Electrical separation of plastics coming from special waste

Minimisation of waste to landfilling is recognised as a priority in waste management by European rules. In order to achieve this goal, developing suitable technologies for waste recycling is therefore of great importance. To achieve this aim the technologies utilised for mineral processing can be taken into consideration to develop recycling systems. In particular comminution and separation processes can be adopted to recover valuable materials from composite waste. In this work the possibility of recycling pharmaceutical blister packaging has been investigated. A suitable comminution process has been applied in order to obtain the liberation of the plastic and aluminium components. Experiments of electrical separation have been carried out in order to point out the influence of the process parameters on the selections of the different materials and to set up the optimum operating conditions.     

Microbial Inoculants on Woody Legumes to Recover a Municipal Landfill Site

Tree and shrubby legumes have great potential in degraded land rehabilitation because of their ability to form symbiotic associations with nitrogen fixing rhizobia and mycorrhizal fungi. Extensive soil disturbance reduces natural microbial propagules thus preventing the formation of beneficial plant-microbes symbiosis. Reintroduction of selected microbial symbionts may improve the recovery rate of disturbed ecosystems. We inoculated selected rhizobia and arbuscular mycorrhizal fungi on two woody legume species, the mediterranean shrub Spartium junceumL. and the exotic tree Acacia cyanophylla Lindl. in order to recover a sealed municipal landfill (Palermo, Sicily, Italy). Inoculated plants showed shoot growth parameters 2 to 12-fold higher than uninoculated plants. After transplanting on the municipal landfill site, inoculated plants showed no transplant shock and low mortality (6–15%). The chemical analysis of P and N plant content showed no differences between inoculated and uninoculated plants suggesting that a dilution effect occurred due to higher biomass production of the inoculated plants. The beneficial effects of mycorrhization and rhizobium inoculum on growth parameters were still detectable one year after transplanting in S. junceum.     

Distal impacts of aquarium trade: Exploring the emerging sandhopper (<Emphasis Type="Italic">Orchestoidea tuberculata</Emphasis>) artisanal shore gathering fishery in Chile

Artisanal fishery activities support the livelihoods of millions of people worldwide, particularly in developing countries. Within these fisheries, distal global drivers can promote switching between alternative target resources. These drivers can promote the rapid development of new, unregulated and previously unexploited fisheries that pose a threat to the sustainability of ecosystems. In this paper, we describe a new artisanal shore gathering activity that targets a previously unexploited resource: the sandhopper (Orchestoidea tuberculata). The activity is driven by aquarium trade demand for food. We used mixed methods to describe the activity, assessed basic socio-economic incentives, and estimated Catches per Unit Effort. Results show that the sandhopper plays an important role for the livelihoods of shore gatherers engaged in the activity. Gatherers have adapted and developed two main extraction methods with different degrees of investment and extraction rates. Furthermore, gatherers have developed local knowledge regarding the ecology and management of the resource. Results show that economic incentives can motivate a rapid expansion of this unregulated activity. Future research gaps and management options to address the development of this fishery are discussed in light of these findings.     

Effect of solid waste landfill organic pollutants on groundwater in three areas of Sicily (Italy) characterized by different vulnerability

The aim of this study was to obtain information on the presence and levels of hazardous organic pollutants in groundwater located close to solid waste landfills. Eighty-two environmental contaminants, including 16 polycyclic aromatic hydrocarbons (PAHs), 20 volatile organic compounds (VOCs), 29 polychlorinated biphenyls (PCBs), 7 dioxins (polychlorinated dibenzo-p-dioxins, PCDDs) and 10 furans (polychlorinated dibenzofurans, PCDFs) were monitored in areas characterised by different geological environments surrounding three municipal solid waste landfills (Palermo, Siculiana and Ragusa) in Sicily (Italy) in three sampling campaigns. The total concentrations of the 16 PAHs were always below the legal threshold. Overall, the Fl/Fl + Py diagnostic ratio revealed that PAHs had a petrogenic origin. VOC levels, except for two notable exceptions near Palermo landfill, were always below the legal limit. As concerns PCB levels, several samples were found positive with levels exceeding the legal limits. It is worth noting that the % PCB distribution differs from that of commercial compositions. In parallel, some samples of groundwater containing PCDDs and PCDFs exceeding the legal threshold were also found. Among the 17 congeners monitored, the most abundant were the highest molecular weight ones.

     

Distribution and human health risk assessment of PAHs in four fish species from a SW Atlantic estuary

Environmental Science and Pollution Research - The aim of this study is to assess—for the first time—the concentration of the 16 polycyclic aromatic hydrocarbons (PAHs) in the muscle...     

Copepods and Larvae of Nematodes Parasiting the White Mullet Mugil Curema (Valenciennes, 1836): Indicators of Anthropogenic Impacts in Tropical Coastal Lagoons?

The relationship between parasites and environmental stress were studied in two tropical coastal lagoons of Northwest Mexico: Urias estuary (highly polluted) and Teacapan estuary (slightly polluted). Metazoan parasites were examined in 292 white mullet (Mugil curema) specimens collected bimonthly during a year from both systems. Haliotrema mugilinus, Metamicrocotyla macracantha, Ergasilus sp., Caligus sp., Holobomolochus sp., and Lernaeopodidae were found in gills, while Contracaecum sp. larvae III was found liver, hepatic portal vein and kidneys. Ecological indices were influenced by the slightly higher number of parasitic species in Urias compared to Teacapan, as well as the clear dominance of two species: Ergasilus sp. and Contracaecum sp. in both systems. In fact, Ergasilus sp. showed considerably higher abundance in Urias, possibly indicating that its success was a result of adverse conditions affecting the host, while Contracaecum sp showed higher abundances in Teacapan, suggesting that the environmental conditions occurring in Urias could have produced negative impacts on the nematode's infective potential.     

Restoring biochemical activity and bacterial diversity in a trichloroethylene-contaminated soil: the reclamation effect of vermicomposted olive wastes

Background, aim, and scope  In this work, the potential for using olive-mill solid waste as an organic amendment for biochemical and biological restoration of a trichloroethylene-contaminated soil, which has previously been stabilized through vermicomposting processes, has been explored. Materials and methods  Trichloroethylene-contaminated water was pumped into soil columns with a layer of vermicompost at 10-cm depth (biobarrier system). The impacts of the trichloroethylene on the microbial community were evaluated by determining: (1) the overall microbial activity (estimated as dehydrogenase activity) and enzyme activities related to the main nutrient cycles (β-glucosidase, o-diphenoloxidase, phosphatase, urease, and arylsulphatase activities). In addition, isoelectric focusing of the soil extracellular humic-β-glucosidase complexes was performed to study the enzymatically active humic matter related to the soil carbon cycle. (2) The soil bacterial diversity and the molecular mechanisms for the bacterial resistance to organic solvents were also determined. For this, polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) was used to detect changes in bacterial community structure and PCR-single-strand conformational polymorphism (SSCP) was developed and optimised for detection and discrimination of the resistance-nodulation-division (RND) genes amplified from the contaminated soils. Results  Vermicompost reduced, with respect to the unamended soil, about 30% of the trichloroethylene leaching during the first month of the experiment. Trichloroethylene had a marked negative effect on soil dehydrogenase, β-glucosidase, urease, phosphatase, and arylsulphatase activities. Nevertheless, the vermicompost tended to avoid this toxic effect. Vermicompost also displays stable humic-β-glucosidase complexes that increased the extracellular activity related to C-cycle in the contaminated soils. The isoelectric focusing technique showed a more biochemically active humic matter in the soil sampled under the vermicompost. The behaviour of the three main phyla of bacteria isolated from the DGGE bands was quite different. Bands corresponding to Actinobacteria disappeared, whereas those affiliated with Proteobacteria remained after the trichloroethylene contamination. The disappeared Actinobacteria became visible in the soil amended with the vermicompost. Bands corresponding to Bacteriodetes appeared only in columns of contaminated soils. In this study, six types of RND proteins were detected by PCR-SSCP in the natural soil, three in the trichloroethylene-contaminated soil and 7/5 in trichloroethylene-contaminated soil above/below the vermicompost in the biobarrier columns. Trichloroethylene tended to reduce or eliminate all the clones detected in the uncontaminated soil, whereas new efflux pumps appeared in the biobarrier columns. Discussion  Although enzymes incorporated into the humic substances of vermicomposted olive wastes are quite stable, trichloroethylene also inhibited the background levels of the soil extracellular β-glucosidase activity in the amended soils. The decrease was less severe in the biobarrier system, but in any case, no relation was found between the levels of trichloroethylene in soil and extracellular β-glucosidase activity, or between the latter and the quantity of humic carbon in soils. The isoelectric focusing technique was carried out in the humic fraction to determine whether the loss of activity occurred in overall extracellular β-glucosidase or in that linked to stable humic substances (humic–enzyme complexes). The contaminated soils showed the lower enzyme activities, whereas contaminated and amended soils presented greater quantity of focalised (and therefore stable) humic carbon and spectra heterogeneity: very different bands with higher enzyme activities. No clear relationship between trichloroethylene concentration in soil and diversity of the bacterial population was noted. Similar patterns could be found when the community structures of bacteria and microbial activity were considered. Since the use of the dehydrogenase assay has been recognised as a useful indicator of the overall measure of the intensity of microbial metabolism, these results could be attributed to PCR-DGGE methodology, since the method reveals the presence of dominant populations regardless of their metabolic state. Trichloroethylene maintained or even increased the number of clones with the DNA encoding for RND proteins, except for the contaminated soil located above the vermicompost. However, the main effect of trichloroethylene was to modify the structure of the community in contaminated soils, considering the type of efflux pumps encoded by the DNA extracted from soil bacteria. Conclusions  Trichloroethylene inhibited specific functions in soil and had a clear influence on the structure of the autochthonous bacterial community. The organic matter released by the vermicomposted olive waste tended to avoid the toxic effect of the contaminant. Trichloroethylene also inhibited the background levels of the soil extracellular β-glucosidase activity, even when vermicompost was present. In this case, the effect of the vermicompost was to provide and/or to stimulate the humic-β-glucosidase complexes located in the soil humic fraction >10⁴, increasing the resistance of the enzyme to the inhibition. The bacterial community from the soil presented significantly different mechanisms to resistance to solvents (RND proteins) under trichloroethylene conditions. The effect of the vermicompost was to induce these mechanisms in the autochthonous bacterial community and/or incorporated new bacterial species, able to grow in a trichloroethylene-contaminated ambient. Coupled biochemical and molecular methodologies are therefore helpful approaches in assessing the effect of an organic amendment on the biochemical and biological restoration of a trichloroethylene-contaminated soil. Recommendations and perspectives  Since the main biochemical and biological effects of the organic amendment on the contaminated soil seem to be the incorporation of biochemically active humic matter, as well as new bacterial species able to grow in a trichloroethylene-contaminated ambient, isoelectric focusing and PCR-SSCP methodologies should be considered as parts of an integrated approach to determine the success of a restoration scheme.     

Multi-causal and integrated assessment of sustainability: the case of agriculturization in the Argentine Pampas

Assessing the sustainability of complex development processes requires multi-causal and integrated analyses. We develop a system-based methodology, rooted in interdisciplinary discussion and consensus building between 15 experts, to construct a multi-causal diagram which examines the sustainability of the Argentine Pampas′ process of agriculturization. The resulting diagram includes 25 factors and provides a big-picture of the multiple dimensions and interrelations affecting sustainability. According to this examination, the increasing concentration of production and the incorporation of technological innovations, triggered by economic and institutional factors, are the cause of environmental distresses and social changes, whose consequences for sustainability are still highly disputed. Nevertheless, the symptoms of both environmental and social unsustainability are more evident in the case of the extra-Pampean regions than in the Pampas. This suggests that the Pampean agriculture model should not be transferred to these regions without substantial modifications. The experts did not reach consensus on whether the agriculturization process is overall sustainable or unsustainable. Lack of consensus revolved mainly around opposing perspectives regarding the significance of the threats to environmental sustainability. The magnitude of socio-distributive unbalance and loss of rural jobs were also contentious. Yet, the paper shows how the exercise of building a joint causal diagram was undoubtedly helpful for linking piece-meal disciplinary facts, brought in from all fronts, into a comprehensive and coherent picture. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Speciation of inorganic arsenic in coastal seawater from Ionian and Tyrrhenian Seas (Sicily, Italy) using derivative anodic stripping chronopotentiometry

The purpose of this paper was to use derivative anodic stripping chronopotentiometry (dASCP) as a sensitive and accurate technique, to determine the concentrations of dissolved As (III) and As (V) in coastal seawater samples from the Straits of Messina, the Ionian and the Tyrrhenian seas, and to investigate the relationship between the anthropogenic activities on the coastal areas and the concentration of dissolved inorganic arsenic in seawaters. The obtained data indicated that As (V) was the most abundant species, with concentration ranging from 26.7 to 307 nM, whereas As (III) levels were lower than 48 nM in all the samples. In particular, As (III) and As (V) levels significantly decreased from high to low anthropogenic activities zones (p < 0.00001, ANOVA), with the reference samples, from a wildlife reserve, showing the lowest values. Furthermore it was observed that human activities influenced inorganic arsenic speciation, since the zones that received high human input presented the highest As(V)/As (III) ratio.     

Metabolic and bacterial diversity in soils historically contaminated by heavy metals and hydrocarbons

The aim of this study was to characterize soils contaminated by different levels of heavy metals and hydrocarbons (Madonna Dell'Acqua, Pisa, Italy). The soils were chemically and biochemically analysed by measuring the standard chemical properties and some enzyme activities related to microbial activity (dehydrogenase activity) and the soil carbon cycle (total and extracellular beta-glucosidase activities). The metabolic capacities of soil microorganisms to degrade hydrocarbons through catechol 2,3-dioxygenase were also described. The microbial diversity of contaminated and uncontaminated soils was estimated by denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA sequences. The PCR/single-strand conformation polymorphism (PCR/SSCP) method was used to estimate the genetic diversity of PAH-degrading genes in both contaminated and uncontaminated soils. A greater bacterial diversity and lower catechol 2,3-dioxygenase activity was detected in unpolluted soils. The complexity of the microbial community (Shannon and Simpson indices) as well as the dehydrogenase soil activity negatively correlated with contamination levels. The greatest PAH-degrading gene diversity and the most intense catechol 2,3-dioxygenase activity were found in the soils with the highest levels of hydrocarbons. Heavy metals and hydrocarbon pollution has caused a genetic and metabolic alteration in microbial communities, corresponding to a reduction in microbial activity. A multi-technique approach combining traditional biochemical methods with molecular-based techniques, along with some methodological improvements, may represent an important tool to expand our knowledge of the role of microbial diversity in contaminated soil.