Stable Isotope and Hydrochemical Sampling

With a purpose of investigation of pollution's possibility transfer by water flows, hydrochemical compounds of all hydrogeological formations and their connection in the region have been studied: mineral water of Eocene-Paleocene flysch formation (5 boreholes), fresh waters (5 springs and 1 boreholes) - of lava formation and surface waters - rivers (5 sampling points). Totally, 16 sampling points have been

Fig. 29.2 Hydrodynamical scheme

OLD RIVERS ALUVIAL FAN

selected within the study area to collect information on chemical and isotopic composition of water.

From May 2007 untill November 2009 ten sampling campaigns were carried out. The main hydrochemical macro- and microcomponents of water sources were tested by the field hydrochemical laboratory (Multi-340i/SET and Spectroquant® Colorimeters), which was also purchased by the IAEA. Stable (2H and 18O) isotopes and tritium content were measured in the several laboratories of Europe (Austria, Poland, Slovak etc.).

29.2.2.1 Hydrochemistry

Results were analyzed by AquaChem computer program. All water types were analyzed separately. Mineral water from boreholes N54, N41, N1, N25 in Borjomi belong to sodium-carbonate type with high total dissolved solids (T.D.S.) (Figs. 29.3 and 29.4).

Springs by composition are richer in magnesium that also points to the groundwater flow in contact with lava bodies along a way of water movement from lava breeds.

In conclusion we can summarize that there are three groups of water by chemical composition: first group of mineral water, second group of fresh water from the rivers and the last one from the springs, which is genetically connected with the second groups.

29.2.2.2 Isotopes

The 82H - 818O relationship (Fig. 29.5) reveals several distinct features of the sampled waters (Table 29.1). All collected river samples (Borjomula river and its three branches, Bakurianischali river) form a tight cluster of points located above the GMWL.

Fig. 29.3 Summary plot of chemical composition for all mineral water (a) and rivers (b)
Fig. 29.4 Groups of springs (a) and all water groups (b)
Fig. 29.5 All data: S18O [%<,] & SD [%<,] vs SMOW

River and spring samples reveal generally high, although quite variable tritium concentrations. Average tritium content in river samples is equal 14.3 ± 0.9 TU. For springs (Daba 0, 1 and 3; Sadgeri spring) the average tritium content is significantly smaller (9.9 ± 0.5 TU) (Fig. 29.6). The deep boreholes most probably do not contain any tritium although, again, the reported data scatter considerably.

Somewhat lower tritium value in springs when compared to rivers, combined with slightly lower 818O and 82H values, might indicate the presence of additional

Table 29.1 Isotopic composition of water measured in 16 sampling sites of the study area

No.

Sampling site

ô18O*(%o)

ô2H*(%o)

D-excess**(%o)

Tritium**(TU)

1

Borjomi park

-13.30 ± 0.05

-98.5 ± 1.1

7.9 ± 0.5

<1

2

Daba 0 spring

-11.52 ± 0.03

-79.8 ± 1.1

12.4 ± 0.5

8.7 ± 1.2

3

Daba 1 spring

-11.56 ± 0.09

-80.5 ± 1.5

12.0 ± 0.5

10.5 ± 1.9

4

Daba 3 spring

-11.48 ± 0.09

-80.5 ± 1.6

11.3 ± 0.6

11.1 ± 2.2

5

Bakuriani Didi

-13.54 ± 0.13

-92.5 ± 1.2

15.8 ± 0.5

<1

Veli borehole

6

Bakurianischali

-11.58 ± 0.22

-78.1 ± 1.7

14.5 ± 0.5

13.1 ± 1.9

river

7

Borjomula river

-11.20 ± 0.20

-77.6 ± 1.4

12.0 ± 0.7

13.6 ± 3.0***

Branch 1

8

Borjomula river

-11.39 ± 0.32

-77.5 ± 1.5

13.6 ± 0.8

12.4 ± 1.9

Branch 2

9

Borjomula river

-11.33 ± 0.29

-77.5 ± 2.1

13.4 ± 0.6

16.6 ± 1.1

Branch 3

10

Borjomula river-

-11.39 ± 0.23

-78.1 ± 1.7

13.0 ± 1.1

15.2 ± 1.4

Bakuriani andesiti

11

Tba borehole

-11.54 ± 0.35

-81.2 ± 1.4

11.2 ± 0.7

9.2 ± 0.9

12

Spring near

-11.38 ± 0.18

-79.6 ± 1.4

11.4 ± 0.2

13.2 ± 3.3***

borehole 67

13

Borjomi 25e borehole

-12.62 ± 0.09

-99.8 ± 0.8

1.2 ± 0.4

<1

14

Borjomi 41e borehole

-13.20 ± 0.11

-99.4 ± 0.8

6.1 ± 0.9

<1

15

Likani 54 borehole

-14.05 ± 0.06

-103.9 ± 1.1

8.5 ± 0.5

<1

16

Sadgeri spring

-11.71 ± 0.15

-80.9 ± 2.1

12.8 ± 0.7

9.3 ± 0.9

* Reported uncertainty of single measurement.

** Reported uncertainty of the mean.

*** Doubtful result (unacceptable scatter of the data).

* Reported uncertainty of single measurement.

** Reported uncertainty of the mean.

*** Doubtful result (unacceptable scatter of the data).

water component, recharged at higher elevation and with longer mean transit time of water to the springs.

0 0

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