Analysis of the potential contamination risk of groundwater resources circulating in areas with anthropogenic activities

The area investigated is located in the province of Brindisi (Italy). It is a generally flat area separated from the nearby carbonatic plateau of the Murgia by quite indistinct and high fault scarps. As regards the geological features, carbonatic basement rocks and post-cretaceous terrains made up of calabrian calcarenites and middle-upper Pleistocenic marine terraced deposits can be distinguished. <P style='line-height: 20px;'> In the examined area there are two different hydrogeological environments. The first is represented by deep groundwater, the main groundwater resource in Apulia. <P style='line-height: 20px;'> The second hydrogeological environment, now of lesser importance than the deep aquifer in terms of size and use, is made up of some small shallow groundwater systems situated in post-calabrian sands and located in the eastern area. <P style='line-height: 20px;'> During some sampling cycles carried out in the studied area, water was withdrawn from both the deep aquifer and from the shallow groundwater. For every sample, the necessary parameters were determined for the physical and chemical characterisation of two different hydrogeological environments. Moreover, some chemical parameters indicating anthropogenic activities were determined. <P style='line-height: 20px;'> Analysis of the aerial distribution of the measured parameters has shown some main areas subject to different conditions of contamination risk, in accordance with the hydrogeological and geological features of the investigated area. <P style='line-height: 20px;'> In the south-eastern part of the investigated area, the important action performed by the surface aquifer for protecting the deep groundwater from contamination of anthropogenic origin is clear.<p> On the other hand, in the shallow groundwater, areas of nitrate and nitrite contamination have been identified, which result from the extensive use of fertilizers

The use of KI as Tracer in groundwater flow measurements

The district of Casalabate (Apulia, Southern Italy) is located on the banks of the Adriatic Sea and has been affected by significant land erosion with some houses collapsing and many others becoming unusable. In order to investigate the causes, a detailed campaign of multidisciplinary investigations was performed. It consisted of an integrated geological survey by drilling 23 boreholes and georadar prospecting as well as chemical-physical analysis, thermo salino-metric logs and groundwater flow measurements. The groundwater discharge to the sea, exclusively horizontal, mainly affects only some calcarenitic levels of fossil dune with a velocity of approximately 250 cm/day. The investigations regarding the measurement of groundwater flow were performed with the method of point dilution in a single well, by adopting and comparing three different surveying systems: 1) salinometric pole; 2) onductometric probe; 3) multiparameter probe with a specific sensor for the Iodine ion. The three different measurement systems has been carried out on a well with constant hydrodynamic and hydrochemical features at least for the time strictly necessary for the tests and have produced very similar results. The differences between the measurements made with different methods are very small: the percentage ratios of groundwater flow estimated with concentration changes of KI tracer and that with other two methods vary from 1% to 3%. The results of test well have been confirmed from a survey of 556 measurements, performed in 11 well of the same area by multiparametric probe and KI tracer. All the greater differences (>10%) have beeen recorded in the fresh-saline groundwater with salinity exceeding 4g/l, presumably due to the variations of basic salinity induced by tidal oscillations. Therefore, elaboration of the measurements performed in interface zone calls for the distinction of the effects of tracer dilution from those of the variations caused by the tide. By the double determina-tion (with the iodine sensor and with the conducting one), a better analysis of data has been performed. Finally. the study highlights that the system based on the Iodine sensor is reliable and can be compared, showing itself to be valid in coastal aquifer

Lineamenti idrogeologici della zona umida di Torre Guaceto (BR)

Nell'ambito di uno studio interdisciplinare finalizzato alla istituzione e gestione della "zona umida di interesse internazionale" di Torre Guaceto(Br), classificata come "riserva naturale orientata" sono state condotte circostanziate indagini idrogeologiche dell'acqìrifero carbonatico cretaceo fessurato e carsico, si sono delineate le carattestiche di permeabilità attraverso lo studio delle portate specifiche desunte da prove di un emungimento condotte nei pozzi presenti nell'area di studio. L'eterogeneità dei caratteri di permeabilità riscontrata viene ben €videnziata dall'andamento delle isopieziche che mostra numerose e ben marcate direttrici principali di deflusso idrico, convergenti verso fronti drenanti costieri o verso gli specchi liquìdì creatì dalle depressioni morfotogiche del terreno Pienamente concordi con tali indicazioni sono quelÌe derivate dall'andamento della distribuizione areale del contenuto salino e dei valorì termici delÌe acque di falda. La stretta connessione esistente fra distribuzìone del contenuto salino delle acque di falda e loro mobilità viene evidenziata dalla marcata contaminazione prodotta dalle acque salate di ingressione marina nelle aree di maggiore comunicabilità con il mare,corrispondenti peraltro alle aree di maggior drenaggio; questa corelazione viene anche evidenziata dalla distribuzione dei valori della temperatura delle acque.L 'analisi della distribuzione dei contenuti salini e termici rileva anche fenomenì di contaminazione salina prodotti dai massicci emungimenti operati nella stagione irrigua che richiamano dal basso acque di ìntrusione marina. Infine, le analisi chimiche condotte sui campioni prelevati dai vari punti acqua hanno dimostrato come le acque presenti nella porzione di territorio studiata siano interessate da una duplice forma di inquinamento:quelÌo salino,naturale e/o indotto dall'uomo, e quello chimico,dovuto alle attività agricole ed agli insediamenti abitativi, di intensità ancora contenut

Characterising the post-Cretaceous aquifer in the Brindisi Plain (South Italy) in order to recover and protect underground bodies of water

The area studied is the province of Brindisi and is represented by a large flat area where mainly sea terraced deposits from upper Pleistocene outcrop. These deposits overlie a middle Pleistocene clay layer which in turn overlies a carbonate substrate made up of Mesozoic limestones and Calabrian calcarenites In the area examined there are two hydrogeological environments : one represented by the "deep groundwater",housed in the carbonatic aquifer; the other consists of a "shallow groundwater" housed by the upper Pleistocene deposits and separated by the deep aquifer from the impermeable clayey level.In this work we made a detailed definition of the geological and hydrological features of the shallow aquifer determining both the main components and the value of ammonia, nitrites, nitrates and S.A.R, considered as specific indicators of pollution for this area.We have estimated the spatial distribution of these parameters with geostatistical methods. This reconstruction shows that the post-Cretaceous aquifer is rather exposed to anthropogenic pollution coming from intensive agriculture practiced in the area studie