Bacterial interactions with uranium: An environmental perspective

The presence of actinides in radioactive wastes is of major concern because of their potential for migration from the waste repositories and long-term contamination of the environment. Studies have been and are being made on inorganic processes affecting the migration of radionuclides from these repositories to the environment but it is becoming increasingly evident that microbial processes are of importance as well. Bacteria interact with uranium through different mechanisms including, biosorption at the cell surface, intracellular accumulation, precipitation, and redox transformations (oxidation/reduction). The present study is intended to give a brief overview of the key processes responsible for the interaction of actinides e.g. uranium with bacterial strains isolated from different extreme environments relevant to radioactive repositories. Fundamental understanding of the interaction of these bacteria with U will be useful for developing appropriate radioactive waste treatments, remediation and long-term management strategies as well as for predicting the microbial impacts on the performance of the radioactive waste repositories.     

Influence of platinum, palladium and rhodium as compared with cadmium, nickel and chromium on cell viability and oxidative stress in human bronchial epithelial cells

The platinum group elements (PGE) Pt, Pd and Rh are increasingly emitted into the environment by automobile catalytic converters. Whereas the biological availability of PGE to plants and animals has been demonstrated, only few studies concentrate on the influence of PGE on a cellular level. The effects of Pt, Pd and Rh compared with Cd, Ni and Cr on cell viability and oxidative stress response using soluble metal salts were studied in the human bronchial epithelial cell line BEAS-2B. Whilst Rh(III) showed little influence, both Pt(II) and Pt(IV) as well as Pd(II) had significant effects on cell viability at levels comparable to Cd(II) and Cr(VI). Arranging metal species in order of increasing toxicity as determined by LC50 yields: Rh(III)=1.2 mmol/L相似文献   

"Venom" of the slow loris: sequence similarity of prosimian skin gland protein and Fel d 1 cat allergen

Bites inflicted on humans by the slow loris (Nycticebus coucang), a prosimian from Indonesia, are painful and elicit anaphylaxis. Toxins from N. coucang are thought to originate in the brachial organ, a naked, gland-laden area of skin situated on the flexor surface of the arm that is licked during grooming. We isolated a major component of the brachial organ secretions from N. coucang, an approximately 18 kDa protein composed of two 70-90 amino-acid chains linked by one or more disulfide bonds. The N-termini of these peptide chains exhibit nearly 70% sequence similarity (37% identity, chain 1; 54% identity, chain 2) with the two chains of Fel d 1, the major allergen from the domestic cat (Felis catus). The extensive sequence similarity between the brachial organ component of N. coucang and the cat allergen suggests that they exhibit immunogenic cross-reactivity. This work clarifies the chemical nature of the brachial organ exudate and suggests a possible mode of action underlying the noxious effects of slow loris bites.     

Measurement of particle concentrations in a dental office

Particles in a dental office can be generated by a number of instruments, such as air-turbine handpieces, low-speed handpieces, ultrasonic scalers, bicarbonate polishers, polishing cups, as well as drilling and air sprays inside the oral cavity. This study examined the generation of particles during dental drilling and measured particle size, mass, and trace elements. The air sampling techniques included both continuous and integrated methods. The following particle continuous measurements were taken every minute: (1) size-selective particle number concentration (Climet); (2) total particle number concentration (PTRAK), and; (3) particle mass concentration (DustTrak). Integrated particle samples were collected for about 5 h on each of five sampling days, using a PM_2.5 sampler (ChemComb) for elemental/organic carbon analysis, and a PM₁₀ sampler (Harvard Impactor) for mass and elemental analyses. There was strong evidence that these procedures result in particle concentrations above background. The dental procedures produced number concentrations of relatively small particles (<0.5 μm) that were much higher than concentrations produced for the relatively larger particles (>0.5 μm). Also, these dental procedures caused significant elevation above background of certain trace elements (measured by X-ray fluorescence) but did not cause any elevation of elemental carbon (measured by thermal optical reflectance). Dental drilling procedures aerosolize saliva and products of drilling, producing particles small enough to penetrate deep into the lungs. The potential health impacts of the exposure of dental personnel to such particles need to be evaluated. Increased ventilation and personal breathing protection could be used to minimize harmful effects.     

Nymphal density, behavioral development, and life history in a field cricket

Population density regulates the strength of intraspecific competition and may thereby be reflected in life-history variables, such as development time, growth rate, or investment in immune defense. However, population density may also affect the fitness payoffs of different behaviors and consequently shape the development of personality. Here we studied if population density during nymphal development (one, four, or ten individuals raised together) affects the level of boldness, measured as the latency time to recover from freezing and emerge from a shelter, aggressiveness towards conspecifics or their correlation at the adult stage in the field crickets, Gryllus integer. In addition, we tested if individuals invest more resources in immune function or speed up their development in response to a high conspecifics density during ontogeny. Nymphal density did not affect adult boldness or aggressiveness towards conspecific males per se, but these variables showed a negative association, i.e., indicated an unconventional behavioral syndrome in the highest density treatment. Supporting the effectiveness of density treatments in inducing plastic responses, individuals reached maturity sooner and invested more resources in immune function in the highest nymphal density group compared to groups consisting of one or four individuals. Our results suggest that population density may play an important role in shaping both the realized life history and development of behavioral syndromes.     

SMEs and voluntary environmental initiatives: a study of stakeholders' perspectives in Hong Kong

The environmental performance of Hong Kong's businesses is currently perceived as rather poor. Small and medium-sized enterprises (SMEs) in particular are mostly unaware of the environmental impact of their business. Government and professional bodies have recently started to develop various initiatives to improve the SME sector's awareness of environmental and social issues, and external factors such as supply chain requirements, consumer preferences and energy prices are also exerting a growing influence. Based on extensive interviews with representatives of seven key stakeholder groups, this paper explores the effectiveness of such drivers to engage SMEs with environmental change and corporate social responsibility (CSR). It finds that most existing efforts, such as environmental support programmes and award schemes, do not have a great impact on the environmental and social performance of Hong Kong's SMEs.     

Re-Meandering German Lowland Streams: Qualitative and Quantitative Effects of Restoration Measures on Hydromorphology and Macroinvertebrates

We investigated the effects of two river restoration projects on hydromorphology and macroinvertebrate fauna in two German lowland rivers, the Schwalm and the Gartroper Mühlenbach. The stream channels were re-meandered and the floodplain levels were lowered to better connect the streams to their floodplains. The restoration was performed 10 years ago in the Schwalm and 2 years ago in the Gartroper Mühlenbach. We compared the restored reaches to nearby anthropogenically straightened reaches. Twenty-five hydromorphological parameters were recorded on twenty transects; between nine and 23 substrate-specific macroinvertebrate samples were taken per reach. Several hydromorphological parameters, such as the number and width of channel features and the number of substrate types, were significantly higher in the restored reaches compared to nearby anthropogenically straightened reaches. Total numbers of invertebrate families, genera, and taxa were also higher in the restored reaches than in the anthropogenically straightened reaches. Biotic substrates like dead wood or macrophytes were more abundant in the restored reaches, and these substrates hosted 28 taxa not found in the straightened reaches. While diversity was high in both restored reaches, overall abundance increased only in the river that was restored 10 years ago. Using NMS-analysis, substrate-specific faunistic samples of the restored reaches were compared to those of the straightened reaches. Our results revealed different invertebrate communities on the same substrates in the recently restored river. In the 10-year-old restoration, however, the same substrates were similarly inhabited. This comparable colonization of substrates may reflect succession in the macroinvertebrate community. The results are discussed according to the re-colonization potentials of the upstream and downstream reaches and the dispersal capacity of taxa.     

Copper release from chemical root-control baskets in hardwood tree production

The City of Montreal, Canada, evaluated the environmental impact and usefulness of in-ground copper (Cu)-treated baskets in controlling root growth of hardwood trees in nursery culture. Using baskets planted with 5-yr-old Norway maple (Acer platanoides L.) trees, the amount and temporal pattern of Cu release from the basket surface into soil was determined for two copper formulations: Cu metal powder and Cu(OH)2. Release of both Cu formulations from the basket surface decreased exponentially over time, with Cu concentration at the basket surface dropping to 2% of the initial Cu applied by the end of the second field season. Total Cu content increased significantly in the soil around the baskets (from 7 to 28 mg Cu kg(-1) soil) and in the baskets (from 7 to 50-70 mg Cu kg(-1) soil) over the two years of the study. Three levels of phosphorus application (33, 66, and 100% of the regular nursery rate of 465 kg ha(-1) yr(-1)) did not affect release of Cu from the basket surface. The release of Cu metal at 28 and 105 d in the field was significantly increased by inoculation with the symbiotic arbuscular mycorrhizal fungus (AMF) Glomus intraradices Schenck & Smith; however, AMF inoculation had no affect on Cu(OH)2 release. Trees grown in Cu-treated baskets and inoculated with G. intraradices had similar colonization to non-inoculated trees, suggesting that inoculation was not very effective and that AMF inoculum was already present in the root ball of the trees at planting. After two years, copper basket-grown trees had significantly less root colonization than isolated control trees growing in the open field. This strongly suggests that conditions inside the baskets were not favorable to AMF.     

The relationship between mining and socio-economic well being in Australia’s regions

This paper examines the relationship between quality of life indicators and the gross value of minerals production from Australian regions. We used quality of life indicators, aggregated for 71 local government areas containing mining activities, of household income, housing affordability, access to communication services, educational attainment, life expectancy, and unemployment. We find no evidence of systematic negative associations between quality of life and the gross value of minerals production. Instead, mining activity has a positive impact on incomes, housing affordability, communication access, education and employment across regional and remote Australia. Whilst we do not establish causality between mining activity and quality of life, our analysis prompts a rethink of the resource curse as it applies within a single country. We did not find evidence of a resource curse, at the local government level, in Australia’s mining regions. Nevertheless, we note observations by many other researchers of negative social impacts on specific demographic sectors, localities, families of fly-in fly-out mining operations, and individuals. This contrast may be a scale issue, with the regional benefits of mineral wealth masking highly localised inequalities and disadvantage. We suggest that there is a need to better understand these impacts and, more importantly, the types of policy mechanisms government and industry can adopt to mitigate or avoid them.