Mining and the environment: a case study from Bijolia quarrying site in Rajasthan, India

Mining is essentially a destructive developmental activity, where ecology suffers at the altar of economy. Unfortunately, in most regions of the Earth, the underground geological resources are superimposed by biological resources (forests). This is particularly evident in India. Hence mining operations necessarily involve deforestation, habitat destruction, biodiversity erosion and destruction of geological records which contain information about past biodiversity. Extraction and the processing of ores and minerals also lead to widespread environmental pollution.However, mankind cannot afford to give up the underground geological resources which are the basic raw materials for development. An unspoiled nature can provide ecological security to people but cannot bring economic prosperity. Scientific mining operations accompanied by ecological restoration and regeneration of mined wastelands and judicious use of geological resources, with search for eco-friendly substitutes and alternatives must provide the answer.A case study from the Bijolia quarrying area in Rajasthan, India, provides some sensational revelations of the impact of mining on the human ecosystem.     

Dissipation behavior of propargite--an acaricide residues in soil, apple (Malus pumila) and tea (Camellia sinensis)

Propargite, recently introduced in India, is an effective acaricide on a large number of crops most of which are consumed by human beings directly or after processing. Therefore, it has become important to check the dissipation behavior of propargite in edible raw commodities, processed products and in the environment. In the present study, dissipation of residue of this acaricide in soil, apple fruit and tea (green tea leaves, manufactured tea, infusion and spent leaves) was studied. Analysis was carried out using high performance-liquid chromatography with UV detection system. The dissipation rate was found to vary with the nature of studied crop/sample. In soil, half-life ranged from 43 to 45 days, while in plant matrices (tea and apple) it ranged 1.66-2.61 days. The percent transfer of propargite residue from manufactured tea to infusion was 23.60-40.00; however, 35.71-53.20% of the residues remained stuck to the spent leaves.     

Antioxidative responses in relation to growth of mustard (Brassica juncea cv. Pusa Jaikisan) plants exposed to hexavalent chromium

Effect of hexavalent chromium (Cr6+) was seen on Brassica juncea cv. Pusa Jaikisan grown for 15 days in hydroponic culture supplemented with 0.2, 2 and 20 microM Cr. The inhibitory response of Cr6+ on growth of B. juncea was concentration and time dependent. The stimulation of plant growth, observed in response to exposure to 0.2 microM Cr6+, during initial 5 days was reversed on prolonged treatment and at higher Cr6+ concentrations (2 and 20 microM Cr6+). Despite reduction in growth, chlorophyll content increased substantially on 15 days exposure to 20 microM Cr6+. Significant increases in lipid peroxidation and tissue concentration of H2O2 occurred in plants exposed to 2 and 20 microM Cr6+. Effect of Cr6+ on antioxidative enzymes in roots and leaves was differential. SOD and CAT activities at lower levels of Cr6+ supply remained higher all through the treatment. While APX was very susceptible to excess Cr6+, GR and GST increased at elevated levels of Cr6+. The results suggested Cr6+ induced depression in plant growth of B. juncea to be a function of increased cellular accumulation of Cr despite increase in the activities of some of the antioxidative enzymes.     

Stress in the workplace: a comparison of gender and occupations

Stressful incidents at work were examined using an open‐ended technique for three different occupations: clerical workers, university professors and sales associates. The study revealed both similarities and differences in stressors and coping techniques reported across occupations. Interpersonal conflict, work overload and time wasters were common across all occupations. Lack of control and work overload were reported as major stressors by the clerical group and interpersonal conflict as a major stressor by the academic and sales groups. Gender differences were also found. Copyright © 1999 John Wiley & Sons, Ltd.     

Soil dehydrogenase, phosphomonoesterase and arginine deaminase activities in an insecticide treated groundnut (Arachis hypogaea L.) field

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2 pyridyl phosphorothioate) 20 EC and Quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate) 25 EC, were applied in groundnut (Arachis hypogaea L.) field as seed treatment at 25 ml/kg and soil treatment at 4 l/ha in 1998 and 1999. The residues of these insecticides were monitored during the entire crop season and their effect on the soil enzymes dehydrogenase, phosphomonoesterase and arginine deaminase were studied. Ninety nine percent of chlorpyrifos residues were dissipated within 60 days from seed treated soil and 98% dissipation was observed in soil treated field for the same days. Its half lives in seed treated soil were 8 days and 7 days and in soil treated field were 9.2 days in and 7.5 days in 1998 and 1999 respectively. Dissipation of quinalphos in comparison to chlorpyrifos was slow both in seed treated and soil treated field. Eighty seven percentage to 92% dissipation of quinalphos residues were observed from seed treated soil and 98% residues were dissipated from soil treated field within 75 days. Its half lives in seed treated soil were 20 days and 18 days and in soil treated field, its half lives were 13 days and 17 days 1998 and 1999 respectively. Inhibition in dehydrogenase activity followed by recovery was observed both in seed and soil treatments with chlorpyrifos. An inhibition of 17.2% was estimated after 60 days of seed treatment in comparison to control. Dehydrogenase activity was significantly reduced to 63% after 15 days of quinalphos seed treatment in comparison to control in 1998. Similar trends were observed in 1999. A significant inhibition in dehydrogenase activity was observed after soil treatment both in 1998 and 1999. Phosphomonoesterase activities were significantly inhibited upto 25.2% as compared to the control, on the 15th day of chlorpyrifos seed treatment in 1998 and similarly, after one day of treatment in 1999. Quinalphos inhibited the phosphomonoesterase activity till the end of the experimental period in the soil treated fields, whereas recovered within 30-60 days of treatment in the seed treated fields. Arginine deaminase activity was significantly stimulated within one day after chlorpyrifos seed and soil treatments in both years. The activity was almost threefold higher on the 30th and the 15th day of soil treatment in 1998 and 1999, respectively. A temporary inhibition of arginine deaminase activity was observed after quinalphos treatment. It was observed that in most of cases insecticides have temporary inhibitory effect on soil enzymes. However, inhibition was smaller in seed treated soil than in direct soil treatment.     

Management of disease complex caused by root knot nematode and root wilt fungus on pigeonpea through soil organically enriched with Vesicular Arbuscular Mycorrhiza, karanj (Pongamia pinnata) oilseed cake and farmyard manure

This investigation was undertaken to compare the percentage response of colonization and development of VA-Mycorrhiza (Glomus fasciculatum) on a number of pulse crops viz. cowpea, chickpea, soybean, pigeonpea and lentil under glasshouse conditions. Among the above-mentioned crops, pigeonpea exhibited the best performance and was selected for further studies. In this host the development and colonization percentage of G. fasciculatum was investigated under two separate substrates i. e. soil amended with FYM and karanj oilseed cake keeping a control treatment of field soil. A third treatment amended with karanj oilseed cake and farm yard manure (FYM) was also kept which responded best in terms of colonization percentage. This treatment showing improved plant health as well as integration with G. fasciculatum was selected as an ideal treatment for the management of disease complex caused by root knot nematode, Meloidogyne incognita and root wilt fungus, Fusarium udum on pigeonpea. Thus the treatment constituting FYM, karanj oilseed cake and VA-Mycorrhiza reduced the disease incidence caused by both maladies to a great extent with the most promising improvement in plant growth parameters as compared to all others. The present investigation, in addition to proposing an ideal eco-friendly treatment for the management of this disease complex also proposed an excellent medium for the proliferation of the obligate bio-protectant, G. fasciculatum.     

Microbial biomass, P-nutrition, and enzymatic activities of wheat soil in response to phosphorus enriched organic and inorganic manures

Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farm yard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of beta- glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.     

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.     

Study of ultrasonic assisted cryogenically cooled EDM process using sintered (Cu–TiC) tooltip

In most EDM operations, the maximum contribution in the total operation cost is the tool cost. Electrode wear is a major problem in EDM process. Therefore, in this paper, the process performance of sintered copper (Cu)–titanium carbide (TiC) electrode tip in ultrasonic assisted cryogenically cooled electrical discharge machining (UACEDM) has been studied. The performance parameters studied in this paper are electrode wear ratio (EWR), material removal rate (MRR), surface roughness (SR), out of roundness and surface integrity. The process parameters considered in this study are discharge current, pulse on time, duty cycle and gap voltage. Cermet was fabricated, having copper content of 75% and titanium carbide content of 25%, by mixing, pressing, and sintering. The performance of the newly formed cermet electrode tip is compared with conventional copper electrode tip for UACEDM process and analyzed. It has been observed that EWR and out of roundness decreases when cermet electrode tip is used as compared to conventional tooltip. It has also been observed that MRR and SR increase when cermet tooltip is used. The surface cracks density and crack width on workpiece machined by cermet tooltip have been found to be lesser as compared to the specimen machined by conventional tooltip.