Comments on and implications of a steady-state in coastal marine ecosystems

Coastal ecosystems can be thought of as being established by a number of physico-geochemical drivers, e.g. geochemistry and bathymetry of the basins, climate, tidal and freshwater flows, natural and anthropogenic inputs of nutrients and toxins, all of which exert an influence on the resulting communities of organisms. Depending on the interactions among the major drivers, ecosystems may occur on both large and small scales and be basin-wide or within basins. For individual and separate ecosystems to exist with some permanence in time, e.g. reach a steady-state, they also have to be ‘defended’. Defences are mechanisms that counter changes to maintain the status quo. We argue, and present evidence to support the notion, that the defence mechanisms are inextricably tied to primary production and the biogeochemical cycling of organic matter and provide buffers that mitigate potentially adverse impacts by trace toxins. Colloid pumping, production of complexing ligands and sulfide formation are some of the mechanisms that control trace substances. Current methods for assessing ecosystems do not address the issue of steady-state, nor do they take account of defence activities, e.g. buffering. Therefore, they cannot assess the ‘robustness’ of ecosystems or their ability to resist change, for good or bad. Also, defence mechanisms may, for a time, mask future potentially serious impacts, suggesting that monitoring efforts with limited budgets should consider the measurement of the inputs into ecosystems as well as the immediate or short-term result of the inputs.     

Atypical homing or self-odour avoidance? Blue petrels (Halobaena caerulea) are attracted to their mate’s odour but avoid their own

Among procellariiform seabirds, many burrowing petrels show good olfactory abilities especially in recognising their nest. In particular, it has been reported that Antarctic prions (Pachyptila desolata) discriminate their own and their mate’s odours and, in Y-maze experiments, prefer the odour of a conspecific bird to their own. While traditionally examined from the perspective of homing mechanisms, these recent results have drawn attention to the possible use of chemical signals in birds’ social behaviours. Indeed, the life history of petrels suggests that a mate choice mediated by olfactory mechanisms may have evolved in this group to ensure genetic compatibility. This study was undertaken to validate and extend results obtained on petrels’ olfactory discrimination capabilities. Following the Y-maze experiment protocol, blue petrels (Halobaena caerulea) were offered three different choices: (1) mate versus conspecific’s odour, (2) own versus mate’s odour and (3) own versus conspecific’s odour. We discovered that birds prefer the odour of their mate not only when presented against conspecific’s odour but also against their own. We further verified that blue petrels also avoid their own odour when presented against conspecific’s odour. Our results confirm that olfactory discrimination in burrowing petrels goes beyond self-recognition and that self-odour avoidance may be widespread. We use two mutually non-exclusive behavioural frameworks for the interpretation of our results, homing and mate choice, and explain why homing mechanisms cannot account for all of our observations. This study opens the door to further research on olfactory mechanisms that, in petrels, might mediate individual recognition and mate choice.     

A note on some mathematical models on the effects of Bt-maize exposure

Some mathematical models for the estimation of the effects of Cry1Ab and Cry1F Bt-maize exposure in the biodiversity are examined. Novel results about these models are obtained and described in this note. The exact formula for the proportion of population that suffers mortality exposed either to Cry1Ab or Cry1AF pollen is derived. Moreover, regarding Cry1F pollen effects, the species sensitivity of Lepidoptera is discussed.     

Characterisation of major component leaching and buffering capacity of RDF incineration and gasification bottom ash in relation to reuse or disposal scenarios

Thermal treatment of refuse derived fuel (RDF) in waste-to-energy (WtE) plants is considered a promising solution to reduce waste volumes for disposal, while improving material and energy recovery from waste. Incineration is commonly applied for the energetic valorisation of RDF, although RDF gasification has also gained acceptance in recent years. In this study we focused on the environmental properties of bottom ash (BA) from an RDF incineration (RDF-I, operating temperature 850-1000 °C) and a RDF gasification plant (RDF-G, operating temperature 1200-1400 °C), by evaluating the total composition, mineralogy, buffering capacity, leaching behaviour (both at the material’s own pH and as a function of pH) of both types of slag. In addition, buffering capacity results and pH-dependence leaching concentrations of major components obtained for both types of BA were analysed by geochemical modelling. Experimental results showed that the total content of major components for the two types of BA was fairly similar and possibly related to the characteristics of the RDF feedstock. However, significant differences in the contents of trace metals and salts were observed for the two BA samples as a result of the different operating conditions (i.e. temperature) adopted by the two RDF thermal treatment plants. Mineralogy analysis showed in fact that the RDF-I slag consisted of an assemblage of several crystalline phases while the RDF-G slag was mainly made up by amorphous glassy phases. The leached concentrations of major components (e.g. Ca, Si) at the natural pH of each type of slag did not reflect their total contents as a result of the partial solubility of the minerals in which these components were chemically bound. In addition, comparison of total contents with leached concentrations of minor elements (e.g. Pb, Cu) showed no obvious relationship for the two types of BA. According to the compliance leaching test results, the RDF-G BA would meet the limits of the Italian legislation for reuse and the European acceptance criteria for inert waste landfilling. RDF-I BA instead would meet the European acceptance criteria for non hazardous waste landfilling. A new geochemical modelling approach was followed in order to predict the leaching behaviour of major components and the pH buffering capacity of the two types of slags on the basis of independent mineralogical information obtained by XRD analysis and the bulk composition of the slag. It was found that the combined use of data regarding the mineralogical characterization and the buffering capacity of the slag material can provide an independent estimate of both the identity and the amount of minerals that contribute to the leaching process. This new modelling approach suggests that only a limited amount of the mineral phases that control the pH, buffering capacity and major component leaching from the solid samples is available for leaching, at least on the time scale of the applied standard leaching tests. As such, the presented approach can contribute to gain insights for the identification of the types and amounts of minerals that control the leaching properties and pH buffering capacity of solid residues such as RDF incineration and gasification bottom ash.     

Assessment of biotechnological strategies for the valorization of metal bearing wastes

The present work deals with the application of biotechnology for the mobilization of metals from different solid wastes: end of life industrial catalysts, heavy metal contaminated marine sediments and fluorescent powders coming from a cathode ray tube glass recycling process. Performed experiments were aimed at assessing the performance of acidophilic chemoautotrophic Fe/S-oxidizing bacteria for such different solid matrices, also focusing on the effect of solid concentration and of different substrata. The achieved results have evidenced that metal solubilization seems to be strongly influenced by the metal speciation and partitioning in the solid matrix. No biological effect was observed for Ni, Zn, As, Cr mobilization from marine sediments (34%, 44%, 15%, 10% yields, respectively) due to metal partitioning. On the other hand, for spent refinery catalysts (Ni, V, Mo extractions of 83%, 90% and 40%, respectively) and fluorescent powders (Zn and Y extraction of 55% and 70%, respectively), the improvement in metal extraction observed in the presence of a microbial activity confirms the key role of Fe/S oxidizing bacteria and ferrous iron. A negative effect of solid concentration was in general observed on bioleaching performances, due to the toxicity of dissolved metals and/or to the solid organic component.     

Two-phase SPH modelling of advective diffusion processes

This paper deals with a two-dimensional numerical model based on the smoothed particle hydrodynamics (SPH) technique for the evaluation of the concentration field of pollutants in water. A SPH model is formulated to solve the fickian diffusion equation applied to pollutants with the same density as the water. A lagrangian SPH formalism of the advective diffusion equation is also developed for pollutant-water, taking into account the effects of molecular diffusion and natural advection induced by differences between the fluid densities. These equations are coupled with the fluid mechanics equations. Attention is paid to the numerical aspects involved in the solution procedure and to the optimization of the model parameters. Environmental engineering problems concerning diffusion and natural advection phenomena occur in the presence of a pollutant in still water. Numerical tests referring to a strip and a bubble of contaminant in a water tank with different initial concentration laws have been carried out. The results obtained by the proposed SPH models are compared with other available SPH formulations, showing an overall better agreement with standard analytical solutions in terms of spatial evolution of the concentration values. Capabilities and limits of the proposed SPH models to simulate advective diffusion phenomena for a wide range of density ratios are discussed.     

Multicriteria Decision Aid in Supporting Decisions Related to Groundwater Protection

In the recent decades, there have been frequent conflicts between groundwater resources and environmentally hazardous activities. An example is the construction of the new highway through the important glaciofluvial esker aquifer Nybroåsen, which passes the protection zone of the water supply for the Kalmar municipality, in the southeastern part of Sweden. The decision to build the new road through this important aquifer has been strongly questioned by the municipality and the public because the value of the water resources in Nybroåsen was not taken into consideration during the first phase of the decision-making process. Multicriteria decision aid (MCDA) is applied as a tool to structure and analyze the four road alternatives proposed in the environmental impact assessment for the above conflict. The alternatives, including the existing road, are in conflict with water resources, agriculture, natural, and cultural values. The impacts on the water resources have been predicted by a two-dimensional physically based time-variant flow and solute groundwater model, which has been calibrated and evaluated. The MCDA illustrates how it can be used to identify (1) actors and their concerns, (2) ranking of alternative road scenarios according to actors preferences, and (3) coalition groups of actors, i.e., groups that have similar views with regard to the road alternatives. The analysis shows that the two best compromise solutions obtained in the MCDA were unacceptable by the strongest coalition group, showing that either the family of criteria was not well chosen or new alternatives should have been developed.     

Pollution from polychlorodibenzo‐p‐dioxins and furans: The case of several foundry plants in the Lombardy region

In 1991 a co‐operation between Public Health Office (U.S.S.L.) n° 18 of Brescia and the Chemical Section Laboratories of U.S.S.L. n° 38 of Milan concerning the possible environmental impact of foundry industrial activities performing metallic scraps recovering, has been undertaken.

Soil and surfaces have been classified in conformity with the National Toxicological Consultative Commission (C.C.T.N.) recommendation dated 12/02/1988'; owing to the characteristics of the processed material, besides heavy metals, polychlorodibenzo‐p‐dioxins (PCDDs), polychlorodibenzofurans (PCDFs) and polychlorobiphenyls (PCBs) have been looked for.

The particulate matter collected from the filters positioned over the arc furnaces in 14 foundry plants has been characterized and classified, according both to C.C.T.N.¹ and to the Interministerial Board regulation dated 27/07/1985 for the first application of the Republic President Decree Law (D.P.R.) n° 915/1982, concerning wastes classification, based, in this case, on these toxic chlorinated compounds concentrations. From the very beginning, high levels of PCDDs and PCDFs have been detected, corroborating the very few literature data from foundry plants². The results obtained on 14 different foundries allow us to draw already some information, acceptable from the point of view of the statistical validity, about the pollution produced by this industry.     

Multivariate tools to investigate the spatial contaminant distribution in a highly anthropized area (Gulf of Naples,Italy)

Environmental Science and Pollution Research - The Gulf of Naples located in a high anthropized coastal area is subjected to an infrastructural intervention for the installation of a submarine...     

Shadows and lights of GSCM (Green Supply Chain Management): determinants and effects of these practices based on a multi-national study

Green Supply Chain Management (GSCM) is an increasingly widely-diffused practice among companies that are seeking to improve their environmental performance. The motivation for the introduction of GSCM may be ethical (e.g., reflecting the values of managers) and/or commercial (e.g., gaining a possible competitive advantage by signalling environmental concern). Drawing upon a database of over 4000 manufacturing facilities in seven OECD countries this paper assesses the determinants and motivations for the implementation of GSCM. We find that GSCM is strongly complementary with other advanced management practices, and that it contributes to improved environmental performance. The effects on commercial performance are more ambiguous.