Facile characterization of polymer fractions from waste electrical and electronic equipment (WEEE) for mechanical recycling

In view of the environmental problem involved in the management of WEEE, and then in the recycling of post-consumer plastic of WEEE there is a pressing need for rapid measurement technologies for simple identification of the various commercial plastic materials and of the several contaminants, to improve the recycling of such wastes.This research is focused on the characterization and recycling of two types of plastics, namely plastic from personal computer (grey plastic) and plastic from television (black plastic). Various analytical techniques were used to monitor the compositions of WEEE. Initially, the chemical structure of each plastic material was identified by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Polymeric contaminants of these plastics, in particular brominated flame retardants (BFRs) were detected in grey plastics only using different techniques. These techniques are useful for a rapid, correct and economics identification of a large volumes of WEEE plastics.     

Gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium<Emphasis Type="Italic"> Azospirillum</Emphasis> spp.

In vitro gluconic acid formation and phosphate solubilization from sparingly soluble phosphorus sources by two strains of the plant growth-promoting bacteria A. brasilense (Cd and 8-I) and one strain of A. lipoferum JA4 were studied. Strains of A. brasilense were capable of producing gluconic acid when grown in sparingly soluble calcium phosphate medium when their usual fructose carbon source is amended with glucose. At the same time, there is a reduction in pH of the medium and release of soluble phosphate. To a greater extent, gluconic acid production and pH reduction were observed for A. lipoferum JA4. For the three strains, clearing halos were detected on solid medium plates with calcium phosphate. This is the first report of in vitro gluconic acid production and direct phosphate solubilization by A. brasilense and the first report of P solubilization by A. lipoferum. This adds to the very broad spectrum of plant growth-promoting abilities of this genus.     

In vitro genotoxicity of exhaust emissions of diesel and gasoline engine vehicles operated on a unified driving cycle

Acetone extracts of engine exhaust particulate matter (PM) and of vapor-phase semi-volatile organic compounds (SVOCs) collected from a set of 1998-2000 model year normal emitter diesel engine automobile or light trucks and from a set of 1982-1996 normal emitter gasoline engine automobiles or light trucks operated on the California Unified Driving Cycle at 22 [degree]C were assayed for in vitro genotoxic activities. Gasoline and diesel PM were comparably positive mutagens for Salmonella typhimurium strains YG1024 and YG1029 on a mass of PM extract basis with diesel higher on a mileage basis; gasoline SVOC was more active than diesel on an extracted-mass basis, with diesel SVOC more active on a mileage basis. For chromosomal damage indicated by micronucleus induction in Chinese hamster lung fibroblasts (V79 cells), diesel PM expressed about one-tenth that of gasoline PM on a mass of extract basis, but was comparably active on a mileage basis; diesel SVOC was inactive. For DNA damage in V79 cells indicated by the single cell gel electrophoresis (SCGE) assay, gasoline PM was positive while diesel PM was active at the higher doses; gasoline SVOC was active with toxicity preventing measurement at high doses, while diesel SVOC was inactive at all but the highest dose.     

Demonstration of sperm head shape abnormality and clastogenic potential of cypermethrin

Adult male Swiss albino mice were administered ip. suspension solution of cypermethrin in 0.15% DMSO at the doses of 30 mg, 60 mg and 90 mg/kg b. wt. daily for 5 days. Another group of animals was injected cyclophosphamide ip. (60 mg/kg b. wt.) in similar manner which served as positive control. Effect of cypermethrin on body and testes weight and sperm head morphology was studied. Clastogenic potential of cypermethrin was studied by using modified Allium test. The cytological changes were studied in the root tip cells of Allium cepa after 3 days treatment with three different concentration of cypermethrin (0.1, 1.0 and 10.0 microg/ml). The results revealed that body weight gain was considerably reduced in higher dose groups, but the testicular weight did not change significantly in any of the cypermethrin treated groups. However, a significant elevation in the number of abnormal shape of sperm head was noticed in higher dose groups as compared to control. It was observed that the abnormality in the shape of sperm head was dose-dependent. The cytological changes in the root tip cells of Allium cepa indicated that cypermethrin is having toxic effects on the root tip cells in the form of stickiness of chromosomes and also affect the mitotic activity. This study suggest that cypermethrin may have the potential to induce adverse effects on sperm head shape morphology of mouse as well as clastogenic effects on root tip cells of Allium cepa.     

Arsenic in groundwater in six districts of West Bengal,India

Arsenic in groundwater above the WHO maximum permissible limit of 0.05 mg l^–1 has been found in six districts of West Bengal covering an area of 34 000 km² with a population of 30 million. At present, 37 administrative blocks by the side of the River Ganga and adjoining areas are affected. Areas affected by arsenic contamination in groundwater are all located in the upper delta plain, and are mostly in the abandoned meander belt. More than 800 000 people from 312 villages/wards are drinking arsenic contaminated water and amongst them at least 175 000 people show arsenical skin lesions. Thousands of tube-well water in these six districts have been analysed for arsenic species. Hair, nails, scales, urine, liver tissue analyses show elevated concentrations of arsenic in people drinking arsenic-contaminated water for a longer period. The source of the arsenic is geological. Bore-hole sediment analyses show high arsenic concentrations in only few soil layers which is found to be associated with iron-pyrites. Various social problems arise due to arsenical skin lesions in these districts. Malnutrition, poor socio-economic conditions, illiteracy, food habits and intake of arsenic-contaminated water for many years have aggravated the arsenic toxicity. In all these districts, major water demands are met from groundwater and the geochemical reaction, caused by high withdrawal of water may be the cause of arsenic leaching from the source. If alternative water resources are not utilised, a good percentage of the 30 million people of these six districts may suffer from arsenic toxicity in the near future.     

Local variation of within-host clonal diversity coupled with genetic homogeneity in a marine trematode

Despite their ubiquity and importance to intertidal ecosystems, information is currently lacking regarding the genetic diversity of trematode parasites within coastal organisms and the distribution of their genetic variation among intertidal habitats. In this study, we quantified the clonal diversity of the coastal marine trematode Maritrema novaezealandensis within Zeacumantus subcarinatus snail hosts from three coastal bays in Otago Harbour, New Zealand, using five microsatellite loci to determine if differences exist in the frequency of occurrence of multi-clone infections. In addition, we examined gene flow among M. novaezealandensis collected from the three bays. The frequency of mixed-clone infections varied fourfold among bays and no genetic differentiation was detected among intertidal bays. Across the coastal bays studied, M. novaezealandensis comprises a single population that is potentially infecting multiple Z. subcarinatus populations with varying life history traits.     

Allelotoxicity of Parthenium leaf extracts on cytomorphological behaviour of sunflower (Helianthus annuus)

In recent decades allelopathy has gained much attention in the sustainable agricultural systems. It is necessary to trace out the mechanism of action of allelochemicals of plants on other plants. Allelochemicals of different plants interact differently with each other. In the present context an attempt has been made to study the influence of allelochemicals released by Parthenium on the growth, morphology and cytology of Helianthus annuus, both being strong allelopathic plants. The lower concentration of decomposed Parthenium leaves showed enhancing effect while higher doses depicted suppressive effect on growth and morphology of Helianthus annuus. However, cytological studies of pollen mother cells (PMCs) revealed increase in abnormality percentage with increasing concentration of allelochemicals. This study suggests better understanding of allelochemicals interaction and their incorporation into the betterment of crop.     

Improving land use inference by factorizing mobile phone call activity matrix

Land use is shaped by human activities. Traditional methods of measuring land uses (e.g. surveys and remote sensing techniques) often have difficulties in capturing human activities. The near-ubiquitous coverage of mobile phones opens up a new way to investigate land use through human activities. We propose to analyze land use by characterizing human activity patterns based on the aggregated call volume, and apply non-negative matrix factorization to identify fundamental behavioral classes. Using tower-based call data from Dakar, Senegal, we discover two fundamental land use patterns: commercial/business/industrial (C/B/I) and residential. Then, the land use of the reception area of each cell tower can be inferred based on the weights obtained for each basis vector. To evaluate the proposed approach, the results are compared with two points-of-interest (POI) data sets obtained from OpenStreetMap and Facebook’s Graph API. We have found that a majority of POIs like embassies, offices, and hotels are located in the predicted C/B/I areas; specifically, there is a strong positive correlation between estimated land use weights and the number of related POIs. Furthermore, we have shown analyzing 24-h call pattern matrix can track daily land use changes.     

Cement‐based solidification/stabilization of phenol‐contaminated soil by bentonite and organophilic clay

The performance of ordinary and organophilic clays in the solidification and stabilization process was investigated with respect to the unconfined compressive strength (UCS) and leaching of phenol‐contaminated soil. The samples contained 2,000 mg/kg of phenol. White cement (15 and 30 percent by weight [wt%]) was used as binder, while ordinary and organophilic clays (8, 15, and 30 wt%) were applied as additives for reducing the harmful effects of phenol interference in cement hydration with a 28‐day curing time. The results revealed that the UCS is reduced by increasing the amount of clays. The values of UCS of all samples met the minimum standards specified for disposal in sanitary landfills determined by developed countries. The leaching test demonstrated that the degree of leaching diminished with increased clay content in all samples of both clay types. This reduction was observed to be greater in samples containing organophilic clay than in bentonite clay samples. Furthermore, the best composition of the materials tested was determined to be 30 wt% white cement plus 13.3 wt% organophilic clay with a compressive strength of 3,839 kPa, phenol removal percentage of 80 percent, and a cost of $67 per ton of contaminated soil.