Geochemistry of two sediment cores from the west coast of India

Abstract

Copper, Pb, Zn, Ni, Co, Mn, AI, Ca, magnetic susceptibility and loss on ignition of sediments from two cores near Mangalore along the western continental shelf of India have been studied. The sediments have high Al and organic matter contents due to the high sedimentation rate and their proximity to river mouths. Down-core variations of elements indicate a decrease of lithogenous component during probably the past few centuries. While abundance of calcareous shells in some zones has lead to the dilution of most of the metals, it appears that Pb and Mn are associated with this phase. Copper, Zn and Fe are associated with organic matter and detrital particles, whereas Ni and Co are predominantly associated with the insoluble fraction. Oxides/hydroxides of Fe and Mn are absent because of the reducing conditions and the high terrigenous influx. Geochemically, Mn and Fe are present in different phases of sediments (in the insoluble fraction and organic matter respectively). The Fe content of one of the cores is positively correlated with magnetic susceptibility.

Speciation of heavy metals in electroplating industry sludge and wastewater residue using inductively coupled plasma

“…The decreasing order of fractions in the samples are reducible > acid extractable > oxidisable > residual > exchangeable. About 15 -30 % is in exchangeable and acid extractable forms which can cause environmental toxicity during mobility (Karbassi and Shankar, 2005). The acid extractable fraction is soluble in the low pH condition.…”

“…It was observed that levels of leachable toxic metals from industrial wastewater sludge were low compared to the amount of metal extracted in the exchangeable fraction of the BCR protocol. Karbassi and Shankar, (2005) reported that in the coastal sediment cores Cu, Zn and Fe are associated with organic matter and detrital particles, whereas Ni and Co are predominantly associated with the insoluble fraction. While abundance of calcareous shells in some zones has lead to the dilution of most of the metals, it appears that Pb and Mn are associated with this phase.…”

Core sediment biogeochemistry in specific zones of Cochin Estuarine System (CES)

“…Geochemical studies of sediment core profiles describe the degree of contamination by encapsulating various amounts of biogenic compounds (including biogenic alkanes, sterols, carbohydrates, protein, hydrocarbons, etc.) and provide furthermore useful information on the changes in the quality of the sediments from past period (Faganelli et al 1987;Holm 1988;Karbassi and Shankar 2005;Al-Juboury 2009;Ahmad et al 2010;Chibunda et al 2010). The present investigation also infers the quality of the biogeochemical constituents in the core sediments of the Cochin estuary which would strengthen the environmental dynamics of the studied site.…”

Geochemistry of heavy metals and sedimentation rate in a bay adjacent to the Caspian Sea

“…However, for more accurate baseline data, chemical-partitioning technique is suggested. By this technique, association of metals with various sedimentary phases would be known (Karbassi, 1993 andShankar, 1993). Thus, a more reliable data can be provided for further investigations.…”