Arsenic biomonitoring using a hyperaccumulator fern (Pteris vittata)

Samples of Pteris vittata L. (brake fern or ladder brake) collected in Genova and in areas outside urban centres, have been analysed for arsenic content in order to assess if hyper accumulating plants are suitable for monitoring purposes. Hyper accumulation ability of the Ligurian fern populations was evaluated by analysing specimens grown with hydroponic media added with As(v). Arsenic concentrations in the range 2-310 microg g(-1) dry weight have been measured in samples collected in different sites along the Ligurian coast. Arsenic concentrations in fern fronds correlate with the estimated arsenic emission in the area, verifying the applicability of P. vittata as an arsenic biomonitor.     

Current and future effectiveness of the Natura 2000 network for protecting plant species in Sardinia: a nice and complex strategy in its raw state?

Sardinia hosts 186 endemic plant species and represents an important centre for Mediterranean biodiversity. In view of the threats facing its flora, 27 terrestrial vascular plants have been listed in international regulations and 124 sites designated for species and habitat conservation. This study analyses gaps in the Natura 2000 network and the current and future distribution of four representative plants. Each plant population was georeferenced and the effectiveness of the Natura 2000 network was compared according to conservation status and distribution. Future species distributions were modelled by considering current climatic conditions and future scenarios. In apparent discordance with other results, we found that the Natura 2000 network represents most plant species well. This research shows a forward-looking survey on the regional effectiveness of protection measures which led us to confirm the need to enhance the current state of the Natura 2000 network by implementing local legislation and regulations.     

Circannual variations of lizard circadian activity rhythms in constant darkness

The daily pattern of locomotor activity of Podarcis sicula in the field changes from unimodal in spring to bimodal in summer, becoming unimodal again in autumn. Short-term experiments in which P. sicula collected in different months were tested under constant conditions immediately after capture showed that the activity pattern typical of each season is retained in the lizard circadian locomotor rhythm. In constant conditions, the bimodal pattern is associated with a short free-running period (τ) of the circadian locomotor rhythm and a long circadian activity (α), while the unimodal pattern is associated with a long τ and short α. To test whether seasonal changes in circadian locomotor rhythms are driven by a circannual clock, we recorded locomotor activity of lizards over 12–15 months in constant temperature and darkness. The present results demonstrate, for the first time in a vertebrate, the existence of circannual changes in constant darkness of both τ and α. In most lizards, the longest τ along its circannual cycle is associated with a short α, and the shortest τ in the same cycle with a long α, so that the pattern of mutual association between τ and α is the same as in short-term experiments. Most lizards, however, stayed unimodal all the time. This shows that changes in activity pattern from unimodal to bimodal (and vice versa) are induced by seasonal changes in environmental factors, instead of being incorporated into a circannual rhythm. Circannual changes in τ and α of locomotor rhythms may adaptively predispose the circadian system of P. sicula to a change in activity pattern as soon as seasonal changes in the environment demand it. Received: 22 January 1999 / Received in revised form: 14 April 1999 / Accepted: 19 April 1999     

Accelerating climate change impacts on alpine glacier forefield ecosystems in the European Alps.

In the European Alps the increase in air temperature was more than twice the increase in global mean temperature over the last 50 years. The abiotic (glacial) and the biotic components (plants and vegetation) of the mountain environment are showing ample evidence of climate change impacts. In the Alps most small glaciers (80% of total glacial coverage and an important contribution to water resources) could disappear in the next decades. Recently climate change was demonstrated to affect higher levels of ecological systems, with vegetation exhibiting surface area changes, indicating that alpine and nival vegetation may be able to respond in a fast and flexible way in response to 1-2 degrees C warming. We analyzed the glacier evolution (terminus fluctuations, mass balances, surface area variations), local climate, and vegetation succession on the forefield of Sforzellina Glacier (Upper Valtellina, central Italian Alps) over the past three decades. We aimed to quantify the impacts of climate change on coupled biotic and abiotic components of high alpine ecosystems, to verify if an acceleration was occurring on them during the last decade (i.e., 1996-2006) and to assess whether new specific strategies were adopted for plant colonization and development. All the glaciological data indicate that a glacial retreat and shrinkage occurred and was much stronger after 2002 than during the last 35 years. Vegetation started to colonize surfaces deglaciated for only one year, with a rate at least four times greater than that reported in the literature for the establishment of scattered individuals and about two times greater for the well-established discontinuous early-successional community. The colonization strategy changed: the first colonizers are early-successional, scree slopes, and perennial clonal species with high phenotypic plasticity rather than pioneer and snowbed species. This impressive acceleration coincided with only slight local summer warming (approximately -0.5 degree C) and a poorly documented local decrease in the snow cover depth and duration. Are we facing accelerated ecological responses to climatic changes and/or did we go beyond a threshold over which major ecosystem changes may occur in response to even minor climatic variations?     

Sperm removal and ejaculate size correlate with chelae asymmetry in a freshwater crayfish species

Asymmetry in traits of sexual relevance may impair copulation behaviour and sexual performance of males, ultimately resulting in a fitness cost. Freshwater crayfish males use chelae, a sexually selected trait, to secure and position the female prior to and during mating. Thus, a relatively large chelae asymmetry, resulting from accidental loss and regeneration of one cheliped after autotomy, could have great consequences for male sexual behaviour. We studied copulatory behaviour and sperm expenditure of males paired to a mated female in Austropotamobius italicus, a freshwater crayfish species where both male and female mate multiply and where last-mating males are able to actively remove previously deposited sperm. We aimed at assessing whether male sperm removal and expenditure varied according to sperm allocated by first-mating males, and according to copulation behaviour and phenotypic traits (carapace length, chelae length and relative chelae asymmetry) of second-mating males. Second-mating males did not adjust their ejaculate size in relation to first-mating male ejaculate, nor to the first-mating male’s sperm removed. Moreover, the amount of sperm removed by second-mating males increased with increasing first-mating males ejaculate size, and first-mating male sperm remaining after removal did not correlate with the original first-mating male ejaculate size. Interestingly, the amount of sperm removed by second-mating males decreased with increasing relative chelae asymmetry, while increasing with male body size. However, second-mating (but not first-mating) asymmetric-clawed males produced larger ejaculates than symmetric-clawed ones. Importantly, the proportion of second-mating male sperm remaining after the two matings did not vary with relative chelae asymmetry nor with body size of second-mating males. Thus, small, asymmetric-clawed crayfish males appear to adopt sperm allocation tactics that allow them to fully compensate for their inferior sperm removal ability.     

Simultaneous radioassays of bacterial production and mercury methylation in the periphyton of a tropical and a temperate wetland

Laboratory radioassays were made to study mercury (Hg) methylation together with bacterial production in the periphyton of two aquatic macrophytes, the submerged Myriophyllum spicatum, from a constructed wetland in Sweden and the floating Eichhornia crassipes, from a eutrophied tropical lake in Brazil. Time course incubations were made by addition of (203)HgCl(2) and the methylmercury formed was extracted at pre-defined time intervals. Bacterial production ((14)C-leucine incorporation) was measured at the same time intervals, with plants removed from parallel incubations made with and without addition of cold HgCl(2). For E. crassipes, higher methylmercury production was observed at elevated bacterial production, whereas for M. spicatum, the bacterial production was significantly lower, and Hg methylation was below the detection limit. The combined results confirm the importance of microbial processes for Hg methylation, although other factors are known to influence this process in complex ways. The addition of Hg did not significantly influence bacterial production, while the incubation temperatures used (25 and 35 degrees C) resulted in different methylation rates. Radiotracer techniques for measurements of bacterial production such as (14)C-leucine uptake can provide useful insights into the Hg cycle in aquatic environments, and our data suggest that they may be used as a proxy of mercury methylation potentials.     

GC-MS analyses and chemometric processing to discriminate the local and long-distance sources of PAHs associated to atmospheric PM2.5

Purpose

This study presents a procedure to differentiate the local and remote sources of particulate-bound polycyclic aromatic hydrocarbons (PAHs).

Methods

Data were collected during an extended PM_2.5 sampling campaign (2009?C2010) carried out for 1?year in Venice-Mestre, Italy, at three stations with different emissive scenarios: urban, industrial, and semirural background. Diagnostic ratios and factor analysis were initially applied to point out the most probable sources. In a second step, the areal distribution of the identified sources was studied by applying the discriminant analysis on factor scores. Third, samples collected in days with similar atmospheric circulation patterns were grouped using a cluster analysis on wind data. Local contributions to PM_2.5 and PAHs were then assessed by interpreting cluster results with chemical data.

Results

Results evidenced that significantly lower levels of PM_2.5 and PAHs were found when faster winds changed air masses, whereas in presence of scarce ventilation, locally emitted pollutants were trapped and concentrations increased. This way, an estimation of pollutant loads due to local sources can be derived from data collected in days with similar wind patterns. Long-range contributions were detected by a cluster analysis on the air mass back-trajectories. Results revealed that PM_2.5 concentrations were relatively high when air masses had passed over the Po Valley. However, external sources do not significantly contribute to the PAHs load.

Conclusions

The proposed procedure can be applied to other environments with minor modifications, and the obtained information can be useful to design local and national air pollution control strategies.     

Pictorial intervention in a pediatric hospital environment: Effects on parental affective perception of the unit

In recent decades, research on health care design and planning has highlighted the strong relationship between environmental characteristics and human health. According to a patient-centered model, the focus on the hospital environment is important in reducing the negative effects of hospitalization on the patient, especially in the case of children.     

Determination of 5-ethylidene-2-norbornene in industrial emission

A method to measure the emissive concentration of 5-ethylidene-2-norbornene (ENB), a reactive compound used in industrial synthesis of terpolymers, has been developed. The starting points for the development of the presented method are European and Italian reference methods for the quantification of nonreactive volatile organic compounds in industrial emission. In this study, sampling conditions and desorption solvent have been optimized in laboratory and the method was applied in an industrial plant. The laboratory tests showed a good recovery (88–95 %). The concentrations of ENB in industrial emission obtained with the developed method were compared with an online gas chromatography–flame ionization results (R ²?>?0.97). In addition, several manual measurements were performed in parallel, and the resulting %RSD repeatability was <9 %. The developed method provides a discontinuous technique to measure reactive volatile organic compounds using easy-to-use instruments and assures a very good accuracy and precision even with high-humidity gas flows. The method could be extended to other reactive compounds of the same class.     

Electrochemical oxidation of benzene on boron-doped diamond electrodes

This work presents an electrochemical investigation of the benzene oxidation process in aqueous solution on boron-doped diamond (BDD) electrodes. Additionally, in order to determine the main products generated during the oxidation process, electrolysis and high performance liquid chromatography experiments were carried out. The complete degradation of this compound was performed aiming to a further application in waste water treatment. The cyclic voltammetry studies indicate that benzene is irreversibly oxidized in acid medium (H₂SO₄ 0.5 M) on the BDD electrode surface at 2.0 V versus Ag/AgCl in a diffusion controlled process. During the cycling, other products are generated, and a pair of peaks was observed that can be associated with the oxi-reduction of anyone of the following species: hydroquinone, benzoquinone, resorcinol or catechol. The electrolysis experiments were carried out at 2.4 and 2.5 V on the BDD electrode surface in a solution containing 1 × 10⁻² M of benzene (below the saturation concentration in aqueous solution), for 3 and 5 h, respectively. The main products measured were: hydroquinone, resorcinol, p-benzoquinone, catechol and phenol. The complete electrochemical benzene degradation was performed in the electrolysis experiments using a rotating BDD disc electrode (2.5 V for 5 h) and the main products detected were all measured at concentrations lower than 10⁻⁵ M in this condition. The boron-doped diamond electrode had proved to be a valuable tool for the electrochemical degradation of the benzene, a very stable chemical compound.