Groundwater chemical composition, analysis

The basic idea is to reconstruct geochemical evolution of the groundwater from its chemical composition. For example, knowing the chemical composition of a well on the one hand and an analysis of the rainwater on the other, it will be possible to reconstruct which geological formation the rainwater must have passed after its infiltration to change its chemical composition as the result of reactions with mineral and gas phases (dissolution, precipitation, degassing) in a way that accounts for the composition of the water from the well. 

The main types of raw data used in the analysis of secondary hydrocarbon migration systems for basin evaluation are those relating to present and past physico-chemical characteristics of groundwater (groundwater pressures, temperatures, salinities, chemical compositions) and porosities and permeabilities of the subsurface. In addition, information on the physicochemical characteristics of source rocks and of hydrocarbon acciuuulations is necessary to complete the quantitative assessment of hydrocarbon migration systems. 

For the analysis of spatial and temporal variations in the chemical composition of the groundwater, data from the quality network of the Institute Geologico y Minero de Espana (major cations and anions but no isotopic analyses), con esponding to period 1981 to 2001 (http //aguas.igme.es/igme/homec.htm), were used the results from June 2006 have been added for comparison (Figure 7). 

Although there is an extensive literature on the chemical analysis of soil (J,2), very little work has been done on the dynamics of soil composition associated with buried bone. The elemental content of human bone has been related to the ancient diet (3). Any significant transfer of specific elements from bone to soil or vice versa would vitiate the analysis of bone in terms of diet. Loss of trace or minor elements from bone could result in build-up of the elements in soil directly adjacent to the bone, unless the newly introduced elements are flushed away by the action of groundwater. Similarly, transfer of contaminative elements from soil to bone could be associated with depletion of elements in soil directly adjacent to the bone, unless groundwater maintains an equilibrium by reintroduction of the depleted materials. Thus, establishment of enhancement or depletion in the soil of elements found in bone should be an important aspect in our understanding of the relationship between... 

The optimal conditions for the preparation of groundwater candidate CRMs were tested in a feasibility study of which the results are published elsewhere [14] two materials were selected, representing typical carbonate and sandstone media. Two batches were prepared from ultrapure water by adding pro-analysis grade chemicals and their homogeneity was verified to evaluate possible effects of the preparation procedure on the sample composition [14]. The stability was also checked at +4°C and +20°C over a period of three months. 

---