Abstract: Eighteen ram samples from Israel have been analyzed for their chemical composmon and S7Sr/S6Sr ratios The Sr-Isotoplc rahos lie In the range 0 7078 and 0 7092, and the Sr concentrations vary from 1 × 10 -4 to 9 x 10 4 meq Sr/l.
Soluble salts in rainwater are inherited from three major natural sources, seaspray, Recent marine minerals and mineral dust eroded from rock outcrops and soft A mixing model is formulated to apply the chemical composmon of rain (CI and Sr 2+) and ~ts isotopic 87Sr/S6Sr ratio, for the identification and est~mahon of the Sr sources.
All the samples fall within the m~xing space predicted by the model for the three end members mentioned above The data indicate that the most important non-seaspray source contributing d~ssolved salts to the rams m Israel comprises a mixture of Senoman to Eocene chalk (and its weathering products) and Recent marine minerals, from local and imported sources.
Most of the samples (67%) contain 50% or more non-seaspray Sr 0 e, Sr dissolved from dust or Recent marine minerals), whereas 56% of the samples display 87Sr/86Sr ratios lower than 0 7090. The rest represent mixtures of seaspray and Recent marine minerals.

Abstract: Seawater intrusion (SWI) has led to salinization of fresh groundwater reserves in coastal areas worldwide and has forced the closure of water supply wells. There is a paucity of well-documented studies that report on the reversal of SWI after the closure of a well field. This study presents data from the coastal carbonate aquifer in northeast China, where large-scale extraction has ceased since 2001 after salinization of the main well field. The physical flow and concomitant hydrogeochemical processes were investigated by analyzing water level and geochemical data, including major ion chemistry and stable water isotope data. Seasonal water table and salinity fluctuations, as well as changes of δ2H–δ18O values of groundwater between the wet and dry season, suggest local meteoric recharge with a pronounced seasonal regime. Historical monitoring testifies of the reversibility of SWI in the carbonate aquifer, as evidenced by a decrease of the Cl− concentrations in groundwater following restrictions on groundwater abstraction. This is attributed to the rapid flushing in this system where flow occurs preferentially along karst conduits, fractures and fault zones. The partially positive correlation between δ18O values and TDS concentrations of groundwater, as well as high NO3− concentrations (\textgreater39mg/L), suggest that irrigation return flow is a significant recharge component. Therefore, the present-day elevated salinities are more likely due to agricultural activities rather than SWI. Nevertheless, seawater mixing with fresh groundwater cannot be ruled out in particular where formerly intruded seawater may still reside in immobile zones of the carbonate aquifer. The massive expansion of fish farming in seawater ponds in the coastal zone poses a new risk of salinization. Cation exchange, carbonate dissolution, and fertilizer application are the dominant processes further modifying the groundwater composition, which is investigated quantitatively using hydrogeochemical models.