waste compost mixed either with lime (S5) or rock phosphate (S6) was the most effective treatment. Conclusions Both S5 and S6 mixtures successfully reduced the environmental risk posed by tailings, suggesting the potential use of these amendments for the remediation of pyrite mines.info:eu-repo/semantics/acceptedVersio

Physical, chemical, and microbiological characterization of Kettara Mine Tailings, Morocco

The mining industry is of major importance to Morocco’s economy. However, the abandoned pyritic mines are a source of potentially toxic elements that can cause the disruption of the surrounding ecosystems, constituting a huge threat to wellbeing and human health. The present study aimed to analyze the physical and chemical characteristics of different types of tailings and to investigate the microbial populations of acidophilic bacteria involved in the oxidation of pyrite. Coarse and fine tailings collected from different zones of the mine (dike and pond) at two different depths (oxidized and non-oxidized residues) were analyzed for their pH, electrical conductivity, total organic carbon, total nitrogen, available P, major elements, and pseudo-total metal concentrations. The abundance of acidophilic bacteria was determined, and some acidophilic bacterial strains were isolated and tested for their metal tolerance. Tailings showed a pH ≈ 2, very low nutritional content, and high concentrations of Cu, As, Zn, and Pb, which were higher in the non-oxidized samples. The microbial counts of iron- and sulfur-oxidizing bacteria were higher than heterotrophic bacteria, with the highest numbers detected in the oxidized fine tailings. The five acidophilic bacteria isolated from the tailings were affiliated to genera Alicyclobacillus and Sulfobacillus, commonly found in this kind of environment.info:eu-repo/semantics/publishedVersio

Analyse de la première expérience de reconversion collective vers l'irrigation localisée: cas du secteur pilote de Tadla

At the heart of Sebou basin, the Saïss plain contains two superimposed and inter-communicating aquifers. These aquifers play a significant role in the socio-economic development of the region through the satisfaction of drinking water and irrigation needs. From the 80’s and with the advent of drought, this groundwater has experienced strong over-exploitation, resulting in an annual deficit of 100 million m3. This issue caught the interest of the scientific community, thus producing a large mass of dispersed and heterogeneous data which need to be integrated into a single data warehouse. Exploring of this warehouse has allowed us to assess the development of Saïss groundwater resources through maps showing the location of water points and graphic drawing up the spatial and temporal evolution of piezometry and water sources flows. Certainly, the integration of spatial and temporal data in one data warehouse, to analyze and exploit them is considered a milestone in the process of a decision support system construction. However, it still faces several constraints and limitations such as uncertainty in the various stages of the integration process. Keywords: Saïss, two aquifers, deficit, inter-communicating, integration, warehouse, uncertainties.Au cœur du bassin du Sebou, la plaine du Saïss renferme un système aquifère composé de deux nappes superposées et inter-communicants, jouant un rôle considérable dans le développement socio-économique de la région, à travers la satisfaction des besoins en eau potable et d’irrigation. A partir des années 80 et avec l’avènement de la sécheresse, cette nappe a connu une forte surexploitation, se traduisant par un bilan annuel déficitaire de 100 Mm3. Cette problématique a suscité l’intérêt de la communauté scientifique,produisant ainsi une importante masse de données hétérogènes et dispersées, qu’il fallait intégrer dans un seul entrepôt de données. L’exploitation de cet entrepôt nous a permis d’évaluer l’évolution des ressources en eau souterraines du Saïss par le biais d’une cartographie indiquant la localisation des points d’eau et des sources, et des graphiques dressant l’évolution spatiale et temporelle de la piézométrie des nappes et des débits de sources. Certes, l’intégration des données spatio-temporelles dans un seul entrepôt de données afin de les exploiter et les analyser est considérée comme étant une étape primordiale dans le processus de construction d’un système d’aide à la décision. Toutefois, elle reste confrontée à plusieurs contraintes et limites telles que l’incertitude dans les différentes étapes du processus d’intégration. Mots clés: Saïss, système aquifère, déficit, inter-communicants, intégration, entrepôt, incertitude

Trace and major element contents, microbial communities, and enzymatic activities of urban soils of Marrakech city along an anthropization gradient

Due to their close proximity with the population, urban soils are extensively affected by human activities that release considerable technogenic inputs resulting in an overall soil degradation and leading to an increase of water-extractable fraction of trace elements. This work aimed to determine the influence of anthropization on trace and major element concentrations and to assess how it might also affect soil biochemical and microbiological parameters in an urban area of Marrakech city, Morocco.info:eu-repo/semantics/publishedVersio

A global perspective on soil science education at third educational level; knowledge, practice, skills and challenges

The pivotal role of soil as a resource is not fully appreciated by the general public. Improving education in soil science represents a challenge in a world where soil resources are under serious threat. Today’s high school students, the world’s future landowners, agriculturalists, and decision makers, have the potential to change society’s apathy towards soils issues. This research aimed to compare the level of soil education in high and/or secondary schools in forty-three countries worldwide, together comprising 62% of the world's population. Comparisons were made between soil science content discussed in educationally appropriate textbooks via a newly proposed soil information coefficient (SIC). Interviews with teachers were undertaken to better understand how soil science education is implemented in the classroom. Statistical analyses were investigated using clustering. Results showed that gaps in soil science education were most commonly observed in countries where soil science is a non-compulsory or optional subject. Soil science concepts are predominantly a part of geography or environmental science curricula. Consequently, considerable variability in soil science education systems among investigated countries exists. Soil information coefficient‘s outcomes demonstrated that a methodological approach combining textbooks and the use of modern digitally based strategies in the educational process significantly improved soil education performances. Overall, soil science education is under-represented in schools worldwide. Dynamic new approaches are needed to improve pivotal issues such as: i) promoting collaborations and agreements between high school and universities; ii) encouraging workshops and practical exercises such as field activities; and, iii) implementing technology tools. This, in turn, will prepare the next generation to contribute meaningfully towards solving present and future soil problems

Trace elements in soils and vegetables from market gardens of (peri)urban areas in Marrakech city

Trace elements in soils and vegetables from market gardens of (peri)urban areas in Marrakech city. 9. International Congress on Soils of Urban, Industrial, Traffic, Mining and Military Areas (SUITMA

Do metal contamination and plant species affect microbial abundance and bacterial diversity in the rhizosphere of metallophytes growing in mining areas in a semiarid climate?

Purpose Mining areas are low-quality habitats for macro- and microorganisms' development, mainly due to the degradation of the soil quality by metal pollution. The present work aimed to analyze the influence of metal contamination and of plant species on the rhizospheric microbial communities of four indigenous metallophytes (Ononis natrix, Haloxylon scoparium, Peganum harmala, and Aizoon canariense) growing along a metal contamination gradient in Kettara mine near Marrakech, Morocco. Materials and methods In pyrrhotite mining areas (Kettara mine, Morocco), rhizosphere soil samples were collected from four predominant indigenous metallophytes (O. natrix, H. scoparium, P. harmala, and A. canariense) growing along a metal contamination gradient (ZC, control zone; Z1, high metal contamination; Z2, moderate metal contamination; Z3, low metal contamination). Microbial communities were analyzed by using microbial counts and by denaturing gradient gel electrophoresis (DGGE). The physicochemical properties (pH, conductivity, total organic carbon, nitrogen, P Olsen, and metal concentrations) of soils were also determined. Results and discussion The physicochemical analysis revealed that rhizospheric soils from Z1, Z2, and Z3 were relatively poor in nutrients as they presented low levels of total organic carbon and nitrogen, organic matter and available P. Moreover, these rhizospheric soils showed high concentrations of metals, especially Cu and Pb, which significantly reduced the abundance of the different groups of soil microorganisms (bacteria, fungi, and actinomycetes) and the activity of soil dehydrogenase. The analysis of bacterial communities by DGGE revealed that bacterial diversity was not negatively affected by metal contamination being higher in the most contaminated area (Z1). Conclusions Overall, the microbial abundance, the composition, and the diversity of rhizospheric bacterial communities were more influenced by the environmental factors in sampling zones than by plant cover. Microbial counts and enzymatic activity were both systematically affected throughout the metal gradient, evidencing as good indicators of the harmful effects of anthropogenic disturbances in soils. H. scorparium and P. harmala proved to be good candidates for the development of phytotechnological programs aiming the revegetation of mining degraded areas.N/

Effect of different amendments on growing of <em>Canna indica L</em>. inoculated with AMF on mining substrate

International audienceCanna indica L. (CiL) was used here in phytoremediation of mining soils. Our work evaluated the effect of AMF (i) on the growth and (ii) on the uptake of heavy metals (HM). The tests were conducted in the greenhouse on mining substrates collected from the Kettara mine (Morocco). The mine soil was amended by different proportions of agricultural soil and compost and then inoculated with two isolates of AMF (IN1) and (IN2) of different origins. After six months of culture, the results show that on mining soils (100%) only AMF (IN2) was able to colonize the roots of CiL with a frequency of 40 +/- 7% and an intensity of 6.5 +/- 1.5%. Also, the lowest values of shoot and root dry biomass are obtained on these mining soils with respectively 0.30g and 0.27g. In contrast, the accumulation of HM was higher and reached more than 50% of that contained in the mining soils, the highest values with 138mg kg(-1) Cu2+, Zn2+ 270mg kg(-1) and 1.38mg kg(-1) Cd was recorded. These results indicate that the colonization of CiL roots by AMF (IN2) could significantly improve its potential to be used in phytoremediation of polluted soil

Fertilisation with potato starch wastewater effect on the growth of Scots pine (Pinus sylvestris L.) forest in Poland

Fertilisation is often used to increase plant productivity in agriculture but has also been used in forestry. In our study, Scots pine forest growing in a nitrogen-poor environment was fertilised with NPK post-production wastewater from a potato starch factory. Our research aimed to investigate the dependence of tree growth on different NPK concentrations. Cell characteristics such as cell wall thickness (CWT), lumen diameter (LD) and tree-ring features such as ring width (RW), total number of cells in annual growth (nTotal), earlywood (EW) and latewood (LW) were investigated. Twenty-six years of regular fertilisation of the forest with different doses of wastewater rich in NPK elements have affected the anatomical structure of Scots pine trees. It is presumed that the reduction in CWT and LD on the fertilised site was due to deficiencies in plant water conductivity, which may have occurred due to physiological drought. The influence of nitrogen on unfertilised site from the wastewater area could contribute to the CWT thickening. The results confirm that the use of NPK in excessive doses is detrimental to trees' conductive system