Converging hazard assessment of gold nanoparticles to aquatic organisms

The gold nanoparticles (Au-NPs) are being increasingly used because of their huge diversity of applications, and consequently, elevated levels in the environment are expected. However, due to their physico-chemical properties and functionalization a high variety of Au-NPs can be found, and complete toxicological information for each type of Au-NPs still lacks, and even, the toxicological information for the same species is sometimes contradictory. Therefore, hazard assessment should be done case by case. Hence, the objective of this study was to obtain ecotoxicological information of the same Au-NPs in aquatic organisms and to find a rationale for Au-NPs toxicity. For such a purpose, bare and hyaluronic acid capped Au-NPs (12.5 nm) along with Au-NPs bulk material were tested on freshwater algae, Daphnia and zebrafish. Results showed that while gold nanoparticles were found to be harmless to the tested organisms, the soluble gold showed to be toxic to algae and Daphnia, with an LC₅₀ between 1 and 2 mg L⁻¹. Comparing our results with those gathered in the literature, it appears that a common hazard assessment of Au-NPs on the studied organisms can be elucidated.     

From green product definitions and classifications to the Green Option Matrix

Hybrid cars, recycled products, photovoltaic cells, bioplastics: why so different products can be called ‘green’? Which practices companies willing to develop green products should implement? How companies can easily and effectively communicate to stakeholders the environmental features of their green products? This paper tries to answer these questions, by developing a Green Option Matrix (GOM), which characterizes green products and practices along different dimensions. This matrix is then used to analyze the different features of green products as well as related green practices developed by a sample of companies belonging to the Dow Jones Sustainability World Index (DJSWI). Relevant data are collected by means of content analysis of companies’ websites and sustainability reports. Green products and practices developed by each company in the sample are positioned in the matrix and results are presented and discussed for each industrial sector. Then, different sectors’ behaviors are compared. The proposed matrix can be used by companies as a market tool to analyze competitors’ green products and practices and as a communication tool to effectively communicate to stakeholders the specific green features of their products and practices.     

Solid wastes integrated management in Rio de Janeiro: input-output analysis

This paper analyzes the socioeconomic aspects of solid waste management in Rio de Janeiro. An "input-output" methodology was used to examine how the secondary product resulting from recycling is re-introduced into the productive process. A comparative profile was developed from the state of recycling and the various other aspects of solid waste management, both from the perspective of its economic feasibility and from the social aspects involved. This was done analyzing the greenhouse gas emissions and the decreased energy consumption. The effects of re-introducing recycled raw materials into the matrix and the ensuing reduction of the demand for virgin raw materials was based on the input-output matrix for the State of Rio de Janeiro. This paper also analyzes the energy savings obtained from recycling and measures the avoided emissions of greenhouse gases.     

The plant physical features selected by wildcats as signal posts: an economic approach to fecal marking

The chemical signals of solitary and territorial felid species are essential for their intraspecific communication. We studied the selection of plant substrates during the fecal marking behavior of the European wildcat Felis silvestris from September 2008 to June 2009 in a protected area in Northwest Spain. The aim of the study was to examine the selection of plants as signal posts with respect to their physical characteristics. We hypothesized that wildcats deposit their fecal marks on plants with physical characteristics (e.g., size, species, and visual conspicuousness) that enhance the olfactory and visual effectiveness of the signal. Our results indicate that diameter, plant group, visual conspicuousness, and interaction between the diameter and plant group influence the decision of wildcats to deposit their fecal marks on plants. The wildcats chose plants with greater diameters and greater visual conspicuousness as scent-marking posts. Moreover, the wildcats chose woody and herbaceous plants, and certain plant species were marked more frequently than expected at random. Indeed, our results indicate that the fecal marks were not randomly distributed on the plants: the wildcats chose to place their marks on plants with certain physical characteristics that maximized the detectability of the signal by intruders and potential mates, thus facilitating the spatial distribution of the species.