Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.     

Natural resources dynamics: Exhaustible and renewable resources,and the rate of technical substitution

In this paper we study both exhaustible and renewable resources in an endogenous growth model. In particular, we consider the hypotheses in which the rate of technical substitution (RTS) between those two inputs is or is not equal to one. Moreover, we depart from a basic theoretical framework to account for the negative externality constituted by waste accumulation. Finally, a comparative analysis is made between Pigouvian tax and waste recycling, as an environmental policy to correct market failure represented by refuse accumulation.     

Electromagnetic fields: principles of exposure mitigation.

Basic principles of reducing exposure to electromagnetic fields are reviewed in this article. Measures to reduce exposure can be divided into organisational/administrative and technical/engineering actions. Both strategies are briefly analysed and the basic principles of the theory of shielding are presented. A definition of shielding effectiveness (SE) is given, and the results from the general Transmission Lines Theory are presented. Practical situations of shielding static and time-varying electric and magnetic fields are discussed on the basis of the physical properties of the fields and of the shield.     

Effect of sewage amendment on the dissipation of terbuthylazine,its degradation compound desethyl-terbuthylazine,and S-metolachlor in a field study

This study evaluates the effect of sewage amendment (SA) on the dissipation of terbuthylazine, its degradation compound desethyl-terbuthylazine, and S-metolachlor in the soil. The experiment was conducted at Padua Experimental Farm (Italy). Herbicides dissipation was evaluated in soils differently fertilized for three years: with inorganic fertilizer, with sewage sludge, and with a combination of them. Terbuthylazine and S-metolachlor were applied on sorghum as a formulated product at a dose of 2.8?L ha^?1, and their dissipation was followed for 2.5 months. The concentrations of herbicides and one metabolite in soil were analyzed by liquid chromatography-mass spectrometry. The dissipation of terbuthylazine and S-metolachlor followed a pseudo first order kinetics; they dissipated faster in soil amended only with inorganic fertilizer than in soils amended with sewage or sewage?+?inorganic fertilizer. The reduction in mineralization of the herbicides after sewage addition can be attributed to the reduced herbicide availability to microorganisms. The degradation of terbuthylazine led to the formation of desethyl-terbuthylazine. SA slowed down the formation and the degradation of desethyl-terbuthylazine, leading to a higher amount measured at the end of the incubation. These findings have practical implications for the assessment of the environmental fate of terbuthylazine and S-metolachlor in agricultural areas.     

Dioxins and furans formation in pilot incineration tests of sewage sludge spiked with organic chlorine

The factors affecting polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) formation were studied in sewage sludge incineration tests carried out on a demonstrative plant. The plant includes a circulating fluidised bed furnace (FBF) and a rotary kiln furnace (RKF), operating alternatively. During the tests sewage sludge was spiked with chlorinated hydrocarbons and the operating parameters of the afterburning chamber were varied. PCDD/F were sampled in each test before the bag filter, thus collecting the above contaminants before abatement systems. From the tests it appeared that PCDD/F were always produced in more abundance in the tests carried out by FBF than by RKF. The higher PCDD/F concentrations in the tests by FBF were reached when sewage sludge was spiked with a high dosage of a surrogate organic mixture of chlorinated hydrocarbons and when the afterburning chamber was used only as transit equipment with the burner off. The distribution of the different PCDD/F homologues was compared. P5CDFs were generally the prevalent fraction, with very few exceptions for the tests by RKF at high temperature of the afterburning chamber. As for FBF tests, it was found that the PCDD/F homologue profile depends on the afterburning chamber temperature.     

A new generation of coastal monitoring platforms

The need for new instruments and systems for environment monitoring encouraged the development of a network of coastal platforms combining a high versatility with ease of use and affordability. Almost every instrument can be fitted on the platforms, thanks to the large amount of available power provided by both solar panels and wind generators. All the platforms host a pumping system that pumps water from five depths into a measurement chamber where a multiparametric probe is fitted and from where other devices (e.g. samplers or analysers) can draw samples. In situ temperature measurements are provided at the same pumping depths. A colorimetric nutrient analyser and a meteorological station complete the basic equipment. On one of the platforms, a remotely controlled water sampler and an ADCP are also fitted. The data-acquisition and transmission system enables the platform to be controlled remotely using a special macro-commands set. Several examples of use are presented.     

Phylogeography of the seaweed Ishige okamurae (Phaeophyceae): evidence for glacial refugia in the northwest Pacific region

Although benthic marine algae are essential components of marine coastal systems that have been influenced profoundly by past and present climate change, our knowledge of seaweed phylogeography is limited. The brown alga Ishige okamurae Yendo occurs in the northwest Pacific, where it occupies a characteristic belt in the exposed intertidal zone. To understand the patterns of genetic diversity and the evolutionary history of this species, we analyzed mitochondrial cox3 from 14 populations (221 individuals) throughout its range. The 17 haplotypes found in this study formed five distinct clades, indicating significant genetic structure. The high differentiation and number of unique (private) haplotypes may result from the recolonization of the species from glacial refugia. Three putative refugia, each with high genetic diversity, were identified: southern Korea (including Jeju Island), northern Taiwan, and central Pacific Japan. Recolonization of I. okamurae was probably determined by ocean currents and changes in sea level during the last glacial period.