Multivariate tools to investigate the spatial contaminant distribution in a highly anthropized area (Gulf of Naples,Italy)

Environmental Science and Pollution Research - The Gulf of Naples located in a high anthropized coastal area is subjected to an infrastructural intervention for the installation of a submarine...     

Hydrolytic degradation of azimsulfuron, a sulfonylurea herbicide

The chemical degradation of the herbicide azimsulfuron was investigated in aqueous solutions at different pH values. The hydrolysis rate, determined by HPLC analyses, was pH dependent and was much faster in acidic than in neutral or weakly basic conditions. The metabolites formed at different pH values were compared with standards when possible or isolated and identified using ESI-LC-MS/MS, (1)H NMR and (13)C NMR. The two main products of hydrolysis in mild acidic solution were identified as 2-amino-4,6-dimethoxy-pyrimidine and 2-methyl-4-(2-methyl-2H-tetrazol-5-yl)-2H-pyrazole-3-sulfonamide, both produced as a result of the sulfonylurea bridge cleavage. Under basic conditions, a new product, a substituted 2-pyrimidinamine, deriving from the contraction of the sulfonylurea bridge, was isolated and completely characterized for the first time.     

Association between biotic and abiotic parameters and the occurrence of cyanobacteria in a Brazilian reservoir

The water reservoir of Vargem das Flores, Brazil, has been subject to eutrophication problems. The occurrence of cyanobacterial blooms in this water body has raised concerns regarding the presence of toxic metabolites. In order to understand the factors that promote the proliferation and distribution of cyanobacteria in the reservoir, physicochemical parameters, species composition, and toxicity of the reservoir water column were analyzed at monthly intervals over a 3-year period (2004-2007) using a range of analytical techniques. The results showed that cyanobacteria were absent in the dry period, returning after the onset of stratification. A succession pattern was observed within this group. The Aphanocapsa genus was dominant in the last rainy period of the study (October 2006 to March 2007). However toxicity was only detected when the genera Microcystis and Sphaerocavum were present (October 2005). The principal components analysis showed negative correlation between cyanobacteria and orthophosphate. The change of dominant cyanobacteria along the 3 years of study and the final prevalence of nontoxic genera in the reservoir is an evidence of water quality improvement in response to the management techniques implemented in the reservoir basin.     

Why Should We Calculate Complex Indices of Ozone Exposure? Results from Mediterranean Background Sites

While moving towards a flux-based approach, exposure-based ozone metrics are still a practical measure for summarising ambient air quality. Ozone hourly concentrations for the period 2000–2004 from sites in the Mediterranean Italy (≤600 m a.s.l.) were examined to define the O₃ summary statistic in the area, and to determine how O₃ exposure indices correlate to each other. Thirty-four of the most common O₃ exposure metrics were calculated. The results show that background O₃ pollution in Italy exceeds the European and North American standards. The exceedances of the target value, information and alert thresholds set by the 2002/3/CE Directive should encourage Italy to take the appropriate measures to reduce the risk. All the O₃ exposure indices, except the maximum permissible ozone concentration (MPOC) for forests, point to the potential for negative effects on vegetation and human health across Italy. As indices evaluated significantly correlated with each other, we suggest use of the most biologically meaningful metric when summarizing air quality information.     

Hyperaccumulation of vanadium in the Antarctic polychaete Perkinsiana littoralis as a natural chemical defense against predation

Background, aim, and scope  

Exceptionally high levels of trace metals have been reported in specific tissues of certain polychaetes. In the present study, the Antarctic fan worm Perkinsiana littoralis was shown to hyperaccumulate vanadium in the branchial tissues, and the hypothesis of an antipredatory strategy has been investigated     

Polybrominated diphenyl ethers, polychlorinated naphthalenes and polycyclic musks in human fat from Italy: Comparison to polychlorinated biphenyls and organochlorine pesticides

Prior to this study, reports of occurrence of polycyclic musks and polychlorinated naphthalenes (PCNs) in human tissues from Italy were not available. In this study, concentrations of PCNs and polycyclic musks were determined in human adipose tissue from Italy collected during 2005-2006; for comparison, legacy organohalogen pollutants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined. ΣPCN concentrations ranged from 0.5 to 14 ng/g lipid wt (lw). Polycyclic musks such as HHCB and AHTN were found in 92% and 83% of the human samples, respectively. Concentrations of PBDEs in Italian adipose tissue ranged between 3.2 and 35.6 ng/g lw.     

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.     

A new hybrid system of QSAR models for predicting bioconcentration factors (BCF)

The aim was to develop a reliable and practical quantitative structure-activity relationship (QSAR) model validated by strict conditions for predicting bioconcentration factors (BCF). We built up several QSAR models starting from a large data set of 473 heterogeneous chemicals, based on multiple linear regression (MLR), radial basis function neural network (RBFNN) and support vector machine (SVM) methods. To improve the results, we also applied a hybrid model, which gave better prediction than single models. All models were statistically analysed using strict criteria, including an external test set. The outliers were also examined to understand better in which cases large errors were to be expected and to improve the predictive models. The models offer more robust tools for regulatory purposes, on the basis of the statistical results and the quality check on the input data.     

Species-dependent chromium accumulation, lipid peroxidation, and glutathione levels in germinating kiwifruit pollen under Cr(III) and Cr(VI) stress

The accumulation of chromium by germinating kiwifruit pollen appears to be significantly affected by Cr species, Cr concentration and calcium availability. Cr(III) accumulation always occurred in a linear manner while Cr(VI) uptake followed a logarithmic model. In the absence of exogenous calcium, Cr(III) accumulation was much higher than that of Cr(VI). It was observed that, as the Cr(III) concentration increased, there was a significant decrease in the endogenous calcium content of pollen, ultimately leading to complete calcium depletion after 90 min of incubation at 150 microM Cr(III). This loss of calcium could be responsible for the strong inhibition of tube emergence and growth following exposure of pollen to Cr(III). Indeed, when exogenous calcium was added to the kiwifruit pollen culture medium, significant growth recovery and reduced Cr(III) uptake occurred; the opposite was true in Cr(VI)-treatments. A significant rise in lipid peroxide production occurs in the presence of both Cr species; the effect was more pronounced following Cr(VI) exposure. Finally, glutathione pool dynamics appears to be differentially affected by chromium species and concentrations. In conclusion, results of the present study have provided important information regarding the different activity profiles of Cr(III) and Cr(VI) in relation to kiwifruit pollen performance, and have also demonstrated differences in some biochemical responses of pollen to metal stress.     

Seasonal, spatial and inter-annual variations of trace metals in mussels from the Adriatic sea: a regional gradient for arsenic and implications for monitoring the impact of off-shore activities

Mussels are widely used as bioindicator organisms for monitoring chemical pollutants including trace metals. These elements are natural constituents in the marine environment and their basal concentrations in the organisms can be influenced by several environmental and biological factors. The aim of this work was to extend our knowledge on the natural variability of trace metals in mussels tissues, focusing on seasonal and inter-annual fluctuations in a coastal reference site of the Adriatic coast (Portonovo); a total of 39 samplings were performed during 5 years, providing an extended data-set for tissue levels of As, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn. Concentrations of trace metals in mussels tissues revealed marked seasonal fluctuations with significant differences between various sampling years. Such fluctuations appeared mostly related to phytoplanctonic blooms and especially to reproductive cycle which exhibited a certain inter-annual shift of the gametogenesis period. Lower concentrations were measured in summer months for the majority of elements while a different seasonal cycle was observed for arsenic, not correlated with gonadic development, neither with other elements. Chemical speciation of arsenic was characterized to distinguish compounds of natural origin from those potentially reflecting an anthropogenic impact. Arsenobetaine and arsenocholine were always the predominant forms (up to 85% of total arsenic), while a significant increase of dimethylarsine and trimethylarsine oxide in spring (24% of total arsenic) might reflect the effect of phytoplanctonic bloom on both geochemistry and trophic transfer of this element. A significant inter-annual variability was observed for both the seasonal cycle and the range of values measured for all the elements, with particularly marked differences for arsenic, ranging from less than 10 to more than 40 microg/g in summer periods of different years. Data obtained on reference mussels were used to assess the impact of 41 off-shore platforms distributed along 5 nautical districts in the Northern and Central Adriatic Sea. Organisms sampled on these structures from 2001 to 2005 exhibited a certain enrichment of cadmium and zinc, probably associated to the use of anodic electrodes. Marked annual and geographical variations were measured for concentrations of arsenic in mussels of different platforms. However, the comparison with results of Portonovo, allowed to exclude the anthropogenic impact of exploitation activities and revealed a natural regional gradient of arsenic levels in mussels tissues associated to the changing influence of the Po river runoff on seawater salinity. In particular the higher concentrations measured in organisms sampled from platforms in the Central compared to Northern Adriatic confirmed a significant relationship between salinity and arsenic bioaccumulation, consistent with a role of arsenobetaine as an acquired osmolyte for mussels. The overall results confirmed the importance of natural variability when assessing the potential impact of anthropogenic activities.