Elango et al. Int. J. Res. Chem. Environ. Vol.3 Issue 2 April 2013(163-171)

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International Journal of Research in Chemistry and Environment Vol. 3 Issue 2 April 2013(163-171)

ISSN 2248-9649

Research Paper

Causes for Variation in Bromide Concentration in Groundwater of a Granitic

aquifer

Brindha K. and *Elango L. Department of Geology, Anna University, Chennai - 600 025, Tamil Nadu, INDIA

Available online at: www.ijrce.org

(Received 12th

February 2013, Accepted 20th

March 2013)

Abstract: Groundwater quality is an important criterion to decide its use for domestic, agricultural and

industrial use. This study was carried out with an aim to understand the spatiotemporal variation and

sources of bromide in groundwater of a granitic formation in a part of Nalgonda district, Andhra

Pradesh, India. Groundwater samples were collected from 46 wells every two months from March 2008

to January 2010. The bromide concentration in groundwater varied from below detection limit to 5.48

mg/l with an average of 0.4 mg/l. Based on the acceptable daily intake of 6 mg/l of bromide by humans as

given by World Health Organisation, the groundwater is safe for consumption. But based on the toxicity

data from literature and the groundwater quality criterion of 1 mg/l, 8.27% of the groundwater samples

were above the limit. Average bromide concentration of 3.07 mg/kg was measured in the five fertiliser

samples collected from this area. The sources of bromide in this region vary from the granitic rocks to

fertilisers.

Keywords: Drinking water, agricultural area, fertiliser composition, acceptable daily intake, domestic use,

Nalgonda, India.

Introduction Several chemical ions are present in trace

quantities in groundwater naturally. The health

concerns due to high arsenic and fluoride are known

historically and there are many studies on groundwater

quality with special reference to arsenic and fluoride[1-

12]. But bromide is not given high importance and

studied worldwide. It is mainly present in seawater,

salt lakes, and underground brines associated with

oil[13]

. Seawater contains bromide ranging from 65

mg/l to above 80 mg/l[14]

. So the presence of bromide

in groundwater has been studied to understand

seawater intrusion and not much explored for other

causes. Bromide is a liquid at room temperature and it

also exists as bromide gas. Bromide reaches human

beings either through inhalation of bromine gas or as

bromide in food and water. It may be in drinking water

due to brominated disinfection by-products formed

during chlorination and ozonation. Bromide contents

in public drinking water supplies in Sicily, Italy was

reported to range from <0.025 to 4.76 mg/l[15]

with 3%

exceeding the groundwater quality criterion of 1

mg/l[16]

. Bromide in groundwater was studied in

Canterbury region, New Zealand[17]

, but could not

identify the source for bromide. Bromide values upto

11 mg/l was observed in groundwater in Rajasthan,

India[18]

. High bromine contents in vegetables in Japan

have also been reported[19]

.

However, there are no scientific studies on

occurrence of bromide in groundwater, especially on

its temporal and spatial variation in any region of the

world. This is evident by the absence of any scientific

publication on the natural bromide concentration in

groundwater. Though bromide has a low degree of

toxicity and hence it is not of toxicological concern[20]

,

it is important to monitor the groundwater quality

regularly with respect to bromide in areas where

groundwater is used for drinking and domestic

purposes without primary treatment. Considering this,

a study was carried out by the collection of

groundwater samples once every two months to

understand the bromide concentration in groundwater

and to identify its sources in a part of Nalgonda

district, Andhra Pradesh, India. The result of this study

for the period from March 2008 to January 2009 was

reported earlier[21]

. This study was continued by the

groundwater sampling and analysis once every two

Elango et al. Int. J. Res. Chem. Environ. Vol.3 Issue 2 April 2013(163-171)

164

months until January 2010. Thus the objective of this

paper is to understand the spatiotemporal variation in

bromide concentration in groundwater over two years

and to identify the causes for the presence of bromide

in groundwater.

Study area: The study area (724 sq km) is a part of

Nalgonda district, Andhra Pradesh, India, located

approximately 85 km ESE from Hyderabad, the capital

of Andhra Pradesh state, India (Figure 1). The northern

boundary is partly bounded by Gudipalli Vagu river

and the southern boundary is bounded by Pedda Vagu

river. The Nagarjuna Sagar reservoir is in the

southeastern boundary of the study area. The climate is

arid to semi-arid. In summer i.e. from April to June the

temperature ranges from 30oC

to 46.5

oC and in winter

i.e. from November to January, the temperature ranges

from 17oC to 38

oC. The average annual rainfall in this

area is about 600 mm which is mostly due to the

southwest monsoon occurring during June to

September. The ground surface slopes towards the

southeast direction. The rainfall, topography and

nature of formation have lead to dentritic to

subdentritic drainage pattern in this area. Numerous

tanks and few small reservoirs are present in the

depressed parts of the undulating topography of this

area. Few lined canal networks also cater for irrigation

activity. There are several small hillocks in this area

with height ranging from 250 m to 300 m.

This area lies in the northern part of the

Cuddapah basin. Geologically this region is largely

comprised of granitic rocks which belong to late

Archean (Figure 2). These rocks are generally medium

to coarse grained. They are traversed by numerous

dolerite dykes and quartz veins[22]

. Dolerite dykes

cutting across the granites are found practically all

over the area and are well exposed in most parts of the

area. The Srisailam formation which is the youngest

member of the Cuddapah supergroup, directly overlay

the basement granite with a distinct unconformity. The

quartzite of Srisailam formation is exposed in the

southeastern part of the study area. Hydrogeologically,

the study area consists of four distinct layers- the top

soil, highly weathered rocks, moderately weathered

rocks and massive rock. There are numerous wells in

this area which meet the domestic and agricultural

needs. Dug wells of this area have a depth ranging

from 1.45m to 20m and have diameters of 2m to 5 m.

Bore wells have depths greater than 10m and

diameters of 15 cm. Rainfall is the major source of

groundwater recharge, apart from irrigation returns.

The forest cover is thin to moderate. Most of the study

area comprises of agricultural land (Figure 3). Rice is

the principle crop grown in this area while other crops

include sweet lime, castor, cotton, grams and

groundnut. The cropping pattern is practised

depending on the climatic conditions and availability

of water sources.

Material and Methods Nearly 240 dug wells and bore wells were

investigated during an initial field survey and 42 dug

wells and 4 bore wells were chosen (Figure 4) for

regular monitoring of groundwater quality with respect

to bromide based on the electrical conductivity (EC).

A representative well in about every 15 km2 was

chosen. The groundwater samples were collected once

every two months from March 2008 to January 2010

leading to twelve sets of groundwater sampling and

analysis. The groundwater samples were collected

based on standard procedures in 500 ml capacity

bottles. Before using the sampling bottles, they were

soaked in 1:1 diluted nitric acid solution for 24 hours,

washed with distilled water and were washed again

prior to each sampling with the water to be sampled. In

the case of bore wells, the water samples were

collected after pumping the water for sufficient time so

as to collect the formation water. In case of dug wells

care was taken to collect the samples 30 cm below the

water table using a depth sampler. Groundwater level

was recorded during each groundwater sampling by

using a Solinst 101 water level indicator. Bromide

concentration in the groundwater samples were

analysed using an ion chromatograph (Metrohm 861)

along with appropriate standards after the samples

were filtered using 0.45µm Millipore filter paper. The

detection limit of the instrument is < 2ppb for anions.

Results and Discussion The minimum, maximum and median values

of bromide concentration in groundwater (mg/l) during

each sampling period is given in Figure 5. Overall, the

concentration of bromide in groundwater varied from

below detection limit (BDL) to 5.48 mg/l with an

average of 0.4 mg/l. The Indian standard specification

for drinking water[23]

does not specify any threshold

limit for bromide content in drinking water. From

previous studies[16]

, a groundwater quality criterion of

1 mg/l was established from literature which is used as

the maximum permissible limit. Based on this 41

groundwater samples of the total 496 had bromide

concentration above 1 mg/l. The percentage of

groundwater samples exceeding this limit had

increased from 5.51% (N=251) as reported in the

previous study[21]

to 8.27% (N=496).

Considering this and based on the monitoring

of bromide concentration in groundwater over a period

of two years of sampling, the areas having bromide

concentration below and above 1 mg/l is identified.

Overlay analysis was carried out using Arc GIS 9.3 by

assigning ranks and weightages using inverse distance

weighted method. Areas having groundwater with

bromide concentration below 1 mg/l was given a rank

of 1 and groundwater with bromide concentration

above 1 mg/l was given a rank of 2. A weightage of

0.083 was assigned to each month as groundwater has

to be within the limit of groundwater criterion during

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the entire study period. The composite suitability index

(CSI) was calculated by multiplying the ranks and

weightages for each month and then by summing them

for twelve months. A CSI of 1 is considered suitable

and above 1 is considered unsuitable based on the

bromide concentration in groundwater. The

groundwater quality map for this area based on the

toxicity data and criterion[16]

is given in Figure 6.

Though the groundwater quality criterion for

bromide is 1 mg/l, it is essential to estimate the intake

by humans through the drinking water pathway. The

acceptable daily intake (ADI) of bromide through

drinking water by humans considering a relative

source contribution of 50%, 60 kg of adult weight and

2 l of water consumed per day was 6 mg/l[20]

. Based on

this, none of the groundwater samples were above the

ADI of 6 mg/l.

The spatial variation in bromide concentration

in groundwater during July 2008 and 2009 is shown in

Figure 7 which does not show any similarity. Bromide

is often used as a tracer in groundwater studies as its

background concentration is very low. The bromine

concentration in granite rocks was reported to be 0.3

mg/kg[24]

. As the granitic rocks are present in most part

of the study area (Figure 2), the rock water interaction

can be a source for bromide concentration in

groundwater. The average concentration of bromide in

seawater is 65 mg/l to above 80 mg/l[14]

. So presence

of bromide in marine environment is a common

phenomenon. The Cuddapah basin present in the

southeastern part of this area has sediments that were

deposited in a shallow marine shelf and beach

environment[25]

. So this could be a reason for the

bromide content in groundwater of this area.

Apart from the natural source, fertilisers

applied to agricultural fields can also contribute to

bromide. For this, five fertilisers commonly used in

this area were collected and analysed for their bromide

content. The concentration of bromide in these

fertilisers varied from 1.48 mg/kg to 7.55 mg/kg with

an average of 3.07 mg/kg (Table 1). Hence the source

for the presence of varying concentration of bromide

in groundwater in this area is also due to the

application of fertilisers. The variation in the bromide

concentration in agricultural and domestic wells is

shown in Figure 8. More wells in the agricultural areas

have bromide above 1 mg/l. However a systematic

variation in bromide concentration in groundwater was

not observed spatially which may be due to varying

sources such as local contamination as well as

groundwater flow.

Conclusion The quality of groundwater based on bromide

was studied in a part of Nalgonda district, Andhra

Pradesh, India from March 2008 to January 2010 by

bi-monthly sampling and analysis. The concentration

of bromide varied from BDL to 5.48 mg/l. Spatial

variation in bromide concentration did not show any

systematic variation which may be due to varied

sources and local contamination. Of the 496

groundwater samples analysed, all were below the

ADI of 6 mg/l as proposed by WHO. The sources of

bromide in groundwater varied from natural to

anthropogenic sources. The granitic rocks present in

this area contain bromide which could have

contributed to bromide in groundwater. The bromide

content in fertilisers collected and analysed from this

area ranged between 1.48 mg/kg and 7.55 mg/kg.

Hence, application of fertilisers can also result in high

bromide in groundwater. This study helped to identify

the various sources for bromide in groundwater in this

area. Also this study will serve as a baseline data on

bromide concentration in groundwater for this area and

has highlighted the contribution of bromide from

fertilisers.

Acknowledgement The authors would like to acknowledge the

Board of Research in Nuclear Sciences, Department of

Atomic Energy, Government of India for funding this

work (Grant no. 2007/36/35). Authors also like to

thank the Department of Science and Technology’s

Funds for Improvement in Science and Technology

scheme (Grant No. SR/FST/ESI-106/2010) and

University Grants Commission’s Special Assistance

Programme (Grant No. UGC DRS II

F.550/10/DRS/2007 (SAP-1)) for their support in

creating laboratory facilities, which helped in carrying

out part of this work.

References 1. Saini, P., Khan, S., Baunthiyal, M. and Sharma, V.,

Mapping of fluoride endemic area and assessment of F

−1 accumulation in soil and vegetation. Environmental

Monitoring and Assessment, 185(2), 2001-2008 (2013)

2. Srikanth R., Gautam A., Jaiswal S. C. and Singh P., Urinary fluoride as a monitoring tool for assessing

successful intervention in the provision of safe drinking water supply in five fluoride-affected villages in Dhar

district, Madhya Pradesh, India. Environmental Monitoring and Assessment, 185(3), 2343-2350 (2013)

3. Rahaman S., Sinha A. C., Pati R. and Mukhopadhyay D.,

Arsenic contamination: a potential hazard to the affected areas of West Bengal, India. Environmental Geochemistry

and Health, 35(1), 119-132 (2013)

4. Simsek C., Assessment of naturally occurring arsenic contamination in the groundwater of Sarkisla Plain

(Sivas/Turkey). Environmental Earth Sciences, 68(3), 691-702 (2013)

5. Brindha K., Rajesh R., Murugan R. and Elango L.,

Fluoride contamination in groundwater in parts of Nalgonda district, Andhra Pradesh, India. Environmental Monitoring

and Assessment, 172, 481- 492 (2011)

Elango et al. Int. J. Res. Chem. Environ. Vol.3 Issue 2 April 2013(163-171)

166

6. Kim Y., Kim J. Y. and Kim K., Geochemical

characteristics of fluoride in groundwater of Gimcheon, Korea: Lithogenic and agricultural origins. Environmental

Earth Sciences, 63(5), 1139-1148 (2011)

7. Young S. M., Pitawala A. and Ishiga H., Factors controlling fluoride contents of groundwater in north-central

and northwestern Sri Lanka. Environmental Earth Sciences, 63(6), 1333-1342 (2011)

8. Brindha K., Rajesh R., Murugan R. and Elango L.,

Natural and anthropogenic influence on the fluoride and nitrate concentration of groundwater in parts of Nalgonda

district, Andhra Pradesh, India. Journal of Applied Geochemistry, 12(2), 231-241 (2010)

9. Reddy D. V., Nagabhushanam P., Sukhija B. S., Reddy A.

G. S. and Smedley P. L., Fluoride dynamics in the granitic aquifer of the Wailapally watershed, Nalgonda District,

India. Chemical Geology, 269(3-4), 278-289 (2010)

10. Shukla D. P., Dubey C. S., Singh N. P., Tajbakhsh M. and Chaudhry M., Sources and controls of Arsenic

contamination in groundwater of Rajnandgaon and Kanker District, Chattisgarh Central India. Journal of Hydrology,

395(1-2), 49-66 (2010)

11. Yidana S. M., Yakubo B. B. and Akabzaa T. M., Analysis of groundwater quality using multivariate and

spatial analyses in the Keta basin, Ghana. Journal of African Earth Sciences, 58, 220–234 (2010)

12. Francisca F. M. and Perez M. E. C., Assessment of natural arsenic in groundwater in Cordoba Province,

Argentina. Environmental Geochemistry and Health, 31(6), 673-682 (2009)

13. Lyday P. A., Bromine. U.S. Geological Survey Minerals

Yearbook-2003, 14, 1-14.10 (2003)

14. Al-Mutaz I. S., Water desalination in the Arabian Gulf region. (In M. F. A. Goosen and W. H. Shayya (Eds.), Water

management, purification and conservation in arid climates. Vol. 2. Water purification, Basel: Technomic Publishing,

245–265 (2000)

15. D’Alessandro W., Bellomo S., Parello F., Brusca L. and

Longo M., Survey on fluoride, bromide and chloride contents in public drinking water supplies in Sicily (Italy).

Environmental Monitoring and Assessment, 145, 303-313

(2008) 16. Flury M. and Papritz A., Bromide in the natural

environment: Occurrence and toxicity. Journal of Environmental Quality, 22(4), 747–758 (1993)

17. Bathurst E. T. J., Thomson L. J. and Wilkinson L. F.,

Bromide in Canterbury ground water. New Zealand Journal of Marine and Freshwater Research, 14(4), 409-411 (1980)

18. Singh R. V., Kumar V., Meenakshi and Gopal R.,

Studies on occurrence of bromide in ground water of Churu district in Rajasthan. Indian Journal of Environmental

Health, 37(3), 149-153 (1995)

19. Mino Y. and Yukita M., Detection of high levels of bromide in vegetables using X-ray fluorescence

spectrometry. Journal of Health Science, 51(3), 365-368 (2005)

20. WHO, Bromide in Drinking-water. Background

document for development of WHO Guidelines for Drinking-water Quality, WHO/HSE/WSH/09.01/6, (2009)

21. Brindha K. and Elango L., Study on bromide in

groundwater in parts of Nalgonda district, Andhra Pradesh. Earth Science India, 3(1), 73-80 (2010)

22. GSI, Geological Survey of India’s Geology and minerals map of Nalgonda district, Andhra Pradesh, India, (1995)

23. BIS, Bureau of Indian Standards specification for

drinking water [B], IS:10500:91. Revised 2003, Bureau of Indian Standards, New Delhi, India, (2003)

24. Bowen H. J. M., Environmental chemistry of the

elements. London: Academic Press, 333 (1979)

Rasheed M. A., Prasanna M. V., Kumar T. S., Patil D. J. and Dayal A. M., Geo-microbial prospecting method for

hydrocarbon exploration in Vengannapalli Village, Cuddapah Basin, India. Current Science, 95(3), 361-366

(2008)

Table 1

Concentration of bromide in fertilisers used in the study area

Fertiliser Bromide (mg/kg)

Zinc sulphate 7.55

Potash 2.66

Ammonium sulphate 1.68

Urea 1.98

NPK complex 1.48

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Figure 1: Location of the study area

Figure 2: Geology of the study area

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Figure 3: Landuse/ land cover in the study area

Figure 4: Location of the sampling wells in the study area

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Figure 5: Minimum, maximum and median levels of bromide concentration in groundwater (mg/l)

Figure 6 Groundwater quality map based on bromide

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Figure 7: Spatial variation in bromide concentration in groundwater (mg/l) during July 2008 and 2009

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Figure 8: Minimum, maximum and median of bromide concentration (mg/l) in groundwater of irrigation and

domestic wells