Isotopic and Geochemical

Characteristics of Groundwater

in Islamabadin Islamabad

By

Sajjad Munir

Introduction

�Groundwater contamination is reported in;

� Mexico, Chile, Argentina, Mangolia, Ghana, Taiwan, Canada, China, America, India, Nepal, Bangladesh, Botswana, Nigeria.Bangladesh, Botswana, Nigeria.

� Isotopic and geochemical techniques are employed greatly to study surface and groundwater contaminant transport.

Water Quality in Pakistan� Deteriorating water quality is reported in;

� Major industrial cities including;

� Sialkot, Gujrat, Faisalabad, Karachi, Qasur, Peshawar, Lahore, Rawalpindi and Sheikhupura.

� Reasons;� Reasons;

� Unchecked disposal of untreated municipal and industrial wastewater,

� Excessive use of fertilizers and insecticides.

� Effects;

� Serious water borne diseases;

� Severe illness, hepatitis, gastro-intestinal problems, chronic diarrhea, abnormalities, skin problems etc.

Problem to be addressed

�Lei Nala provides main drainage for industrial and domestic wastewater.

�Many tube wells have been installed alongside the stream bank (within a reach of 15-50 the stream bank (within a reach of 15-50 meters) are;� Most susceptible to infiltration of polluted water

through Lei Conglomerate into shallow groundwater reservoir.

� K-values ranges between 1.2 x 10-4 to 9.8 x 10-4

cm/sec.

� Groundwater recharge –5.4 liters/cm.km2.

Objectives

�Study of contaminant transport in potable groundwater systems in Islamabad city using;

� Environmental stable and radio-isotope trace � Environmental stable and radio-isotope trace techniques,

� Conventional (hydro-geochemical and physiochemical) techniques.

�To help management of potable groundwater.

The Study Area� Islamabad – National capital

� Latitude – 33º 29’ and 33º 49’ N

� Longitude – 72º 50’ and 72º 24’ E

N

Hydrogeology� Area lies in Soan River catchment basin

� Formed as part of Indo-Gangetic synclinorium of Tertiary and Pre-Tertiary sediments.

� Sedimentary deposits belong to Eocene to Recent in age.in age.

� Consolidated deposits are;

� Limestone, sandstone, clay, shale and conglomerates,

� Do not serve as aquifer.

� Unconsolidated deposits are found as;

� Terrace gravel and alluvial fill.

� Serving as groundwater aquifers.

General Geology�Area exhibits intensive tectonic activities;

� Folding and faulting forms current landform.

�Precambrian to Tertiary consolidated sedimentary rocks are exposed in the areasedimentary rocks are exposed in the area

�These are covered by Miocene to Pleistocene deposits composed of;

� Limestone, sandstone, shale with clay.

�Recent age unconsolidated deposits are clay, silt and medium to fine sand.

Generalized composite stratigraphic section of consolidated rocks in the consolidated rocks in the Islamabad- Rawalpindi area.

Field Sampling�Samples collected are as under;

� 4 surface water samples from Lei Nala,

� 10 shallow groundwater samples not deeper than 60 meters,than 60 meters,

� 12 deep groundwater samples from tube wells installed at depths greater than 100 meters.

S.#. Sample Code Type LocationCoordinates

Elevation (m)Latitude Longitude

1 IBD-01 Nala I-9 33°39'58.06"N 73°3'14.755"E 507

2 IBD-02 Nala H-9/2 33°40'17.6" N 73°02'40.6" E 511

3 IBD-03 Tube well H-9/2 near Christian Graveyard 33°40'19.9" N 73°02'41.7" E 512

4 IBD-04 Nala G-9 33°40'39.7" N 73°02'08.7" E 526

5 IBD-05 Tube well H-8/1, infront of Polytechnic Istiture for Women 33°40'32.5" N 73°03'16.6" E 520

6 IBD-06 Tube well I-8 33°39'38.6" N 73°03'57.5" E 512

7 IBD-07 Nala I-8 33°40'15.4" N 73°03'39.9" E 509

8 IBD-08 Tube well I-8/2 33°40'17.4" N 73°03'51.1" E 513

9 IBD-09 Boring G-9/4, Al-Furqan Mosque 33°40'56.7" N 73°02'22" E 531

10 IBD-10 Boring G-9/4 , Block 78, I & T Centre, Abdullah Catering 33°40'57.3" N 73°02'20.7" E 530

11 IBD-11 Boring G-9/1 33°41'00.7" N 73°01'53.2" E 535

12 IBD-12 Boring Fatima Jinnah Park, F-9 33°42'58.0" N 73°01'44.1" E 557

13 IBD-13 Boring Bahria University, Shangrilla Road, Naval Complex E-8 33°42'58.0" N 73°01'44.1" E 563

14 IBD-14 Boring Madni Mosque, Infront of Khaldunia High School F-8/2 33°42'50.9" N 73°02'03.3" E 567

15 IBD-15 Tube well G-9/2, near Haydri Market 33°41'20.2" N 73°01'37.1" E 541

16 IBD-16 Boring G-7/2-4 33°42'10.5" N 73°03'59.8" E 544

17 IBD-17 Boring Alipur, infront of Mosque 33°38'40.9" N 73°10'47.6" E 529

18 IBD-18 Boring Village Majuhan, Chak Shehzad 33°40'19.09" N 73°09'56.34" E 502

19 IBD-19 Tube well G-10/4 33°40'29.614" N 73°01'34.271" E 525

20 IBD-20 Tube well G-10/3 33°41'4.727" N 73°0'46.465" E 540

21 IBD-21 Tube well G-10/2 33°40'29.17" N 73°00'32.19" E 545

22 IBD-22 Tube well I-10/2 33°38'51.434" N 73°02'21.123" E 514

23 IBD-23 Tube well I-10/4 33°38'53.737" N 73°02'53.794" E 499

24 IBD-24 Tube well F-10/1 33°41'03.1" N 72°59'57.4" E 549

25 IBD-25 Boring H-10/1 33°39'21.4" N 73°00'49.2" E 541

26 IBD-26 Tube well G-9/4 33°40'47" N 73°02'18.6" E 528

Sample Preservation

Sampling Type Type of Bottle Method Used Preservation

δ13C 250 ml plastic bottles Filled with beakerAdd few grains of

Mercuric ChlorideMercuric Chloride

δ�3H 1L Plastic Bottles Completely filled No Preservation

Trace Metals 500 ml plastic bottles Filled with beakerAdd HNO3 to lower

pH to 2.

Major Ions 500 ml plastic bottles Filled with beaker No preservation

Physiochemical Analysis

� Electrical Conductivity and Total Dissolved Solids are measured with;

� Portable conductivity meter (Model HI 8633, M/S HANNA Instruments).

pH and temperature are measured with;� pH and temperature are measured with;

� Portable pH meter ( Model PS-19, M/S Corning, Canada).

� Dissolved Oxygen was measure with;

� Portable DO meter ( Model Sension 6, M/S HACH)

Isotopic Analysis� δ13C is analysed using isotope ratio mass spectrometer

after CO2

extraction using vacuum system.

Vacuum lines for extraction of CO

2

from inorganic matter

Isotopic Analysis� Tritium Isotope was analysed using a

scintillation counter after tritium enrichment is being done.

Liquid Scintillation counter for counting tritium units in water samples

Metal Analysis�Major cations namely Sodium, Potassium,

Calcium and Magnesium were analysed by ICP-OES.

�Major Anions were analysed by;�Major Anions were analysed by;

� Nitrates by HPLC,

� Sulphates by Spectrophotmeter,

� Carbonate, Bicarbonate and Chloride were anlysed by titration method.

Metal Analysis�Toxic metals were

analysed by;� Chromium and Total

Iron by SpectrophotometerSpectrophotometer

� Zinc, Cadmium, Lead, Copper, Nickel, Cobalt and Arsenic were analysed by 797 VA Computrace Polarograph.

Groundwater CharacterizationParameter

WHO Standard Values (1993)

Pak-EPA Standard Values(2008)

EU Standard Values (1998)

TDS <1000 mg/L <1000 mg/L Not mentioned

pH 6.5-8.5 6.5-8.5 6.5-8.5

Conductivity Not mentioned Not mentioned 2500 μS/cm

Cadmium 0.003 mg/L 0.003 mg/L 0.005 mg/L

Chloride 250 mg/L 250 mg/L 250 mg/L

Copper 2 mg/L 2 mg/L 2 mg/LCopper 2 mg/L 2 mg/L 2 mg/L

Lead 0.01 mg/L 0.01 mg/L 0.01 mg/L

Nickel 0.02 mg/L 0.02 mg/L 0.02 mg/L

Arsenic ≤0.05 mg/L ≤0.01 mg/L 0.01 mg/L

Chromium ≤0.05 mg/L 0.05 mg/L 0.05 mg/L

Nitrate 50 mg/L 50 mg/L 50 mg/L

Zinc 3.0 mg/L 3.0 mg/L Not mentioned

Sodium 200 mg/L Not mentioned 200 mg/L

Sulphate 500 mg/L Not mentioned 250 mg/L

Hardness No guideline <500 mg/L 150-500 mg/L

Chemical Analysis�Major cations and anions are analysed

namely;

� Sodium, Potassium, Calcium, Magnesium, Nitrate, Sulphate, Chloride, Carbonate and Bicarbonate.Bicarbonate.

�Trace metals analysed are;

� Zinc, Cadmium, Lead, Copper, Nickel, Cobalt, Arsenic, Chromium, Total Iron.

Nitrates

100.00

150.00

200.00

250.00

Nit

rate

co

ncen

trati

on

(p

pm

)

No

t A

naly

sed

� Permissible limit ≤ 50 ppm

� Anthropogenic source

0.00

50.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Nit

rate

co

ncen

trati

on

(p

pm

)

No

t A

naly

sed

Sulphates

60.00

80.00

100.00

120.00

140.00

160.00

180.00

Su

lph

ate

Co

ncen

trati

on

(p

pm

)

� Permissible limit –500 ppm

0.00

20.00

40.00

60.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Su

lph

ate

Co

ncen

trati

on

(p

pm

)

Carbonates and Bicarbonates

150.0

200.0

250.0

300.0

350.0

400.0

450.0

500.0

Bic

arb

on

ate

Co

ncen

trati

o (

pp

m)

� Carbonates are absent

� Margalla Hill Limestone is contributing to Bicarbonates.

0.0

50.0

100.0

150.0

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Bic

arb

on

ate

Co

ncen

trati

o (

pp

m)

Chlorides

40.00

50.00

60.00

70.00

80.00

90.00

100.00

Ch

lori

de

Co

nc

en

tra

tio

n (

pp

m)

� Permissible limit – <250 ppm

0.00

10.00

20.00

30.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Ch

lori

de

Co

nc

en

tra

tio

n (

pp

m)

Sodium

60

80

100

120

140

160S

od

ium

Co

ncen

trati

on

(p

pm

)

No

t A

naly

sed

� Permissible limit –200 ppm

0

20

40

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

So

diu

m C

on

cen

trati

on

(p

pm

)

No

t A

naly

sed

Potassium

30

40

50

60

70

80

Po

tassiu

m C

on

cen

trati

on

(p

pm

)

No

t A

naly

sed

� Permissible limit – 200 ppm

0

10

20

30

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Po

tassiu

m C

on

cen

trati

on

(p

pm

)

No

t A

naly

sed

Calcium

60

80

100

120

140

160

Co

ncen

trati

on

of

Calc

ium

(p

pm

)

No

t A

naly

sed

� Permissible limit –200 ppm

� Margalla Hill Limestone is the main source of calcium in water

0

20

40

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Co

ncen

trati

on

of

Calc

ium

(p

pm

)

No

t A

naly

sed

Magnesium

30

40

50

60

70

80

Mag

nesiu

m C

on

cen

trati

on

(p

pm

)

No

t A

naly

sed

� Permissible limit –150 ppm

� Increasing trend is evident in shallow groundwater

0

10

20

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Mag

nesiu

m C

on

cen

trati

on

(p

pm

)

No

t A

naly

sed

Groundwater Facies Characterization

Groundwater Facies Characterization

Subdivision of diamond

Characteristics of Corresponding subdivisions of diamond-shaped fields

Percentage of samples in this

category

1 Alkaline earth (Ca+Mg) Exceed alkalies (Na+K) 53.86

2 Alaklies exceeds alkaline earths 46.15

3 Weak acids (C03+HCO

3) exceed Strong acids (SO

4+Cl) 96.15

4 Strong acids exceeds weak acids 3.84

5 Magnesium bicarbonate type 0

6 Calcium-chloride type 0

7 Sodium-chloride type 0

8 Calcium-Bicarbonate type 96.15

9 Mixed type (No cation-anion exceed 50%) 3.85

Groundwater Facies Characterization

100

80

60

Calc

iu

40

20

0

esiu

m %

Legend

Lei Nala

Deep Groundwater

Shallow Groundwater

0 20 40 60 80 100

Sodium %

40

20

0

ciu

m %

100

80

60

Magnes

Groundwater Facies Characterization

100

80

60SO

4 -2

40

20

0

ori

de %

Legend

Lei Nala

Deep Groundwater

Shallow Groundwater

0 20 40 60 80 100

HCO3 %

40

20

0

O4 -2

%

100

80

60

Chlo

ri

Legend

A= Calcium Type

B= No Dominant Type

C= Magnesium Type

D= Sodium and Potassium

Type

E= Bicarbonate Type

F= Sulphate Type

G= Chloride Type

Zinc

2.00

3.00

4.00

5.00

6.00

Zin

c C

on

cen

trati

on

(p

pm

)

� Permissible limit – 3 ppm

� Low quality pipes –anthropogenic source

0.00

1.00

2.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Zin

c C

on

cen

trati

on

(p

pm

)

Cadmium

0.30

0.40

0.50

0.60

0.70

0.80

Cad

miu

m C

on

cen

trati

on

(p

pb

)

� Permissible limit – 0.003 ppm

� More frequent in deeper horizons

0.00

0.10

0.20

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Cad

miu

m C

on

cen

trati

on

(p

pb

)

Lead

10.00

15.00

20.00

25.00

30.00

35.00

40.00

Lead

Co

ncen

trati

on

(p

pb

)

� Permissible limit – 0.01 ppm

� Corrosion from pipes and atmospheric pour down of lead through rain.

0.00

5.00

10.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Lead

Co

ncen

trati

on

(p

pb

)

Copper

200.00

250.00

300.00

350.00

400.00

450.00

500.00

Co

pp

er

Co

ncen

trati

on

(p

pb

)

� Permissible limit –2 ppm

� Associated with distribution systems

0.00

50.00

100.00

150.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Co

pp

er

Co

ncen

trati

on

(p

pb

)

Nickel

0.15

0.20

0.25

0.30

0.35

0.40

0.45

Nic

kel

Co

ncen

trati

on

(p

pm

)

� Permissible limit – 0.02 ppm

0.00

0.05

0.10

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Nic

kel

Co

ncen

trati

on

(p

pm

)

Cobalt

20

30

40

50

60

70

80

Co

balt

Co

ncen

trati

on

(p

pb

)

� Permissible limit – 0.05 ppm

� Much frequent in shallow groundwater

0

10

20

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Co

balt

Co

ncen

trati

on

(p

pb

)

Arsenic

0.06

0.08

0.10

0.12

0.14

0.16

Ars

en

ic C

on

cen

trati

on

(p

pm

)

� Permissible limit – 0.01ppm

� Local source of contamination

0.00

0.02

0.04

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Ars

en

ic C

on

cen

trati

on

(p

pm

)

Chromium

3

4

5

6

7

8

Ch

rom

ium

Co

ncen

trati

on

(p

pb

)

� Permissible limit – ≤ 0.05 ppm

0

1

2

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

Ch

rom

ium

Co

ncen

trati

on

(p

pb

)

Total Iron

8.00

10.00

12.00

14.00

16.00

18.00

20.00

To

tal

Iro

n C

on

cen

trati

on

(p

pm

)

� No guidelines

� No evidence of industrial source of contamination

0.00

2.00

4.00

6.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-25

IBD-16

IBD-17

IBD-18

IBD-09

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-20

IBD-21

IBD-22

IBD-23

IBD-24

IBD-26

Sample Code

To

tal

Iro

n C

on

cen

trati

on

(p

pm

)

Metals Correlation Coefficients

Metals Correlation Coefficients

�Strong Correlation exists between;

� Zn and Cd,

� Cd and Co, K, As,

� Ni and Co,� Ni and Co,

� Co and As,

� Na and K and Mg,

� K and Mg.

�Suggests that these metals have same source of origin.

Metals Correlation Coefficients

�Weak Correlation exists between;

� Zn and As and Cr,

� Cd and Cu, Mg and Cr,

� Cu and Na, K, As and Cr,� Cu and Na, K, As and Cr,

� K and As,

� Mg and As and Cr.

�Suggests that these metals have different source of origin.

Carbon-13 (13δC)

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

IBD-01

IBD-02

IBD-04

IBD-07

IBD-16

IBD-17

IBD-18

IBD-10

IBD-11

IBD-12

IBD-13

IBD-14

IBD-03

IBD-05

IBD-06

IBD-08

IBD-15

IBD-19

IBD-21

IBD-22

IBD-23

C v

alu

e(‰

)

� Bicarbonate is the main source of dissolved inorganic carbon (DIC).

� No evidence of mixing of domestic wastewater.

-10.00

-9.00

-8.00

-7.00

-6.00

Sample Code

13 C

valu

e(‰

)

Tritium (13δH)

4

6

8

10

12

Tri

tiu

m U

nit

s (

TU

)

� IBD-13, IBD-15, IBD-20 show mixing of meteoric/ sewage water

� Depleted contents show older waters.

0

2

4

IBD-07

IBD-16

IBD-17

IBD-09

IBD-13

IBD-14

IBD-03

IBD-06

IBD-15

IBD-20

IBD-22

IBD-23

Sample Code

Tri

tiu

m U

nit

s (

TU

)

Conclusion� Physiochemical parameters are well within the

permissible limits defined by WHO.

� Nitrate concentration is higher in shallow groundwater than the deep groundwater thus showing input from external sources.showing input from external sources.

� Ca-Mg-HCO3 type of water is dominant.

� Margalla Hill Limestone is contributing to Ca-Mg-HCO3 dominance in the area.

� No significant change in hydrochemical facies indicates natural source of origin for most of ions.

Conclusion� δ13CTDIC indicates no domestic input from surface.

� Tritium content shows mixing of surface/rain water in some of the shallow and deep groundwater wells namely;

� IBD-15, IBD-20 and IBD-13.

Recommendations

� The wells should be installed at greater distances from the Lei Nala embankment.

� The depth of tubewells should be increased to avoid infiltration from the surface.avoid infiltration from the surface.

� Peak load of Lei Nala should be monitored and tube wells should not be operated during peak load times of Lei Nala.

� Filtration plants must be installed on the tubewells along the Lei embankment.