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In this work, the effects of alloying elements in the as cast microstructures and mechanical properties of heavy section ductile cast iron were carrying out a systematic to build up press die mater...

In this paper, monitoring of amplitude variation in the torsional–axial frequency is proposed for evaluating drill flank wear. Vibration signals were captured from the experiments resulting to the drilling process and investigation was focused on the role of torsional–axial coupling on instability predictions arising as a result of drill flank wear in the frequency spectrum. The first and second modes of torsional axial coupling frequencies were found through use of finite element analysis (FEA) and verified using experimental modal analysis (EMA) by the resonance frequency test. The proposed strategy uses dominant peaks of torsional–axial first mode (Tp1) and second mode (Tp2) frequency. The ratio of torsional–axial amplitudes (TP1/TP2) was considered for the monitoring and the evaluation of drill wear and also to nullify process parameter variation. Drill frequencies verified through experimental study showed their capability of predicting drill flank wear. The validation showed the proposed methodology having 80% accuracy and its ability for effective use for monitoring tool wear.

Multi–locational supervised field trials were conducted in different agro–climatic regions in India to study dissipation of trifloxystrobin and tebuconazole in tomato after spraying a combination formulation (trifloxystrobin 25% + tebuconazole 50%, 75WG) at recommended doses: (i) single (trifloxystrobin 87.5 g a.i. ha−1 + tebuconazole 175 g a.i. ha−1) and (ii) double (trifloxystrobin 175 g a.i. ha−1 + tebuconazole 350 g a.i. ha−1). Fruit samples were extracted with ethyl acetate using a modified QuEChERS method. The residues (parent fungicides + metabolite) were analyzed and confirmed by GC–ECD and GC–MS, respectively. The half–life (t1/2) of trifloxystrobin and tebuconazole in tomato varied from 1.08 to 1.72 and 1.13 –to 1.64 days at single; and 1.27 to 2.13 and 1.24 to 1.96 days at double dose, respectively. Since maximum residue limit (MRL) at pre–harvest interval (PHI) of 5 days is impractical, as tomato is usually harvested and consumed almost everyday after the last spray, the risk assessment was performed at minimum PHI of 1 day. Accordingly, on the basis of supervised field trial data and using OECD MRL calculator, MRL of 0.5 and 1.5 mg kg−1 at single dose were proposed for trifloxystrobin and tebuconazole in/on tomato, respectively.

Titanium alloy found major applications in aerospace, automobile and chemical factories due to its large strength at elevated temperature, good corrosion resistance, low thermal conductivity and light weight. Because of its superior qualities, this alloy found difficult to machine. The machinability of titanium alloy can be improved by adding low frequency vibrations (less than 1000 cycles per second) to the cutting tool. An enhancement in the machining performance can be attained by applying minimum quantity lubrication (MQL) in the cutting zone. In this study an attempt has been made to enhance the machinability of Ti6Al4V alloy by using MQL technique during low frequency vibration assisted turning (LFVAT). Experiments were conducted and the influence of low frequency vibrations plus MQL on the turning process was estimated by measuring the average surface roughness, main cutting force and tool wear. The performance of LFVAT, LFVAT + MQL, conventional turning (CT) and CT+MQL compared in terms of the aforesaid output parameters.

Herbicides have proved very effective for the control of weeds in cropped areas in India. However, the herbicide use in the country is far less as compared to insecticides and fungicides. While persistent herbicides remain in crops, soil, ground and surface water for a considerable period of time, they may pose hazard to human and animal life as well as the environment. From risk assessment point of view, herbicide residues are monitored through multi-location supervised field trials at various centres of ICAR-sponsored All India Network Project (AINP) on Pesticide Residues and DAC-sponsored central sector scheme on Monitoring of Pesticide Residues at National Level at IARI New Delhi, and All India Coordinated Project on Weed Management (AICRP-WM) at the Directorate of Weed Research, Jabalpur. Besides focusing on weeds and weed management strategies, these laboratories generate globally acceptable data under good agricultural practices (GAP) for export certification and international trade. So far, edible commodities in India have been found to be mostly safe from herbicide residues. Since in future, the herbicide use is likely to increase, therefore herbicide residues problems will be more frequent and may have implications for human health.

The paper explains why we get many peaks during gas–liquid chromatography (GC) and attempts to rationalize the complicated GC spectra by identifying the major fragments of synthetic pyrethroids. In the present research, gas chromatography conditions in the electronic ionization (EI) mode were established that served as a benchmark in the development of a chemical ionization (CI) protocol for the selected ester and non-ester synthetic pyrethroids. CI technique is a lower energy process than EI. The lower energy yields less fragmentation, and usually a simpler spectrum with identifiable molecular ion. Common major peak in case of cypermethrin, deltamethrin, fenvalerate, and fenpropathrin was due to meta-phenoxybenzaldehyde moiety at m/z 208 (C14H10NO)+ ion. Etofenprox after protonation of ether oxygen loses one molecule of water producing m/z 359 instead of m/z 377 and it further fragmented to m/z 177 (C12 H17O)+ and 135 (C9H11O)+ ions. Above 70 % recoveries of all the pyrethroids at 0.1 and 1 μg ml−1 levels were achieved from environmental samples. Improving analytical sensitivity and selectivity is important for quantifying trace pyrethroids in matrices. In EI mode, selecting base ion for single ion monitoring or using a precursor ion for MS/MS analysis, the lower limits of quantification (less than 0.1 ppm) become possible for the analysis of synthetic pyrethroids in water.

The study was aimed to develop a nano form of an existing fungicide for improving plant protection and reducing crop losses caused by fungal pathogens. The protocol for the preparation and estimation of nanohexaconazole was developed. Technically pure hexaconazole was converted into its nanoform using polyethyleneglycol-400 (PEG) as the surface stabilizing agent. Nanohexaconazole was characterized using Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS) studies. The average particle size of nanohexaconazole was about 100 nm. An analytical method was also developed for quality control of the nanofungicide by GLC fitted with flame ionization detector. Its limit of detection was 2.5 ppm. Fungicidal potential of nanohexaconazole was better in comparison to that of conventional hexaconazole. Hydrolytic and thermal stability studies confirmed its stability at par with the conventional formulation of fungicide. Impact of nanohexaconazole on soil nitrifiers was tested in vitro and there were no significant adverse effect in their numbers observed as compared to conventional registered formulation, proving the safety of the nanofungicide.

Multi-location supervised field trials were conducted in India at four locations of the All India Network Project (AINP) on Pesticide Residues to study the persistence, dissipation and risk assessment of flubendiamide and deltamethrin on cucumber (Cucumis sativus). Residues of flubendiamide and deltamethrin on cucumber resulting from three spray applications of a combination formulation (flubendiamide 90% + deltamethrin 60%, 150 SC) at recommended (22.5 + 15 g a.i./ha) and double the recommended (45 + 30 g a.i./ha) dose were analysed. On the basis of persistence and dissipation studies, the half- life (T1/2) of flubendiamide on cucumber varied from 1.40 to 2.98 (recommended dose) and 1.55 to 2.76 days (double the recommended dose), while that of deltamethrin ranged from 2.5 to 4.9 (recommended dose) and 2.7 to 3.9 days (double the recommended dose) at the four locations. On the basis of supervised field trial data and using OECD calculator, MRLs in the combination product of 3 mg kg-1 for flubendiamide and 1.5 mg kg-1 for deltamethrin has been proposed for consideration by the Food Safety and Standards Authority of India (FSSAI). Codex, EU and EPA have fixed MRL of 0.2 mg kg-1 for flubendiamide and deltamethrin.

In this study, the relationship between vibration and tool wear and also influence of sensor positioning in tool codition monitoring were investigated during drilling. For this purpose, a series of experiment were conducted in a CNC vertical milling machine using drilling cycle. A 6 mm diameter HSS drill and EN24 as workpiece material were used in these experiments. The vibration was measured in the transverse direction of sensor which is positioned on the workpiece with constant distance from the holes to be drilled for monitoring tool wear as in previous studies. But, positioning of sensor in a constant place with equal distance from all holes to be drilled is not possible for all the workpiece profiles in actual practice. Experiments show that the distance of sensor from the holes in drilling affects the vibration signals for the same state of wear.It shows that the tool wear models presented in previous studies using acceleration signals are sensor location dependent. This work presents a Variance-amplitude of the vibration signals received for tool condition monitoring which is the most sensitive statistical parameter than other statistical parameters such as Root Mean Square (RMS), Exponential, Peak, max-min, mean and standard deviation. Results showed that there was no considerable increase in the vibration amplitude of variance until flank wear value of 0.30 mm was reached, above which the vibration amplitude increased significantly.

Bacteria capable of degrading the sulfonated azo dye Red HE7B were isolated from textile mill effluent contaminated soil. The most efficient isolate was identified as Bacillus sp. Azo1 and the isolate could successfully decolorize up to 89 % of the dye. The decolorized cultural extract analyzed by HPLC confirmed degradation. Enzymatic analysis showed twofold and fourfold increase in the activity of azoreductase and laccase enzymes, respectively, indicating involvement of both reductive and oxidative enzymes in biodegradation of Red HE7B. Degraded products which were identified by GC/MS analysis included various metabolites like 8-nitroso 1-naphthol, 2-diazonium naphthalene. Mono azo dye intermediate was initially generated from the parent molecule. This mono azo dye was further degraded by the organism, into additional products, depending on the site of cleavage of R–N=N–R molecule. Based on the degradation products identified, three different pathways have been proposed. The mechanism of degradation in two of these pathways is different from that of the previously reported pathway for azo dye degradation. This is the first report of a microbial isolate following multiple pathways for azo dye degradation. Azo dye Red HE7B was observed to be phytotoxic, leading to decrease in root development, shoot length and seedling fresh weight. However, after biotreatment the resulting degradation products were non-phytotoxic.

The objective of this study was to evaluate in vitro the insecticidal activity of pyridalyl nanosuspension in comparison to technical material and commercial formulation against larvae of Helicoverpa armigera. Suspension of pyridalyl nanocapsules was prepared, for reducing its dose of application. Compatibility of pyridalyl with sodium alginate was ascertained and a formulation was obtained by optimizing various parameters. Average micelle size of different formulations was around 138 nm and size of pyridalyl was less than 100 nm. Spherical shape and nanosize of capsules was confirmed by Transmission electron microscopy. Zeta potential of optimized formulation was found to be about (−)20 ± 1 Mv indicating acceptable range for expressing physical stability of the nano-capsules. The pyridalyl nanosuspension insecticidal activity increased remarkably, with LC50 values of 40 μg mL−1 in comparison to LC50 values of technical material (90 μg mL−1) and commercial product (250 μg mL−1). Bioassay results by leaf d...

Carbon Nanotubes (CNTs) are used as ideal reinforcement due to their high strength, high elastic modulus and high aspect ratio in fabrication of metal matrix composites. But the uniform distribution of the nano reinforcements (CNTs) in the matrix is very difficult to achieve due to their high aspect ratio and Van der Waals force among them. Due to this effect the expected properties may not be achieved in the resulting composites. To overcome this issue and improve the distribution of CNTs in the matrix the Molecular Level Mixing (MLM) of CNTs with Cu/Ni followed by Mechanical Alloying (MA) can be used effectively with functionalized CNTs. Micron sized Cu-CNTs and Ni-CNTs composite powders were prepared by MLM. Then the composite powder was mixed with Al matrix powder by MA. The composite powder obtained after MA were consolidated using spark plasma sintering (SPS). The Microstructure of the sintered Al/Cu-CNT and Al/Ni-CNT composites was characterized by Optical microscope, Scanning Electron Microscope (SEM). Also hardness, wear and thermal expansion were measured. The results show that mechanical properties of the Cu and Ni coated CNTs reinforced composites are enhanced when compared with Al/CNT composite and pure Al sample. This is due to uniform distribution of CNTs in the Al matrix and strong interfacial bonding.

Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hexaconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.

Drawbeads are often applied in the deep drawing process to improve control of the material flow during the forming operation. Drawbeads restrain the sheet from flowing freely into die cavity. This paper deals with analysis of effect of draw bead geometry in sheet metal drawing process. Finite element analysis of drawing of circular blanks into axi-symmetric hemispherical cup was done. Circular and rectangular drawbeads were introduced into the Finite Element models and their influence in distribution of strain and thickness were investigated. DYNAFORM and LS-DYNA, a commercially available explicit FEA code were used to model and analyze the forming process respectively. These outcomes are compared with experimental results. The numerical results were found in good agreement with the experimental results. Plastic strain and Von-Mises stresses produced by rectangular drawbeads are higher when compared with the use of circular drawbead. Due to its geometry rectangular drawbead bends and unbends the sheet four times and restrains the material more than circular drawbead.

Eggplant shoot and fruit borer (ESFB), Leucinodes orbonalis G. is a key pest of eggplant, Solanum melongena L. Organophosphates (OP) having high toxicity and persistence are used to control the pests in many developing countries, despite availability of new insecticides with better qualities. Field evaluation of thiacloprid and indoxacarb were carried out against ESFB, with an OP insecticide, methyl parathion. Two Bacillus thuriegensis (Bt) based formulations namely Biolep and PUSA Bt and two azadirachtin formulations namely Neem Seed Kernal Extract (NSKE) and Nimbo Bas were also evaluated against ESFB for the management of the pest. HPLC and GC methods for the estimation of indoxacarb, thiacloprid and methyl parathion from the fruits were developed and their dissipation patterns and safety parameters were compared. For indoxacarb, the method involving Florisil gave highest recovery (88%) whereas average recoveries of other methods varied from 59% to 82%. The mean initial deposits of indoxacarb on fruits were 2.60 mg/kg to 3.64 mg/kg and 2.63 mg/kg to 3.68 mg/kg from 75 and 150 g·ai/ha treatments from two-year field studies. The half-life of indoxacarb was 3.0 d - 3.8 d from both years. The Theoretical Maximum Daily Intake (TMDI) was found to be 0.446 mg/person/day to 0.643 mg/person/day for day-1 residues which is in par with the Maximum Permissible Intake (MPI) of 0.6 mg/person/day. The TMDI from 3 d residues was found to be less than the MPI calculated with the data of 3 d residues which ensures better margin of safety. For thiacloprid, the method involving Florisil gave highest recovery (89%). The mean initial deposits of thiacloprid on fruits were 3.39 to 5.40 mg/kg and 3.40 to 5.39 mg/kg from 30 and 60 g·ai/ha treatments from both years. The half-life values were determined to be 11.1 and 11.6 d for both years. The TMDI from maximum residues observed for first day for both the treatments during first year trials was found to be 0.682 to 1.098 mg person/day, which was higher than the MPI of 0.72 mg/person/day, which proved that the application is toxic to humans. Thiacloprid at the experimented doses (30 and 60 g·ai/ha) was found not effective to manage ESFB and was not safe for human consumption after a waiting period of 3 days. For methyl parathion, the method involving Florisil gave highest average recovery (89%). The initial residues on fruits from recommended dose declined from 3.60 to 3.12 mg/kg in one day and 0.27 mg/kg in twentyfive days from 100 g·ai/ha. Similar pattern was observed with higher dose also. The dissipation rate constants were 0.123 and 0.140 for 100 and 200 g·ai/ha treatments, respectively. The half life values ranged from 6.0 to 7.4 days. Using dose (100 g·ai/ha), the residues reached safe level only after 20 days. A minimum gap of 20 days after the last application of the insecticide to the harvest is impractical for this crop. The efficacy of methyl parathion against ESFB was good at lower dose, but due to its toxic residue profile there is a high health risk. Biolep at both doses were not effective against ESFB, however PUSA Bt gave better control against ESFB at similar dose. NSKE was found effective against ESFB, however NimboBas found to be non-effective against ESFB.

A series of twenty substituted 3,4-dihydropyrimidine derivatives were prepared and characterized by TLC, IR, 1H NMR, 13C NMR spectroscopic data and elemental analysis. These were screened for insecticidal activity by the film residue method against the pulse beetle (adzuki bean weevil, Callosobruchus chinensis). 4-(2′-Chlorophenyl)-6-phenyl-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00201 mg/cm2), 4-(2′-chlorophenyl)-6-p-tolyl-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00122 mg/cm2), 4-(4′-methoxyphenyl)-6-(4″-methylphenyl)l-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00164 mg/cm2), 4-(4′-chlorophenyl)-6-(4″-methoxyphenyl)-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00175 mg/cm2) were found to be more effective than dichlorvos (2,2-dichlorovinyl dimethyl phosphate, LC50 0.00243 mg/cm2), a commercial insecticide recommended for managing Callosobruchus chinensis.

An alkalotolerant Pseudomonas strain was enriched and isolated from effluent of the pulp and paper industry. This strain was able to degrade dibenzofuran and utilize it as a sole source of energy and carbon. The GC-MS based detection of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. The GC-MS based detection of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. This diverse dioxygenation property of the strain allowed it to utilize various recalcitrant chlorinated xenobiotics and PAHs compounds. This strain showed optimum utilization (~85%) of dibenzofuran (200 mg l⁻¹) within 36 h at pH 10 at 40 °C. The growth of the strain was supported by a wide range of environmental conditions such as temperature, pH, and concentration of dibenzofuran, suggesting that it can be used for in situ bioremediation of dioxin-like compound.

A series of twenty 3,5-disubstituted isoxazoles were synthesized (using conventional and microwave methods) by the reaction of substituted chalcones with hydroxylamine hydrochloride and characterized by TLC, IR, 1H NMR, 13C NMR spectroscopic data and elemental analysis. The compounds were screened for insecticidal activity against the pulse beetle, Callosobruchus chinensis. Compounds 1a (LC50 36 mg L−1), 1d (LC50 110 mg L−1), 2c (LC50 93 mg L−1) and 5b (LC50134 mg L−1) were more effective than the recommended organophosphorous insecticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate) (LC50 155 mg L−1). These compounds provide a lead for designing new substances endowed with insecticidal activity.

Studies were undertaken to analyze the residues of commonly used pesticides viz. chlorpyrifos, endosulfan, dicofol, cypermethrin, fenvalerate, propargite, malathion, phorate, carbendazim, carbosulfan, thiamethoxam, and mancozeb in apple of integrated pest management (IPM) and non-IPM samples collected from the IPM and non-IPM fields of Shimla. We also present a method for the determination of these pesticides in apple samples. Residues of chlorpyrifos, endosulfan, dicofol, cypermethrin, fenvalerate, and propargite were analyzed by gas chromatography, while residues of carbendazim, carbosulfan, and thiamethoxam were analyzed by high-performance liquid chromatography. Residues of mancozeb were determined by a colorimetric method. Recoveries of all of the pesticides ranged from 61.30 to 95.46% at 0.1, 0.2, and 1.0 microg g(-1) levels of fortification with relative standard deviations ranging between 0.8 and 8.7. Apples from IPM and non-IPM orchards were analyzed for these pesticides using a developed method. Except for carbendazim and chlorpyrifos, the residues of all of the pesticides analyzed were below detectable limits. Although residues of carbendazim and chlorpyrifos were below the prescribed limits of maximum residue levels in both IPM and non-IPM orchards, residues were lower in apples from IPM orchards.

BACKGROUND: Thiacloprid [(Z)-3-(6-chloro-3-pyridylmethyl)-1,3-thiazolidin-2-ylidenecyanamide; Calypso™] is a systemic insecticide having persistence in the plant system. It was chosen for the management of the eggplant shoot and fruit borer, Leucinodes orbonalis Guen. Management of this insect pest is difficult because it harbours inside the shoot and fruit portions of eggplant. The persistence of thiacloprid on eggplant has not been studied in India. The Food and Agriculture Organisation (FAO) has proposed its maximum residue limit (MRL) on eggplant as 0.7 mg kg−1, and there is a need to validate this value. Since residues were found to be above this level, five different decontamination agents were tested for the decontamination of thiacloprid from eggplant. RESULTS: The half-life of thiacloprid was 11.1 and 11.6 days from trials in 2 years. Safety factors such as theoretical maximum daily intake (TMDI) and maximum permissible intake (MPI) were used to arrive at a risk assessment to human health from the analytical data obtained from the field trials. Thiacloprid at the doses tested (30 and 60 g AI ha−1) was not effective in managing eggplant fruit borer. A waiting period of 3 days before harvest of the fruits after insecticide application and a processing factor (PF) could not ensure a sufficient margin of safety (MOS). Subjecting the data to a processing factor of 60% could not bring the residues below the proposed MRL. CONCLUSION: Thiacloprid is not found to be an appropriate and effective agent for application to eggplant. Either the proposed MRL needs to be revised or good agricultural practice involving thiacloprid for plant protection in eggplant cultivation is required. Copyright © 2008 Society of Chemical Industry

Mango (Mangiferae indica L.) is an important exporthorticultural crop of India. Various insects and diseasesinfest the fruit especially in the fruiting season. The com-mon insect pests are mango leafhopper, mealy bug, leafwebber, inflorescence midge and fruit fly. The major lossof about 60% is due to leafhopper and mango leafhopper.These pests infest the mango at the floral and bud stage tofruit setting, tender leaves and small fruits. The crop pro-tection measures undertaken to control pest infestation in-volves spray of insecticides along with biological andcultural practices.India produces 65% of the world’s mango crop,9,000,000 MT, but with very little export. Although, Asiaaccounts for 75% world production, its dominance does nottranslate into international trade. The presence of pesticideremnants in mango lowers the export quality of mangofruits in the international market. To increase foreign trade,under the WTO regime, it is imperative to produce pesti-cide free mangoes.The insecticides commonly applied by the farmers areendosulfan, parathion methyl, chlorpyrifos, cypermethrinand fenvalerate. This paper presents a method for theestimation of the multi-class pesticides in mango and theirrecovery.Materials and MethodSolvents like acetone, dichloromethane, hexane (analyticalgrade), were distilled before use. Adsorbents neutral alu-mina and Florisil were activated before use. Pesticidestandards of methyl parathion, endosulfan, chlorpyrifos,cypermethrin and fenvalerate were of analytical gradequality. Gas Chromatogram instrumen-Shimadzu GC-17Afitted with an auto-sampler and ECD detector was used foranalysis. Other minor equipments required were rotaryevaporator and Waring blender, etc.Individual stock standard solutions (1,000 lg/mL) ofparathion methyl, endosulfan, chlorpyrifos, cypermethrinand fenvalerate were prepared in hexane (analytical grade).Working standard solutions of each pesticide was preparedby serial dilutions to 100 lg/mL, which was further dilutedto 0.1–10 lg/mL as per detector response. All the stocksolutions were stored at 4 C. Appropriate aliquot of indi-vidual pesticides solutions were taken and a mixture of fivepesticides of 100 lgmL

Lactofen, a member of the diphenyl ether chemical family, shows great potential for the control of broadleaf weeds associated with leguminous crops. It presents a high degree of selectivity when applied post-emergence to soybean and peanut crops. This paper presents the persistence of lactofen under a soybean crop under various conditions, including without remediation techniques, under soil solarization with polyethene sheets, and soil solarization followed by straw amendment. The results indicate that dissipation is faster when using the soil solarization technique (set II) compared to no treatment (set I) and is further enhanced by tstraw amendment, where almost 90% dissipation was recorded (set III). The dissipation followed first-order kinetics with a half-life that varied from 30 to 10 days. The half-life of lactofen was 15 days in treatments of soil solarization and straw amendments alone, indicating that both techniques have to be used in combination to achieve successful remediation of soil. Use of biodegradable polythene/substitute material will make this process a popular technique and may also improve its commercial viability.

Smart formulations based on nanomaterials have the capability to reduce the consumption of hazardous pesticides and their impact on human health and environment. Nanoformulations of agrochemicals have the potential to improve food productivity without compromising with the ecosystem. In the present work, controlled release nanocapsules containing acetamiprid were prepared by polyelectrolyte complexation of two natural macromolecules, i.e. alginate and chitosan. The size, morphology and chemical interaction studies of the prepared nanocapsules were investigated by Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The zetapotential studies revealed stability of the nanocapsules. TEM results show spherical morphology of the nanocapsules. The encapsulation efficiency was found to be 62% as quantified by Ultra High Pressure Liquid Chromatography (UHPLC). Nanocapsules were analysed for controlled release in vitro at three different pH. Maximum release was observed at pH 10 followed by pH 7 and 4, respectively. A non-Fickian release mechanism was found to be followed by the nanoformulation. A controlled release pattern was also found from nanoformulation as compared to commercial formulation in soil. Thus this formulation can reduce the frequency of application of pesticides by controlling the release and will subsequently reduce their side effects.

A study was undertaken to evaluate the decline of the residues of pyridalyl in tomatoes grown in two different cultivation systems: open field (conventional cultivation) and net house (pot experiment). Field experiment was conducted with commercial (10 EC) and nanoformulation of pyridalyl on tomato crop. Tomato plants were subjected to pesticide spray, when fruits were close to ripeness. Fruit samples were taken periodically and cleaned up using QuEChERS methodology, and the residue of pyridalyl was analyzed by ultrahigh-performance liquid chromatography (UHPLC). It dissipated in tomato fruit following the first-order kinetics. In field, average initial deposit of pyridalyl in tomato was observed to be 0.222 and 0.371 μg g(-1) at recommended and double the recommended application rate, respectively, using nanoformulation while it was 0.223 and 0.393 μg g(-1) on using commercial formulation, respectively. The half-life (t1/2) value of nanopyridalyl in tomato fruit was 2.8 and 3.2 days while for commercial formulation, it was 2.5 and 2.6 days for recommended and double the recommended dose, respectively. In India, maximum residue limit (MRL) on tomato has not been fixed for pyridalyl but its residues were always below European MRLs (5 μg g(-1)) on tomato at both application rates. The results of terminal residue showed that pyridalyl residues were below the available MRL. Low residues in tomatoes suggested that this pesticide is safe to use under the recommended dosage. No statistical differences were observed between the cultivation systems in relation to the residue levels of pyridalyl.

β-Cyfluthrin [α-cyano-4-fluoro-3-phenoxybenzyl-3(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate] pesticide has been in agricultural use in the recent years for controlling Lepidopteran pests affecting solanaceous crops. The extensive use of synthetic pyrethroids like β-cyfluthrin has resulted in wide spread environmental contamination. The purpose of this study was to isolate bacteria from soil and to determine their ability to degrade β-cyfluthrin and identify the intermediates in culture broth using spectroscopy. An aerobic bacterium capable of degrading β-cyfluthrin was isolated by enrichment culture. The 16S ribosomal DNA sequence of the isolate (strain S1) had 100% identity to the sequence from Pseudomonas stutzeri. Finally products formed during degradation of β-cyfluthrin have been identified as α-cyano-4-fluoro-3-phenoxybenzyl-3(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate (M.W. 341); 4-fluoro-3-phenoxy-α-cyanobenzyl alcohol (M.W. 243) and 3(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanecarboxylic acid (M.W. 208).

The impact of seed dressing and standing crop treatment (SC) with chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro pyridyl) phosphorothioate] and quinalphos [O,O-diethyl O-quinoxalin-2-yl phosphorothioate] on the oxidative capability of the soils of two semi-arid regions of tropical India were studied by monitoring their dehydrogenase activities (DHA) and capacities for reduction of iron (Fe3+) for three consecutive crop seasons. In the sandy loam, the metabolites of quinalphos inhibited both reduction of Fe3+ and DHA whereas chlorpyrifos was found stimulatory. The metabolites of chlorpyrifos namely 3,5,6-trichloro-2-pyridinol (TCP) and 3,5,6-trichloro-2-methoxy pyridine (TMP) stimulated DHA but were significantly inhibitory to reduction of Fe3+. The stimulatory effect of TCP and TMP suggested their utilization as substrates by soil microbes. In the loamy sand, chlorpyrifos and quinalphos inhibited the overall DHA within a field but stimulated DHA of the rhizospheric microbes. Standing crop treatments with quinalphos and chlorpyrifos caused prolonged inhibitory effects on reduction of Fe3+ while seed treatments caused fluxes of shorter durations. The inhibitory effects on reduction of Fe3+ were more prolonged with chlopyrifos than with quinalphos. Pesticide treatments at the recommended doses increased the yield of groundnut (Arachis hypogaea L.) pods that had no residual pesticides. Adverse effects of agronomic importance on DHA and reduction of Fe3+ were not observed during this study.

Esterase enzyme was isolated from goat intestine and partially purified to explore whether it can degrade β-cyfluthrin, a synthetic pyrethroid insecticide. The products of the reaction were identified in order to propose its path of degradation to innocuous non-toxic compounds. This is the first report for testing the suitability of such esterase enzyme for degrading a synthetic pyrethroid insecticide.

Effects of seed treatments with chlorpyrifos [5 g of active ingredient (ai) kg(-1) of seed] and quinalphos (6.25 g of ai kg(-1) of seed) and standing crop treatments with chlorpyrifos (800 g of ai ha(-1)) and quinalphos (1000 g of ai ha(-1)) on arginine deamination and mineralizable nitrogen were monitored, in the sandy loam and loamy sand soils of two tropical semiarid fields, for three consecutive crop seasons. The arginine ammonification activity of rhizospheric microbes was inhibited after seed treatment with chlorpyrifos and quinalphos and their principal metabolites, 3,5,6-trichloro-2-pyridinol (TCP) and 3,5,6-trichloro-2-methoxypyridine (TMP) and 2-hydroxyquinoxaline and quinoxaline-2-thiol, respectively. Quinalphos produced transient inhibitions, whereas chlorpyrifos and its metabolites (TCP and TMP) exerted a greater inhibition in both loamy sand and sandy loam soils. Arginine ammonification by nonrhizospheric microbes was stimulated by standing crop treatments with both pesticides. In the loamy sand soil, the parent compounds stimulated rhizospheric N-mineralization, whereas the metabolites were inhibitory. However, nonrhizospheric N-mineralization was inhibited by both chlorpyrifos and quinalphos and stimulated by their metabolites. A higher magnitude of inhibition of arginine deamination in the loamy sand than in the sandy loam soil could be due to greater bioavailability of the pesticides in the former, resulting from lesser sorption of the pesticides due to alkalinity of the soil and its low content of clay and organic carbon. Although both pesticides affected mineralizable nitrogen, seed treatment with quinalphos and standing crop treatment with quinalphos and chlorpyrifos produced the most significant effects. The recommended doses of the pesticides not only efficiently controlled whitegrubs, which increased pod yields, but also left no residues in harvested kernels. They also caused no long-term inhibition of ammonification, which could have been of significant concern during the short crop period in semiarid areas where nitrogen determines plant productivity.

Five fungal species, namely, Trichoderma viride strain 5-2, T. viride strain 2211, Aspergillus niger, A. terricola, and Phanerochaete chrysoporium were screened for degradation study of beta-cyfluthrin. Each fungal species was allowed to grow in Czapek dox medium containing beta-cyfluthrin (5 mg/mL) as the major carbon source of the medium. The highest degradation of beta-cyfluthrin was observed by T. viride 5-2 (T(1/2) = 7.07 days), followed by T.viride 2211 (T(1/2) = 10.66 days). The degradation of beta-cyfluthrin followed first-order kinetics with a fast degradation rate during first 7 days of growth of the fungi. In the case of T. viride strain 5-2, five degradation products were isolated after 20 days of growth of the fungi, out of which three products were identified as alpha-cyano-4-fluorobenzyl-3- (2,2-dichlorovinyl)-2,2-dimethyl cyclopropane carboxylate, alpha-cyano-4-fluoro-3-phenoxy benzyl alcohol, and 3(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanoic acid.

The dissipation of 14C carbaryl in undisturbed soil cores, and of quinalphos (25EC and 20AF) after seed and soil treatments, was investigated under field use conditions, in a semi-arid groundnut field. Residues were analyzed by TLC and HPLC and additionally by LSC for 14C carbaryl. The harvested seed kernels were also tested for the presence of insecticide residues. The movement of carbaryl was limited to 15 cm depth in the loamy sand of Jaipur and was detected till 120 days (DT50 of 14.93 days) after application. Bound residues and 1-naphthol had a DT50 of 11.45 and 13.68 days, respectively. Irrespective of the three types of soil samples investigated, the principal metabolite formed on seed and soil treatments with quinalphos, was 2-hydroxyquinoxaline. With seed treatment, a thiol metabolite of quinalphos was also detected. Higher yields of groundnut were realized with quinalphos treatments in comparison to those from control. Post-harvest, no pesticide residues were found in seeds.

The study deals with the facile synthesis of catenated nanosulfur by entrapping elemental sulfur with polyethylene glycol 400 with the help of bottom up approach. The synthesized nanosulfur was studied by transmission electron microscope (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and thermogravimetric analysis (TGA). The average size was about 35.5 ± 8.5 nm which was confirmed by TEM distribution curve fitted with Gaussian model. XRD shows that the synthesized nanosulfur was crystalline in nature. FTIR study confirmed that PEG was encapsulated over catenated nanosulfur. TGA confirmed the stability of nanosulfur up to 200 °C as there was no significant change in the differential weight with respect to temperature 200 °C. The active ingredient of this encapsulated nanosulfur was 0.62 g/g which was estimated by UHPLC.

A comparative study on residues and rate of dissipation of a new nanoformulation of pyridalyl and commercial pyridalyl was carried out on okra under net house and field conditions. Okra crop was sprayed with commercial and nanoformulation of pyridalyl at recommended (75 g a. i./ha) and double the recommended dose (150 g a. i./ha) at the time of fruiting. Quantitation of residues of pyridalyl in okra was done by ultra high performance liquid chromatography over a period of 15 days, and recovery of the method ranged from 79 to 87 %. The half life calculated from the dissipation pattern of pyridalyl on okra for commercial and developed nanoformulation proved that residues of nanopyridalyl did not persist much longer than that of conventional formulation in net house as well as in field trials. The risk quotient value of pyridalyl in okra was significantly lower than 1, implying its negligible risk to the humans.

A multiresidue method was developed for the estimation of 15 organochlorine pesticides in water. 50 samples of drinking water supplied by the Municipal Corporation to the residential areas of Delhi and 20 ground water samples from nearby villages used for irrigation were monitored for the presence of organochlorine insecticides by the method developed. Although, organochlorine pesticides were detected in the ground water and irrigation water samples, the levels of pesticides were below the Maximum Contaminant Level as prescribed by WHO. No organochlorine insecticides were detected in any of the drinking water samples.

The recently registered insecticide, imidacloprid, was applied to three vegetable crops at 20 and 40 g AI ha−1. The persistence of the parent insecticide and its translocation, along with the quantification of the metabolites formed on these crops are presented. The parent insecticide dissipated with a half-life of 3–5 days and persisted longest on mustard leaves. The detectable limit of the HPLC method was 0.01 µg g−1. The metabolites 1-(6-chloropyridin-3-yl-methyl)imidazolidin-2-one and 6-chloronicotinic acid were found to be translocated by day 10 in eggplant, cabbage leaves and mustard leaves but not in cabbage curd. The MRL of imidacloprid is not documented by the FAO/WHO on these crops and comparison of the MPI with the TMRC, calculated on the residue data generated in this study, establishes the safety of the schedule. © 2000 Society of Chemical Industry

Intensive application of organochlorine pesticides in agriculture and medicinal parasitology coupled with high stability of these pesticides in the environment resulted in their spreading all over the globe.The world over the use of HCH in agriculture has been banned . However , it is still being used in animal sheds and public health . The compulsive use of HCH is the low cost of the insecticide. Its use has recently been banned and the use of lindane is being favoured in agriculture. Lindane is the active constituent of HCH and its use should be beneficial in terms of insect control and it will not pose any environmental problem due to the accumulation of the more persistent beta isomer of HCH. Though, HCH is not used in many countries there are reports of its residues in the environment, probably caused by long range transport from other areas (Cleeman et.al 1995 ). Monitoring of vegetables ( Lal et al. 1969; Mukherjee and Gopal 1996), milk (Mukherjee and Gopal 1993) ,drinking and ground water (Gopal and Mukherjee,1999; Allchin 1991) 1 lakes ( Dua et al. 1998), fishes ((Mugachia et al.1992) have recorded the presence of HCH residues . Because of the ability of HCH to dissolve in fats they get accumulated in the adipose tissues of animals and men (Waliszewskei et.al.1995) and have also been detected in breast milk ( Barkatina et .al .1998) .

In order to identify the most suitable method for the estimation of nanosulfur for studying its residue dynamics, the present work was taken up. HPLC and GC methods were explored for its analysis. A comparative study of the existing analytical methods for the quality control of nanosulfur was undertaken. UV spectrophotometry and HPLC methods were superior with lower LOD when compared to GC-MS, which was not satisfactory due to breakage of catenated S20 into S6 and S8 . The method has been validated by analyzing various nanosulfur formulations of known concentrations. The recovery of the UV and HPLC methods ranged from 80.71 to 109.51% and 82.31 to 109.84%, respectively. The LOD of UV, GC-MS, and HPLC is 4, 20, and 1 ppm, respectively. The retention time of sulfur was 13.77 (HPLC), 2.89 (ultra high performance liquid chromatography), and 12.715 + 21.524 min (GC-MS). The method was successfully utilized for estimating sulfur in natural samples such as water from a sulfur hot spring and wastewater. The method has been validated by following the method recommended by the American Society for Testing and Materials. The HPLC method emerged as the best analytical method for the estimation of elemental sulfur.