Distribution and speciation of heavy metals in Apulian coastal sediments

In the framework of the Interreg II Project Italy–Greece, distribution and speciation of trace metals in surface coastal sediments of Apulian regions were studied. A sequential extraction technique was used to determine the chemical association of heavy metals (Zn, Pb, Ni, Fe, Cr, Mn, Cu and Cd) with major sedimentary phases (acid soluble phases, easily reducible fraction and oxidizable matter). The relationship between the metals' content and the grain-size composition of the sediments was also considered: generally the elements resulted associated with the fine fraction, even if in some cases (Cu in the oxidizable phase) the opposite behaviour was observed. The studied area is not particularly polluted, except for some defined zones, as for example Brindisi's harbour. Speciation analysis revealed that the major part of the heavy metals are not easily mobilizable and bioavailable. Even in this case, there are some exceptions to the general behaviour: Cu and Pb in several samples are largely present in the oxidizable phase, which even if not immediately available can become a source of associated elements when redox conditions change.     

A new method for obtaining barnacle cement in the liquid state for polymerization studies

A new method for collecting barnacle cement in the liquid state is described. This permits studies on the transformation of cement from liquid to solid states not heretofore possible. Preliminary analyses showed that polymerization, i.e., the in vitro change from a clear liquid to an opaque solid mass is not affected by temperatures ranging from-10° to 45°C, by diluting with distilled water up to two-fold, or by treating with selective enzymes; some chemical inhibitors induce the formation of a white precipitate, possibly indicating denaturation of the protein. It is concluded that the liquid cement contains all the necessary components for self-assembly, progressively changing from a clear liquid to an opaque rubbery insoluble mass. The polymerization process is time-dependent and requires no exogenous catalyst. A mechanism that may be involved in the adhesion process of the barnacle is suggested.     

Spatial and seasonal variability of dissolved oxygen and nutrients in the Southern Adriatic coastal waters

The main objective of this paper is to present vertical and horizontal patterns of dissolved oxygen and nutrients found during four seasonal surveys (March, June, September and December 2000) in the Southern Adriatic Sea coastal waters. The multivariate technique Principal Component Analysis has been applied to our dataset considering the following parameters: seawater temperature, salinity, dissolved oxygen and nutrients (nitrate, nitrite, phosphate, silicate). The resulting plot shows in a self-explanatory way that a seasonal trend was not observable in the investigated period and that no significant differences occur between the stations sampled in the Taranto Gulf and those along the Adriatic coast. Water column stratification persists in all seasons, except in spring, in the shallowest stations. The surface layer is characterized by a low nutrient content. The influence of the Northern Adriatic Surface Water in the Southern Adriatic sub-basin seems to be very low and can be traced by nitrate and silicate only in spring and winter. Regarding deep waters, nitrate distribution shows an increasing gradient moving from the coast to the open sea, having the lowest concentration in the shelf area and the highest in the most offshore stations of the Otranto Strait. In the Otranto Strait area the vertical distributions of physical and chemical parameters show, at middle depths, the inflow of Levantine Intermediate Water, traced by both the maximum of salinity, nitrate and phosphate and the minimum of oxygen. The LIW signal is lost moving northward. The outflow of Adriatic Dense Water is less evident, being traced only in spring by an oxygen increase at the bottom layer in the shelf area. The N:P ratio is highly variable but in the range already observed in the Southern Adriatic, suggesting a P-limitation, which can both contribute to the low primary productivity of the area and support the N:P ratio anomaly of the Eastern Mediterranean.     

Spatial and seasonal variability of dissolved oxygen and nutrients in the Southern Adriatic coastal waters

The main objective of this paper is to present vertical and horizontal patterns of dissolved oxygen and nutrients found during four seasonal surveys (March, June, September and December 2000) in the Southern Adriatic Sea coastal waters. The multivariate technique Principal Component Analysis has been applied to our dataset considering the following parameters: seawater temperature, salinity, dissolved oxygen and nutrients (nitrate, nitrite, phosphate, silicate). The resulting plot shows in a self-explanatory way that a seasonal trend was not observable in the investigated period and that no significant differences occur between the stations sampled in the Taranto Gulf and those along the Adriatic coast. Water column stratification persists in all seasons, except in spring, in the shallowest stations. The surface layer is characterized by a low nutrient content. The influence of the Northern Adriatic Surface Water in the Southern Adriatic sub-basin seems to be very low and can be traced by nitrate and silicate only in spring and winter. Regarding deep waters, nitrate distribution shows an increasing gradient moving from the coast to the open sea, having the lowest concentration in the shelf area and the highest in the most offshore stations of the Otranto Strait. In the Otranto Strait area the vertical distributions of physical and chemical parameters show, at middle depths, the inflow of Levantine Intermediate Water, traced by both the maximum of salinity, nitrate and phosphate and the minimum of oxygen. The LIW signal is lost moving northward. The outflow of Adriatic Dense Water is less evident, being traced only in spring by an oxygen increase at the bottom layer in the shelf area. The N:P ratio is highly variable but in the range already observed in the Southern Adriatic, suggesting a P-limitation, which can both contribute to the low primary productivity of the area and support the N:P ratio anomaly of the Eastern Mediterranean.     

A multi-lysimeter investigation on the mobility and persistence of pesticides in the loam soil of the Fucino Plain (Italy)

In order to evaluate the impact of intensive horticulture on the water resources of the Fucino Plain, one of the most important agricultural settlements of Central Italy, the mobility and persistence in the soil of five commonly used pesticides was investigated by means of multi-lysimeter experiments. The fate of simazine, carbaryl, dicloran, linuron and procymidone was evaluated in the laboratory under experimental conditions simulating as closely as possible both pesticide application and irrigation practices required by the local crops. An efficient extraction procedure followed by chromatographic analysis, allowing the simultaneous determination of the applied chemicals, was used to monitor the pesticide residues in the soil columns as a function of time from application and depth. The experiment, carried out for about 60 days, revealed that soil contamination apparently involves only the surface layer since none of the investigated pesticides was detected at depths greater than 20-30 cm. However, the five pollutants exhibit a quite different behaviour that can be related to their physico-chemical properties.     

Weathering patinas on the medieval (S. XIV) stained glass windows of the Pedralbes Monastery (Barcelona, Spain)

Background, aim, and scope  The first step in the restoration of a medieval stained glass window is the evaluation of its degree of degradation. This implies the study of the chemical composition of the stained glass as well as the new mineral phases developed on its surface (patinas). Patinas are clearly related to glass composition, time, environmental conditions, microenvironments developed in local zones, bioactivity, physical and chemical factors, etc. This study was carried out on patinas developed in selected Na-rich stained glass of the Santa Maria de Pedralbes Monastery (Barcelona, Spain). The location of this monument in the city (about 5 km from the shoreline and close to the Collserola hill flank) helped to determine the environmental conditions in which patinas developed. The aim of our study was to characterize the patinas formed on the surface of the selected glass of this monastery in order to understand the role of the chemical composition of the original glass (Na-rich) as well as the environmental conditions in which they developed. Materials and methods  Powdered samples of two different color-type patinas (ochre-orange and brownish) were collected in the external and internal parts of the stained glass windows of the Prebystery and Chapter House of the Pedralbes Monastery by using a precision (odontological) drill. These patinas were subsequently analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Results  XRD analyses evidenced the presence of sulfates (gypsum and thenardite), calcite, Ca-oxalates (whewellite and weddellite), and quartz forming part of the patinas. Although these mineral phases can be found in both color-type patinas, whewellite and thenardite are more common in the ochre-orange patinas. The results obtained were validated by the FTIR measurements. It has been observed, when thenardite is present, that gypsum occurs as traces. Thenardite is in most of the cases associated with whewellite and mainly occurs in the internal parts of the glass. In contrast, weddellite is limited to the absence of thenardite and whewellite and to the external parts of the stained glass. Quartz is present in all the patinas independent of their location and color. Calcite also occurs in many samples. It appears in both color-type patinas and, in some cases, is associated to the presence of weddellite but not to whewellite and/or thenardite. Discussion  Glass composition together with environmental conditions and location of the patinas (internal or external parts of the stained glass window), as well as the provenance of the glass within the monastery, are the main factors that define the development of the new mineral phases. Moreover, the action of microorganisms, when present, can also strongly influence the development of some mineral phases. For example, the formation of calcite in the external parts of the stained glass (associated with the presence of oxalates) is related to the action of microorganisms. When calcite is formed in the internal parts of the glass and it is not associated with the presence of Ca-oxalates, an inorganic origin can be invoked. The presence of weddellite requires a very humid microenvironment with very little exposure to sunlight. In fact, this mineral phase has only been observed in the external parts of some glass located in the humid and shady side of the monastery. Whewellite (which only appears in the internal parts) needs a low degree of relative humidity. It has been observed that sulfur precipitating in basically one mineral phase (thenardite or gypsum) depends on the microenvironmental conditions of the moment and the glass composition. When thenardite occurs, it can be maintained that the original glass is of Na composition. The occurrence of quartz in all samples is interpreted as being due to the deposition of atmospheric particulate matter. The color of the patinas can be originated by different processes (presence of carotenes, organic pigmentation, atmospheric contamination, etc.). Conclusions  In the case of moderately weathered stained glass windows, the combination of XRD and FTIR techniques is very useful to obtain a fast preliminary evaluation of the degree of weathering of a stained glass window. The presence of specific mineral phases in the patina (e.g., thenardite) confirms the Na composition of the original stained glass. This is important since Na-rich glass underwent a lesser degree of weathering than K- or K-Ca-rich glass. However, their absence cannot preclude other possibilities. It has been extensively evidenced through time that environmental conditions play an important role on the formation of the different mineral phases which form part of the patinas. Recommendations and perspectives  The first step in the restoration of a stained glass window is the evaluation of the degree of deterioration of the glass. This evaluation includes a chemical analysis of the glass as well as a characterization of the patinas developed on their surfaces. The obtained results will be essential in order to define the best restoration practices to be followed.     

Recovery of organic wastes in the Spanish wine industry. Technical,economic and environmental analyses of the composting process

The main organic wastes produced in modern wine industries include grape pomace (62%), lees (14%), stalk (12%) and dewatered sludge (12%). Some of these wastes are being used as by-products (grape pomace and lees) whereas the rest of organic wastes (stalk and wastewater sludge) has been traditionally incinerated or disposed in landfill. In this work, composting is proposed for the recovery of stalk and wastewater sludge to produce a sanitized organic amendment for application in the vineyard, closing the organic matter cycle. The environmental and economical analyses of the different alternatives to manage organic wastes from the wine industry are also presented. Composting costs are almost negligible when compared to other management options. From the environmental point of view, in-situ composting presents the best performance in 8 of the 10 impact categories analysed. Finally, the energy balance shows that the 4 composting systems involved less energy than the systems based on Mineral Fertilizer consumption.     

Heavy metals in albanian coastal sediments

Heavy metals (Fe, Mn, Cr, Ni, Cu, Cd, Pb, Sn) concentration has been determined on 39 coastal sediment samples collected in Albania. The relationship between the heavy metals content and the grain size has been considered. All metals, except Cu and Cd, resulted accumulated in the finest fraction, which constituted up to 95% of most of the considered sediments. A good correlation has been found for Ni, Cr, Fe, Zn, Cu in the entire area, indicating a common origin for these metals in the analyzed sediments. Concentration values fall in the range reported for Dinaric chain derived sediments, revealing, generally, a natural origin of the metal contents. Though in some selected areas such as the Drin and the Skumbin Bay, an antropogenic input of Cr, Fe, Ni and Cu can be observed, as the result of discharging of mines and smelter activities.