Abstract: In order to identify the origin of the salinity and formation of saline plumes in the central part of the Mediterranean coastal aquifer of Israel, we determined the elemental and boron, strontium, and oxygen isotopic compositions of fresh and brackish groundwater (C1 up to 1500 mg/L). We distinguish between two key anthropogenic sources: (1) sewage effluents used for irrigation with high Na/C1, SO4/C1, and B/C1 ratios and low Br/C1 ratios relative to seawater ratios, low ;5•B values (0-10%o) and high ;5•80 values (>-4%0); and (2) imported water from the Sea of Galilee that is artificially
recharged tothe aquifer with high Br/C1 (3 x 10 -3) and ;5•80 values (-1%o) and a low 87Sr/86Sr ratio of 0.70753. The brackish groundwater from the saline plumes have relatively low Na/C1 ratios (0.5-0.8) and high Ca/Mg, Mg/C1, and Ca/(SO 4 q- HCO3) (> l) ratios relative to seawater ratios; marine SO4/C1 and Br/C1 ratios;5•B values of 24.8-49.9%0; 18 87 86 ;50 of -2.95%0 to -4.73%0; and Sr/ Sr ratios of 0.708275-0.708532. The composition of most of the investigated groundwater from the saline plumes differs from those of the 87 86 anthropogenic sources, imported water, fresh uncontaminated groundwater (Sr/ Sr of 0.70866, ;5•B of 20-30%o), and saline water from the adjacent Eocene aquitard. Only in ß 18 areas of artificial recharge does local groundwater have high Br/C1 and ;50 values that are typical to the Sea of Galilee. The linear relationships between chloride and most of the ions, including Band Sr, the relatively high ;5•B (>30%0) and low ;5•80 (<-4%0) values, and the chemical signature of the saline plumes (e.g., marine Br/C1 and SO4/C1 ratios), suggest that (1) mixing processes control the chemical composition of the brackish water within the aquifer, and (2) the saline postulated end-member has a chemical composition that resembles modified seawater with a marine and higher ;5•B values, and a 87Sr/86Sr ratio of <0.7083. We propose that most of the salinization phenomena and the formation of saline plumes in the inner parts of the coastal aquifer are derived from upconing of underlying natural saline water bodies and enhanced by overexploitation and draw-down of the overlying fresh groundwater.

Abstract: Soil and groundwater degradations have taken considerable attention, recently. We studied spatial and temporal variations of groundwater table depth and contours, and groundwater pH, electrical conductivity (EC), and nitrate (NO3) content in a large irrigated area in Western Mediterranean region of Turkey. These variables were
monitored during 2009 and 2010 in previously constructed 220 monitoring wells. We analyzed the data by geostatistical techniques and GIS. Spatial variation of groundwater table depth (GTD) and groundwater table contours (GTC) remained similar across the four sampling campaigns. The values for groundwater NO3 content, EC, and pH values ranged from 0.01 to 454.1 g L−1 , 0.06 to 46.0 dS m−1 and 6.53–9.91, respectively. Greatest
geostatistical range (16,964 m) occurred for GTC and minimum (960 m) for groundwater EC. Groundwater NO3 concentrations varied both spatially and temporally. Temporal changes in spatial pattern of NO3 indicated that land use and farming practices influenced spatial and temporal variation of groundwater NO3. Several hot spots occurred for groundwater NO3 content and EC. These localities should be monitored more frequently and
land management practices should be adjusted to avoid soil and groundwater degradation. The results may have important implications for areas with similar soil, land use, and climate conditions across the Mediterranean region.