Ramasamy Nagarajan

Provenance and tectonic setting of Miocene siliciclastic sediments, Sibuti formation, northwestern Borneo

Provenance and tectonic setting of sandstone and mudstone units of the Miocene Sibuti Formation from northwest Borneo have been studied based on the mineralogy, major and trace element geochemistry data. The X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) data revealed that the sandstones and mudstones were abundant in quartz, pyrite, clay, and heavy minerals such as zircon, rutile, and some detrital cassiterite. Geochemically, the sandstones and mudstones are classified into quartz arenite, litharenite, sublitharenite, arkose, and wacke. Quartz arenites are enriched with SiO2, Zr, and Th and depleted in Al2O3, CaO, and other elements compared to other sandstone types, indicating high maturity and intensive weathering. Chemical index of alteration (CIA: 77–90), plagioclase index of alteration (PIA: 86–100), and A-CN-K diagram suggest intense weathering in the source area. Elemental ratios such as La/Sc, Th/Sc, Cr/Th, La/Co, and Th/Co are similar to sediments derived from the felsic rocks. Also, the provenance discrimination diagrams suggest recycled continental nature of these clastic sediments which are mostly derived from metasedimentary source (Rajang Formation). Discriminant-function diagram for the tectonic discrimination of siliciclastic sediments revealed that the sediments of Sibuti Formation were derived from a collision zone, which is consistent with the geology of the study area.

Metal concentrations in sediments from tourist beaches of Miri City, Sarawak, Malaysia (Borneo Island)

Forty-three sediment samples were collected from the beaches of Miri City, Sarawak, Malaysia to identify the enrichment of partially leached trace metals (PLTMs) from six different tourist beaches. The samples were analyzed for PLTMs Fe, Mn, Cr, Co, Cu, Ni, Pb, Sr and Zn. The concentration pattern suggest that the southern side of the study area is enriched with Fe (1821-6097 μg g(-1)), Mn (11.57-90.22 μg g(-1)), Cr (51.50-311 μg g(-1)), Ni (18-51 μg g(-1)), Pb (8.81-84.05 μg g(-1)), Sr (25.95-140.49 μg g(-1)) and Zn (12.46-35.04 μg g(-1)). Compared to the eco-toxicological values, Cr>Effects range low (ERL), Lowest effect level (LEL), Severe effect level (SEL); Cu>Unpolluted sediments, ERL, LEL; Pb>Unpolluted sediments and Ni>ERL and LEL. Comparative results with other regions indicate that Co, Cr, Cu, Ni and Zn are higher, indicating an external input rather than natural process.

Assessment of trace metal contamination in a historical freshwater canal (Buckingham Canal), Chennai, India

The present study was done to assess the sources and the major processes controlling the trace metal distribution in sediments of Buckingham Canal. Based on the observed geochemical variations, the sediments are grouped as South Buckingham Canal and North Buckingham Canal sediments (SBC and NBC, respectively). SBC sediments show enrichment in Fe, Ti, Mn, Cr, V, Mo, and As concentrations, while NBC sediments show enrichment in Sn, Cu, Pb, Zn, Ni, and Hg. The calculated Chemical Index of Alteration and Chemical Index of Weathering values for all the sediments are relatively higher than the North American Shale Composite and Upper Continental Crust but similar to Post-Archaean Average Shale, and suggest a source area with moderate weathering. Overall, SBC sediments are highly enriched in Mo, Zn, Cu, and Hg (geoaccumulation index (Igeo) class 4–6), whereas NBC sediments are enriched in Sn, Cu, Zn, and Hg (Igeo class 4–6). Cu, Ni, and Cr show higher than Effects-Range Median values and hence the biological adverse effect of these metals is 20%; Zn, which accounts for 50%, in the NBC sediments, has a more biological adverse effect than other metals found in these sediments. The calculated Igeo, Enrichment Factor, and Contamination Factor values indicate that Mo, Hg, Sn, Cu, and Zn are highly enriched in the Buckingham Canal sediments, suggesting the rapid urban and industrial development of Chennai Metropolitan City have negatively influenced on the surrounding aquatic ecosystem.

Assessment of Metals Distribution and Microbial Contamination at Selected Lake Waters in and Around Miri City, East Malaysia

A baseline study was carried out to assess the metal concentrations and microbial contamination at selected Lake waters in and around Miri City, East Malaysia. Sixteen surface water samples were collected at specific Lakes in the environs of major settlement areas and recreational centers in Miri City. The Physico-chemical parameters [pH, Electrical Conductivity (EC) and Dissolved Oxygen (DO)], metals (Fe, Mn, Cu, Cd, Ni and Zn) and Escherichia coli (E. coli) were analysed. The concentrations of Fe, Mn and Ni have been found to be above the permissible limits of drinking water quality standards. The metals data have also been used for the calculation of heavy metal pollution index. Higher values of E. coli indicate microbial contamination in the Lake waters.

Occurrence of cymothoid isopod from Miri, East Malaysian marine fishes.

To identify the isopod parasite, which has been recorded from Miri, East Malaysian marine fishes. During the present study, four cymothoid isopods are reported three genera, including Cymothoa eremita, Lobothorax typus, Nerocila longispina and Nerocila loveni. Nerocila longispina and N. loveni are also previously reported from Malaysia and two additional cymothoids C. eremita and L. typus are reported for the first record of Miri coast, East Malaysia. New hosts were identified for N. loveni on Chirocentrus dorab for the first time in the world fauna. The Parasitological indexes were calculated. The site of attachment of the parasites on their hosts was also observed. These parasites can cause the damage in gill, eye and internal organ including swim bladder. Marine fish parasitology is a rapidly developing field of aquatic science.

Runnel development on granitic boulders on the foothills of Mount Kinabalu (Pinosuk Gravel Formation, Sabah, N Borneo)

Runnels are characteristic erosional features on karstified soluble rocks and can occasionally develop on less soluble rocks (i.e. sandstones and granites) but are poorly reported in Malaysia. This research summarizes boulder distribution, size, petrology and runnel morphology in a Pleistocene post-glacial mudflow on Mount Kinabalu. The goal is to investigate the runnel formation on granites. Colonization of boulders by cyanobacteria, mosses, lichens and higher plants is observed and related to rock surface meso-scale and micro-scale features. The coarse porphyritic texture of the granite contributes to the fragmentation and mechanical weathering of large K-feldspar crystals in the runnels. The damp runnel micro-environment is preferentially covered with mosses further enhancing weathering and erosion. As runnels deepen, the remnant protruding fins of rock weaken and may break off. The runnels are subaerial pseudokarst features, not the result of dissolution.

Water quality monitoring: A comparative case study of municipal and Curtin Sarawak's lake samples

In this study, particle size distribution and zeta potential of the suspended particles in municipal water and lake surface water of Curtin Sarawaks lake were compared and the samples were analysed using dynamic light scattering method. High concentration of suspended particles affects the water quality as well as suppresses the aquatic photosynthetic systems. A new approach has been carried out in the current work to determine the particle size distribution and zeta potential of the suspended particles present in the water samples. The results for the lake samples showed that the particle size ranges from 180nm to 1345nm and the zeta potential values ranges from -8.58 mV to -26.1 mV. High zeta potential value was observed in the surface water samples of Curtin Sarawaks lake compared to the municipal water. The zeta potential values represent that the suspended particles are stable and chances of agglomeration is lower in lake water samples. Moreover, the effects of physico-chemical parameters on zeta potential of the water samples were also discussed.

Paleo-Redox Conditions of the Albian-Danian Carbonate Rocks of the Cauvery Basin, South India: Implications for Chemostratigraphy

Abstract To understand the paleo-redox conditions that occurred during the Albian-Danian, we have analyzed major and trace elements from limestone samples collected from three sections of the Cauvery Basin. In the Vadugarpettai quarry section, coral algal limestone (CAL) and bedded limestone show small variations in CaO content (54.4–55.5%; 51.3–54.1%, respectively) than marl and gray shale (GS) (31.9–49.7%; 26.9–40.3%, respectively). In the Vellipirangiyam quarry section, oyster Gryphaea limestone (OGL) shows larger variations in CaO content (42.5–53.9%) than Inoceramus limestone and fossiliferous limestone (52.00–52.50%; 52.70–52.80, respectively). The concentrations of immobile trace elements (Zr and Th) varied significantly between different litho-units of the sedimentary rocks of Albian-Danian age. In addition, Al2O3 shows a positive relationship with immobile trace elements such as Zr and Th, suggesting a terrigenous origin for these elements. Enrichment of U and V contents is higher in the GS and particular intervals of CAL and marl bedded limestone (MBL) of the Vadugarpettai quarry section, lower and upper parts of the OGL of the Vellipirangiyam quarry section, and lower and middle parts of the limestone sequence of the Periakurichchi quarry section. The GS and lower part of MBL (Vadugarpettai quarry section); lower and upper parts of the OGL (Vellipirangiyam quarry section); and lower, middle, and upper parts of the Periakurichchi quarry section also show enrichment of Mo. Furthermore, high values of U/Th were noticed in the CAL and MBL of the Vadugarpettai quarry section, OGL of the Vellipirangiyam quarry section and certain intervals of the Periakurichchi quarry section. Such variations in U, V, and Mo contents and the U/Th ratio in the studied sections suggest that the Cauvery Basin experienced oxic to suboxic-anoxic conditions during Albian-Danian.

Human health risk assessment and bioaccumulation of trace metals in fish species collected from the Miri coast, Sarawak, Borneo

The concentrations of nine trace metals (Cr, Mn, Co, Ni, Cu, Zn, Rb, Cd, and Pb) were measured in different tissues of two pelagic and five demersal fish species collected from the Miri coast, Sarawak. The sequence of accumulation of trace metals in different tissues were: liver > gill > gonad > muscle. Zn (301.00 μg g-1) and Cd (0.10 μg g-1) was the maximum and minimum accumulated elements. According to the Hazard Index calculation, none of the elements will pose any adverse health effects to humans for both ingestion rates (normal and habitual fish consumers) proposed by USEPA, except for Pb and Cd in certain fish species. On the basis of the results, the level of elements in the edible muscle tissues of all the analyzed fish species from the Miri coast are below the maximum permissible limits of Malaysian and International seafood guideline values and safe for consumers.

CO2 storage in heterogeneous aquifer: A study on the effect of injection rate and CaCO3 concentration

Trapping mechanisms taken place during and after CO2 injection in a geologic storage medium are impacted by a number of parameters including injection rates together with rock and pore fluid compositions. There have been many studies on the factors controlling the capillary trapping and injectivity of CO2 storage sites. However, there are only few works carried out discussing on the effect of flow rate and rock and fluids compositions in controlling the trapping mechanisms. In this paper a CO2 storage site located in a heterogeneous aquifer is simulated to investigate the efficiency of structural, capillary and dissolution trappings as a function of injection rate and concentration of calcium carbonate. The results obtained from numerical analysis indicated that CO2 injection must be made within an optimum injection rate for having an effective storage in place. It was also found that concentration of CaCO3 is an important parameter to consider during the analysis as it drastically controls the fate of trapping mechanisms at high injection rates.