Plot of CFC 11 vs. CFC 12 for a variety of spring and borehole samples across a limestone aquifer. The concentrations are compared with atmospheric equilibrium history and indicate CFC contamination, probably from dumped household waste (e.g. refrigerators). A.Foley
Plot of CFC 11 vs. CFC 12 for a variety of spring (circles) and borehole (squares) samples across a limestone aquifer. The concentrations are compared with atmospheric equilibrium history and indicate CFC contamination, probably from dumped household waste (e.g. refrigerators). A.Foley
Plot of Major Ion chemistry of groundwaters from a limestone aquifer, showing varying groundwater facies. A.Foley.
Plot of Major Ion chemistry of groundwaters from a limestone aquifer, showing varying groundwater facies. A.Foley.

Natural hydrochemical tracers are already present in surface and groundwater due to natural environmental processes, such as the weathering of rocks or interaction between water and the atmosphere. Natural hydrochemical tracers provide abundant information about the flow, provenance, history and quality of surface and groundwaters.

Water Tracing Services UK are able to offer expert advice on the design and conduct of hydrochemical sampling campaigns, in both water resource assessment and contaminated land situations. We offer sampling services according to the relevant British Standards and always use UKAS and MCERTS accredited laboratories for analysis. Data go through a thorough QA/QC procedure prior to further analysis and interpretation.

Hydrochemical data interpretation is a skilled endeavour and one in which we have many years’ experience (see Publications). We recognise that the quality of data is more important than the quantity, as firm conclusions may only be based upon reliable data. Proper data interpretation also offers an additional level of scrutiny against the inclusion of suspect data in a final dataset.

Standard methods of analysing hydrochemical data include time series, spatial distributions, Piper and Stiff diagrams, mixing models, groundwater apparent age dating, facies diagrams, major and minor element ratios, comparison with assumed connate water concentrations, influence of abstraction and other hydrologic and hydrogeologic factors, isotopic and other ambient tracer analyses, water-rock interaction, and so forth. These methods of interpretation may be tailored to project requirements and will normally be coupled with other elements of hydrological/hydrogeological survey.