Composting and bioremediation process evaluation of wood waste materials generated from the construction and demolition industry

The suitability of using bioremediation and composting techniques for diverting construction and demolition (C&D) waste from landfill has been validated in this study. Different timber products from C&D waste have been composted using various composting approaches. The present work demonstrates the quality of compost produced as a result of composting of mixed board product wood waste, which is frequently obtained from the construction and demolition industry. Three compost mixes were prepared by mixing shredded chip board, medium density fibre, hardboard and melamine. Poultry manure, Eco-Bio mixture and green waste were used as nutrient supplements. The results revealed that compost produced from mixtures of poultry manure and green waste used as nutrient supplements improved the performance in plant growth trials (phytotoxicity tests). Results obtained from the experimental study clearly indicate that the composts produced comply with the criterion suggested in BSI PAS 100 (A specification for compost materials) for use in different applications. Composting can also be demonstrated to be a very practical approach to material management including transport reduction to and from the site. The economic suitability of the process will be improved with the increase in landfill tax. In the current regulatory scenario, it is recommended that these materials should be composted at a centralised facility.     

Butyltins in water, biofilm, animals and sediments of the west coast of India

Biofilm, fish, oyster, mussel, clam, surface seawater, suspended particulate matter (SPM), and sediment samples were collected from marine and/or estuarine waters of the west coast of India. These samples were analysed for butyltin derivatives such as dibutyltin (DBT) and tributyltin (TBT). The concentrations DBT plus TBT varied between 2.4 and 8.3, 163 and 363 ng/l, 5 and 2853 ng/g dry wt in the SPM, seawater and sediment samples, respectively, of the Marmugao harbour. The values of DBT plus TBT ranged between 0.60 and 29, 123 and 242 ng/l and 1.4 and 65 ng/g dry wt in SPM, water and sediment samples, respectively, collected from the Mandovi estuary. In the Dona Paula Bay the DBT plus TBT varied from 10 to 89 ng/l in surface seawater, and TBT from 10 to 513 ng/g in biofilm samples. For the coastal sediment samples the concentration of DBT plus TBT ranged between 36 and 133 ng/g dry wt of sediment. For the animal samples the DBT plus TBT ranged between 58 and 825 ng/g dry wt of the tissue. Mussel tissues contained the highest amount of DBT plus TBT (825 ng/g dry wt tissue), whereas highest TBT concentration was recorded in the oyster (732 ng/g dry wt). TBT was generally the most abundant butyltin compound in most of the samples suggesting fresh inputs and/or less degradation of TBT. A wide range of the observed butyltin concentrations suggests the presence of localized areas of contamination. Leaching of tributyltin-containing antifouling paints from the ocean going ships, fishing and recreational boats, barges, and the inputs of TBT from the Goa shipyard and dry dock facility situated in the harbour are the probable sources of the DBT and TBT in the samples of the west coast of India. Higher levels of TBT were observed in biofilm relative to that in the surrounding seawater. When fed on TBT contaminated biofilm of the diatom Navicula subinflata, butyltin concentrations in the clam Paphia malabarica increased over the period of feeding suggesting the importance of biofilm in the transfer of butyltins to higher group of organisms.     

Microbial dechlorination of chloroorganics and simultaneous decolorization of pulp–paper mill effluent by Pseudomonas putida MTCC 10510 augmentation

The physicochemical analyses of pulp-paper mill effluent revealed that it was dark brown with 1761?±?2.3 color PtCo units having slightly alkaline pH, high biological oxygen demand and chemical oxygen demand values, and contained large quantities of organic and inorganic constituents, well above the prescribed standards. The bacterial growth, color reduction, and dechlorination were evident in all the four sets of experiments with different possible combinations of nutrient supplementation and Pseudomonas putida augmentation. A high degree of decolorization at 29.7% and 27.4% was observed by the effluent native microflora during 48 and 24 h, in unaugmented effluent supplemented with glucose + yeast extract and glucose + peptone, respectively. The extent of decolorization in glucose + yeast extract unaugmented effluent also corresponded with high degree of dechlorination (59.3%) during 60-h incubation (SET III). An appreciable level of growth, decolorization, and dechlorination was evident in nutrient unsupplemented P. putida augmented effluent as well as in the control natural effluent. However, a maximum level of growth response (OD 1.641-1.902) during 36-48 h, removal of color (39.72-48.2%) during 24-36 h, and chloride ions (80.1-83.5%) during 36 h was achieved in P. putida augmented effluent supplemented with glucose + yeast extract or peptone. Therefore, supplementation of effluent with glucose and yeast extract or peptone and concomitant augmentation with P. putida is required for efficient effluent decolorization and detoxification.     

Physiological and metabolic effect of mercury accumulation in higher plants system

Heavy metals, lead (Pb) and mercury (Hg) are non-essential elements. Plants absorb these metals from soil, water and air through their roots and leaves. Heavy metals are the major environmental pollutants, which spread to soil through the use of pesticides, herbicides and micronutrient fertilizers, industrial effluents, decay of junk materials and sewage sludge, vehicular emissions, re-suspended road dust, diesel generator sets and coal-based thermal power plants. Sewage and sludge have contributed to heavy metal contamination of peri-urban lands and vegetable crops. The present review focuses on the effects of various concentrations of Hg on growth of young and mature seedlings as well as on nitrate reductase activity and nitrate assimilation in intact and excised seedling, especially the mechanism underlying nitrate reductase regulation by this heavy metal. Evidence indicates that mercury exerts significant adverse effects on the physiological activity of plants.     

Vitamin E-mediated protection on methomyl-induced alterations in rat liver

The present study was carried out to observe the possible beneficial effects of Vitamin E, a natural antioxidant on methomyl-induced biochemical and histological alterations in rat liver. To carry out the investigations, animals were segregated in four different groups. Animals in Group I served as normal controls. Animals in Group II were given single methomyl dose orally in water (9 mg kg^?1 b.wt). Animals in Group III were injected intraperitoneally with Vitamin E (50 mg kg^?1 b.wt) for 1 week on alternate days. Animals in Group IV were administered Vitamin E 1 week before subjecting them to methomyl treatment. Animals in all the groups were sacrificed 24 h after the end of treatments. Different biochemical estimations were carried out, which included estimation of aspartate aminotransaminase (AST), alanine aminotransaminase (ALT), alkaline phosphatase (ALP) and acetylcholinesterase (AChE). Further, to examine the oxidative damage lipid peroxidation (LPO) and glutathione (GSH) levels as well as antioxidant enzymes such as superoxide dismutase (SOD), catalase, glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GSHPx), and glutathione-6-phosphate dehydrogenase were estimated in liver samples. AchE activity was inhibited significantly both in serum and liver following methomyl treatment. Administration of methomyl caused a significant increase in serum AST, ALT and ALP which indicated hepatic damage. LPO was found to be significantly increased, whereas GSH levels were decreased in the liver of methomyl-treated animals. The activities of SOD and catalase were significantly decreased whereas GST and GSHPx activities were found to be elevated significantly following methomyl treatment. No significant change in the enzyme activity of GR and glutathione-6-phosphatase dehydrogenase was observed after methomyl treatment. Vitamin E supplementation was able to attenuate appreciably the methomyl-induced changes in LPO levels along with SOD and GST activities. Histopathological studies following methomyl treatment revealed that hepatocytes, were not very well delineated and nuclei showed degenerative changes. Whereas, following Vitamin E supplementation in combined treatment group nuclei showing degenerative changes become less in number. The study, therefore, concludes that Vitamin E has a potential in mitigating most of the adverse effects induced by methomyl acute toxicity.     

Hydro-chemical Survey of Groundwater of Hisar City and Assessment of Defluoridation Methods Used in India

Ground water quality of Hisar city was assessed for its suitability for drinking purposes. Samples collected from the Bore-wells (forms a part of municipal water supply) and handpumps (direct consumption) were analyzed for the various physico-chemical parameters including pH, electrical conductivity, total dissolved salts, total hardness, total alkalinity, sodium, potassium, calcium, magnesium, carbonate, bicarbonate, chloride and sulfate. The concentrations of magnesium, sodium, potassium, sulfate and especially of chloride were found moderately higher than the WHO standards for the drinking water. Further a comparison of fluoride (F⁻) levels in groundwater of various cities and towns of Haryana state was performed. The relatively higher concentrations of F⁻ in groundwater of Haryana raise the risk of fluorosis and hence groundwater must be used with proper treatment. Promising defluoridation methods using locally available materials and technologies are discussed for the prevention and control of fluorosis. Data were assessed statistically to find the suitable markers of ground water quality as an aid to monitoring groundwater quality.     

Silver nanoparticles from Tabernaemontana divaricate leaf extract: mechanism of action and bio-application for photo degradation of 4-aminopyridine

Silver nanoparticles (Ag NPs) were synthesised by the reduction of Ag⁺ to Ag⁰ in the presence of enol form of flavonoids present in plant extract of Tabernaemontana divaricate (T. divaricate). Prepared Ag NPs were characterised using UV–Vis, XRD, HR-TEM with EDX and XPS techniques. XPS spectra exhibited peaks at 366 eV and 373 eV, which specified spin orbits for Ag 3d_3/2, and Ag 3d_5/2 that confirmed the formation of Ag NPs. Ag NPs were spherical in shape with an average size of 30 nm as revealed by HR-TEM and FE-SEM techniques. EDX studies verified the high purity of Ag NPs with silver 46.96%, carbon 16.35%, oxygen 16.22%, nitrogen 20.25% and sulphur 0.21%. LC–MS analysis of plant extract confirmed the qualitative presence of alkaloids, tannins, flavonoids, phenols, and carbohydrates. Prepared Ag NPs showed good photocatalytic activity towards degradation of 4-Amniopyridine with 61% degradation efficiency at optimum conditions in 2 h of reaction time under visible light. The ten intermediates were found within the mass number of 0–450. Ag NPs synthesised using bio-extract have also shown good inactivation against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria due to the availability of free radicals.

Graphical abstract

     

Lead-induced alterations in protein-deficient rat liver–role of zinc

This study was designed to determine the protective effects of zinc (Zn) using liver marker enzymes in the serum and liver along with hepatic elemental profile in lead (Pb)-treated protein-deficient (PD) Sprague–Dawley male rats. Zn in the form of zinc sulfate at a dose of 227?mg?L^?1 in drinking water was administrated to control, PD as well as Pb-treated PD rats for 8 weeks. Pb treatment was given orally as lead acetate at a dose level of 100?mg?kg^?1 body weight to control and PD rats. The effects of different treatments were studied on the activities of enzymes that included alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum. The status of different elements (Cl, K, Mn, Fe, Cu, Zn, Se, Rb, Pb) in liver was also studied. Rats given PD diet and Pb showed significant inhibition in serum ALP activity associated with significant elevation in both AST and ALT activities. Serum ALP activity showed a significant inhibition week 1 until week 8 in Pb-treated PD rats. In contrast, serum AST activity was elevated both at 3 and 8 weeks while serum ALT activity was elevated at 8 weeks in Pb-treated PD rats. Pb treatment to PD rats elevated hepatic ALP, AST and ALT activities but depressed hepatic AST. Zn supplementation to Pb-treated PD rats restored the altered enzyme activities. The levels of K, Fe, Cu, Zn, Se and Rb were altered in protein deficiency. Furthermore, treatment with Pb to these animals depressed the Cu levels. Zn treatment to Pb-treated PD animals tended to restore the levels of altered elements. Hence, the present study clearly suggests that Zn plays an important role in regulating the liver marker enzymes and essential elements under conditions of Pb toxicity and protein deficiency.