Estimation of β-cyfluthrin and imidacloprid in okra fruits and soil by chromatography techniques

Dissipation of β-cyfluthrin and imidacloprid in okra was studied following three applications of a combination formulation of Solomon 300 OD (β-cyfluthrin 9 % + imidacloprid 21 %) @ 60 and 120 g a.i. ha(-1) at 7 days interval. Residues of β-cyfluthrin and imidacloprid in okra were estimated by gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC), respectively. Residues of β-cyfluthrin were confirmed by gas chromatograph-mass spectrometry (GC-MS) and that of imidacloprid by high performance thin layer chromatography (HPTLC). Half-life periods for β-cyfluthrin were found to be 0.91 and 0.68 days whereas for imidacloprid these values were observed to be 0.85 and 0.96 days at single and double the application rates, respectively. Residues of β-cyfluthrin dissipated below its limit of quantification (LOQ) of 0.01 mg kg(-1) after 3 and 5 days at single and double the application dosage, respectively. Similarly, residues of imidacloprid took 5 and 7 days to reach LOQ of 0.01 mg kg(-1), at single and double dosages respectively. Soil samples collected after 15 days of the last application did not show the presence of β-cyfluthrin and imidacloprid at their detection limit of 0.01 mg kg(-1).     

Combined biodegradation and ozonation for removal of tannins and dyes for the reduction of pollution loads

Purpose  

Tannins and dyes pose major threat to the environment by generating huge pollution problem. Biodegradation of wattle extract, chrome tannin and dye compounds using suitable fungal culture namely Aspergillus niger, Penicillium sp. were carried out. In addition to these, ozone treatment was carried out to get higher degradation rate.     

Adsorption of ammonium ion by coconut shell-activated carbon from aqueous solution: kinetic, isotherm, and thermodynamic studies

Ammonium ions are one of the most encountered nitrogen species in polluted water bodies. High level of ammonium ion in aqueous solution imparts unpleasant taste and odor problems, which can interfere with the life of aquatics and human population when discharged. Many chemical methods are developed and being used for removal of ammonium ion from aqueous solution. Among various techniques, adsorption was found to be the most feasible and environmentally friendly with the use of natural-activated adsorbents. Hence, in this study, coconut shell-activated carbon (CSAC) was prepared and used for the removal of ammonium ion by adsorption techniques. Ammonium chloride (analytical grade) was purchased from Merck Chemicals for adsorption studies. The CSAC was used to adsorb ammonium ions under stirring at 100 rpm, using orbital shaker in batch experiments. The concentration of ammonium ion was estimated by ammonia distillate, using a Buchi distillation unit. The influence of process parameters such as pH, temperature, and contact time was studied for adsorption of ammonium ion, and kinetic, isotherm models were validated to understand the mechanism of adsorption of ammonium ion by CSAC. Thermodynamic properties such as ?G, ?H, and ?S were determined for the ammonium adsorption, using van't Hoff equation. Further, the adsorption of ammonium ion was confirmed through instrumental analyses such as SEM, XRD, and FTIR. The optimum conditions for the effective adsorption of ammonium ion onto CSAC were found to be pH 9.0, temperature 283 K, and contact time 120 min. The experimental data was best followed by pseudosecond order equation, and the adsorption isotherm model obeyed the Freundlich isotherm. This explains the ammonium ion adsorption onto CSAC which was a multilayer adsorption with intraparticle diffusion. Negative enthalpy confirmed that this adsorption process was exothermic. The instrumental analyses confirmed the adsorption of ammonium ion onto CSAC.     

Cellulose supported layered double hydroxides for the adsorption of fluoride from aqueous solution

Cellulose supported layered double hydroxides (CSLDHs) were synthesized and tested for adsorption of fluoride in aqueous medium. Three samples of cellulose supported LDHs were synthesized by varying the LDH loading on cellulose. The raw cellulose, unsupported LDH and cellulose supported LDHs were characterized by XRD, SEM and BET surface area. Batch adsorption as well as fixed-bed column experiments were performed for determining the fluoride adsorption characteristics of CSLDHs. The fluoride adsorption properties of CSLDHs were found to be superior to that of reported adsorbents, including activated alumina and carbon nanotubes. Defluoridation capacity of the CSLDHs was 2-4 times higher than that of unsupported LDH. The cellulose supported LDH, CSLDH-50, having an LDH loading of 27% showed maximum fluoride uptake capacity (5.29 mg g(-1) of CSLDH, 25.18 mg g(-1) of LDH) in fixed-bed column study.     

Rice and wheat straw ashes: Characterization and modeling of pretilachlor sorption kinetics and adsorption isotherm

The rice straw ash (RSA) and wheat straw ash (WSA) were explored as low cost adsorbent for pretilachlor removal from water. The ashes were characterized and sorption behavior of pretilachlor was evaluated. Kinetics study suggested that the modified Elovich model best explained the pretilachlor sorption on both the ashes. The adsorption data were analyzed using 2-, 3- and 4-parameter models and nine error functions were used to compute the best fit isotherm by nonlinear regression analysis. The pretilachlor was more sorbed onto the RSA (22.0–92.2%) than the WSA (11.4–61.4%) and percent adsorption decreased with increase in the herbicide concentration in solution. Isotherm model optimization analysis suggested that the Freundlich and the Temkin isotherms were the best models to predict the pretilachlor adsorption onto the RSA and the WSA. The error analysis suggested that the reciprocal of the observed squared (ROS) and the reciprocal of the predicted squared (RPS) error functions provided the best determination of the adsorption constants for the Freundlich and the Temkin isotherms, respectively. The RSA, which exhibited higher pretilachlor sorption potential, can be utilized as low cost adsorbent for pesticide removal from contaminated water.     

Location wise comparison of mixture distributions for assessment of wind power potential: A parametric study

Scientific literature discussed various types of mixture models and models derived from maximum entropy principle using short-term wind speed data for their relative assessment. The literature on suitability of these mixture models for long-term data is rarely available. However, for correct assessment of wind power potential both wind speed and wind direction are equally important. Therefore, in this paper, both wind speed and wind direction are simultaneously analyzed using several types of mixture distribution and compared the same with conventional Weibull distribution. For wind speed and wind power density assessment, the mixture distributions such as Weibull--Weibull distribution, Gamma--Weibull distribution, Truncated Normal--Weibull distribution, Truncated Normal--Normal distribution, proposed Truncated Normal--Gamma distribution and Gamma--Gamma distribution along with MEP-distribution are compared with conventional 2-parameter Weibull distribution. Similarly, for wind direction analysis, the finite mixtures of von-Mises distribution are compared with conventional von-Mises distribution. Judgment criteria include R², RMSE, Kolmogorov--Smirnov test and relative percentage error in wind power density. The sites selected are the three onshore locations of India, viz., Calcutta, Trivandrum, and Ahmedabad. The results show that for wind speed assessment, mixture distribution performs better than the conventional Weibull distribution for analyzing wind power density. However, location wise comparison of all mixture distribution is of prime importance. For wind direction analysis, finite mixture of two von-Mises distributions proved to be a suitable candidate for Indian climatology.     

Impact of Diwali celebrations on urban air and noise quality in Delhi City,India

A study was conducted in the residential areas of Delhi, India, to assess the variation in ambient air quality and ambient noise levels during pre-Diwali month (DM), Diwali day (DD) and post-Diwali month during the period 2006 to 2008. The use of fireworks during DD showed 1.3 to 4.0 times increase in concentration of respirable particulate matter (PM₁₀) and 1.6 to 2.5 times increase in concentration of total suspended particulate matter (TSP) than the concentration during DM. There was a significant increase in sulfur dioxide (SO₂) concentration but the concentration of nitrogen dioxide (NO₂) did not show any considerable variation. Ambient noise level were 1.2 to 1.3 times higher than normal day. The study also showed a strong correlation between PM₁₀ and TSP (R ² ≥ 0.9) and SO₂ and NO₂ (R ² ≥ 0.9) on DD. The correlation between noise level and gaseous pollutant were moderate (R ² ≥ 0.5). The average concentration of the pollutants during DD was found higher in 2007 which could be due to adverse meteorological conditions. The statistical interpretation of data indicated that the celebration of Diwali festival affects the ambient air and noise quality. The study would provide public awareness about the health risks associated with the celebrations of Diwali festival so as to take proper precautions.     

Magnetic particulate matters in the ashes of few commonly used Indian cigarettes

Physical aspects of tobacco samples, used in some commonly available Indian brands of cigarettes, with emphasis on their magnetic characterization before and after they get burnt into ashes, are described. The present work highlights the ultrafine nature of the cigarette ashes and provides a compositional insight of their constituent particulate matters as revealed by the XRD and SEM studies. Based on the EDX spectra, elemental distributions of different tobacco samples, before and after they get burnt, are presented. In this work, magnetic measurements of the un-burnt tobacco samples are reported. An attempt is made to shed light on the origin of magnetism observed in these samples.     

Persistence and risk assessment of spiromesifen on tomato in India: a multilocational study

Supervised field trials were conducted at four different agro-climatic locations of India to evaluate the dissipation pattern and risk assessment of spiromesifen on tomato. Spiromesifen 240 SC was sprayed on tomato at 150 and 300 g a.i.?ha^?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10 and 15 days after treatment and soil at 15 days after treatment. Quantification of residues was done on gas chromatograph–mass spectrophotometer in selective ion monitoring mode in the mass range of 271–274 (m/z). The limit of quantification of the method was found to be 0.05 mg kg^?1, while the limit of determination was 0.015 mg kg^?1. Residues were found below the LOQ of 0.05 mg kg^?1 in 10 days at both the doses of application at all the locations. Spiromesifen dissipated with a half-life of 0.93–1.38 days at the recommended rate of application and 1.04–1.34 days at the double the rate of application. Residues of spiromesifen in soil were detectable level (<0.05 mg kg^?1) after 15 days of treatment. A preharvest interval (PHI) of 1 day has been recommended on tomato on the basis of data generated under All India Network Project on Pesticide Residues. Spiromesifen 240 SC has been registered for its use on tomato by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of spiromesifen on tomato has been fixed by Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India as 0.3 μg/g after its risk assessment.     

Development of fuzzy air quality index using soft computing approach

Proper assessment of air quality status in an atmosphere based on limited observations is an essential task for meeting the goals of environmental management. A number of classification methods are available for estimating the changing status of air quality. However, a discrepancy frequently arises from the quality criteria of air employed and vagueness or fuzziness embedded in the decision making output values. Owing to inherent imprecision, difficulties always exist in some conventional methodologies like air quality index when describing integrated air quality conditions with respect to various pollutants parameters and time of exposure. In recent years, the fuzzy logic-based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental issues. In the present study, a methodology based on fuzzy inference systems (FIS) to assess air quality is proposed. This paper presents a comparative study to assess status of air quality using fuzzy logic technique and that of conventional technique. The findings clearly indicate that the FIS may successfully harmonize inherent discrepancies and interpret complex conditions.