Detailed landfill leachate plume mapping using 2D and 3D electrical resistivity tomography - with correlation to ionic strength measured in screens

Leaching of organic and inorganic contamination from landfills is a serious environmental problem as surface water and aquifers are affected. In order to assess these risks and investigate the migration of leachate from the landfill, 2D and large scale 3D electrical resistivity tomography were used at a heavily contaminated landfill in Grindsted, Denmark. The inverted 2D profiles describe both the variations along the groundwater flow as well as the plume extension across the flow directions. The 3D inversion model shows the variability in the low resistivity anomaly pattern corresponding to differences in the ionic strength of the landfill leachate. Chemical data from boreholes agree well with the observations indicating a leachate plume which gradually sinks and increases in size while migrating from the landfill in the groundwater flow direction. Overall results show that the resistivity method has been very successful in delineating the landfill leachate plume and that good correlation exists between the resistivity model and leachate ionic strength

Antibacterial potential of Saussurea obvallata petroleum ether extract: A spiritually revered medicinal plant

Uttarakhand Himalayan region holds Asteraceae or Compositae as the largest family of flowering, medicinal and aromatic plants. Species belonging to this family rises from low altitude to the alpine region. Among Asteraceae, Saussurea obvallata (DC.) Edgew. is widely used in several indigenous systems of medicine. Flowers, leaves and rhizomes of S. obvallata are used for several traditional, religious, therapeutic and ornamental purposes. Aim of this study was to determine the chemical composition and antibacterial efficacy of petroleum ether extract (PEE) of S. obvallata. Gas chromatography-mass spectrometry (GC-MS) analysis was used for identifying phytochemicals present in the plant extract. Furthermore, the PEE was assessed for in-vitro antibacterial activity against selected Gram positive and negative strains. Structure of squalene and \u3b1-linolenic acid methyl ester were identified in PEE by GC-MS analysis, by comparing the results obtained with NIST library and literature reports. PEE exhibited significant activity against Staphylococcus aureus, Escherichia coli, Bacillus cereus, Bacillus subtilis with IC50 value of 87.2 \ub1 1.6, 98.4 \ub1 1.1 and 90.2 \ub1 1.8 \u3bcg/ml, respectively. These results showed that squalene and a-linolenic acid derivative identified in S. obvallata may be responsible for the observed antibacterial activity. To the best of our knowledge, this is the first report focused on the chemical composition and antibacterial activity of S. obvallata

Detailed landfill leachate plume mapping using 2D and 3D electrical resistivity tomography - with correlation to ionic strength measured in screens

Leaching of organic and inorganic contamination from landfills is a serious environmental problem as surface water and aquifers are affected. In order to assess these risks and investigate the migration of leachate from the landfill, 2D and large scale 3D electrical resistivity tomography were used at a heavily contaminated landfill in Grindsted, Denmark. The inverted 2D profiles describe both the variations along the groundwater flow as well as the plume extension across the flow directions. The 3D inversion model shows the variability in the low resistivity anomaly pattern corresponding to differences in the ionic strength of the landfill leachate. Chemical data from boreholes agree well with the observations indicating a leachate plume which gradually sinks and increases in size while migrating from the landfill in the groundwater flow direction. Overall results show that the resistivity method has been very successful in delineating the landfill leachate plume and that good correlation exists between the resistivity model and leachate ionic strength