Determination of uranine tracer dye from underground water of Mecsek Hill, Hungary

In Situ Downhole Fluid Analysis Systems Using LED, Laser-Induced Fluorescence, and Uranine-Traced Drilling Water

The paper discusses a novel three-channel method to distinguish the formation oils, water, and uranine-based drilling mud and to monitor the clean-up process in the downhole fluid analysis systems. The proposed method is based on the study of the fluorescence spectra of the formation fluid or drilling mud samples. The experiment for different excitation sources (365 nm, 395 nm LEDs, and 405 nm, 460 nm laser sources) was carried out; the spectra were recorded with a VISION2GO VIS spectrometer. The characteristic features in fluorescence spectra of the crude oil sample and various concentrations of the uranine solution in pH-neutral water (5 mg/l, 10 mg/l, 25 mg/l, 50 mg/l, 100 mg/l) were observed. The sufficient unambiguous criterion for differentiating the type of fluid and clean-up process analysis is presented.

A curve-shift technique for the use of non-conservative organic tracers in constructed wetlands

Understanding the flow behaviour and accounting for time in constructed wetlands is necessary for the modelling and design of these systems. The addition of a tracer into the feed of a horizontal subsurface flow wetland allows the researcher to understand the flow of the fluid through the system, especially if the mass of the tracer is conserved (i.e. the mass of tracer injected is equal to the mass of tracer leaving the system). Conservative tracers, however, may pose a problem when it comes to the disposal of the effluent of the system if they are hazardous to the environment. In this study, the use of benzoate as a non-conservative degradable hydraulic tracer was investigated. The response curve of such a tracer is distorted due to its degradation within the wetland and hence the mass leaving the system is not equal to the mass injected. As a result, the typical hydraulic performance parameters obtained from tracer-response curves cannot be accurately calculated. In this paper, a curve-shift technique was developed by using a benzoate step-change curve as an input and using mathematical techniques to transform it into a conservative tracer-response curve. This was done through establishing a mathematical relationship between the retardation and hydrodynamic dispersion of benzoate and a known conservative tracer, uranine. This methodology was tested by conducting a dual tracer study using both benzoate and uranine and comparing the shifted benzoate response curve with the uranine response curve. Hydraulic parameters including mean residence time, effective volume ratio and hydraulic efficiency for each of these tracers were also compared.

The Montellina Spring as an Example of Water Circulation in an Alpine DSGSD Context (NW Italy)

Alpine areas, with normally fissured bedrock outcrops, do not typically contain important hydrologic reservoirs, except for small aquifers located in Quaternary sediments. By contrast, mountainous areas affected by deep-seated gravitational slope deformations (DSGSD), especially if covered by glacial sediments, contain large aquifers and are consequently promising for water exploitation. This last geological setting is observed, for example, in the lower Dora Baltea Valley (near the confluence with the Renanchio Basin) in which the Montellina Spring is located and exhibits a very high discharge. A multidisciplinary approach (detailed geological survey of the bedrock and Quaternary cover, as well as hydrogeological research based on tracer tests, hydrochemical analyses, and water balance studies) was used, allowing for a reconstruction of the geological and hydrogeological setting of the investigated area, also considering its environmental implications. The consequent hydrogeological model derives from the coexistence of some factors. In detail, the thick glacial cover, widespread in the intermediate sector of the slope, represents an important aquifer with a slow groundwater flow to the spring. The buried glacial valley floor, hosting this cover, can convey the groundwater from the high Renanchio Basin zone towards the low sector. The loosened bedrock of the low sector, consequent to DSGSD phenomena, favors the concentration of groundwater along the contact with the underlying normal fissured bedrock outcropping at the base of the slope. Finally, the flow until the spring essentially takes place through N100° trend open fractures and trenches. Part of the Montellina Spring discharge is also fed by the low Renanchio Stream, as highlighted by fluorescein tests, essentially using NE-SW oriented open fractures on the bedrock. The results of the investigation on the Montellina Spring can provide some insight regarding the hydrological potential of other alpine areas with a similar geological setting.