Pierluigi Barbieri

Levels of cadmium and zinc in hepatopancreas of reared Mytilus galloprovincialis from the Gulf of Trieste (Italy).

Cadmium and zinc concentrations were determined in hepatopancreatic tissues of Mytilus galloprovincialis, reared in three non-contaminated hatcheries of the Gulf of Trieste (Northern Adriatic Sea). Mussels were collected in 13 sampling exits with monthly frequency for verifying possible seasonal variations. Freeze dried hepatopancreatic tissues were dissolved by nitric acid procedure using a microwave system; analysis of Zn and Cd followed by AAS technique. Metal concentrations were below the critical values for mollusc soft tissues, but xenobiotic cadmium had values requiring monitoring attention. Cadmium and zinc showed moderate variations along the months, with a slight winter maximum followed by a summer pre-spawning minimum, matching the seasonal trends of temperature/salinity. The estuarine site appears to have the best quality of the examined area in terms of metal contents. The results can constitute a guideline for the water quality in the Northern Adriatic Sea, and permit comparisons with the quality of other areas of the Mediterranean Sea.

Using chemical and physical parameters to define the quality of karstic freshwaters (Timavo River, North-eastern Italy): a chemometric approach

Abstract The Timavo River, rising in Monte Nevoso (Slovenia), sinks into a limestone fissure and proceeds subterraneously toward the Adriatic Sea, feeding many springs and ponds in the Karst region near Trieste (Italy). In order to characterize and discriminate the freshwaters of this complex hydrological system, 84 samples were taken in 14 selected sites during the autumnal flood. Six chemical-physical parameters were determined: temperature, pH and conductivity in situ ; chloride, nitrate and sulphate contents in the laboratory, by high-performance ion-exchange chromatography (HPIEC). Univariate analysis of dispersion and centrality estimates of the populations of the experimental data allow us to discriminate a group of typically-karstic springs situated near S.Giovanni di Duino, as well as a group—to the north—of “mixed waters” that receive run-off from the northern Isonzo and Vipacco river-beds, and also seem affected by seasonal conditions. The multivariate cluster analysis (CA) confirms the discriminating ability of the considered parameters, and allow us to observe occasional intrusions of waters belonging to a group within a different group. The principal component analysis (PCA) supports the results of CA and permits us to assert the existence of a common watershed for the examined karstic freshwaters, which are characterized by 2 PCs: the ionic solutes are associated with the first component, whereas temperature and pH are associated with the second one. Factor scores show seasonal and meteorological effects on the chemical composition of the freshwaters.

Effects of four carbamate compounds on antioxidant parameters.

The effect of four carbamates, aldicarb and its metabolites (aldicarb sulfone and aldicarb sulfoxide) and propoxur on glutathione content and the activity of the enzymes involved in the sulfur-redox cycle in the mammalian cellular model CHO-K1 cells after 24-h exposure were determined. Carbamate exposure resulted in a depletion of intracellular reduced glutathione (GSH) content, no change was observed in oxidized glutathione (GSSG) and a decrease in GSH/GSSG ratio was detected. After carbamates exposition a GSH/GSSG decreases in ranged from 12.44% to 21.35% of control was observed. Depletion of GSH levels was accompanied by the induction of glutathione reductase (GR) after 24h exposure with each of the four carbamates to CHO-K1 cells. After aldicarb sulfone, aldicarb sulfoxide, and propoxur exposure, glutathione peroxidase (GPx) activity increased in CHO-K1 cells by 198%, 32%, and 228% of control, respectively. After aldicarb sulfone and propoxur exposure, glutathione transferase (GST) activities increased by 49% and 230% of control, respectively. Due to the role played by GSH in preventing cytotoxicity via free-radical scavenging, results obtained suggest that high concentrations of aldicarb sulfone and propoxur closely resembling oxidative stress in CHO-K1 cells.

Validation of counter propagation neural network models for predictive toxicology according to the OECD principles: a case study

The OECD has proposed five principles for validation of QSAR models used for regulatory purposes. Here we present a case study investigating how these principles can be applied to models based on Kohonen and counter propagation neural networks. The study is based on a counter propagation network model that has been built using toxicity data in fish fathead minnow for 541 compounds. The study demonstrates that most, if not all, of the OECD criteria may be met when modeling using this neural network approach.

Detecting and characterising sources of persistent organic pollutants (PAHs and PCBs) in surface sediments of an industrialized area (harbour of Trieste, northern Adriatic Sea)

A sediment sampling based on a two-dimensional mapping was performed in the harbour of Trieste (northern Adriatic Sea), considering 28 sites exposed to pollutant inputs from harbour and industrial activities. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in surface sediments, because these very persistent pollutants seem to be responsible for the depletion of benthic populations observed in this area. The correlation matrix indicates that PAHs and PCBs are non-correlated, and probably have different sources. Both cluster analysis performed on the sampling sites and graphical drawing of the PAH sediment contents make it possible to locate along the shoreline a band of more polluted sediments, clustered around a site facing a steelmaking factory, to be considered as the main source point for PAHs. The evaluation of phenanthrene to anthracene (P/AN) and fluoranthene to pyrene (FL/PY) ratios permits the assessment of the pyrolytic, industrial origin of these PAHs, rejecting a second possible source of hydrocarbons (i.e., an oil-pipeline terminal, situated near the steelmaking factory). Graphical drawing of the total PCB iso-concentrations reveals a different source-point for this other category of very persistent pollutants.

A three-way principal factor analysis for assessing the time variability of freshwaters related to a municipal water supply

Abstract Chemical analyses (total hardness, HARD; dissolved oxygen, DO; chlorides; sulfates; nitrates; nitrites; ammonia; orthophosphates; and UV-absorbing organic constituents, UV-ORG), physical data (turbidity, TURB; temperature, TEMP; conductivity, COND), and biological monitors (total and faecal coliforms, FAEC; faecal streptococci, STREPTO) constitute the 15 parameters, monitored with monthly frequency in the space of 4 years on freshwaters sampled at seven sites in a karstic area of northeastern Italy. The data set was used for a three-way principal factor analysis aimed at exploring the pattern of information about the environmental quality of the monitored freshwaters, since four wells are feeding the municipal water supply of the Province of Trieste, and the other water courses can influence them. The selected three-way (3,3,2) model uses three components for describing the analytical parameters, three for temporal variations and two for spatial variations. The method optimising the ‘variance of squares’ of the core elements has permitted a simple and meaningful interpretation of the Tucker-3 solution. The procedure succeeded in decomposing the overall temporal variation in three parts, thus highlighting nonperiodic critical events, a periodic seasonal component and a constant term. The seasonality has been confirmed by the examination of the autocorrelation function of the second temporal component. An environmental interpretation and an estimate of the relative relevance of phenomena conditioning the considered water body, detected by the multiway analysis, have been proposed.

Modeling bio-geochemical interactions in the surface waters of the Gulf of Trieste by three-way principal component analysis (PCA)

Abstract Data of temperature, salinity, dissolved oxygen, nutrients and chlorophyll measured on samples of surface seawater and collected monthly during 2 years in different sites of the Gulf of Trieste are modeled by means of three-way principal component analysis (PCA). Missing values are handled using an expectation maximization algorithm, regression or substitution with random numbers, depending on their origin. Physicochemical parameters are described by three different components that explain the effect of the river input on the seawater pattern, the effect of temperature, and metabolic–catabolic activity of the phytoplankton, respectively. One spatial component accounts for the gradient of influence of the estuarine waters in the Gulf, and three temporal components characterize three main seasonal conditions. Anomalous situations, generated by meteoclimatic events, are highlighted.

An improved index for monitoring metal pollutants in surface sediments

An approach for defining the quality of surface sediments of limited areas in terms of heavy metal contents is proposed. Sediments were taken on a bi‐dimensional mapping, for checking possible different sources of pollution in the case study, a harbour zone. Non residual metals were determined by ICP‐AES in cold diluted hydrochloric acid leachates of sediments. An “enrichment factor”;, r, can be computed for each metal: metals with r values exceeding unity can be considered as indicators of metal pollution. A “total enrichment factor”;, R, was proposed in order to assess the degree of pollution of sediments for each site. R is an adimensional value that accounts for the presence of metals that exceed threshold values determined by background concentrations.

Non-invasive Assessment of Exhaled Breath Pattern in Patients with Multiple Chemical Sensibility Disorder

Multiple chemical sensitivity (MCS) is a complex disorder initiated by chemical exposure, particularly through the airways. MCS patients report sensitivity or intolerance to low levels of a wide spectrum of chemicals. Symptoms could include asthma-like signs, rhinitis, fatigue, cognitive dysfunction, psycho-physiological alteration, and other specific tissue reactions resembling hypoxic and oxidative stress effects. To recognize physiological signs that would allow the diagnosis of MCS in a non-invasive way we investigated the potential application of a new sensor system. In healthy volunteers, we measured exhaled breath content in the control condition and under exposure to olfactory stressors that mimic hypoxic or pollutant stressors playing a potential role in the generation of the MCS disorder. The recording system used is based on metal oxide semiconductor (MOS) sensor having a sensing range of 450-2,000 ppm CO(2) equivalents, which is able to detect a broad range of compounds playing a potential role in the generation of the MCS disorder, while correlating directly with the CO(2) levels. The results indicate that the recording system employed was suitable for the analysis of exhaled breath content in humans. Interestingly, the system was able to detect and discriminate between the exhaled breath content taken from the control condition and those from conditions under stress that mimicked exposures to pollutant or hypoxia. The results suggest that chronic hypoxia could be involved in the MCS disorder.

Survey of environmental complex systems: pattern recognition of physicochemical data describing coastal water quality in the Gulf of Trieste.

A data set reporting temperature, salinity, dissolved oxygen, nitrogen as ammonia, nitrite and nitrate, silicate, chlorophyll a and phaeopigment values, determined in seawaters sampled during two years with a monthly frequency in 16 stations in the Gulf of Trieste, and at different depths of the water column, has been studied. In order to find synthetic descriptors useful for following the spatial and temporal variations of biogeochemical phenomena occurring in the considered ecosystem, the data set has been factorized using principal component analysis. A graphical display of scores, by means of boxplots and biplots, helped in the interpretation of the data set. The first factor conditioning the system is related to the input of freshwater from the estuary of the Isonzo River and to the stratification of the seawater (thermohaline discontinuity), while the second and third components describe interactions between biological activity, nutrients and physicochemical parameters; typical spring and autumn phytoplankton blooms were identified, in addition to an exceptional winter bloom conditioned by anomalous meteorological/climatic conditions. The fourth principal component explains the reducing activity of seawaters, which often increases when the decomposition of organic matter is relevant. The simple linear model proposed, and the related graphs, are shown to be useful tools for monitoring the main features of such a complex dynamic environmental system. The outlined approach to the considered complex data structure presents in a cognitive easy way (graphical outputs) the significant variations of the data, and allows for a detailed interpretation of the results of the monitoring campaign. Temporal and spatial effects are outlined, as well as those related to the depth in the water column.