Effects of salinity on the clam <Emphasis Type="Italic">Chamelea gallina</Emphasis>. Part I: alterations in immune responses

In the present study, the effects of differing salinities on some important functional responses of haemocytes from the clam, Chamelea gallina, were investigated. The animals were kept for 7 days at 28‰ (hyposalinity), 34‰ (control) and 40‰ salinity (hypersalinity), and total haemocyte count (THC), haemocyte volume, phagocytosis, lysozyme-like activity (in both haemocyte lysate and cell-free haemolymph) were measured. The survival-in-air test was also performed. Clams kept at 28‰ showed significantly increased THC with respect to animals kept at 34 and 40‰. The analysis of haemocyte size frequency distribution highlighted that in clams kept at 28‰ the haemocyte fraction of about 5 μm in diameter and 50–100 femtolitre in volume increased markedly. Conversely, in animals kept at 40‰ an increase was observed in the haemocyte fraction having about 8–10 μm diameter and 400–500 femtolitre volume. Higher phagocytic activity was recorded in haemocytes from control clams, with respect to that of clams kept at 28 and 34‰. Lysozyme-like activity in haemocyte lysate was shown to increase significantly in animals kept at 28‰ with respect to that of clams kept at 40‰, whereas enzyme activity in cell-free haemolymph from clams kept at 34‰ was significantly higher with respect to that of clams maintained at 40‰. A relationship between phagocytosis and lysozyme secretion is suggested. The resistance to air exposure of clams kept at 28 and 40‰ was shown to decrease significantly; LT₅₀ values fell from 7 days in clams kept at 34‰ to 4 and 5 days in those kept at 28 and 40‰, respectively. Results demonstrated that salinity values far from 34‰ affects the functional responses of haemocytes and reduce the resistance of clams to exposure to air.     

Elemental Composition of Urban Aerosol Collected in Florence, Italy

An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. For our investigation, we use the external PIXE-PIGE beam facility of the I.N.F.N. Van de Graaff accelerator at the Physics Department of the Florence University. In order to gather information on both the longer- and shorter-time trends of the aerosol elemental composition, we are analysing both long temporal series (about 1 year) of 24-h Millipore filters collected by the health authorities in 3 different sites, and filters collected simultaneously in two of the above sites for about one month, by two streakers with one-hour resolution, providing size fractionation between particle size smaller than 2.5 µm and from 2.5 µm to 10 µm. The streakers sampling period includes two days during which the Municipality of Florence has banned the circulation of non-catalytic cars, due to the increase of NO₂ above the "recommended safety values". We present here the first obtained results for the sampling site located near a heavy traffic road.     

Reference criteria for the identification of accident scenarios in the framework of land use planning

Land use planning (LUP) around industrial sites at risk of major accidents requires the application of sound approaches in the selection of credible accident scenarios. In fact, the ‘technical’ phase of LUP is based on the identification and assessment of relevant accident scenarios. An improper choice of scenarios may critically affect both the ‘technical’ phase of risk assessment and the following ‘policy’ phase concerning decision making on land-use restrictions and/or licensing. The present study introduces a procedure aimed at the systematic identification of reference accident scenarios to be used in the gathering of technical data on potential major accidents, which is a necessary step for LUP around Seveso sites. Possible accident scenarios are generated by an improved version of the MIMAH methodology (Methodology for the Identification of Major Accident Hazards). The accident scenarios are then assessed for LUP relevance considering severity, frequency and time scale criteria. The influence of prevention and mitigation barriers is also taken into account. Two applications are used to demonstrate the proposed procedure. In both case-studies, the proposed methodology proved successful in producing consistent sets of reference scenarios.     

First evidence of gender-related differences in immune parameters of the clam Ruditapes philippinarum (Mollusca, Bivalvia)

For the first time, gender-related differences in some important functional parameters of haemocytes from the clam Ruditapes philippinarum have been studied. Clams were collected during the pre-spawning phase, when sex can be distinguished by microscopic observation of gonadal smears, in order to ascertain whether the two sexes reach the stressful spawning period with different degrees of immunosurveillance. Total haemocyte count (THC), haemocyte size frequency distribution, capability of haemocytes to assume the vital dye neutral red (NR, indicative of endocytotic activity), lysozyme-like and acid phosphatase activities in both haemocyte lysate (HL) and cell-free haemolymph (CFH), and superoxide dismutase (SOD) and catalase (CAT) activities in HL were all evaluated. No differences in THC values were found between the two sexes, but differing haemocyte size frequency distributions were observed: the fraction of larger haemocytes (7–9 μm diameter, 200 fl volume) was markedly increased in females and that of smaller haemocytes (<5 μm diameter, <200 fl volume) markedly increased in males. Interestingly, when haemocytes were observed under the light microscope, a significantly higher percentage of granulocytes was found in haemolymph from females, compared with that of males. Significantly increased NR uptake was recorded in female haemocytes. No significant variation in lysozyme-like activity was observed in HL, whereas in CFH, enzyme activity was significantly higher in females. HL acid phosphatase activity was significantly higher in males with respect to females; no significant variations in enzyme activity were observed in CFH. HL SOD and CAT activities were significantly higher in females than in males. Overall, on the basis of the cell parameters studied here, gender-related differences in immune parameters were found in R. philippinarum, indicating that females have more active haemocytes than males during the pre-spawning period.     

Risk-based optimization of the design of on-shore pipeline shutdown systems

Crude oil and other liquid materials are transported in large quantities through pipelines. Pipelines are an efficient and safe transport way as compared to both rail and road transportation, both from the economical and environmental points of view. Nevertheless, loss of containment accidents can occur due to external action –a mechanical impact, for example– or to corrosion, aging, etc. Even though the frequency of such events is certainly very low, the effects and consequences on environment can be very important.The consequences of accidents in pipelines can be efficiently reduced through a suitable design of the whole system. One of the points which must be decided in the design is the installation of blocking valves at appropriate distances, so that emergency shutdowns can interrupt the flow of substance and isolate the section where the loss of containment has taken place. In the case of pipe rupture the amount released is therefore limited to the content between two consecutive valves, usually placed according to heuristic criteria. However, if too many valves are used, the capital cost of equipment increases excessively, and if too few are used, the risk of serious accidents increases.In this paper we consider the possibility of improving the design of such systems by applying risk-based optimization criteria. We propose an optimization methodology to solve this conflict by means of an objective function that analyzes the variations in overall costs, including the cost of the investment (with specific reference to blocking valves) and the cost of accidents. The result is an optimum situation in which costs are kept to a minimum. As an example, we apply the methodology to the transportation of gasoline by pipeline.     

Supporting the selection of process and plant design options by Inherent Safety KPIs

Effective support of inherent safety implementation in process design requires a quantitative metric for monitoring and communicating the expected safety performance of alternative design options. The Inherent Safety Key Performance Indicators (IS-KPIs) methodology was developed to provide both a flexible procedure for the identification of the hazards, and a sound consequence-based quantification of the safety performance. The integration of different hazard identification techniques yields the relevant accident scenarios for each unit in the plant. The calculation of credible damage distances by consolidate consequence simulation models provides a sound basis for the definition of the KPIs based on worst case effects. Specific indicators were devoted to hazards from external actions, as natural events and intentional malicious acts. The methodology was demonstrated by the comparison of alternative technological options for LNG regasification. The application evidenced the potential of the IS-KPI method in pinpointing the critical issues related to each alternative configuration.     

Pinus nigra and Pinus pinaster needles as passive samplers of polycyclic aromatic hydrocarbons

Nine polycyclic aromatic hydrocarbons (PAHs) were analysed in pine needles of different ages (from 6 to 30 months) collected from two species, Pinus nigra and Pinus pinaster, in seven sites located along a transect from a suburban to a rural area of Genoa (Italy). In all sites and for both species, concentrations of more volatile PAHs (phenanthrene, anthracene, fluoranthene, pyrene) were higher than those for other less volatile PAHs, which are preferentially sorbed to airborne particulates (benzo[a]anthracene, chrysene, benzofluoranthenes, benzo[a]pyrene). Concentrations of total PAHs found in P. nigra in the rural sites were, on the average, 2.3 times higher than those in P. pinaster growing nearby. In both pine species, concentrations of volatile PAHs increased according to needle age. Annual trends of other PAHs were more variable, with a general decrease in older needles. P. pinaster needles are shown to be more reliable passive samplers, since they are more resistant to plant diseases, and considerable variation in PAH concentration was observed in P. nigra needles with moulds and fungi.     

Do Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs use vibrational communication?

Small Auchenorrhyncha use substrate-borne vibrations to communicate. Although this behaviour is well known in adult leafhoppers, so far no studies have been published on nymphs. Here we checked the occurrence of vibrational communication in Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs as a possible explanation of their aggregative distributions on host plants. We studied possible vibratory emissions of isolated and grouped nymphs, as well as their behavioural responses to vibration stimuli that simulated presence of conspecifics, to disturbance noise, white noise and predator spiders. None of our synthetic stimuli or pre-recorded substrate vibrations from nymphs elicited specific vibration responses and only those due to grooming or mechanical contacts of the insect with the leaf were recorded. Thus, S. titanus nymphs showed to not use species-specific vibrations neither for intra- nor interspecific communication and also did not produce alarm vibrations when facing potential predators. We conclude that their aggregative behaviour is independent from a vibrational communication.     

Immunotoxic effects of organotin compounds in Tapes philippinarum

One of the most harmful groups of coastal pollutants is the organotin compounds (OTCs) which have severe effects on both aquatic organisms and mammals including humans. The immunotoxic effects of OTCs were studied in the cultivated clam Tapes philippinarum by determining the immunosuppressant role on in vitro yeast phagocytosis at low doses (0.01, 0.05, 0.1 μM). The phagocytic index was significantly reduced in an irreversible non-lethal manner depending on concentration and lipophilic affinity. The order of inhibition was TBT≥DBT>MBT for butyltins and TPTC>TPTA≥TPTH for triphenyltins.