Table 1 Raw groundwater sampling locations and chemical composition

Coordinates of well

56 °05′ 49.0″ N

12°23′55.6"E

55° 44′ 29.4″N

12° 33′ 04.8″ E

55° 36′ 35.7″ N

8° 56′ 27.1″ E

55° 38′ 09.9″ N

8° 29′ 45.3″ E

55° 36′ 50.7″ N

8° 47′ 08.7″ E

pH

7.8

7.0

5.9

5.8

4.7

Temp (°C)

9.5

11

8.3

8.5

8.1

Conductivity ( mS/m)

46

141

12

27

27

Evaporation residue

300

913

87

160

170

Oxygen

 < 0.2

0.2

0.7

0.5

3.0

Carbon dioxide

 < 2

 < 5

30

35

50

Organic carbon

2.2

2.9

0.2

0.5

0.7

Ammonia + ammonium

0.62

0.01

0.08

0.04

0.01

Calcium

64

173

11

19

12

Iron

1.2

 < 0.01

2.2

0.58

1.3

Magnesium

10

22

1.5

5.8

7.9

Manganese

0.16

0.52

0.10

0.08

0.07

Phosphorus

0.14

0.05

0.06

0.01

0.02

Potassium

2.6

26

0.92

2

1.8

Sodium

23

82

9.3

22

19

Bicarbonate

250

452

41.2

16.1

4.3

Chloride

22

190

15

34

34

Fluoride

0.32

0.27

0.35

0.12

0.75

Nitrate

 < 0.3

3.35

 < 0.5

17

32

Nitrite

0.011

0.046

 < 0.005

0.011

0.011

Sulfate

12

54

6.9

45

35