► The aquatic toxicity of ionic liquids has been modeled by QSAR. ► A more accurate model can be obtained by performing QM calculation in water environment by PCM. ► The model is able to reproduce ...well the experimental toxicity. ► Toxicity of new ionic liquid can be predicted by the model.
Quantitative structure–toxicity relationships were developed for the prediction of toxicity to
Vibrio fischeri using the CODESSA treatment. A four-parameter correlation was found for a class of ionic liquids based on halide. All the descriptors utilized are calculated only from the structures of the molecules, which makes it possible to predict unavailable or unknown ILs, in gas phase and in water (PCM treatment). Satisfactory correlations with the same descriptors were found for both cases but the employment of descriptors calculated in solvent assure a better correlation and a bigger reliability on the foresight.
The aim of this study was to isolate arsenic-resistant bacteria from contaminated sediment of the Orbetello Lagoon, Italy, to characterize isolates for As(III), As(V), heavy metals resistance, and ...from the phylogenetic point of view. Enrichment cultures were carried out in the presence of 6·75 mmol l⁻¹ of As(III), allowing isolation of ten bacterial strains. Four isolates, ORAs1, ORAs2, ORAs5 and ORAs6, showed minimum inhibitory concentration values equal or superior to 16·68 mmol l⁻¹ and 133·47 mmol l⁻¹ in the presence of As(III) and As(V), respectively. Isolate ORAs2 showed values of 1·8 mmol l⁻¹ in the presence of Cd(II) and 7·7 mmol l⁻¹ of Zn(II), and isolate ORAs1 pointed out a value of 8·0 mmol l⁻¹ in the presence of Cu(II). Analysis of 16S rRNA gene sequences revealed that they can be grouped in the three genera Aeromonas, Bacillus and Pseudomonas. Phylogenetic analysis of the four more arsenic-resistant strains was also performed. Isolates are highly resistant to both As(III) and As(V) and they could represent good candidates for bioremediation processes of native polluted sediments. This study provides original results on levels of resistance to arsenic and to assigning genera of bacterial strains isolated from arsenic-polluted sediments.
To isolate and characterize an anaerobic bacterial strain from the deeper polluted lagoon sediment able to use as electron acceptors As(V) and sulfate ( graphic removed ), using lactate as an ...electron donor. Methods for isolation from polluted lagoon sediments included anaerobic enrichment cultures in the presence of As(V) and graphic removed . Reduction of As(V) to As(III) was observed during the growth of the bacterial strain, and the final concentration of As(III) was lower than the initial As(V) one, suggesting the immobilization of As(III) in the yellow precipitate. The precipitate was identified by energy dispersive spectroscopy X-ray as arsenic sulfide. Scanning electron microscopy (SEM) revealed rod-shaped bacterial cells embedded in the precipitate, where net-like formations strictly related to the bacterial cells were visible. The surface of the precipitate showed the adhesion of bacterial cells, forming clusters. Transmission electron microscopy (TEM) also highlighted precipitates inside the bacterial cells and on their surface. Following 16S rRNA sequencing, the bacterial strain 063 was assigned to the genus Desulfosporosinus. This study reports, for the first time, the isolation from the polluted lagoon sediments of a strain capable of respiring and using As(V) and graphic removed as electron acceptors with lactate as the sole carbon and energy source with the formation of an arsenic sulfide precipitate. The identification of these properties provides novel insight into the possible use of the anaerobic strain in bioremediation processes and also adds to the knowledge on the biogeochemical cycling of arsenic.
► Results show PFOS in most samples, while PFOA was just in one breast milk sample. ► Fish was the most contaminated food. ► Cereal-based foods, eggs, vegetables, honey and beverages were always ...<LOD. ► Consumption of most breast milk analysed would not result in children exceeding their tolerable daily intakes for perfluorinated compounds.
Despite the health risks associated with perfluorinated compounds (PFC) exposure and the detection of these compounds in many countries around the world, little is known on their occurrence in Italy. The results of a study on levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), analysed by HPLC-ESI-MS, in human milk and food samples from the city of Siena and its province (central Italy) are here reported. PFOS was found in 13 out of 49 breast milk samples (0.76±1.27ng/g), while PFOA was detected in one sample (8.04ng/g). Only PFOS was found in food samples. Fish were the most contaminated samples (7.65±34.2ng/g); mean concentrations in meat and milk and dairy products were similar (1.43±7.21ng/g and 1.35±3.45ng/g, respectively). In all cereal-based food, eggs, vegetables, honey and beverages PFOS concentration was <LOD. These data show that consumption of most breast milk analysed would not result in children exceeding their total daily intakes for perfluorinated compounds.
Background. Impairments of endocrine system may be associated with exposure to perfluorinated compounds that are able to bind nuclear receptors, including the peroxisome proliferator-activating ...receptors. Aim of this study was to assess perfluorooctane sulfonate and perfluorooctanoic acid concentrations in children and adolescents at the onset of type 1 diabetes compared to healthy controls. Methods. Forty-four children and adolescents were recruited and subdivided into two groups: (A) 25 subjects with type 1 diabetes and (B) 19 healthy controls. Perfluorinated compounds were measured using high performance liquid chromatography with electrospray ionization tandem mass spectrometry. Nonparametric statistical analysis was performed. Results. Perfluorooctane sulfonate concentrations were significantly higher in patients with type 1 diabetes compared to controls (1.53 ± 1.50 versus 0.55 ± 0.15 ng/mL, resp.; p<0.001). Multivariate linear regression analysis identified lipid levels as significant predictive factors for perfluorooctane sulfonate levels. Conclusions. Our data suggests that higher serum levels of perfluorooctane sulfonate may be considered a biomarker of exposure and susceptibility to develop type 1 diabetes.
A mixture made of Olive Mill Waste (OMW) and hygroscopic organic additives was stored in indoor and outdoor stack piles. A significant decrease in organic matter and polyphenols was detected in ...indoor stack pile (51.5% and 75% of initial contents, respectively). Three bacterial strains isolated from OMW indoor stack pile were able to grow in the presence of tannic acid as sole carbon and energy source, and were named 2AT1, 2AT2, and 2AT3. 16S rRNA gene sequencing assigned isolates 2AT1 and 2AT3 to the genus
Serratia, and strain 2AT2 to the genus
Pantoea. The highest tannase activity was pointed out in the
Pantoea sp. strain 2AT2, and growth tests showed a maximum degradation rates of tannic acid within 6 h and a complete depletion in 24 h for all isolates. Glucose and gallic acid were detected in the bacterial cultures as breakdown products of tannic acid added to the mineral culture-medium as the sole carbon and energy source. This was the first evidence of bacterial strains able to degrade tannic acid isolated from OMW.
Bacillus sp. ORAs2 and Pseudomonas sp. ORAs5, two arsenic-resistant bacterial strains previously isolated from sediments of the Orbetello Lagoon, Italy, were tested for their adaptation to mixed ...contaminants on the level of membrane fatty acid composition. The two bacterial strains were characterized by high levels of arsenic resistance, and Pseudomonas sp. ORAs5 was also shown to be solvent-tolerant. The bacterial strains were exposed to mixtures of two toxic compounds: arsenic at fixed concentrations and toluene in variable amounts or, alternatively, toluene at constant values along with arsenic added at variable concentrations. Both strains react to the contaminants by changing the composition of their membrane fatty acids. Bacillus sp. strain ORAs2 showed a correlation between growth rate decreases and fatty acids degree of saturation increases in both cases, although pointedly in the presence of 1, 2, and 3 mM of toluene and different additions of arsenic, counteracting membranes fluidity induced by toxic compounds. In Pseudomonas sp. ORAs5, adaptive changes in membrane composition was observed both in terms of increases in the degree of saturation and in the trans/cis ratio of unsaturated fatty acids in the presence of varying toluene and constant arsenic concentrations, whereas only minor changes occurred with increasing arsenic and constant toluene concentrations. Thus, on the level of membrane composition, Bacillus sp. ORAs2 showed a higher potential for adaptation to the presence of mixed pollutants, suggesting its probable suitability for bioremediation purposes.
The current study was aimed to characterize a bacterial strain isolated from Cr(VI)-polluted sediments for its role in Cr(VI)-reduction as whole cell and by cell free extract. A new moderately ...halophilic Cr (VI)-resistant bacterial strain TA-04 was isolated from polluted marine sediments near a stainless steel plant in Southern Italy, 16S rRNA analysis placed the isolate close to the species
Halomonas aquamarina. Growth was inhibited at 4.0 mM Cr (VI), and reduction of Cr (VI) in the presence of 80 g l
−1 NaCl was highlighted. Immobilized cells showed removal of Cr (VI) from sediment leachate. The cell free extract reduced Cr (VI) with a maximum of activity at pH 6.5 and at temperature of 28 °C, in the presence of NADH. Cr (VI) reduction activity was improved by Cu
2+ and Fe
2+ additions, whereas Hg
2+ depleted it. Free and immobilized cells of the isolate could be used for bioremediation of Cr (VI)-contaminated sites. Cell free extract could represents an alternative in conditions where the whole cells result difficult to apply. A bacterial strain of the genus
Halomonas is characterized in term of whole cells and cell-free extract Cr(VI)-reduction. The results suggest a good potential for bioremediation processes, in particular concerning detoxification of saline polluted environments.
► An efficient hexavalent chromium reduction by whole cells and cell free extract of
Halomonas acquamarina. ► Chromate removal capacity of immobilized
Halomonas aquamarina cells of 91.2% from sediments leachate. ► Hexavalent chromium reduction at moderate halophilic conditions by whole cells.
•PFOA/S levels in a trophic web of a heavily human-stressed lagoon are measured.•High levels were found in mussels, clams and crabs.•The principal PFCs inflow sources for the ecosystem is the ...river.•Biota (i.e. macroalgae proliferation) contributes to redistribute pollutants in the lagoon.•Human daily dietary intakes are below maximum tolerable levels suggested by the EFSA.
The results of a study on levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), analyzed in terms of HPLC-ESI-MS in water, sediment, macrophyte, bivalve, crustacean and fish samples, are reported here. The aim of the research is to define, for the first time, PFOA/S levels in a heavily human-stressed transitional water ecosystem (Orbetello lagoon, Italy) and evaluate trophic web enrichments and human dietary intakes. The results obtained show that: (i) levels significantly higher than those reported in the literature were found in mussels, clams and crabs; (ii) the river is a significant pollution source; (iii) although absolute levels are relatively low, macroalgae proliferation contributes to redistribute pollutants from river-affected areas throughout the entire lagoon basin; (iv) to the best of our current knowledge, water-filtering species considered in this study are the most exposed to PFOA/S pollution; (v) human daily dietary intakes of PFOA/S through Slow Food-endorsed product consumption are below maximum tolerable levels suggested by the EFSA.
Two bacterial strains were isolated in the presence of naphthalene as the sole carbon and energy source from sediments of the Orbetello Lagoon, Italy, which is highly contaminated with both organic ...compounds and metals. 16S rRNA gene sequence analysis of the two isolates assigned the strains to the genera Paenibacillus and Pseudomonas. The effect of different contaminants on the growth behaviors of the two strains was investigated. Pseudomonas sp. ORNaP2 showed a higher tolerance to benzene, toluene, and ethylbenzene than Paenibacillus sp. ORNaP1. In addition, the toxicity of heavy metals potentially present as co-pollutants in the investigated site was tested. Here, strain Paenibacillus sp. ORNaP1 showed a higher tolerance towards arsenic, cadmium, and lead, whereas it was far more sensitive towards mercury than strain Pseudomonas sp. ORNaP2. These differences between the Gram-negative Pseudomonas and the Gram-positive Paenibacillus strain can be explained by different general adaptive response systems present in the two bacteria.
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