Shri Dhar Pandey

Role of humic acid entrapped calcium alginate beads in removal of heavy metals.

Most of the available techniques for removal of heavy metals from solution such as leachates from waste sites are very expensive. The technique described in this paper is designed to study the removal of humic acid by alginate beads and the subsequent binding of the metals within the beads thus decreasing the leachability of heavy metals from a hazardous waste site. The entry of 500 mg/l humic acid into 3% calcium alginate beads in 24 h showed a distinct fluorescence as compared to the fluorescence shown by the entry of 100 and 250 mg/l of humic acid into alginate beads. Further, on treatment of calcium alginate beads containing 500 mg/l humic acid with metals such as Cu, Mn, Zn, Cr and Fe, quenching of fluorescence was noticed, which was maximum with Cu and minimum with Fe.

Removal of chromium and reduction of toxicity to Microtox system from tannery effluent by the use of calcium alginate beads containing humic acid

Removal of chromium (Cr) from tannery effluents by recovery of metal also reduces the ecotoxicological impact. To develop such a process, columns packed with calcium alginate (CA) beads with or without humic acid (HA) have been used as an adsorbent and tannery effluent was passed through it. Concentration of Cr in beads and in different fractions collected after adsorption was measured. Change in total organic carbon content during the process was also noticed. The fractions were also tested for toxicity towards Microtox assay. EC(50) values were determined with the help of Microtox analyser 500. Data showed that the CA beads along with HA could be effectively utilised in removal of 54% Cr and also in reducing the toxicity (EC(50) (%) in 5 min=>100 in fractions collected after 72 h).

Formation of Soluble Complexes of Metals with Humic Acid and Its Environmental Significance

Abstract In order to investigate the role of functional groups present in humic acid(s) (HA) during complex formation, water soluble complexes between HA isolated from soil and metals (Pb, Ca, As, Ni, Cr, Co, Cu, Cd, Fe, Mn, Mg and Zn) were prepared and subjected to infrared (IR) spectroscopy. the IR data revealed the involvement of the - OH group of humic acid in complex formation with all metals except copper and arsenic, whereas the - COOH group of HA was found to be the preferred site of binding for all the metals. the significance of findings in relation to detoxification of environmental pollutants is discussed in this paper.

Biochemical alterations in fish fingerlings (Cyprinus carpio) exposed to sublethal concentration of linear alkyl benzene sulphonate

Fish fingerlings (Cyprinus carpio) were exposed to sublethal concentrations of linear alkyl benzene sulphonate (0.005 ppm) for 24, 48, and 96 h under static laboratory conditions. Alterations were noted in the levels of glycogen, lactic acid, sialic acid, and acid and alkaline phosphatases in the gill, liver, and kidney. This chemical may impair metabolic processes in fingerling carp, because increased exposure resulted in significant increases in lactic acid and decreases in glycogen and sialic acid along with inhibition of acid and alkaline phosphatase activity.

Role of free radicals in the binding of organochlorine pesticides and heavy metals with humic acid

Abstract The formation of soluble complexes between humic acid (HA) and γ-HCH or different metals (Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn,Pb, Cd, As and Mg) was studied, along with any generation of free radicals by electron spin resonance spectroscopy. Free radical generation was noticed in case of interaction of humic acid with γ-HCH, Cu and Cr. A hyperfine splitting pattern was noticed only in case of Mn. However, with Ca, Cd, Pb, As, Ni, Co, Zn and Fe, neither free radicals were generated nor hyperfine splitting was observed. The possible significance of free radicals in the binding of environmental pollutants with humic acid is discussed together with ecotoxicological implications.

Environmental Significance of Humic Acid in the Sequestration of Metals

Abstract Change in the fluorescence of humic acid was studied using various metals, such as iron, cadmium, chromium, mercury, manganese, nickel and lead, to test the significance of humic acid in the sequestration of metals. On keeping the concentration of humic acid fixed (10 μg) and varying the concentration of metals (1-40 μg), the following order of magnitude of quenching was noticed: Cu > Fe > Cr > Mn > Ni > Hg > Pb > Cd. However, humic acid concentration (1-40 μg) and metal concentration (10μg) showed a reverse trend. to test the humic acid-metal interaction in an aquatic system and on aquatic organisms such as fish, the LC50 values at 96 h for metals such as iron, copper, mercury, nickel and chromium were determined against common guppy fish (Poecilia reticulata). A 20 μg dose of humic acid showed a reduction in toxicity of metals towards fish as compared to a control exposed to metals only. the significance of results in relation to ionic interactions in ecotoxicology are discussed.

Carbohydrate metabolism changes in fish fingerlings and yearlings exposed to linear alkyl benzene sulphonate

Exposure of fish fingerlings (Cirrhina mrigala) and yearlings (Puntius sophore) to a concentration of 0.005 mg L−1 of linear alkyl benzene sulphonate for 24, 48, and 96 hr caused alterations in glycogen, lactic acid and sialic acid content in gill, liver, muscles and kidney. Significant decreases in the level of glycogen and elevation in the level of lactic acid demonstrated impairment of carbohydrate metabolism. Decrease in the sialic acid content suggested functional changes in membranes in toxicity.

Effect of Humic Acid on the Bioavailability of γ-Hexachlorocyclohexane in Marsilea Minuta (L.)

Effect of various concentrations of humic acid (0.2 to 1%) on thebioavailability of γ-HCH in vegetative clones of theaquatic fern Marsilea minuta was studied in a staticexperimental bioassay system on different photoperiods. Additionof humic acid showed the reduction in the bioavailability ofγ-HCH in all the photoperiods (72 hr light to 144 hrlight) at the interval of 16 hr light (L) and 8 hr dark (D) inboth aerial and submerged portion as compared to controlindicating its protective role in toxicity.

Amino acid changes and pulmonary response of rats to silica dust

Abstract The effect of intratracheal injection of quartz on the free amino acids of lung, serum, and liver and the bound amino acids of lung was studied in rats, at intervals preceding and following the formation of collagen. The studies revealed that amino acid metabolism is significantly altered in silicotic rat lung. Changes in the body pool of amino acids seem to be related to both collagen and noncollagen formation in silicotic lung. It appears that some of the amino acid residues for collagen formation in lung in response to silica exposure are made available by the in situ formation from available precursors, while others are contributed by other organs, especially liver. A central role for glutamic acid metabolism in the genesis of pulmonary fibrosis is discussed.

Uptake and distribution of 203Hg by fish fingerlings, Cirrhina mrigala, exposed to linear alkyl benzene sulphonate.

Ecological changes caused by the continued pollution of the aquatic environment by chemicals through industrial effluents and domestic sewage and emanations settling into water pose grave concern. Synthetic detergents are one of the most important in this respect since they find their way into aquatic ecosystems thereby affecting the food chain. Earlier studies with diverse aquatic fauna and flora suggested the potential ecotoxicological impact of synthetic detergents. A large number of reports are available on the pollutants toxic to fish. Fish are known to accumulate mercury by virtue of efficient uptake and slow rate of elimination. Mercury also causes morphological and physiological defects with consequent behavioral abnormalities in fish. Even though in actual situations the stress to the ecosystem is caused by a mixture of pollutants, the interactive effect of two or more pollutants present together is poorly understood. Also, in the presence of one toxicant, the capacity of the ecosystem to deal with others can be impaired so that even biodegradable water pollutants may tend to accumulate. Therefore, an attempt has been made to study the uptake and distribution of mercury in presence and absence of detergent to test for any combined effects.