The pH would not be a good indicator as the bog water first flows along a 5 km mineral bedded stream and becomes more alkaline (from pH ~3 to ~ 5-6) before point-infiltrating into the karst system.
The method should be affordable to be carried out on monthly basis for few to tens of samples in the framework of a low-budget phd project.
You might try fluorescent constant concentration injection of fluorcein into bog, and check for peak concentration in water entering karst system using fluorometer. If through constant injection into bog, bog concentration continues to increase and there is no sign of karst entry, then not much being released. Fluorcein may breakdown in sunlight, so if that is a problem, maybe another florescent dye would work better.
Check out Garrett et Al on end member analysis to separate waters.
Perhaps high DOC or other component in bog water might be indicator if DOC in groundwater is normally low.
Thank you William!
Unfortunately the uranine won't be a good idea due to UV-decay. The article is very interesting. I will look into DOC, this seems promising!
Rhodamine B is another fluorescent dye I have used as a detector in pesticides entering streams from accident drift or runoff, but I am unsure about its breakdown in underground flow, adsorption to soil and organic particles. The advantage of fluorescent dyes, is they can be detected at very low levels with a fluorometer, and could be used as an indicator of flow connectivity, if not a quantification.
Oxygen and deuterium isotopes might be a good choice. Another possibility are tannins. Simple mixing analysis could be used to determine quantities.
Попробуйте галлит - NaCl. В мелких грунтовых водах его мало, он не поглощается биотой и не взаимодействует с минералами. Очень хорошо растворим. Для соблюдения ограничения в концентрации питьевых вод распределите равномерно на площади болот.
Thank you for the suggestions!
I should clarify, because my initial explanation could have led to a false impression. The karst connection has been proved by tracing tests, there is no question in whether the water from the bog makes it to the karst system or not, it does.
What interest me is that after the stream water sinks, majority of this blackwater again discharges downstream in the main spring group. However, one could assume that some of this blackwater, while mainly traveling through conduits and fissures, leaks into and mixes with the groundwater from the adjacent aquifer. Now, I will be taking water samples from the drilled wells (pumping the same aquifer) of the households situated in the karst area and I am wondering, if and how much (roughly) of the sinking bog water could affect the water quality of the wells.
Here's a link to an abstract published by a colleague of mine that was doing work very similar to what you describe.
http://fl.water.usgs.gov/Abstracts/ja_hydrochem_crandall.html
I forgot to mention the paper I have on researchgate spring water quality in Missouri 1975 shows relationship of flow discharge in several karst springs to several water quality components. You might find it of interest.
Chromophoric dissolved organic carbon relative to TOC is a low cost option when you need to correlate/quantify high concentration blackwater with highly diluted karst aquifer concentrations. The field unit is perfect for the range of blackwater concentrations. Lab UV-VIS spectrophotometry would likely be needed for the dilute aquifer samples.
http://diginole.lib.fsu.edu/islandora/object/fsu%3A181151
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