Limnochemistry and nutrient dynamics in Upper Lake, Bhopal, India

In limnetic ecosystem, water quality depends upon physical, chemical, and biological factors. Effects of temperature, light scattering, and absorption by suspended and dissolved matter, transport, and mixing of nutrients within the lake are the significant factors as far as water quality is concerned. Nutrient loading into the lake and internal cycling of nutrients is always a matter of concern and critical to number of processes. During the winter season, heat and momentum transfer at the lake surface and the temperature-density relation of water destabilize the water column and drive vertical mixing and transport processes. The deepening of the surface layer produces nutrient transfer from the hypolimnion into the euphotic zone of epilimnion. It may also resuspend sediments that would have settled under stratified conditions, or redistribute particles that may still be in suspension. Thus, there exists a complex connection between the hydrodynamics and water quality issues. Present study is an effort to understand how seasonal changes in the limnetic ecosystem regulate the limnochemistry and movement of nutrient. The study revealed that significant variations of nutrients and organic load were observed between epilimnion and hypolimnion during summer season, and the lake was found in hyper-eutrophic condition throughout the study period.     

Management of root knot nematode on tomato through application of fungal antagonists, Acremonium strictum and Trichoderma harzianum

Management of root knot nematode disease infecting tomato, by the use of fungal bioagents Acremonium strictum and Trichoderma harzianum isolated from egg masses of M. incognita infecting tomato has been carried out. The rhizosphere and rhizoplane of root knot nematode infested tomato revealed consistent association of Acremonium strictum. In the present study A. strictum and other fungal bioagents viz. Aspergillus niger, Paecilomyces lilacinus, Rhizoctonia solani and Trichoderma harzianum isolated earlier from egg-masses of M. incognita, identified and maintained have been investigated through in-vitro and in-vivo trials for their potentiality against M. incognita. Out of the above, isolated mycoflora A. niger was identified to be toxic against M. incognita while A. strictum and T. harzianum was found to possess both egg parasitic or opportunistic and toxic properties. A field trial with all the above fungal bioagents both alone and together showed significant promising performance by the dual treatment of A. strictum and T. harzianum in improving the health of the tomato plant with a remarkable reduction in M. incognita population.     

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).     

Effects of diazinon on serum calcium and inorganic phosphate levels as well as ultrastructures of parathyroid and calcitonin cells of Rattus norvegicus

Daily intramuscular administration of two doses--0.50 LD550 (150 mg/kg b w) and 0.75 LD50 (225 mg/kg b w) of diazinon for 14 days induced progressive hypocalcemia without altering serum inorganic phosphate value in Rattus norvegicus. Hypocalcemic response of the pesticide was dose- as well as time-dependent. Parathyroid chief cells of the experimental rats exhibited degranulation, vacuolation, loss of secretory granules and lipid droplets, decreased chromatin, and degenerative changes in endoplasmic reticulum, Golgi complex as well as cristae of the mitochondria. Not much of ultrastructural changes could be seen in the C cells of the rats treated with diazinon.     

Bronchial contamination with toxic metals in mineral-based industrial areas of India

Selected toxic metals (Zn, Pb, Cu, Cr, Co, Cd, Ni and Mn) were determined by atomic absorption spectrophotometry in 55 samples of bronchial washouts obtained from patients with respiratory ailments. These subjects either worked or lived in industrial locations which have mineral-based industries such as steel plants, thermal power plants, cement plants, limestone mines and iron ore mines. Half of the samples analysed were from the plant workers and the other half from the non-workers living in the respective industrial areas. Samples from subjects living outside the industrial areas were also collected and analysed. The highest occurrence of toxic metals was found in the subjects living in the steel plant area. The occurrence was of the order: steel plant > thermal power plant > cement plant > iron ore mines > limestone mines > non industrial areas. Plant workers showed a higher presence of metals in their respiratory tracts compared to the non-workers in each industrial area. Higher depositions were noticed in areas of coal-fired industries compared to non-coal-fired industries. Zn, Cu and Pb were more likely to reach the respiratory tracts. The occurrences were found to increase with the age of the subjects. A slightly higher susceptibility to bronchial contamination was noticed in females.To whom correspondence should be addressed.     

Complex dynamics of toxin producing algal species and primary productivity in two water ponds of Faizabad

In order to develop a method of predicting and assessing pond eutrophication, which is a serious environmental problem, and to propose effective measure of improvement of water quality. The present study was performed to measure water quality variables, primary productivity, chl-a and biomass of toxin producing algal species and fish production. High nutrient influx and toxin producing algal species have been observed during June 1999 to May 2000 in two water bodies [Girija Kund (A) and Maqubara pond (B)] of Faizabad. The maximum chl-a concentration, toxins producing algal species biomass were found to be 415.00 and 515.00 in pond A, while 451.00 microg/l and 541.22 mg/l in pond B, respectively in the case of Microcystis aeruginosa. Ecological parameters to evaluate GPP, NPP and CR were found to be 297.00, 134.000 and 182.00 mgCm3/h in summer season in pond B, respectively which is higher than pond A. A poor association existed between chl-a and GPP. Temporal variation (Photosynthetic rate) in A(max) & P(max) was also observed to evaluate the productivity of pond. Annual fish production potential of the ponds A and B has been estimated to be around 342.00 Kg and 204. 00 Kg, respectively which may be due to the presence of toxin producing algal species.     

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.     

Distribution of heavy metals in sediment and water of river Gomti

Gomti river receives industrial as well as domestic wastes from various drains of Lucknow city. In the process the water and sediment of the river Gomti get contaminated with heavy metals and other pollutants. In the present study, impacts of domestic/industrial wastes on the water and sediment chemistry of river Gomti with special reference to heavy metals have been investigated in different seasons (summer, winter and rainy). For this, seven sampling sites: Gaughat, Mohan Meakin, Martyrs Memorial, Hanuman Setu, Nishatganj bridge, Pipraghat and Malhaur, in the river Gomti in Lucknow region were identified and samples of water and sediments were collected in all the three seasons. In the collected water and sediment samples, six metals (Cd, Cr, Cu, Ni, Pb, and Zn) were analyzed on ICP-AES (Inductively coupled plasma emission spectroscopy) Labtam Plasmalab 8440. High concentrations of all the metals were noticed in water and sediment in rainy season compared to summer and winter. Because in rainy season runoff from open contaminated sites, agricultural field and industries, directly comes into the river without any treatment. In both the cases, the concentration of zinc was maximum (0.091 g/ml in water and 182.13 g/g in sediment) and the concentration of cadmium (0.001 g/ml in water and 17.26 g/g in sediment) was minimum. Higher concentration of metal in water and sediment during rainy season could be due to the industrial/agricultural/domestic runoff coming into the river.     

Adaptational strategy of a tropical shrub Carissa Carandas L. to urban air pollution

This paper reports the adaptational response of a tropical shrub Carissa Carandas L. to urban air pollution stress in Varanasi, India. Saplings of C. carandas were grown at a density of one per pot and kept for two years at 25 selected sites in the urban environment. Different sites received different levels of air pollution input. Changes in vegetative growth pattern (leafing and branching), in morphological features and in the distribution of biomass to above and below ground structures were considered in relation to the ambient air quality.Different levels of air pollution input produced different sets of harmful effects. Although the air pollution level at Varanasi reduced the plant height, basal diameter, canopy area, leaf area and total plant biomass of C. carandas, this species retained a major fraction of its photosynthate to above-ground plant parts where foliage assumes predominance. Since carbon gain is dependent not only on the rate of carbon acquisition per unit leaf tissue but also on the amount of photosynthetic tissue present, a shift in relative contribution of photosynthate to leaf production and shoot growth appears to be a pollution-induced adaptive response in C. carandas.     

N:P stoichiometry and transparent exopolymeric particles buffer ecological impacts of nutrients in the Ganga River: a mesocosm study

We investigated the possible drivers of the N:P stoichiometric shift and its relationship with micro-algal production of transparent exopolymeric particles (TEP) along a 35?km gradient of the Ganga River. The objective was to evaluate if the trade-off between N:P stoichiometry and production of TEP helps in maintaining water quality of the river. Mesocosm experiments were conducted to examine N:P-TEP linkages and its role in turbidity removal. In situ measurements did not show Si to be a limiting nutrient (N:Si?Aulacosira granulata and Fragilaria intermedia. Settling efficiency, turbidity removal and sedimentation of TEP, biogenic silica (BSi) and biomass all increased with decreasing N:P ratio proportionately to the amount of TEP produced in the mesocosm. The study demonstrates that trade-off between N:P stoichiometry and the production of TEP generates feedback to buffer the ecological impacts of nutrient pollution.