Geochemistry of core sediments from Mullipallam creek,South East coast of India

The Mullipallam creek in Muthupet mangroves region is the only E-W trending coastal strip in the SE coast of India and is very important, as the mangrove acts as a barrier to natural diasters. Natural, anthropogenic signals and accumulation of elements were made by collecting sediment samples at various depths in a core. All sediments were analyzed for carbonates (CaCO₃), organic carbon (OC), major (Si, Al, Fe, Na, K, Ca, Mg, P), and trace (Mn, Cr, Cu, Ni, Co, Pb, Zn). Normalization with Al values has been done for all the major and trace elements and enrichment factors have been calculated. The calculated enrichment factors and comparison indicate that the trace metals (especially Pb) are enriched mainly due to the external (anthropogenic) activities in the land as well as in the coastal zone (Palk Strait).     

Heavy metals in nearshore sediments of Kalpakkam,southeast coast of India

Kalpakkam, a tiny fishing hamlet dotting the east coast, halfway between Chennai and Pondicherry has become prominent due to the Madras Atomic Power Station. The present study aims at assessing the spatial and temporal distribution pattern of heavy metals (Cd, Pb, Zn, Cu, Ni, Cr, and Fe) from 12 stations along the inner shelf of Bay of Bengal, India, during pre-monsoon (PRM), monsoon, and post-monsoon (POM) seasons. The order of occurrence of the metals in sediments of Kalpakkam is Cr > Zn > Ni > Cu > Pb > Cd (excluding Fe since unit is in %) and exhibits a unique seasonal pattern with the highest values (average) during POM except for Cd which shows highest (average) concentration during PRM. In order to determine the sample association according to their geochemical composition and their granulometric characteristics, a correlation matrix was generated and sediment pollution indices viz., sediment enrichment factor and geoaccumulation index were computed. The results confirm anthropogenic input of Cd to nearshore sediments of Kalpakkam. Sources of Cd can be attributed to dredging activities at Edaiyur, direct dumping and sewage sludge from anthropogenic activities, which reach the study area through the Buckingham Canal opening at the backwaters—Sadras and Edaiyur, and extreme use of antifouling paints by fishing trawlers.     

Mangrove sediments a sink for heavy metals? An assessment of Muthupet mangroves of Tamil Nadu,southeast coast of India

Mangrove forests are one of the most productive and biodiverse wetlands on earth. Yet, these unique coastal tropical forests are among the most threatened habitats in the world. Muthupet mangroves situated in the southeastern coast of India, has a reverse “L” shaped structure. Four cores were collected in 2008, sliced and subsampled at 2.5 cm length. The heavy metals (Mn, Cu, Zn, Ni, Pb, Cr, Cd) and other associated geochemical parameters were evaluated to determine pollution history of Muthupet. An evaluation of the status of heavy metal pollution through the index analysis approach was attempted by computing geoaccumulation index, anthropogenic factor, enrichment factor, contamination factor and degree of contamination, pollution load index and metal pollution index. To compensate for the natural variability of heavy metals in the core sediments, normalization using Al was carried out so that, any anthropogenic metal contributions may be detected and quantified. Results of the study reveal that significant metal contamination exists, and all the metals are found to be higher than continental crustal values. The fine sediments of Muthupet vary between uncontaminated and moderately contaminated with almost no enrichment (EF < 1) to severe enrichment (EF > 10). On comparison, the core collected close to aquafarms and dense mangrove forest (C3) is the most polluted core and the core retrieved where minor rivers drain (C2) is the least polluted.     

Estimation of wave heights during cyclonic conditions using wave propagation model

Natural Hazards - Data from satellites are invaluable for applications including long-term climate studies and engineering design. Most present applications of wind-wave research for coastal...     

Geochemical characteristics and depositional environment of Kalpakkam, southeast coast of India

Sediments from Kalpakkam, southeast coast of India were geochemically analyzed to document the provenance, tectonic setting, and role of chemical weathering. The sediments are dominated by quartz (Si), and the higher concentration of Si suggests the presence of quartz (±feldspar) dominated terrigenous sands. The study demonstrates that the sediments are derived from the granitic to gneissic or from a sedimentary source. Beach sediments are deposited in a passive continental margin setting and seabed sediments are deposited in active continental margin. In the A–CN–K diagram, most of the samples fall in the lower part, i.e., below the plagioclase feldspar joint which indicates a low degree of alteration. Only S6 falls just above the plagioclase feldspar joint, close to the AK boundary suggesting a slightly advanced weathering of sediment and source. Beach and seabed sediments lie close to CNK and FM region suggesting the presence of ferromagnesian minerals (likely to be pyroxene) except S6 which falls in the inner triangle of the minerals feldspar, garnet, and biotite in A-CNK-FM diagram. Both CIA and CIW values depict the unweathered nature of the sediments under humid to semi-humid climatic conditions.     

Geochemical and statistical approach for evaluation of heavy metal pollution in core sediments in southeast coast of India

Industrialization coupled with urbanizaton has led to stress in the Buckingham Canal which runs parallel to Bay of Bengal at a distance of around 1 km from the coastline. 4 sediment cores were collected along Ennore — Pulicat stretch to determine acid leachable trace metal concentration. Core samples were collected using gravity corer. The cores were sliced horizontally at 2.5 cm to determine the grain size, sediment composition, pH, organic matter, calcium carbonate, acid leachable trace metals; cadmium, chromium, copper, lead, zinc. The trace metals were extracted using acid mixture containing hydro fluoric acid, nitric acid and sulphuric acid and analysed by atomic emission spectrophotometer. In an attempt to infer anthropogenic input from geogenic input, several approaches including comparison with sediment quality guidelines — ecotoxicological sense of heavy metal contamination and classification by quantitative indexes such as geoaccumalation index, anthropogenic factor, enrichment factor, contamination factor and degree and pollution load index was attempted. Grain size analysis and sediment composition of core samples shows Ennore is sandy in nature having a neutral pH. Organic matter enrichment is observed to a higher extent in core 3. Core 2 at a depth of 5 cm shows organic matter of 9.4 %. calcium carbonate is totally absent at the surface sediments in core 2. Cores collected within the canal showed a higher heavy metal concentration than the cores collected from Pulicat lagoon and 2 km into the Ennore Sea. The trace metal concentration for cadmium, lead and zinc in Ennore does not pose a threat to the sediment dwelling fauna whereas chromium and copper are likely to pose a threat. Quantitative indexes place Ennore under moderately polluted. Ennore is likely to face a serious threat of metal pollution with the present deposition rates unless stringent pollution control norms are adopted.     

International Emission Trading and the Cost of Greenhouse Gas Emissions Mitigation and Sequestration

The deployment of carbon capture and sequestration (CC&S) technologies is greatly affected by the marginal cost of controlling carbon emissions (also the value of carbon, when emissions permits are traded). Both the severity and timing of emissions limitations and the degree to which emissions limitation obligations can be traded will affect the value of carbon and thereby the timing and magnitude of CC&S technology deployment. Emissions limits that are more stringent in the near term imply higher near-term carbon values and therefore encourage the local development and deployment of CC&S technologies.Trade in emissions obligations lowers the cost of meeting any regional or global emissions limit and so affects the rate of penetration of CC&S technologies. Trade lowers the marginal value of carbon and CC&S penetration in high cost regions and raises the marginal value of carbon and CC&S penetration in low cost regions. The net impact on the world CC&Stechnologies depends on whether their increased use in low-cost regions exceeds the reduced use in high-cost regions.In the long term, CC&S technologies must not only remove carbon but permanently sequester it. If reservoirs are not permanent, then the emissions and costs of control are merely displaced into the future. The paper presents quantitative estimates for the impacts of trade in emissions limitation obligations on the timing, magnitude, and geographic distribution of CC&S technologies and the marginal and total costs of carbon control.     

Influence of enzymatic lime on clay mineral behavior

Atterberg Limit Tests, unconfined compressive strength tests, and California Bearing Ratio Tests were conducted on the two minerals—kaolinite and bentonite—after subjecting them to stabilization with lime, enzyme, and enzymatic lime. The purpose of the study was to evaluate the effectiveness of enzymatic lime as a stabilizer over lime and enzyme. Results establish that enzymatic lime stabilization is the better stabilizer in terms of strength development. The unconfined compressive strength and California Bearing Ratio values of enzymatic lime stabilized samples have increased up to 5 and 30 times in the case of kaolinite mineral, but to only less than 1.5 times in the case of bentonite mineral. The study thus indicates that enzymatic lime stabilization is predominantly effective for clays containing kaolinite minerals.