Remediation of heavy metals contaminated soils by ball milling

In the present work, the use of ball milling reactors for the remediation of lead contaminated soils was investigated. Lead immobilization was achieved without the use of additional reactants but only through the exploitation of weak transformations induced on the treated soil by mechanical loads taking place during collisions among milling media. The degree of metal immobilization was evaluated by analyzing the leachable fraction of Pb(II) obtained through the "synthetic precipitation leaching procedure". The reduction of leachable Pb(II) from certain synthetic soils, i.e., bentonitic, sandy and kaolinitc ones, was obtained under specific milling regimes. For example, for the case of bentonitic soils characterized by a Pb(II) concentration in the solid phase equal to 954.4 mg kg(-1), leachable Pb(II) was reduced, after 7 h of mechanical treatment, from 1.3 mg l(-1) to a concentration lower than the USEPA regulatory threshold (i.e., 0.015 mg l(-1) for drinkable water). Similar results were obtained for sandy and kaolinitic soils. X-ray diffraction, scanning electron microscopy, electron dispersive spectroscopy and granulometric analyses revealed no significant alterations of the intrinsic character of sandy and bentonitic soils after milling except for a relatively small increase of particles size and a partial amorphization of the treated soil. On the other hand, the mechanical treatment caused the total amorphization of kaolinitic soil. The increase of immobilization efficiency can be probably ascribed to specific phenomena induced by mechanical treatment such as entrapment of Pb(II) into aggregates due to aggregation, solid diffusion of Pb(II) into crystalline reticulum of soil particles as well as the formation of new fresh surfaces (through particle breakage) onto which Pb(II) may be irreversibly adsorbed.     

Bioassays for the evaluation of reclaimed opencast coal mining areas

Environmental Science and Pollution Research - This study aimed to use bioassays (single and multispecies) with organisms from different trophic levels to assess soil quality in reclaimed coal...     

Groundwater flow velocities in karst aquifers; importance of spatial observation scale and hydraulic testing for contaminant transport prediction

Environmental Science and Pollution Research - We review scale dependence of hydraulic conductivities and effective porosities for prediction of contaminant transport in four UK karst aquifers....     

Satellite tracking of migrating loggerhead sea turtles (<Emphasis Type="Italic">Caretta caretta</Emphasis>) displaced in the open sea

Loggerhead turtles (Caretta caretta) are known to migrate towards fixed, individually-specific residential feeding grounds. To study their spatial behaviour and their navigational ability, five loggerheads nesting in South Africa were captured when about to start their postnesting migration and tracked by satellite after having been displaced from their usual migratory route. The first turtle, released south of Madagascar about 1,148 km from the capture site, moved west up to mainland Africa and then reached her feeding grounds by following the coast. A second turtle, released farther away (2,140 km) close to La Réunion Island, stopped for some time on the Madagascar east coast, then turned southwards to round the island and regain the African mainland in the northwest, without however allowing us to establish the location of her residential grounds. Three other turtles were released off the Tanzanian coast, 2,193 km north of their nesting area, at the northern edge of the distribution of the feeding grounds along the African coast. All of them headed north, and one turtle found her residential grounds located north of the release site. The other two females started long-distance oceanic wanderings in which they crossed nearly the entire Indian Ocean, apparently being transported by the sea currents of the region. We conclude that adult loggerhead turtles are apparently unable to compensate for the displacement and can return to a pelagic life style characteristic of juvenile turtles. These findings suggest that South African loggerheads rely on simple orientation mechanisms, such as the use of the coastline, as a guide, and compass orientation, possibly integrated by spatiotemporal programmes and/or acquired maps of familiar sites.Communicated by R. Cattaneo-Vietti, Genova     

Ozone sensitivity of Fagus sylvatica and Fraxinus excelsior young trees in relation to leaf structure and foliar ozone uptake

During the summer of 2001, 2-year-old Fraxinus excelsior and Fagus sylvatica plants were subjected to ozone-rich environmental conditions at the Regional Forest Nursery at Curno (Northern Italy). Atmospheric ozone concentrations and stomatal conductance were measured, in order to calculate the foliar fluxes by means of a one-dimensional model. The foliar structure of both species was examined (thickness of the lamina and of the individual tissues, leaf mass per area, leaf density) and chlorophyll a fluorescence was determined as a response parameter. Stomatal conductance was always greater in Fraxinus excelsior, as was ozone uptake, although the highest absorption peaks did not match the peaks of ozone concentration in the atmosphere. The foliar structure can help explain this phenomenon: Fraxinus excelsior has a thicker mesophyll than Fagus sylvatica (indicating a greater photosynthesis potential) and a reduced foliar density. This last parameter, related to the apoplastic fraction, suggests a greater ability to disseminate the gases within the leaf as well as a greater potential detoxifying capacity. As foliar symptoms spread, the parameters relating to chlorophyll a fluorescence also change. PI (Performance Index, Strasser, A., Srivastava, A., Tsimilli-Michael, M., 2000. The fluorescence transient as a tool to characterize and screen photosynthetic samples. In: Yunus, M., Pathre, U., Mohanty, P., (Eds.) Probing Photosynthesis: Mechanisms, Regulation and Adaptation. Taylor & Francis, London, UK, pp. 445-483.) has proved to be a more suitable index than Fv/Fm (Quantum Yield Efficiency) to record the onset of stress conditions.     

Male-biased predation of western green lizards by Eurasian kestrels

Selective predation can be an important force driving the evolution of organisms. In particular, sex-biased predation is expected to have implications for sexual selection, sex allocation and population dynamics. In this study, we analysed sex differences in the predation of the western green lizard (Lacerta bilineata) by the Eurasian kestrel (Falco tinnunculus) during the reproductive season. In addition, we investigated whether the rate of predation differed during the 8-year study period and among the three habitats studied. We collected lizard remains from nest boxes of kestrels. Freshly killed lizards were sexed by visual inspection, whilst the sex of head remains was assigned by analysing the cephalic scale morphology using geometric morphometrics. Our results show that the risk of being predated by a kestrel in our population was overall about 3.55 times higher for males than for females. To our knowledge this is the first study showing a male-biased predation in a lizard species. The selective predation of males was consistent between years over the 8-year study period (1999-2006) and also consistent between the three types of kestrel hunting habitat. Overall predation rates on lizards differed between habitats, depending on the year. We propose that the observed sex-biased predation is mainly due to sex differences in lizard behaviour.     

A multi-objective approach to solid waste management

The issue addressed in this paper consists in the localization and dimensioning of transfer stations, which constitute a necessary intermediate level in the logistic chain of the solid waste stream, from municipalities to the incinerator. Contextually, the determination of the number and type of vehicles involved is carried out in an integrated optimization approach. The model considers both initial investment and operative costs related to transportation and transfer stations. Two conflicting objectives are evaluated, the minimization of total cost and the minimization of environmental impact, measured by pollution. The design of the integrated waste management system is hence approached in a multi-objective optimization framework. To determine the best means of compromise, goal programming, weighted sum and fuzzy multi-objective techniques have been employed. The proposed analysis highlights how different attitudes of the decision maker towards the logic and structure of the problem result in the employment of different methodologies and the obtaining of different results. The novel aspect of the paper lies in the proposal of an effective decision support system for operative waste management, rather than a further contribution to the transportation problem. The model was applied to the waste management of optimal territorial ambit (OTA) of Palermo (Italy).     

Incipient speciation within a subgenus of rockfish (<Emphasis Type="Italic">Sebastosomus</Emphasis>) provides evidence of recent radiations within an ancient species flock

The high frequency of speciation events associated with species flocks (i.e., radiations of closely related species) provides invaluable insight into the speciation process. Investigations of the speciation process in the marine environment are rare, and therefore, the genetic analysis of the rockfish genus Sebastes, considered an ancient marine species flock, provides an opportunity to investigate this process in the sea. Using both mitochondrial and nuclear markers, we analyzed five closely related species within the rockfish subgenus Sebastosomus. Our goal was to understand the evolutionary history and genetic relationships among species within this group and to provide evidence of recent speciation events within the subgenus. In the genetic analysis of the subgenus, we found different stages of the speciation process, with greater genetic divergences among three of the five species, evidence of recent divergence between two of the five species, Sebastes entomelas and S. mystinus, and significant genetic divergence between two lineages within S. mystinus revealing a signature of incipient speciation. We also found frequency differences of the two S. mystinus lineages among sample locations and found no evidence of introgression between the lineages at the location where both coexist. Although Sebastes is an example of an ancient species flock, this study provides evidence of ongoing speciation within the genus and reveals stages of this process from incipient to distinct species.     

Comparison of seasonal variations of ozone exposure and fluxes in a Mediterranean Holm oak forest between the exceptionally dry 2003 and the following year

Ozone and energy fluxes have been measured using the eddy covariance technique, from June to December 2004 in Castelporziano near Rome (Italy), and compared to similar measurements made in the previous year. The studied ecosystem consisted in a typical Mediterranean Holm oak forest. Stomatal fluxes have been calculated using the resistance analogy and by inverting the Penmann-Monteith equation. Results showed that the average stomatal contribution accounts for 42.6% of the total fluxes. Non-stomatal deposition proved to be enhanced by increasing leaf wetness and air humidity during the autumnal months. From a comparison of the two years, it can be inferred that water supply is the most important limiting factor for ozone uptake and that prolonged droughts alter significantly the stomatal conductance, even 2 months after the soil water content is replenished. Ozone exposure, expressed as AOT40, behaves similarly to the cumulated stomatal flux in dry conditions whereas a different behaviour for the two indices appears in wet autumnal conditions. A difference also occurs between the two years.