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Main problems in the Salento peninsula are related to the increase of water table depths and to the groundwater salinization due to over abstractions and sea water intrusion, as it is shown in Figure 4.2. At several places of the Salento coastal area the electrical conductivity of the groundwater already exceeds 15,000 ?S/cm. The groundwater flows under low pressure inside karstic fractures and it is affected by withdrawals for drinking and irrigation uses, as explained above. Artificial recharge has been considered in Nardò as a pilot study to counteract saltwater intrusion and overexploitation of the aquifer, and groundwater recharge operations have started in 1991.

Per valutare il grado di diffusione nell'ambiente di batteri antibiotico resistenti, sono stati esaminati campioni di acqua superficiale e sotterranea provenienti da una zona costiera della Puglia. Ceppi di Salmonella spp. e di E. coli sono stati isolati dalle acque superficiali di un canale che convoglia a mare gli effluenti di un impianto di trattamento di reflui urbani e acque piovane. Nella stessa area sono state campionate acque sotterranee prelevate da 3 pozzi artesiani posti a diversa distanza dal mare, e che costeggiano il canale stesso. 82 ceppi batterici isolati da 24 campioni d'acqua sono stati sottoposti a test di antibiotico resistenza con due metodi: manuale, di diffusione da disco e automatizzato, VITEK ® 2 (bioMérieux, Marcy L'Etoile,France). I risultati ottenuti con le due metodiche non appaiono significativamente discordanti. I campioni di acqua superficiale sono risultati più contaminati rispetto a quelli di acqua sotterranea e con un numero più elevato di ceppi resistenti. Complessivamente lo studio mostra una notevole diffusione di batteri farmaco resistenti nell'ambiente e ciò potrebbe determinare implicazioni sulla salute dell'uomo rendendo più difficili le terapie antibiotiche.

The study investigates the fate and transport of microorganisms introduced by artificial groundwater recharge at the Nardo` fractured aquifer in Salento, Italy. Microbial indicators of faecal contamination, parasitic protozoa (Giardia and Cryptosporidium) and pathogenic bacteria (Campylobacter spp.), were monitored into injected water and groundwater to test the efficiency of the "natural disinfection" into the fractured aquifer. A remarkable decrease of microbial indicators and pathogens was observed suggesting that pathogens removal or inactivation may be possible during water flow in fractured aquifer. The recently described PNA probe CJE195 (Lehtola et al. 2005) was utilised for the rapid and specific detection of Campylobacter spp. by fluorescence in situ hybridization (FISH) after enrichment. FISH results were consistent with those of traditional cultural method (ISO 17995) applied in parallel: time required for Campylobacter identification was reduced of 4 days.

Seawater intrusion into fresh water aquifers occurs in many coastal hydrogeologic settings due to overexploitation of freshwater resources. It can be exacerbated by seawater level increases as a result of climate change on which there is wide consensus in the scientific community. Basin scale water balance deficits may be used together with hydrogeologic modelling and water quality monitoring data to track the advance of seawater intrusion. Due to the growth of population and increased exploitation of the ground water resources in coastal areas, the problem is truly global in proportion. The situation is particularly acute in the Mediterranean, the Yucatan peninsula in Mexico, the Middle East, the SE and SW United States as well as on many islands with arid to semi arid climates. Continued exploitation of limited freshwater resources can also lead to up flow of relict marine waters underlying the fresh water zone compounding the effects of seawater intrusion. This study has been designed to test the feasibility of creating a subsurface barrier to seawater intrusion by induced gypsum precipitation in fractured carbonate aquifers. The barriers design was supported by laboratory experiments and by a mathematical model which simulated sweater intrusion in a costal aquifer at Salento, in Southern Italy. The results will assist regional, national, and local water management interests to better regulate water use and protection as well as to avoid conflicts over scarce resources.

This study investigates the fate and transport of pathogens introduced by artificial groundwater recharge at the Nardò fractured aquifer in Salento, Italy. Wastewater effluents from a municipal treatment plant with known pathogen concentrations were injected into a sinkhole and the migration of pathogens in the fractured aquifer was monitored at various sampling wells. Two tracer tests using iodine and chlorophyll were carried out. The spatial variability of the mean fracture aperture was determined by well-established geostatistical procedures and local aperture measurements evaluated by pumping borehole field tests. The preliminary experimental field data suggest that the required setback distance for drinking wells should be larger than 200 m limit imposed by Italian regulations.

The Salento groundwater supplies over 70% (=4000 l/s) of drinking water requirements. The Puglia carbonate aquifer is an important water reservoir but presents also high vulnerability to wastewater injections. Under these conditions, hazardous pathogens could affect drinking water quality even at long distance from pollution sources. Recent epidemiological studies focused that the population on the Salento Coast (Puglia, Southern Italy) have an higher exposure to gastroenteritis in comparison to Italian population. The quantitative estimation of the pathogens effects on contaminated wells water has been carried out in the Nardò aquifer, where a channel (Asso) outflows raw water in a natural sinkhole. The systematic monitoring of groundwater quality in the wells was carried out during Winter 2002 and allowed the evaluation of the natural inactivation of pathogen injected in the fractured subsoil. This estimation was supported by mathematical model simulations of the groundwater flow and pathogens migration in fractures. Moreover on water samples derived from a wells affected by injected wastes at 500 m of distance, has been tested the impossibility of total inactivation of some viral indicators (Clostridi perfringens e somatic phages anti-E. coli) by hypochlorination.

In Puglia several coastal aquifers are polluted by uncontrolled discharges of domestic wastes and sea water intrusion. The Italian rule D. Lgs. 152/99 and the European Community Directive 2000/60/EC, known as the Water Frame Directive, encourage basic and supplementary measures for water resources protection such as rehabilitation projects and artificial aquifers recharge (see (xiii) and (xiv), part B annex VI). Moreover, in the semiarid environments the water derived from municipal treatment plants can conveniently be reclaimed for groundwater artificial recharge. Treated wastewater injections could improve groundwater quality by reducing the extent of seawater intrusion and increasing the groundwater storage. An experimental study has been carried out in the Salento Region where the Nardò injection sink has been used in the last 11 years as a natural way to increase groundwater replenishment. A mathematical model has been applied to simulate the effect of 140 l/s treated waste injection in the sink and to study contaminant pathways and concentrations in the fractured aquifer. Moreover water sampled in monitoring wells positioned at different distances from injection allowed the inactivation times for pathogens released in ground water to be estimated. The rates for pathogen inactivation have been also estimated by means laboratory tests carried out on horizontal pilot-plants able to reproduce waste filtration through fractures. Model results allowed two zones around the sink to be drawn by means the set back distances calculation in every direction and, the minimum distances required for virus (zone A) and fecal coliforms (zone B) inactivation in fractures were estimated in the case studied.

A new starch-based polymeric system, ZI1OU from Novamont, mainly composed of starch and polycaprolactone, was reprocessed several times in an extruder to investigate the recyclability of this biodegradable polymer. A previous investigation of the thermomechanical degradation in a mixer has been also done. The degradation is mostly due to the thermal stress but the presence of the mechanical stress strongly increases the degradation kinetic. During melt processing two concurrent processes take place: the first is the degradation, i.e. the breaking and shortening of polymeric chains, mostly occurring in the PCL phase; the second is the formation of some crosslinked structure in the starch phase. The rheological and mechanical properties, measured on samples subjected to repetitive extrusion operations carried out in a single screw extruder, clearly indicate that, in the adopted processing conditions, no significant modifications are observed. Only after five extrusions some decrease of these properties was measured.

The compatibilization of blends of polyamide-6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two-steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy and scanning electron microscopy (SEM). The rheological and mechanical properties of the blends were also investigated. The results show that functionalization of the polyethylenes can be achieved by melt blending with ricinoloxazoline maleinate even in the absence of free radical initiators. The compatibilization of the blends enhances the dispersion of the minor phase significantly, increases the melt viscosity, and improves the mechanical properties. The one-step preparation of the compatibilized blends was also found to be effective, and is thought to be even more promising in view of commercial application.

Polyethylene-polycaprolactone graft copolymers with different chemical structures (i.e. different number and length of PCL grafts and molecular weight of PE backbone) were synthesized from various EVOH copolymers and e-caprolactone, using Aluminum isopropoxide as catalyst, and were tested for their compatibilizing capability in PE/PVC blends. PE and PCL segments in the graft copolymers were found completely immiscible, while PCL segments of the graft copolymers were found completely miscible with PVC. When graft copolymers were added to PE/PVC blends they proved to be good agents for the dispersion of PVC phase in the PE matrix. SEM showed also improved adhesion between the dispersed PVC phase and PE matrix. Moderate improvements in mechanical properties were also observed in preliminary tensile tests.

The compatibilization mechanism of some compatibilizers for blends of polyolefins with a liquid crystalline polymer (LCP) was studied. Polyethylene (PE) and polypropylene (PP) were blended with a semirigid LCP (SBH) in a batch mixer, either with and without compatibilizers. The latter were two commercially available samples of functionalized polyolefins, that is, a PE-g-MA (HDM) and a PP-g-AA (Polybond 1001) copolymer and some purposely synthesized PE-g-LCP and PP-g-LCP copolymers. Microtomed films of the binary and the ternary blends were annealed at 240 degrees C on the hot stage of a polarizing microscope and the changes undergone by their morphology were recorded as a function of time. The results indicate that the compatibilizers lower the interfacial tension, thereby providing an improvement of the minor phase dispersion. In addition to this, the rate of the coalescence caused by the high-temperature treatment is appreciably reduced in the systems compatibilized with the PE-SBH and PP-SBH graft copolymers. Among the commercial compatibilizers, only Polybond 1001 displayed an effect comparable to that of the above copolymers. HDM improved the morphology of the as-prepared PE blends, but failed to grant sufficient morphological stabilization against annealing-induced coarsening. The results are discussed with reference to the chemical structure of the different compatibilizers.

The rheology, morphology, and mechanical properties of blends of high-density polyethylene (HDPE) with a semiflexible liquid crystalline copolyester (SBH) were studied in order to assess the compatibilizing ability of added PE-g-SBH copolymers, and its dependence on the molar mass of the PE matrix, and on the technique used for blend preparation. The PE-g-SBH copolymers were synthesized as described in previous articles, either by the polycondensation of the SBH monomers in the presence of a functionalized PE sample containing free carboxyl groups, or by reactive blending of the latter polymer with preformed SBH. Two samples of HDPE having different molar masses, and two samples of SBH with different melt viscosity and different microstructure, were used for preparing the blends. The two components and the compatibilizer were either blended in a single batch or used to prepare binary master blends to which the third component was added at a later stage. The results indicate that the PE-g-SBH copolymers do, in fact, compatibilize the PE–SBH blends and that the effect is more pronounced with the lower molar mass PE matrix and with the SBH sample having lower viscosity. The experiments carried out on blends prepared with different techniques show that the compatibilizing ability of the graft copolymer is improved if the latter is first blended with either of the two main components. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 603–613, 1999

The mechanical properties of blends with liquid crystalline polymers are in general poor and lower than those expected on the basis of additivity rule because of the strong incompatibility between the flexible and rigid components. Compatibilization is then necessary to enhance the adhesion between the two phases and then to improve the final properties of these blends. The addition of maleic anhydride functionalized polymers could give rise to some compatibilization because of possible reactions between the maleic anhydride group and the end groups of the liquid crystalline polymers. These reactions do not seem to occur in blends of polyethylene and a semirigid liquid crystalline polymer. The small increase of viscosity and of some mechanical properties can be ascribed to the occurrence of polar interactions, such as hydrogen bonding between the components.

Fluoroelastomers (FEs) usually have working temperatures above 150 degrees C and a great resistance to aggressive agents such as oils, fuels, aliphatic and aromatic solvents, steam, moderate acid, and basic environments. Liquid crystal polymers (LCPs) can be effective processing aids and reinforcing agents for elastomers. These characteristics are very attractive to lower melt viscosity and to stiffen and strengthen the final product through a simple blending. Among the LCPs, the semirigid LCPs seem the most appealing for blending with flexible thermoplastics (FTs) because their processing temperatures can be arranged to be in the same processing temperature range of FTs and because the presence of flexible segments can improve the compatibility with the flexible matrix. This is very important especially for FEs that are subjected not only to mechanical degradation, but also to thermal degradation. Blends of FEs with two types of semirigid LCPs show easy processability and enhanced mechanical and thermomechanical properties. These improvements were observed both for pure FEs and for filled vulcanized systems. The improvement of the mechanical properties is below that expected on the basis of the additive rule due to the incompatibility between the components; nevertheless, an impressive increase of the elastic modulus, up to 40 times, was noticed by adding 20% of LCP. In vulcanized systems, the tensile strength is also increased, whereas the elongation at break is slightly reduced. The working temperature is also drastically increased both in vulcanized and in unvulcanized systems.