Determination of the certain major and trace elements was carried out in drinking water supply scheme in three districts of Meghalaya. This work aims to identify trends resulting in the deterioration of drinking water which is also a potential source of environmental contaminants. About 50 samples, each from one district, were collected both from the source and various tanks and tap. The elements determined are Li, Na, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Ag, Au, Pb, Cd, Se, Ca, K, and Mg. The pH is slightly lower than neutral pH of 7 while the turbidity is very high even after treatment. The concentrations of Ca and Mg are found to be deficient. The elements Cr, Fe, Co, Ni, Zn, Mo, and Pb decrease after treatment while Mn, Cu, and Cd increase slightly after treatment. Se concentration is found to be much higher than expected. The results were compared with the standard recommendation values for the quality of drinking water. This study provides a general indication of where water-quality constituent concentrations met or exceeded water-quality standards and the data presented in this report will be useful from public health point of view.

Cymbopogon citratus (DC.) Stapf commonly known as lemon grass is used extensively as green tea and even as herbal tea ingredient across the world. Plants have the ability to uptake metals as nutrient from the soil and its environment which are so essential for their physiological and biochemical growth. Concentrations of these twelve trace elements, namely, Mg, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Mo, As, Cd, and Pb, are analysed by graphite furnace-atomic absorption spectroscopy (GF-AAS) and are compared with the permissible limits of FAO/WHO, ICMR, and NIH, USA, which are found to be within permissible limits. Toxic metals like As, Cd, and Pb, analysed are within the tolerable daily diet limit and at low concentration.

The present work is on the transesterification of soybean oil to biodiesel under microwave irradiation using a biomass and MOF−derived CaO−ZrO2 heterogeneous catalyst. The optimisation of different parameters was processed by adopting a central composite design for a response−surface methodology (RSM). The experimental data were fitted to a quadratic equation employing multiple regressions and investigated by analysis of variance (ANOVA). The catalyst was exhaustively characterised by XRD, TGA, FTIR BET, SEM, TEM, CO2 TPD and XPS. In addition, the synthesized biodiesel was characterized by 1H and 13C NMR, GCMS. The physicochemical properties of the biodiesel were also reported and compared with the ASTM standards. The maximum yield that was obtained after optimization using RSM was 97.22 ± 0.4% with reaction time of 66.2 min, at reaction temperature of 73.2 °C, catalyst loading of 6.5 wt.%, and methanol−to−oil ratio of 9.7 wt.%.

Ten trace elements (Mg, Ca, V, Cr, Mn, Fe, Cu, Zn, Mo, and Cd) were determined in seven traditionally used wild medicinal plants of the Nagas in the NorthEast India viz Cynoglossum furcatum Wallich, Elsholtzia blanda Bentham, Lycopodium cernuum Linnaeus, Potentilla fulgens Wallich ex Hooker, Swertia macrosperma C.B. Clarke, Thalictrum foliolosum DC and Valeriana jatamansi Jones. Plant samples were dried, weighed, digested and analyzed for their mineral distribution level ranging from trace to major elements by graphite furnace-atomic absorption spectroscopy. All the medicinal herbs studied were found to contain the ten elements analyzed. The elemental concentration is given in mg/kg. Mg and Ca are present in high concentrations in both the roots and leaves of the plant samples. Among trace transition metals Fe had the highest concentration, followed by Mn, Cr, Cu, V, Zn, and Mo. Analysis showed that the toxic Cd element was at a lower concentration and is within the permissible limit of FAO/WHO, California standards and United States Pharmacopeia Limit for Nutritional Supplements.