[en] The Inhamuns region is one of the most arid in Ceara Waters exhibit very high salinity. Here we evaluate measurements of chemical parameters (electrical conductivity, EC, and major ions) and δ¹⁸ O for waters from wells, springs and surface reservoirs. Results show that springs, with EC of up to nearly 5000 μS/cm, are fed by pluvial water, exchange through dams can be excluded. Electrical conductivity is well correlated with Na⁺ Mg⁺⁺ and Cl^- for waters of various origins, whereas Ca⁺⁺ correlates reasonably only for wells. We conclude that aerosol deposition is a major source of salt, Enrichment through evaporation constitutes the most important process for surface water salination. Dissolution of chlorite-silicates is the cause for the magnesian character of underground water. (author)

[en] The isotopic composition of snow profiles taken from snow pits at Alpine glacier sites was measured. The study showed that the isotopic signature of the snow deposited at elevations above 3000 m during the winter is well preserved within the snow pack. The pronounced seasonal variation of the isotopic composition, a well dated Saharan dust layer found in all snow profiles, and the sampling of snow packs on two different dates made it possible to establish a snow pack chronology necessary for matching snow profiles sampled at different times and thus covering different deposition time periods. The temporal changes in the δ values of snow packs occurred coincidentally over the entire Alpine ridge. This suggests that the snowfall over the Alps is governed by a mesoscale air mass circulation pattern rather than by local meteorological conditions. Major changes in the isotopic composition were found to be linked to changes in the origin of the air masses. Furthermore, the temporal changes of the isotopic composition in snowfall reconstructed from snow profiles at different locations appear to be well correlated with the isotopic variations observed in precipitation collected at relevant meteorological stations. (author)

[en] The analysis of mercury, cadmium and lead in water samples from different environments (Lake Naivasha, River Malewa boreholes and Olkaria geothermal wells) in Naivasha region and their possible origins are reported. The levels of mercury and lead in the water samples were above the maximum permissible limits of 0.005 mg/1 and 0.1 mg/1 respectively, as stipulated by the WHO. On the other hand, 83.3% of the samples had cadmium levels above the maximum permissible limit of 0.01mg/1 in drinking water by WHO. The mercury and lead levels were also higher than those previously obtained from different regions of Kenya, while those for cadmium were within the corresponding range. Possible sources of elevated values were the geology of the surrounding area, sewage treatment works, use of phosphate rock fertilizers and lead fuels.(author)

[en] AECL is investigating a concept for disposing of nuclear fuel waste deep in plutonic rock of the Canadian Shield. As part of this investigation, we have performed a model simulation of regional groundwater flow in the Atikokan Research Area, a fractured plutonic rock environment of the Canadian Shield, and used the distribution of oxygen-18 (¹⁸O) and tritium (³H) in groundwater to test the model. At the first stage of model calibration, groundwater flow was simulated using a three-dimensional finite-element code, MOTIF, in conjunction with a conceptual framework model derived from field geological, geophysical and hydrogeological data. Hydraulic parameters (permeability and porosity) were systematically varied until simulated recharge rates to the water table compared favourably with estimated recharge rates based on stream flow analysis. At the second stage, vertical average linear groundwater velocities from the first stage of the calibration process were combined with conceptualized one-dimensional models of the system to generate depth concentration profiles of ¹⁸O and ³H. Recharge-, midline-and discharge area models of both the fracture zones and the rock mass were employed. The simulated profiles formed 'envelopes' around all field ¹⁸O and ³H data, indicating that the calibrated velocities used in the model are reasonable. The models demonstrate that the scatter of δ¹⁸O and ³H field data from the Atikokan Research Area is consistent with the groundwater flow model predictions and can be explained by the complexity arising from different hydraulic regimes (recharge, midline, discharge) and hydrogeologic environments (fracture zones, rock mass) of the regional flow system. 50 refs., 14 figs., 3 tabs

[en] Isotopes techniques based on the natural stable isotopes are efficient hydrological tool for the determination of the origin of springs and other waters. Through practical example, this paper presents the application of stabile isotopes deuterium (H-2) and oxygen-18 (O-18) for determination of the origin of spring's water 'Biljanini Izvori', near Ohrid (Macedonia). The results show that the waters from the spring 'Biljanini Izvori' have originated from the Galichica mountain precipitates, not from the Prespa Lake waters

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[en] The current issue provides and overview on historical aspects, present status and developments of the Global Network for Isotopes in Precipitation (GNIP) operated by the IAEA jointly with the WMO. It also contains two contributions from New Zealand and Switzerland which demonstrate the relevance of national efforts and achievements to the GNIP's programme and activities

[en] In order to get the optimization of conventional water treatment facility, radioisotope tracer technique was applied. It is desirable to set the baffles inside of mixing basin for the enhancement of mixing effect. It was appeared that most of flocs were settled down within 60 - 70 % of total length of sedimentation basin even with high flow rate. (author). 2 tabs., 32 figs

[en] The objective of the work presented is to evaluate the use of isotopic methods for the dating of very old groundwaters. It represents an IAEA sponsored study designed to test various methods available for that purpose. The Milk River Aquifer, in Alberta, Canada, was chosen for this study because it fits the definition of an idealized artesian system that dips gently from the recharge area and is confined by aquitards above and below. This feature, coupled with the fact that the groundwater in the Milk River Aquifer becomes 'old' (beyond ¹⁴C dating range) a short distance downflow from the dominant recharge area, makes this aquifer potentially useful in evaluating various dating techniques for old groundwaters. Numerous wells have been sampled in the course of many studies of the aquifer. Sampling for the IAEA sponsored campaign in 1985 took place in 16 wells. Samples for the following measurements were taken: major and minor ions (Alberta Agriculture and the IAEA), the stable isotopes δ¹⁸O, δ²H and δ¹³C, and ¹⁴C (IAEA, Universities of Waterloo and Arizona), ³⁹Ar, ⁸¹Kr and ⁸⁵Kr (University of Bern), noble gases, including Rn (University of Bath), ³⁶Cl (University of Arizona and Technical University of Munich), ¹²⁹I (University of Arizona) and uranium isotopes (Harwell Laboratory). The study concluded that groundwater ages based on the hydrodynamic model should be considered as being a lower limit of the average groundwater age in the Milk River Aquifer (< or approx. 0.500 Ma), while those based on ³⁶Cl/Cl data uncorrected for any dilution by dead Cl should be considered as being an upper limit (<2 Ma). The Milk River Aquifer project is an excellent illustration of a successful flow system analysis when multiple, independent dating methods are combined with detailed hydrogeological studies. The conclusion of the present study is that the potential for the dating of very old groundwaters by a variety of isotope techniques is very high provided a combination of methods is applied (i.e. never a single method by itself). (author). 18 refs, 5 figs