1,721,155 research outputs found
Elementi essenziali e tossici nel suolo e nelle colture in funzione della fertilizzazione minerale e con compost
No full textcpa: Confirmatory Path Analysis through the d-sep tests. R package version 1.0
No full textThe package includes functions to test and compare causal model
Usefulness of different vascular plant species for passive biomonitoring of Mediterranean rivers
No full textChoosing native vascular plants as nutrient and toxic element accumulators for passive biomonitoring of urban river quality is not an easy task in Mediterranean rivers, due to the particular climate determining high variations in river hydrology. To identify potential biomonitors for this area, the roots of seven species (Angelica sylvestris, Apium nodiflorum, Tradescantia fluminensis, Nasturtium officinale, Persicaria lapathifolia, Arctium lappa, Typha latifolia), growing in seven sites along the River Irno (Southern Italy), were collected in July 2010 and analyzed regarding their capability to accumulate Cd, Cr, Cu, Fe, K,
Mg, Mn, Na, Ni, Pb, V, and Zn through atomic absorption spectrometry. Notwithstanding the expected different accumulation degree among the species, they highlighted similar spatial contamination gradients, and all of them appeared suitable, alone or in combination, for river passive biomonitoring. A. nodiflorum, in particular, appeared the best biomonitor for the River Irno, where severe anthropogenic impacts were detected: high Cu and Cd contamination from vine cultivation in the upper stretch, and Pb, Zn, and Mn contamination in the medium stretch from airborne dusts coming from a cast iron foundry
Investigating anthropogenic disturbance across a hierarchical progression of ecological system complexities – insights from low-frequency magnetic fields
No full textThe multiple feedback mechanisms involved in complex systems modulate the
propagation of stresses through the hierarchical progression of ecological systems,
yielding adaptive dynamics and unpredictable outcomes, ultimately making its study a
highly non-trivial task. This is especially true when the mechanistic understanding of
stress-response relationships is still rudimentary, as in the case of oscillating magnetic
field (MF) interactions with ecological systems, where the responses may depend on
frequency, intensity, phase and time of exposure.
With a view to shedding light on these interactions, we focused on natural low
frequency MFs potentially interfered by anthropogenic MFs, i.e. the first mode of the
Schumann resonances (7.83 Hz), studying the effects of varying intensities and
exposure times on multiple levels of ecological organization, purposefully choosing the
analytical targets in relation to system properties. In particular, effects were
investigated at the level of organism, focusing on animal behavioral ecology and plant
ecophysiology and development, of population, analyzing seed recruitment and
germination kinetics, and of ecosystem, investigating organic matter decomposition
by soil microbial community. System responses were studied under controlled
conditions in order to highlight potentially small effects, using exposure devices and
settings purposefully developed and chosen according to finite element modelling
analyses.
Preliminary results highlight the presence of invariant responses across different levels
of organization, with MF eliciting clearer dynamics to the varying field intensity (7.5
μT, 15 μT, 30 μT) at short exposure times (15’ in respect to 30’ and 60’), especially at
the population and ecosystem levels. Considering the interaction between the artificial
and the natural MFs, differing in field intensities and phases, findings can be explained
in terms of intermediate disturbance. Overall, our research demonstrates the coupling
between low frequency magnetic fields and the functioning of ecological systems at
different levels of complexity, with responses modulated by interfering anthropogenic
fields
Biomonitoring potentially toxic elements in freshwater ecosystems
No full textMonitoring of water ecosystems, especially rivers, represents an exceptionally complex task, due to the fluctuating discharges and continuous water movements, with the consequent need to consider either the temporal dynamics in the parameters analysed or time-integrated measures. Even if chemical analyses of water and/or sediments allow obtaining challenging and expensive information on concentration gradients, the actual pollutant bioavailability cannot be ascertained without taking into account the aquatic biota. Biomonitors, providing space- and time-integrated information on environmental quality, allow cheaply and accurately detecting the actual availability, mobility, transfer through the food webs and fate of pollutants in the aquatic environment over a wide range of concentrations. Among biomonitors, selected aquatic autotropic organisms act as effective bioaccumulators, which continuously absorb and accumulate pollutants from sediments and water, integrating pollution peaks, without detectable effects on physiological functions and with pollutant concentrations in their biomass linearly related to their exposure time. The current legislations on the topic, like the EU Water Framework Directive, boosted the application of biomonitoring in the evaluation of aquatic ecosystem quality and strengthened the use of aquatic plants in river quality assessment.
Identifying vascular plants as nutrient and non-essential element accumulators for passive biomonitoring (using native organisms) of both urban and remote rivers is a challenging task, especially in the Mediterranean area, where the particular climate determines severe variations in river hydrology. Thanks to several years of research, we validated various candidate passive biomonitors of potentially toxic elements for this area and performed extensive biomonitoring studies using the roots (Helosciadium nodiflorum and Mentha aquatica) or the shoots (Potamogeton pectinatus) of cosmopolitan species growing along the urban Irno and Sarno rivers and along the remote Bussento and Calore Salernitano rivers (southern Italy). Notwithstanding the expected different accumulation degree among the species, they allowed obtaining clear and detailed spatial concentration gradients, either attributable to anthropogenic impacts or to natural peculiarities. However, to overcome the limitations imposed by the spatial distribution of passive bioaccumulators, we expanded our research also to active biomonitors (transferred organisms), validating novel species and developing effective exposure devices. Apart from the opportunity to monitor areas lacking native bioaccumulators, this choice reduces sample variability and allows precise timings of exposure and the derivation of accurate mean accumulation rates. In particular, our researches allowed validating the macrophytic alga Chara gymnophylla as a novel active biomonitor of potentially toxic elements and, in combination with a long-established biomonitor, the aquatic moss Fontinalis antipyretica, deriving clear contamination scenarios in sensitive areas, with indications of the alleged sources
High cadmium concentrations in leaves of leafy vegetables
No full textCadmium is a toxic element for all living beings, even at low concentrations, and it is a human carcinogenic according to IARC. Since food is reported as the main source of Cd intake in non-smoking individuals, FAO and WHO set limits for the maximum permitted human intake. Leafy vegetables have a relatively high potential for Cd uptake and translocation, therefore they are often considered Cd accumulators. As they are important salad crops of the Mediterranean diet and are available worldwide, their consumption may represent an effective risk for human health.
Lettuce (Lactuca sativa) and endive (Cichorium endivia), grown on different agricultural soils in Campania region (southern Italy), subjected to different fertilisation treatments (unfertilisation, compost amendment and mineral fertilisation), were analysed to clarify if the highest concentrations found are linked to external (older and inedible) or internal (younger and edible) leaves.
All the leafy vegetables analysed showed on average 2-fold higher (α=0.05) Cd concentrations in leaves than in roots. Leaf Cd concentrations in both lettuce and endive significantly differed among fertilisation treatments, with values highest in the plants grown on mineral fertilised soils. Apart from the soil fertilisation treatments, however, Cd leaf concentrations were often higher than maximum levels deduced by the CE 629/2008 Regulation. External leaves of endive plants showed significantly higher (α=0.05) concentrations than internal leaves (in some cases the values were 3-fold higher).
This study highlights worrying Cd concentrations in the edible parts of the studied vegetables, with concentrations up to 4-fold higher than the threshold. Moreover, it points out two major drawbacks in the Italian and European regulatory frameworks: 1) metal concentration (as total and/or available fraction) limits in agricultural soils are lacking; 2) metal concentration thresholds reported in the CE 629/2008 Regulation, expressed on the fresh weight basis rather than on the dry weight basis, appear not suitable
Lampenflora growth-control: the challenge of the show caves
No full textShow caves are subjected to tourist adaptations, often with negative consequences on the ecological
equilibria of the system. Among the worst problems, photosynthetic biofilms, called “lampenflora”, can
develop on surfaces due to the artificial lighting system, covering with green patinas every lit rocks,
included speleothems, such as the still few known vermiculations. They implement biodeteriorations
processes on surfaces, damaging them irreversibly. The aim of this study was to investigate the efficacy of
lampenflora growth-control strategies, carried out monthly using chemical (15% hydrogen peroxide2 or
commercial bleach) and physical (UV-C) remedies, on surfaces with and without vermiculations. The tests
were performed in the tourist trail of the Pertosa-Auletta Cave (southern Italy), lit and frequented by
human beings, analyzing, before and after the treatments, the chlorophyll fluorescences (MINI-PAM, Walz),
an in situ non-destructive method representing a proxy of the biofilms photosynthetic activities. The results
highlighted an evident reduction of the lampenflora photosynthetic activity already after the 1st treatment.
Before every actions, the dark-adapted surfaces, with and without vermiculations, displayed Fv/Fm values
between 0.766-0.713 and 0.710-0.663, respectively. After chemical treatments, using H2O2 or commercial
bleach, the maximal PSII photochemical efficiency was close to 0, showing an almost complete reduction of
the photosynthetic activity. Such values have been maintained until the 2nd treatment, in pre- and post
phase. After three months without treatments due to the pandemic lockdown closure of the show cave,
there was a slight recovery of lampenflora on the surfaces treated with H2O2, immediately stopped after
the 3rd treatment. No effect occurred on the surfaces treated with UV-C, probably in relation to the low
frequency of treatments (one night) in a month
PAHs in decaying Quercus ilex leaf litter: mutual effects on litter decomposition and PAH dynamics
No full textThe investigation of the relationships between litter decomposition and polycyclic aromatic hydrocarbons (PAHs) is important to shed light not only on the effects of these pollutants on fundamental ecosystem processes, such as litter decomposition, but also on the degradation of these pollutants by soil microbial community. This allows to understand the effect of atmospheric PAH contamination on soil PAH content via litterfall. At this aim, we studied mass and PAH dynamics of Quercus ilex leaf litters collected from urban, industrial and remote sites, incubated in mesocosms under controlled conditions for 361 d. The results highlighted a litter decomposition rate of leaves sampled in urban > industrial > remote sites; the faster decomposition of litter of the urban site is also related to the low C/N ratio of the leaves. The PAHs showed concentrations at the beginning of the incubation of 887, 650 and 143 ng g-1 d.w., respectively in leaf litters from urban, industrial and remote sites. The PAHs in litter decreased along the time, with the same trend observed for mass litter, showing the highest decrease at 361 d for the urban leaf litter. Anyway, PAH dynamics in all the litters exhibited two phases of loss, separated by a PAH increase observed at 246 d and mainly linked to benzo[e]pyrene
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