Potential of Hemidesmus indicus for phytoextraction of lead from industrially contaminated soils

Many sites in the industrial region of Kattedan near Hyderabad, Andhra Pradesh (AP), India are contaminated with high concentrations of lead. The use of plants to remove toxic metals from soils (phytoremediation) is emerging as a potential strategy for cost-effective and environmentally sound remediation of contaminated soils. We studied remediation of soils contaminated with lead using a lead hyperaccumulating plant, Hemidesmus indicus. The ability of this plant to accumulate lead in shoots and roots was studied with pot experiments. The results showed that accumulation was maximum in roots for the first 1-3 weeks and later for a contact period of three months, the accumulation rate was maximum in shoots. In addition we used various chelating agents such as EDTA, HEDTA, DTPA and CDTA to determine the best chemical modifier for efficient lead removal from contaminated soils. The effect on lead accumulation of plant in the presence of various metal co-ions was also studied. An attempt was made for the decontamination of lead from five different "Real-life" soils of Kattedan using H. indicus.     

Comparative Toxicological Evaluation of Untreated and Treated Tannery Effluent with Nostoc Muscorum L. (Algal Assay) and Microtox Bioassay

The relative sensitivity of tannery effluent before and after treatment was compared by employing Nostoc muscorum and microtox assay in laboratory. The effect on chlorophyll, protein and biomass content of Nostoc muscorum was studied with the luminescent property inhibition of Photobacterium phosphorium and compared with algal bioassay. The results of microtox assay after 5, 15 and 30 min of exposure were compared with data obtained from algal bioassay. It was observed that the luminescent property of Photobacterium phosphorium in microtox assay as well as the chlorophyll content of Nostoc muscorum in algal assay were the most sensitive parameters in toxicity evaluation of tannery effluent. The microtox assay produced notably comparable EC50 values with that of algal bioassay. The microtox assay of toxicity showed that EC50 (%) in 30 min was 3.19 and 63.49 for untreated and treated tannery effluent, respectively while in algal bioassay the EC50 for chlorophyll was in between 0-2.5% and 100%, respectively, in untreated and treated effluent. More than 60% reduction of toxicity was noted in treated tannery effluent in both test system.     

Bioccumulation and toxicity of Cu and Cd in Vallisneria spiralis (L.)

Accumulation of Cu and Cd by Vallisneria spiralis was studied under laboratory conditions. Plants showed ability to reduce 5 µg ml^–1 Cu background concentration to below 0.05 µg ml^–1 (m.p.l., WHO 1985) within 48 h. The Cd concentration of 1.0 µg ml^–1 was reduced to below m.p.l. (0.005 µg ml^–1) in 168 h. Cysteine synthesis was more under Cd stress condition. Both the metals were toxic to the plants at higher concentrations; more in the case of Cd.NBRI Rsearch Publication No. 417 (N.S.).     

Metal biomonitoring in water resources of Eastern Ghats,Koraput (Orissa), India by aquatic plants

Biomonitoring of toxic metals in the water resources used by indigenous tribal communities in Koraput district, Orissa, India was carried out under the National Technology Mission Project. Most of the water bodies catering for the day-to-day needs of the local inhabitants were found to contain high concentrations of Fe and Mn in addition to Cr, Cd, Pb and Cu. The water bodies supported by a great number of phytodiversity and the plants growing therein accumulated significantly high amounts of these toxic metals, submerged plants being more efficient than floating ones. The species like Chara corallina and Spirogyra spp. showed significant potential to magnify Cd and Pb in their tissue several times more than the concentrations in surrounding water. The levels of metals in the plants occurring at places where the metal content is very high could be used for indicating the status of water.NBRI Research Publication No. (437) NS.     

In vivo and in vitro control activity of plant essential oils against three strains of Aspergillus niger

Environmental Science and Pollution Research - Contamination of environment and food from the prevalent spores and mycotoxins of Aspergillus niger has led to several diseases in humans and other...     

Impact of climate change on agricultural production of Odisha (India): a Ricardian analysis

Regional Environmental Change - The present study examines the climate sensitivity of the agricultural production of Odisha, a state at the east coast of India. The two climatic variables which...     

Bacterial diversity in mining and non-mining regions with emphasis on plant growth-promoting traits

A total of 20 soil samples were collected from mining and non-mining areas of coal field regions of Dhanbad, India. These samples were grown on different types of selective media and a total of 141 isolates, each having plant growth-promoting (PGP) characteristics were obtained. The isolates were further tested for PGP traits (phosphate solubilisation, production of indole acetic acid, hydrogen cyanide, ammonia and siderophores) and a biochemical analysis was done to determine the prevalent species of the region. All the strains selected showed at least two PGP characteristics, which indicated that they can be used as plant growth promoters. Bacillus and Pseudomonas species were prevalent in both mining and non-mining areas, whereas Rhizobium, Azospirillum and Azotobacter were found mostly in the non-mining area. A total of 48 Bacillus, 29 Pseudomonas, 4 Rhizobium, 11 Azospirillum and 10 Azotobacter species were obtained from the two selected regions. The soil samples from the mining region were poor in nutrient content and thus relatively lower numbers of PGP isolates were attained.     

Physicochemical characterization of hydroxyapatite and its application towards removal of nitrate from water

A laboratory study was conducted to investigate the efficiency of hydroxyapatite (HAP) towards removal of nitrate from synthetic nitrate solution. In the present research HAP synthesized from egg-shell was characterized using SEM, XRD, FTIR and TGA–DSC. The removal of nitrate was 96% under neutral conditions, using 0.3 g of adsorbent in 100 mL of nitrate solution having an initial concentration of 100 mg/L. An adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to a linearly transformed Langmuir isotherm with correlation coefficient (R²) > 0.98. Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. In order to understand the adsorption type, equilibrium data were tested with the Dubinin–Radushkevich isotherm. The process was rapid and equilibrium was established within the first 40 min.     

Forest structure and regeneration along the altitudinal gradient in the Binsar Wildlife Sanctuary,Uttarakhand Himalaya,India

Forest structure and regeneration were studied along the altitudinal gradient in the Binsar Wildlife Sanctuary of Uttarakhand Himalaya in India. Stratified random sampling of tree species was done by placing minimum 15 quadrats of 10 × 10 m at each aspect and altitude. The results reveal that along the altitudinal gradient there were three types of forest communities in the Sanctuary viz., chir pine (Pinus roxburghii), oakchir pine (Quercus leucotrichophora and Pinus roxburghii) and oak (Quercus floribunda and Quercus leucotrichophora). Rhododendron arboreum, Cornus macrophylla and Lyonia ovalifolia were main associates of these forest communities. The oak forests had larger shrub population as compared to chir pine. Myrsine africana was the most dominant shrub across the altitudinal gradient, whereas few shrub species were restricted to a certain altitudinal range. The regeneration of chir pine was best at lower altitude on south and east aspects, which indicates that it mostly regenerates on warm and dry slopes. In general, the regeneration potential in most of the tree species declines with the altitude. The density of saplings and seedlings also represented the dominant species at each altitudinal range, which indicates the cyclic regeneration of forests in the Sanctuary area.