Accumulation of total trace metals due to rapid urbanization in microtidal zone of Pallikaranai marsh, South of Chennai, India

The article presents the results for enrichment of total trace metals (TTMs) from Pallikaranai salt marsh in South Chennai, a metropolis on the southeast coast of India. TTMs Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, Sr, V, and Hg along with sediment texture, OC, and CaCO₃ were analyzed in 36 surface sediments collected during August 2008 to recognize and observe the input of TTMs in the marsh from various sources in the city limits. In view of the rapid urbanization and industrialization in Chennai City, especially on the southern side, uncontrolled input of sewage, garbage, and industrial effluents into the Pallikaranai marsh land, the elevated concentrations are not surprising. The level of enrichment of TTMs has also increased by 20% to 60% for most of the elements when compared with all other ecosystems in the world as well as the nearby area. The results also indicate that the marshy region is more heavily contaminated with Cd, Hg, Cr, Cu, Ni, Pb, and Zn than other regions on the southeast coast of India. The Enrichment Factor, Contamination Factor, and I _geo indexes are calculated, and these values are useful to assess the degree of pollution in sediments. The spatial distributions of TTMs are also controlled by other factors like geochemical, precipitation, and flocculation of particulate substances in the marsh. The results of the present study suggest the need for a regular monitoring and management program which will help to improve the quality of Pallikaranai pristine marsh land.     

The effects of fenvalerate on different tissues of freshwater fish Cirrhinus mrigala

The histopathological changes of fenvalerate on the gill, kidney, liver and intestine tissues of the Cirrhinus mrigala were determined by light microscopy. The fish were exposed to two sub-lethal concentrations of fenvalerate (1.5-3.0 ppb). The most common gill changes at all concentrations of fenvalerate were epithelial hyperplasia, epithelial necrosis, desquamation and lamellar fusion. Besides, epithelial lifting, oedema, swelling at the tips of secondary lamellae and curling of secondary lamellae were other histopathological changes. Necrosis of tubular epithelium, pycnotic nuclei in the hematopoietic tissue, hypertrophied epithelial cells of renal tubules, narrowing of the tubular lumen, expansion of space inside the Bowman's capsule and contraction of the glomerulus were observed in kidney tissues of fish. Hepatic lesions in the liver tissues of fish exposed to fenvalerate were characterized by congestion, cloudy swelling of hepatocytes and focal necrosis. Atrophy of epithelial cells, necrosis of epithelial cells, desquamation of mucosal epithelium and infiltration of lymphocytes into the lamina propria were detected in intestine tissues of fish after exposure to fenvalerate.     

Phycocyanin from Spirulina platensis bio-mimics quantum dots photocatalytic activity: A novel approach for dye degradation

Environmental Science and Pollution Research - In our present study, the photocatalytic degradation of malachite green (MG) an organic dye was carried out using a phycocyanin extract of Spirulina...     

A novel approach to preparation of nano-adsorbent from agricultural wastes (Saccharum officinarum leaves) and its environmental application

Environmental Science and Pollution Research - Saccharum officinarum leaves (SL) assisted nano-silica (NS) were synthesized and used as adsorbent to remove Pb2+ and Zn2+ from aqueous solutions. The...     

Influence of preparation techniques of cellulose II nanocrystals as reinforcement for tannery solid waste–based gelatin composite films

Environmental Science and Pollution Research - Tannery waste–based gelatin composite film reinforced with cellulose II nanocrystal (CNC II) extracted from wet wipes using three different...     

Isolation,identification, Pb(Ⅱ) biosorption isotherms and kinetics of a lead adsorbing Penicillium sp. MRF-1 from South Korean mine soil

A heavy metal contaminated soil sample collected from a mine in Chonnam Province of South Korea was found to be a source of heavy metal adsorbing biosorbents. Chemical analyses showed high contents of lead (Pb) at 357 mg/kg and cyanide (CN) at 14.6 mg/kg in the soil. The experimental results showed that Penicillium sp. MRF-1 was the best lead resistant fungus among the four individual metal tolerant fungal species isolated from the soil. Molecular characterization of Penicillium sp. MRF-1 was determined using ITS regions sequences. E ects of pH, temperature and contact time on adsorption of Pb(II) by Penicillium sp. MRF-1 were studied. Favorable conditions for maximum biosportion were found at pH 4 with 3 hr contact time. Biosorption of Pb(II) gradually increased with increasing temperature. E cient performance of the biosorbent was described using Langmuir and Freundlich isotherms. Adsorption kinetics was studied using pseudo first-order and pseudo second-order models. Biosorbent Penicillium sp. MRF-1 showed the maximum desorption in alkali conditions. Consistent adsorption/desorption potential of the biosorbent in repetitive cycles validated the e cacy of it in large scale. SEM studies given notes on surface modification of fungal biomass under metal stress and FT-IR results showed the presence of amino groups in the surface structure of the biosorbent. In conclusion, the new biosorbent Penicillium sp. MRF-1 may potentially be used as an inexpensive, easily cultivatable material for the removal of lead from aqueous solution.     

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 (I_geo) class 4–6), whereas NBC sediments are enriched in Sn, Cu, Zn, and Hg (I_geo 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 I_geo, 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.     

Rapid biological synthesis of silver nanoparticles using <Emphasis Type="Italic">Leucas martinicensis</Emphasis> leaf extract for catalytic and antibacterial activity

A novel green approach for the synthesis and stabilization of silver nanoparticles (AgNPs) using water extract of Leucas martinicensis leaf has been developed. As obtained, the nanoparticles are characterized by UV-visible (UV-Vis), transmission electron microscope (TEM), and X-ray diffraction (XRD). The crystalline nature of the AgNPs is confirmed by the prominent peaks in the XRD pattern. FTIR spectra suggest that the possible biomolecules are responsible for the efficient stabilization of the sample. The effects of leaf quantity on the biosynthesis of AgNPs are investigated by UV-Vis spectrophotometer. The synthesized AgNPs are observed to have a good catalytic activity on the reduction of methylene blue by L. martinicensis leaf. This is confirmed by the decrease in absorbance maximum values of methylene blue with respect to time through UV-Vis spectrophotometer. Moreover, the antibacterial activity of synthesized AgNPs against Staphylococcus aureus, Bacillus subtilis, Salmonella typhi, and Escherichia coli are screened.     

Taxonomy of groundwater quality using multivariate and spatial analyses in the Tuticorin District,Tamil Nadu,India

A holistic appraisal of the quality of groundwater from the Tuticorin District has been conducted using multivariate statistical and spatial analyses. The objectives of the study were to delineate the spatial and temporal variabilities in groundwater quality and to understand its suitability for human uses. A total of 100 groundwater samples were collected and analyzed for major cations and anions during pre-monsoon and post-monsoon. Water quality index rating was calculated to quantify overall water quality for human consumption. The PRM samples exhibit poor quality in greater percentage when compared with POM due to the dilution after rainfall. Correlation, factor analysis, and plot of the factor scores reflect the seawater intrusion and weathering process. The mineral stability diagrams indicated that the groundwater is in equilibrium with kaolinite and Ca-montmorillonite, whereas Gibbs plot showed that the chemical composition of groundwater in both districts is controlled by the natural weathering processes irrespective of seasons. The major water type identified in this study is the Ca²⁺–Mg²⁺–HCO₃ ^? type, which degrades into predominantly Na⁺–Cl^?–SO₄ ^2? more saline groundwater toward the coast.