Novel imazethapyr detoxification applying advanced oxidation processes

Different degradation methods have been applied to assess the suitability of advanced oxidation process (AOPs) to promote mineralization of imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid], a widely used imidazolinone class herbicide, the persistence of which has been demonstrated in surface and ground waters destined to human uses. Independent of the oxidation process assessed, the decomposition of imazethapyr always followed a pseudo-first order kinetic. The direct UV-irradiation (UV) of the herbicide as well as its oxidation with ozone (O?), and hydrogen peroxide tied to UV-irradiation (H?O?/UV) were sufficiently slow to permit the identification of intermediate products, the formation pathway of which has been proposed. Ozonation joined to UV-irradiation (O?/UV), ozonation joined to titanium dioxide photo-catalysis (TiO?/UV+O?), sole photo-catalysis (TiO?/UV), and photo-catalysis reinforced with hydrogen peroxide-oxidation (TiO?/UV+H?O?) were characterized by a faster degradation and rapid formation of a lot of small molecules, which were quickly degraded to complete mineralization. The most effective oxidation methods were those using titanium dioxide photo-catalysis enhanced either by ozonation or hydrogen peroxide. Most of all, these last processes were useful to avoid the development of dangerous by-products.     

The effect of clock-shift on the initial orientation of wild rock doves (<Emphasis Type="Italic">Columba l. livia</Emphasis>)

Previous experiments on wild rock doves ( Columba l. livia Gmelin) released within their familiar area revealed an evident effect of fast-shifting, although shifted doves, but not controls, tended to orient homeward. Such an outcome suggested a possible influence of the release time per se on the directional choices of the tested doves. In the present study, this hypothesis was investigated by comparing the orientation of slow-shifted birds to that of two control groups released at different times of the day. As would be expected if doves make use of a time-compensated sun compass, the bearings of shifted birds were deflected clockwise with respect to controls. The time of release itself seemed to influence only the scatter of the vanishing bearings of controls. These findings testify to the substantial similarity of clock-shift effects on the initial orientation of rock doves to those on homing pigeons released from familiar sites.     

Heavy metal contamination in the seaweeds of the Venice lagoon

The concentrations of heavy metals (Fe, Zn, Cu, Cd, Ni, Pb, Cr, As) were determined in seven seaweeds of environmental and commercial relevance (Ulva rigida C. Ag., Gracilaria gracilis (Stackhouse) Steentoft, L. Irvine and Farnham, Porphyra leucosticta Thuret, Grateloupia doryphora (Montagne) Howe., Undaria pinnatifida (Harv.) Suringar, Fucus virsoides J. Agardh, Cystoseira barbata (Good. et Wood.) Ag.) collected in four sampling sites in the lagoon of Venice, in spring and autumn 1999. Metals were extracted using hot concentrated acids in a Microwave Digestion Rotor and analysed by absorption spectrophotometry using a flame mode for Fe and Zn and a graphite furnace for Pb, Cr, Cd, Cu, Ni and As. High contamination levels, especially for Pb, were detected in Ulva and to a lesser extent in Gracilaria. Brown seaweeds, especially Cystoseira was highly contaminated by As. The least contaminated genera with all metals except As were Porphyra and Undaria. A concentration decrease for Zn and Cd was observed from the inner parts of the central lagoon, close to the industrial district, towards the lagoon openings to the sea.     

Spatial scales of variation in lichens: implications for sampling design in biomonitoring surveys

The variability of biological data is a main constraint affecting the quality and reliability of lichen biomonitoring surveys for estimation of the effects of atmospheric pollution. Although most epiphytic lichen bioindication surveys focus on between-site differences at the landscape level, associated with the large scale effects of atmospheric pollution, current protocols are based on multilevel sampling, thus adding further sources of variation and affecting the error budget. We test the hypothesis that assemblages of lichen communities vary at each spatial scale examined, in order to determine what scales should be included in future monitoring studies. We compared four sites in Italy, along gradients of atmospheric pollution and climate, to test the partitioning of the variance components of lichen diversity across spatial scales (from trunks to landscapes). Despite environmental heterogeneity, we observed comparable spatial variance. However, residuals often overcame between-plot variability, leading to biased estimation of atmospheric pollution effects.     

Ecotoxicological evaluation of industrial port of Venice (Italy) sediment samples after a decontamination treatment

This work assesses the ecotoxicological effects of polluted sediment after a decontamination treatment process using a new sediment washing technique. Sediment samples were collected from four sites in Marghera Port industrial channels (Venice, Italy). Ecotoxicological evaluations were performed with Vibrio fischeri and Crassostrea gigas bioassays. Whole sediment and elutriate were deemed as the most suitable environmental matrices for this study. Toxicity scores developed in the Lagoon of Venice for V. fischeri on whole sediment and for C. gigas on elutriate were considered for the final ranking of samples. Ecotoxicological results showed that the treated sediment samples presented both acute and sub-chronic toxicities, which were mainly attributed to the presence of some remaining chemicals such as metals and polyaromatic hydrocarbons. The acute toxicity ranged from low to medium, while the sub-chronic one from absent to very high, suggesting that treated sediments could not be reused in direct contact with seawater.     

Moderating effects of empathic concern and personal distress on the emotional reactions of disaster volunteers

This study examines stress and mood outcomes in community volunteers who undertook one week's worth of post‐disaster relief work in L'Aquila, Italy, which had been hit by an earthquake four months earlier. The study team obtained pre‐ and post‐relief work data from 130 volunteers involved in activities such as preparing food for the displaced, cleaning the camps and distributing clean linen. The Perceived Stress Scale, the State‐Trait Anxiety Inventory and the Profile of Mood States were administered at the start and at the end of the aid activities. Psychopathological symptoms and empathy were assessed in the beginning, using the Symptom Checklist 90 Revised and the Interpersonal Reactivity Index, respectively. The results show that, following the assistance work, volunteers displayed decreases in perceived stress, general distress, anxiety and anger, as well as increases in positive emotions. The empathy facets empathic concern and personal distress showed different patterns in modulating the post‐disaster relief work adaptation for some of the mood outcomes.     

Extraction of anthropogenic heavy metals from reduced sediments: Indeterminations due to authigenic sulphides and clay minerals

A mineralogical and micro‐chemical study was performed by X‐ray diffraction and SEM/EDS techniques in a reduced sediment sample from the Venice Lagoon to investigate selectivity and significance of two widely used acid extractions (cold IN HCl and hot 8N HNO₃) for the evaluation of anthropogenic metal concentrations. Hydrochloric acid determines an incomplete and variable solubilization of authigenic iron sulphides, yielding a partial extraction of the associated metals (Hg, Mn, Zn and less Ni and Cu). Nitric acid is effective in solubilizing all sulphides, however, it leads to an overestimate of the anthropogenic metal content since it partially dissolves the lattice of some clay‐minerals, particularly chlorites. When these acid extractions are used to asses metal pollution in aquatic ecosystems, the possible over or under‐estimate of the anthropogenic concentration must be taken into account, considering the mineralogical composition of the sediment.     

Bioaccessibility of metals in soils: comparison between chemical extractions and in vitro tests

It is well-known that the total metal content in soils is not a good indicator of their harmful effects, leading to an overestimation of risks. Toxicological and environmental hazards depend on the chemical species and on its bioavailability to target organisms. Because a good estimation of bioavailability is difficult, a good compromise is to assess bioaccessibility, defined as the maximum amount of a pollutant which is potentially absorbable by a target organism. This study presents a comparison of different strategies to measure metal bioaccessibility in soils. Three procedures were applied to real soil samples with different levels of metal contamination: pseudo-total metal attack, selective sequential extractions and in vitro tests (deliberately developed to simulate human or mammals digestion). Considering the first step of the selective extraction procedure, which can provide the bioaccessible fraction for deposit-feeder organisms, data obtained for each metal were lower than those obtained from in vitro tests. Therefore, it is possible to highlight that this extraction tends to underestimate metal bioaccessibility in soils for humans, while in vitro tests certainly will overestimate bioaccessibility for organisms as invertebrates. If the sum of first and second step of sequential procedure is considered, results are quite similar to those obtained from in vitro tests, but this kind of procedure would require two days of work rather than a few hours required to perform an in vitro test. Results highlight the diversity among the differently defined bioaccessible fractions and the need to apply the most suitable procedure depending on the target organism.     

Effects of long-term land use on arbuscular mycorrhizal fungi and glomalin-related soil protein

The maintenance of soil health and productivity is a central aim of sustainable agriculture. Arbuscular mycorrhizal fungi (AMF) are soil biota fundamental for soil fertility and plant nutrition, which may be used in the evaluation of the impact of agronomic practices on soil quality. In the present study we evaluated the influence of three different land uses on AMF populations and correlated glomalin-related soil protein (GRSP) content with AMF biomass parameters, such as spore density and biovolume. Among the differently managed sites – maize monoculture, grassland and poplar grove – maize soil showed the lowest AMF spore number and GRSP content. The same morphological taxa were found in the three sites, except for one additional morphotype in poplar grove. A good correlation between GRSP and spore biovolume was found, suggesting that GRSP may represent a useful biochemical parameter for the assessment of biological soil fertility in sustainable agriculture.     

A methodology for treating missing data applied to daily rainfall data in the Candelaro River Basin (Italy)

Environmental time series are often affected by the “presence” of missing data, but when dealing statistically with data, the need to fill in the gaps estimating the missing values must be considered. At present, a large number of statistical techniques are available to achieve this objective; they range from very simple methods, such as using the sample mean, to very sophisticated ones, such as multiple imputation. A brand new methodology for missing data estimation is proposed, which tries to merge the obvious advantages of the simplest techniques (e.g. their vocation to be easily implemented) with the strength of the newest techniques. The proposed method consists in the application of two consecutive stages: once it has been ascertained that a specific monitoring station is affected by missing data, the “most similar” monitoring stations are identified among neighbouring stations on the basis of a suitable similarity coefficient; in the second stage, a regressive method is applied in order to estimate the missing data. In this paper, four different regressive methods are applied and compared, in order to determine which is the most reliable for filling in the gaps, using rainfall data series measured in the Candelaro River Basin located in South Italy.