Validation of a QuEChERS-based gas chromatographic method for analysis of pesticide residues in Cassia angustifolia (senna)

A simple multi-residue method based on modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach was established for the determination of 17 organochlorine (OC), 15 organophosphorous (OP) and 7 synthetic pyrethroid (SP) pesticides in an economically important medicinal plant of India, Senna (Cassia angustifolia), by gas chromatography coupled to electron capture and flame thermionic detectors (GC/ECD/FTD) and confirmation of residues was done on gas chromatograph coupled with mass spectrometry (GC-MS). The developed method was validated by testing the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effect, accuracy–precision and measurement uncertainty; the validation study clearly demonstrated the suitability of the method for its intended application. All pesticides showed good linearity in the range 0.01–1.0 μg mL^?1 for OCs and OPs and 0.05–2.5 μg mL^?1 for SPs with correlation coefficients higher than 0.98. The method gave good recoveries for most of the pesticides (70–120%) with intra-day and inter-day precision < 20% in most of the cases. The limits of detection varied from 0.003 to 0.03 mg kg^?1, and the LOQs were determined as 0.01-0.049 mg kg^?1. The expanded uncertainties were <30%, which was distinctively less than a maximum default value of ±50%. The proposed method was successfully applied to determine pesticide residues in 12 commercial market samples obtained from different locations in India.     

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.     

Assessing the global zoo response to the amphibian crisis through 20‐year trends in captive collections

Global amphibian declines are one of the biggest challenges currently facing the conservation community, and captive breeding is one way to address this crisis. Using information from the International Species Information System zoo network, we examined trends in global zoo amphibian holdings across species, zoo region, and species geographical region of origin from 1994 to 2014. These trends were compared before and after the 2004 Global Amphibian Assessment to assess whether any changes occurred and whether zoo amphibian conservation effort had increased. The numbers of globally threatened species (GTS) and their proportional representation in global zoo holdings increased and this rate of increase was significantly greater after 2004. North American, European, and Oceanian GTS were best represented in zoos globally, and proportions of Oceanian GTS held increased the most since 2004. South American and Asian GTS had the lowest proportional representation in zoos. At a regional zoo level, European zoos held the lowest proportions of GTS, and this proportion did not increase after 2004. Since 1994, the number of species held in viable populations has increased, and these species are distributed among more institutions. However, as of 2014, zoos held 6.2% of globally threatened amphibians, a much smaller figure than for other vertebrate groups and one that falls considerably short of the number of species for which ex situ management may be desirable. Although the increased effort zoos have put into amphibian conservation over the past 20 years is encouraging, more focus is needed on ex situ conservation priority species. This includes building expertise and capacity in countries that hold them and tracking existing conservation efforts if the evidence‐based approach to amphibian conservation planning at a global level is to be further developed.     

Prediction models for the flash point of pure components

The flash point for a liquid is defined as the lowest temperature at which its vapor forms a spontaneously ignitable mixture when brought in contact with air. Having a good estimation of the flash point temperature at normal conditions is relevant because it is one of the main properties used to characterize fire and explosion hazards for liquids. Most of predictive correlations in the literature include a physical effect by including the normal boiling temperature in their formulation. To achieve combustion, sufficient evaporation is required and then a part of the liberated energy from the combustion is used to support the evaporation. Thus the evaporation energy and a chemical effect given by the heat of reaction are incorporated in this work. It is firstly verified that the relation between the flash point temperature and the normal boiling temperature tends to be a constant. Thus a heuristic approach based on 611 chemical species of diverse families indicates that this relation is around 0.75. The dispersion of the error has been reduced by using two proposed correlations where both physical and chemical properties are included in the model. In particular, the second equation is based on the group contributions method, which has been developed for alkanes. This method is in fact a combination of the group contributions method and the first model to overcome the difficulties in predicting isomeric differences.     

Electrospun ZnO Nanoparticles Doped Core–Sheath Nanofibers: Characterization and Antimicrobial Properties

Coaxial electrospinning technique was used to fabricate the core–sheath composite nanofibers of ZnO nanoparticle (Nps) (10%, 20% w/w) doped polymethyl methacrylate (PMMA) (as sheath) and polyvinyl alcohol (PVA) (as core). Fourier transform infrared (FT-IR) spectra were confirmed the weak forces arise between ZnO Nps, PMMA and PVA matrixes. The hexagonal (wurtzite) structure of ZnO Nps with ~?30.8 nm of diameter was confirmed from the X-ray diffraction pattern. The morphology and microstructure of core–sheath composite nanofibers were confirmed from the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is clearly seen from the TEM images that the PMMA encapsulate the PVA core. Core–sheath composite nanofibers were assessed against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria through quantitative, disk diffusion and viable cell count methods. It was found that ZnO Nps doped core–sheath nanofibers were effectively inhibit the growth of gram positive bacteria, B. subtilis.     

Rinodina sophodes (Ach.) Massal.: a bioaccumulator of polycyclic aromatic hydrocarbons (PAHs) in Kanpur City, India

The aim of this study is to determine the possibility of using Rinodina sophodes (Ach.) Massal., a crustose lichen as polycyclic aromatic hydrocarbons (PAHs) bioaccumulator for evaluation of atmospheric pollution in tropical areas of India, where few species of lichens are able to grow. PAHs were identified, quantified and compared to evaluate the potential utility of R. sophodes. The limit of detection for different PAHs was found to be 0.008–0.050 μg g^− 1. The total PAHs in different sites were ranged between 0.189 ± 0.029 and 0.494 ± 0.105 μg g^− 1. The major sources of PAHs were combustion of organic materials, traffic and vehicular exhaust (diesel and gasoline engine). Significantly higher concentration of acenaphthylene and phenanthrene indicates road traffic as major source of PAH pollution in the city. Two-way ANOVA also confirms that all PAHs content showed significant differences between all sampling sites (P 1%). This study establishes the utility of R. sophodes in monitoring the PAHs accumulation potentiality for development of effective tool and explores the most potential traits resistant to the hazardous environmental conditions in the tropical regions of north India, where no such other effective way of biomonitoring is known so far.     

Hydrogeochemical processes controlling the high fluoride concentration in groundwater: a case study at the Boden block area,Orissa, India

The present investigation reports the assessment of hydrochemical/geochemical processes controlling the concentration of fluoride in groundwater of a village in India (Boden block, Orissa). Boden block is one of the severely affected fluoride-contaminated areas in the state of Orissa (India). The sampling and subsequent analysis of water samples of the study area was carried out following standard prescribed methods. The results of the analysis indicate that 36.60% groundwater F⁻ concentration exceeds the limit prescribed by the World Health Organization for drinking water. The rock interaction with groundwater containing high concentration of HCO₃⁻ and Na⁺ at a higher pH value of the medium could be one of the important reasons for the release of F⁻ from the aquatic matrix into groundwater. Geochemical classification of groundwater based on Chadha rectangular diagram shows that most of the groundwater samples having fluoride concentration more than 1.5 mg L⁻¹ belongs to the Na-K-HCO₃ type. The saturation index values evaluated for the groundwater of the study area indicated that it is oversaturated with respect to calcite, whereas the same is undersaturated with respect to fluorite content. The deficiency of calcium ion concentration in the groundwater from calcite precipitation favors fluorite dissolution leading to excess of fluoride concentration. The risk index was calculated as a function of fluoride level in drinking water and morbidity of fluorosis categorizes high risk for villages of Amera and Karlakote panchayat of Boden block.     

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.     

Occurrence of phthalic acid esters in Gomti River Sediment, India

Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4–150 mg/kg and Cd at 0.02–20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C _ul) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers’ fields. Lead and Cd concentration limits in soil were calculated by dividing C _ul with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.     

Identification of polycyclic aromatic hydrocarbons in unleaded petrol and diesel exhaust emission

Inhalation of emissions from petrol and diesel exhaust particulates is associated with potentially severe biological effects. In the present study, polycyclic aromatic hydrocarbons (PAHs) were identified from smokes released by the automobile exhaust from petrol and diesel. Intensive sampling of unleaded petrol and diesel exhaust were done by using 800-cm³ motor car and 3,455-cm³ vehicle, respectively. The particulate phase of exhaust was collected on Whatman filter paper. Particulate matters were extracted from filter paper by using Soxhlet. PAHs were identified from particulate matter by reverse phase high performance liquid chromatography using C₁₈ column. A total of 14 PAHs were identified in petrol and 13 in case of diesel sample after comparing to standard samples for PAH estimation. These inhalable PAHs released from diesel and petrol exhaust are known to possess mutagenic and carcinogenic activity, which may present a potential risk for the health of inhabitants.