Macro Landslide Hazard Zonation Mapping - Case Study from Bodi – Bodimettu Ghats Section,Theni District,Tamil Nadu - India

Landslide is a common natural hazard that usually occurs in mountainous areas. Rapid urban development and high traffic intensity movements have been hampered to a great extent by phenomenon of landslides. In Ghat section, vertical cuttings and steep slopes are induced slope failures. An assessment of landslide hazards is therefore a prerequisite for sustainable development of the hilly region. In the present study, Macro Landslide Hazard Zonation was carried out in the Bodi – Bodimettu ghats section, Western Ghats, Theni district. The slope spreads over an area of about 10.09 sq km encompassing Puliuttu Ar. sub-watershed. The study was made with help of different types of data including Survey of India topographic map, geology map, important inherent factors like lithology, structure, slope morphometry, relative relief, land use/land cover and hydrogeological conditions using Bureau of Indian Standard (BSI 14496 (Part 2):1998) and related thematic maps. Based on the thematic layers, landslide hazard evaluation factor (LHEF) and total estimated hazard (TEHD) were calculated and the macro hazard zonation map was prepared. Landslide Hazard Zonation (LHZ) of the terrain shows that out of 17 facets, facets 1 to 5 and 8 falls under Moderate Hazard zone category and facets 6, 7 and 9 to 17 under the High Hazard zone category. The field study with further analysis for hazard concluded that about 68% of the total area falls in the high hazard zone.     

Polychlorinated biphenyls (PCBs) in a benthic ecosystem in Gwangyang Bay, South Korea

Benthic ecosystem in Gwangyang Bay, a fast developing industrial area with steel production, port container handling, petroleum and other chemical processing in South Korea was studied. The average levels of polychlorinated biphenyls (ΣPCB) in the benthic components were: seawater 2.99 ± 0.13 (ng/L); sediment 294 ± 118 (ng/g TOC); [biota=ng/g lipid] starfish 92; prawn 131 ± 2; mussels 127 ± 22; crab 182 ± 114; clam 187; polychaeta 215; sea cucumber 497 ± 90; squill 603 ± 38; fish 396 ± 159. Levels in the inner bay samples were higher than the outer bay samples suggesting land based pollution. Good correlation (r(2)=0.79; p<0.05) existed between PCB concentration and lipid content indicating partitioning processes in action. PCB signature in the abiotic and biotic components shows enrichment of lower chlorinated congeners emitted by a unique source nearby, viz. steel manufacturing plant.     

Efficiency of Pleurotus florida Laccase on Decolorization and Detoxification of the Reactive Dye Remazol Brilliant Blue R (RBBR) under Optimized Conditions

Laccase from the white‐rot fungus Pleurotus florida, produced under solid‐state fermentation conditions, was used for the decolorization of reactive dye Remazol Brilliant Blue R (RBBR). RBBR was decolorized up to 46% by P. florida laccase alone in 10 min. In the presence of N‐hydroxybenzotriazole (HBT), the rate of decolorization was enhanced 1.56‐fold. Central composite design of response surface methodology with four variables namely, dye, enzyme, redox mediator concentrations, and time at five levels was applied to optimize the RBBR decolorization. The predicted optimum level of variables for maximum RBBR decolorization (87%) was found to be 52.90 mg L^?1 (RBBR), 1.87 U mL^?1 (laccase), 0.85 mM (HBT), and 7.17 min (time), respectively. The validation results showed that the experimental value of RBBR decolorization (82%) was close to the predicted one. The disappearance of C–N and C–X groups, and a small shift in N–H groups in Fourier‐transform infra red (FTIR) spectroscopy confirms the degradation of RBBR chromophore by laccase enzyme. The phytotoxicity of RBBR was considerably reduced after the treatment with laccase. RBBR decolorization kinetics; K_m and V_max were calculated to be 145.82 mg L^?1 and 24.86 mg L^?1 min, respectively.     

Morphometrical analysis of two tropical mountain river basins of contrasting environmental settings, the southern Western Ghats, India

The morphometric analysis of river basins represents a simple procedure to describe hydrologic and geomorphic processes operating on a basin scale. A morphometric analysis was carried out to evaluate the drainage characteristics of two adjoining, mountain river basins of the southern Western Ghats, India, Muthirapuzha River Basin (MRB) in the western slopes and Pambar River Basin (PRB) in the eastern slopes. The basins, forming a part of the Proterozoic, high-grade, Southern Granulite Terrain of the Peninsular India, are carved out of a terrain dominantly made of granite- and hornblende-biotite gneisses. The Western Ghats, forming the basin divide, significantly influences the regional climate (i.e., humid climate in MRB, while semi-arid in PRB). The Survey of India topographic maps (1:50,000) and Shuttle Radar Topographic Mission digital elevation data were used as the base for delineation and analysis. Both river basins are of 6th order and comparable in basin geometry. The drainage patterns and linear alignment of the drainage networks suggest the influence of structural elements. The Rb of either basins failed to highlight the structural controls on drainage organization, which might be a result of the elongated basin shape. The irregular trends in Rb between various stream orders suggest the influence of geology and relief on drainage branching. The Dd values designate the basins as moderate- to well-drained with lower infiltration rates. The overall increasing trend of Rl between successive stream orders suggests a geomorphic maturity of either basins and confirmed by the characteristic I _hyp values. The Re values imply an elongate shape for both MRB and PRB and subsequently lower vulnerability to flash floods and hence, easier flood management. The relatively higher Rr of PRB is an indicative of comparatively steeply sloping terrain and consequently higher intensity of erosion processes. Further, the derivatives of digital elevation data (slope, aspect, topographic wetness index, and stream power index), showing significant differences between MRB and PRB, are useful in soil conservation plans. The study highlighted the variation in morphometric parameters with respect to the dissimilarities in topography and climate.     

Isolation and characterization of phosphate-solubilizing bacteria from seagrass rhizosphere soil

Phosphate-solubilizing bacterial strains(6 Nos.) were isolated from the rhizosphere soils of two seagrasses(Halophila ovalis(R.Br.) Hook and Halodule pinifolia(Miki) Hartog) in the Vellar estuary.Experimental studies found that the strain PSSG6 was effective in phosphate solubilization with Phosphate Solubilization efficiency index E = 375 ± 8.54,followed by the strain PSSG5 with Phosphate Solubilization efficiency index E = 275 ± 27.3.Of the 6 strains isolated,the strains PSSG4 and PSSG5 be-longed to the genus Bacillus,and PSSG1,PSSG2 and PSSG3 were identified as Citrobacter sp.,Shigella sp.,and Klebsiella sp.,respectively,by conventional method,and PSSG6 was identified as Bacillus circulans using conventional and molecular methods.     

Temporary fluoride concentration changes in groundwater in the context of impact assessment in the Vaniyar sub-basin,South India

India’s surface water and groundwater distribution is temporally variable due to the monsoon. Agriculture is one of the dominant economic sectors in India. Groundwater quality is regularly assessed to determine usability for drinking and irrigation. In this study, World Health Organization and Bureau of Indian Standards guidelines were used to determine suitability of groundwater near artificial recharge structures (ARS) with a focus on the structures´ impact on groundwater quality. Groundwater resources were evaluated for irrigation suitability using electrical conductivity (EC), sodium adsorption ratio, the US Salinity Laboratory diagram, sodium concentration, Wilcox’s diagram, Kelly’s index, and Doneen’s permeability index. EC and major ions were tested in recharge areas at different distances from the ARS. The construction of ARS at optimal distances along major streams has improved groundwater quantity and quality in the sub-basin. Before construction of ARS, fluoride concentrations were higher; after construction, fluoride was reduced in most locations. Water stored in the check dam and groundwater in the wells closer to the structure were suitable for both drinking and irrigation purposes. Impact of ARS on nearby groundwater quality was observed at Pallipatti, Mulayanur, Venkadasamuthram, Pudupatti, Poyyappatti, Harur1, and Sekkampatti. More distant sites included Pappiredipatti, Nambiyappati, Menasi, Harur, Todampatti, and Adikarapatti. Data demonstrated improved groundwater quality in the area of the ARS. Through recharge, the non-potable fluoride in the region is reduced to the permissible limit for human consumption.     

A composite fall-slippage model for cliff recession in the sedimentary coastal cliffs

A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination of several factors. The fall model in the present study accounts both spring seepage and wave action, resulting in undercutting and this fall affects only the topmost laterite and the just below sandstone in the cliff. Slippage in this area affects all the litho-units and hence the geologic characteristics of all the litho-units are considered for developing the slippage model. This mathematically derived model can be used in other cliffs exhibiting the same morphology as well as the one controlled by the same influencing factors. This model differs from other models in incorporating multi-lithounits as well as multi-notches. Varkala cliffs form a part of the aspiring geopark in the Global Geopark Network and hence a study on the cliff recession is a pressing requirement.     

Perfluorinated compounds in minke whales (Balaenoptera acutorostrata) and long-beaked common dolphins (Delphinus capensis) from Korean coastal waters

This is the first study to report the concentrations and accumulation profiles of PFCs in marine mammals from Korea. The concentrations and profiles of 10 PFCs in the liver of minke whales and common dolphins from Korean coastal waters were recorded in this study. The mean concentrations of PFOS and PFUnDA were 3-20 times higher than that found for other PFCs analyzed. The concentrations of PFOS in cetaceans from Korea were relatively lower than those reported in other countries. Inter-species differences in the concentrations of PFOS, PFOSA and PFNA were found between two cetacean species, while no difference was observed in the concentrations of PFDA, PFUnDA and PFDoDA between the species. The dominant PFC compounds found in cetaceans were PFUnDA and PFOS, accounting for 70-80% of the PFCs. The accumulation profiles and correlation analysis indicated that two cetacean species have different exposure routes and metabolic capacity for PFCs.     

Environmental effects on grinding

The effect of surface-active agents in improving the grinding efficiency for haematite, expressed as a measure of reduction ratio, has been studied. Drying of the feed before grinding has been found to improve the grinding efficiency. The effect of surfactant additions on hardness, microhardness, crushing strength and wet grinding of haematite has shown that dispersants are better than flocculants, and each dispersant has a critical concentration at which the grinding efficiency is maximum.