L'evoluzione dell'inquinamento salino delle acque sotterranee della Murgia e del Salento

In order to assess the evolution of seawater intrusion and the resulting saline Contamination, the trends of the 0,5 g/l isohatine over three time lags (1981, 1989. and 1997) were compared, since, at First approximation, water whose salinity is equal or lower than the above value is salt contamination free. In large areas along the Adriatic and lonian shoreline groundwater saline contamination is resulted to be a long-standing phenomenon. Only the Murgia interior and a restricted strip in the middle of the salentine peninsula have not been contaminated so far. From 1981 to 1989, the reference isohaline was reported to recede gradually. Then, the phenomenon either stopped or was reversed, as was the case in some Murgia and salentine areas, where, however, sorn additional withdrawals of the isohaline have occurred. The increasing saline Contamination in the salentine peninsula is confirmed by the evolution of the chlorine ion concentration (a parameter which indicates seawater contamination) over thirty years in eighteen wells. The analysis of data shows that the increased groundwater saline contamination is closely related to overdrafts. Before 1980. no significant concentration increase was reported in the majority of wells. The phenomenon became apparent in the late 80s after some dry years that result in a reduced recharge of aquifers and increased groundwater withdrawals. However, a less marked rise in salinity has been reported over the past thirty years.