Journal of Environmental Protection, 2011, 2, 571-580
doi:10.4236/jep.2011.25066Published Online July 2011 (http://www.scirp.org/journal/jep)
Health Risk Assessment for Bromate (BrO3–)
Traces in Ozonated Indian Bottled Water
Ajay Kumar1*, Sabyasachi Rout1, Rakesh Kumar Singhal2
1Health Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India; 2Analytical Chemistry Division, Bhabha
Atomic Research Centre, Trombay, Mumbai, India.
Received May 19th, 2011; revised June 14th, accepted July 11th, 2011.
ABSTRACT
For this study, bromide and bromate ions in various commercial brands of Indian bottled wa ter samples were estima ted
using ion chro matography. The measured mean concentrati on of bro mid e and bromate i o ns in wat er sa mpl es w as f ou nd
to be 28.13 µg/L and 11.17 µg/L respectively. The average level of bromate in Indian bottled water was found to be
slightly higher (~ 12%) than the acceptable limits (10 µg/L) recommended by USEPA (US Environmental Protection
Agency). Though, kinetically, it is predicted that 62.5% (6.25 µg/L) of bromide in bottled water is needed to convert
into bromate upon ozonation to exceed the minimum acceptable limits, but the average formation of bromate deter-
mined to be only 26.77% of the predicted con centration. Bromate concentration in bottled water showed a strong cor-
relation with bromide su gg esting tha t its form a tion in wate r is very mu ch influen ced and con tro lled b y brom ide con tent.
The objective of the present study was to determine the BrO3– content in commercially available different brands of
bottled drinking water in India and to estimate the health risks to populatio n due to ingestion. Results of estimated ex-
cess cancer risk and chemical toxicity risk to Indian population due to ingestion of bottled water were presented and
discussed.
Keywords: Bromide, Bromate, Excess Cancer Risk, Chemical Toxicity Risk, Bottled Water
1. Introduction
1.1. Genesis
During the 1970’s, it was realized that the chlorination of
drinking water produced carcinogenic disinfection by
products (DBPs) such as trihalomethane. Since then, al-
ternative disinfection methods that minimize the produc-
tion of toxic by-products have been investigated. Ozona-
tion has emerged as one of the most promising alterna-
tives to chlorination [1]. Although ozonation is already
an established method of water purification in the water
industry, it suffers from a major problem which is attra-
cting increasing concern, namely the formation of bro-
mate ions due to oxidation of bromide ion.
1.2. Bromine
Bromine is an important precursor to bromate in drinking
water. Bromine has both natural and anthropogenic
sources. Natural sources include seawater, subsurface
brines and evaporite deposits. Anthropogenic sources for
bromine include pesticides, medicines and industrial sol-
vents, gasoline additives and water purification. Hydro
chemical characteristics of bromide compounds are low
concentration in most rock-forming minerals and gene-
rally low bioconcentrations in aqueous systems. Because
of these characteristics, it behaves as conservative spe-
cies and widely used as tracers in hydrological systems.
During the evaporite deposits, bromine shows some ad-
sorption characteristics particularly at low pH, on Kao-
linite and iron oxide surface.
The sources of bottled water in India are mainly sur-
face and subsurface water like river water, lake water and
ground water. The common technique for preparation of
bottled water is based on reverse osmosis, ultra filtration,
ozonisation, electrolytic methods etc. which are itself the
removal technique of bromide ion. In spite of applying
the removal processes, trace quantities of bromide are
found in the bottled water.
The bottled water is a highly regulated as a food pro-
duct by FDA (Food Development Authority) under the
Federal Food, Drug and Cosmetic Act (FFDCA), subject
to federal, state, and industry standards and includes in
smaller containers as well as larger containers distributed
to the home and markets.

Health Risk Assessment for Bromate (BrO–) Traces in Ozonated Indian Bottled Water 572 3
1.3. Bromate
Bromate is not normally found in water. Conversion of
bromide to bromate upon ozonation may be affected by
physico-chemical parameters including natural organic
matter, pH, temperature and some other factors. The rel-
ative increase of bromate depends on measures used for
comparison (over time or as a function of concentration
of bromide (C) × retention time with the amount of
ozone (T)). The use of CT has been suggested as a more
useful indicator to describe the relative rate of bromate
formation because it also gives a simultaneous descriptor
for disinfection efficiency [2]. The rate of formation of
bromate ion may also increase with temperature [3,4]. In
addition, many studies on the effect of alkalinity on the
formation of bromate during ozonation indicate that in-
creased alkalinity increases bromate formation [5]. How-
ever, the rate of formation of bromate during ozonation is
also affected by ozone characteristics. Thus, a smaller
CT may result because ozone becomes less stable with
increasing temperature and/or alkalinity. All factors be-
ing equal, bromide concentration and ozone dose are the
best predictors of bromate formation during ozonation
[6]. It should be noted that some of the studies demon-
strating high rates of conversion of bromide to bromate
are pure laboratory studies with very high bromide levels
and thus may not be representative of conversion rates at
environmentally relevant doses.
In the ozonised bottled water, naturally occurring
bromide causes a catalytic disintegration of ozone and
forms hypobromite (OBr–) as an intermediate product
which is predominantly present at higher pH values, but
at lower pH, more hypobromous acid (HOBr) is formed.
Hypobromite reacts further with an excess of ozone to
form bromate. Hypobromous acid does not react further
with ozone; therefore, at low pH, no bromate is formed.
In the presence of organic matter, HOBr leads to the
formation of brominated organic compounds, such as
bromoform, mono- and dibromoacetic acid, dibromoace-
tonitrile, bromopicrin and especially cyanogen bromide.
Under certain conditions, bromate may also be formed in
concentrated hypochlorite solutions used to disinfect
drinking-water [6]. This reaction is due to the presence of
bromide in the raw materials (chlorine and sodium hy-
droxide) used in the manufacture of sodium hypoch- lo-
rite and to the high pH of the concentrated solution.
Bromide is not oxidized by chlorine dioxide, so the use
of chlorine dioxide will not generate hypobromous acid,
hypobromite ion or bromate [7]. Although bromate can
be formed on simultaneous exposure to chlorine dioxide
and light, the reaction is thermodynamically unfavour-
able and bromate is unlikely to be formed under water
treatment conditions [8,9]. Bromate can also be formed
in electrolytically generated hypochlorous acid solutions
when bromide is present in the brine [10]. Since bromate
contains 62.5% (0.625) bromide only hence this fractions
need to be converted to form bromate upon ozonation to
exceed maximum acceptable concentration. The follow-
ing equations show the pathway by which bromide (Br–)
is oxidized by ozone to bromate (BrO3
–) through the in-
termediate formation of hypobromite (OBr–). These
equations also show that ozone does not oxidize hypo-
bromous acid (HOBr) to bromate. Since increased acid
(H3O+) will favor the formation of hypobromous acid,
this suggests that ozonation at a low pH will tend to
minimize bromate formation [11].
Br– + O3 + H2O —> HOBr + O2 + OH–
HOBr + H2O —> H3O+ + OBr–
OBr– + 2O3 —> BrO3
– + 2O2
HOBr + O3 —> No Reaction
1.4. Provisional Guideline Values
Bromate is mutagenic both in vitro and in vivo. [12,13]
has classified potassium bromate in Group 2B (possibly
carcinogenic to humans), concluding that there is inade-
quate evidence of carcinogenicity in humans but suffi-
cient evidence of carcinogenicity in experimental ani-
mals. [14] has classified bromate as a probable human
carcinogen by the oral route of exposure under the 1986
EPA guidelines for Carcinogen Risk Assessment [15] on
the basis of adequate evidence of carcinogenicity in male
and female rats. Under the 1999 EPA draft Guidelines
for Carcinogen Risk Assessment [16], bromate is likely
to be a human carcinogen by the oral route; the data on
the carcinogenicity of bromate via the inhalation route
are inadequate for an assessment of its human carcino-
genic potential. [17] has classified bromate as probably
carcinogenic to humans (sufficient evidence in animals;
no data in humans). At this time, there is not sufficient
evidence to conclude the mode of carcinogenic action for
potassium bromated [6,13,14,18]. Because of insufficient
information on the mode of carcinogenic action of bro-
mate, IPCS (2000) developed both a carcinogenicity as-
sessment based on the linearized multistage model as
well as a TDI based on a non-linear approach for the car-
cinogenicity of bromate. A TDI of 1 μg/kg of body weight
was calculated based on a no-effect level for the forma-
tion of renal cell tumours in rats at 1.3 mg/kg of body
weight per day in the [19] study and the use of an uncer-
tainty factor of 1000 (10 each for inter- and intraspecies
variation and 10 for possible carcinogenicity). The IPCS
(2000) value of 0.1 μg/kg of body weight per day for a
10–5 excess lifetime cancer risk level was based on an
increased incidence of renal tumours in male rats given
potassium bromate in drinking-water for 2 years using
the same study [19]. The upper-bound estimate of the
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Health Risk Assessment for Bromate (BrO3
–) Traces in Ozonated Indian Bottled Water
573
cancer potency for bromate is 0.19 per mg/kg of body
weight per day. The concentrations in drinking water
associated with upper-bound excess lifetime cancer risks
of 10–4, 10–5 and 10–6 are 20, 2 and 0.2 μg/litre, respec-
tively.
Both the World Health Organization (WHO) and the
U.S. Environmental Protection Agency (EPA) have
judged bromate as a potential carcinogen, even at very
low µg/L levels. The U.S. EPA has estimated a potential
cancer risk of 1 × 10–4 (1 in 104) for a lifetime exposure
to drinking water containing bromate at 5 µg/L and re-
cently issued new rules that require public water sup-
plies to control previously unregulated microbes (e.g.,
cryptosporidium and giardia) and cancer-causing DBPs
in finished drinking water. The Stage 1 D/DBP Rule spe-
cifies a Maximum Contaminant Level (MCL) for bro-
mate of 10 µg/L. The EPA intends to convene Stage 2 of
the D/DBP Rule in the near future, while both Germany
and Japan are considering regulatory limits for inorganic
DBPs. As per WHO-1993 guidelines, the recommended
level for bromate is 25 µg/L corresponding with a cancer
risk of 10–5 (life time exposure [20]).
2. Materials and Methods
2.1. Sample Collection and Sample Preparation
In present work, 31 different brands of 500 mL ozonated
bottled water samples were collected from different re-
gions of India during the months of September and Oc-
tober, 2010. During collection of bottled water, ozona-
tion for purification as well as date of packing were taken
care of to avoid any discrepancies. The collected bottled
water samples were filtered through 0.45 µ filter paper,
acidified with 0.01M of nitric acid (AR Grade, Merck,
Mumbai, India) and stored in a pre-cleaned plastic bottle
of 500 ml capacity. The bottles were thoroughly washed
and rinsed with acid followed by demineralised water
prior to storing the samples.
2.2. Measurement and Standardization of
Bromide and Bromate in Bottled Water
Bromide and bromate in bottled water were estimated by
conductivity suppressed ion chromatography system (DI-
ONEX600) using an Ion Pac AS17 (anion-exchange
column) as a stationary phase with 15 mM of NaOH (0 –
15 mts) as a mobile phase and an IonPac AS19 (anion-
exchange column) as a stationary phase with 10 mM (0 -
15 mts) and 10 - 45 mM (15 - 35 mts.) of NaOH as a
mobile phase respectively. For estimation of bromate ion,
the instrument was calibrated in the range of 1 - 100
µg/L using a stock solution of standard which was pre-
pared by dissolving 1.31 g of potassium bromate (KBrO3)
in 1 L of Millipore elix-3 water. Similarly, for bromide
ion, calibration and standardization were done in the
range of 1 - 10 mg/L with the stock solution of Fluka
standard. Figure 1 shows the chromatogram of blank
sample, standard solution of bromated and bromide as
(a)

Health Risk Assessment for Bromate (BrO–) Traces in Ozonated Indian Bottled Water 574 3
(b)
(c)
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Health Risk Assessment for Bromate (BrO3
–) Traces in Ozonated Indian Bottled Water
575
(d)
Figure 1. Chromatogram (Conductivity vs retention time) of blank sample (Figure 1(a)), standard solution of Bromate (Fig-
ure 1(b)) and Bromide (Figure 1(c)) ions as well as bromate contents in bottled water (Figure 1(d)) using conductivity sup-
pressed ion-chromatography syste m.
well as bromated content in bottled water using conduc-
tivity suppressed ion chromatography. In the chroma-
togram, the concentration of ions in unknown sample
was analyzed by measuring their peak area as conductiv-
ity and comparing it with the standard curve. Finally, the
concentration of unknown ion in the unknown solution
was identified by retention time. The relative standard
deviation (2.6% - 8.27%) in the measurement was evalu-
ated by repeated analysis of same strength of standard
solution of bromide and bromate ions. Quality assurance
was made by spike recovery, replicate analysis and cross
method checking. The blank sample containing Millipore
elix-3 water was also measured for the concentration of
both ions. All the reagents used for experimental work
were of ultrapure/ analytical grade, by Merck, Mumbai,
India. Bromate and bromide ions were estimated under the
following conditions: 1) Separation of Bromate in blank,
standard solution and bottled water using gradient method:
separator column: IonPac AS19 (4 mm), eluent: 10 mM (0
- 15 mts) and 10 - 45 mM (15 - 35 mts.) of NaOH, flow
rate: 1 mL/min, temperature: 30˚C, detection: anion self-
regenerating suppressor-ULTRA, auto suppression - recy-
cle mode, expected background conductivity: <2 µS.
2) Separation of Bromide in the same strength of
mixed standard solution using isocratic method: separa-
tor column: Ion Pac AS17 (2 mm), eluent: 15 mM NaOH,
flow rate: 0.25 mL/min, injection volume: 25 µL, tempe-
rature: 30˚C, detection: anion self-regenerating suppres-
sor- ULTRA, auto suppression - recycle mode, expected
background conductivity: <2 µS.
2.3. Risk Assessment
For this study, two types of risks were evaluated, sepa-
rately, because the human health effects can be classified
as carcinogenic risk and chemical toxicity risk. Firstly,
the excess cancer risk due to ingestion of bromate in bot-
tled water was evaluated based on the general US EPA
standard method.
2.3.1. Methodology of Excess Cancer Risk Assessment
The Individual excess cancer risk (IECR), as defined in
USEPA, 2000 a, can be evaluated by the following ex-
pression
0bw
I
ECR URC

 (Equation (1))
where UR0 is the risk factor expressed as (µg·L–1)–1 due
to ingestion of drinking water and US EPA, has consid-
ered the toxicological values of inorganic bromate for the
cancer risk calculation at the case-study area, UR0= 2 ×
10–5 (µg·L–1)–1. Cbw is the estimated concentration of bro-
mate in bottled water, expressed as µg·L–1.
2.3.2. Methodology of Chemical Risk Assessment
Secondly, to evaluate the hazard quotient for bromate,
the chemical toxicity risk as lifetime average daily dose
(LADD) was estimated with the help of Equation (3)
[21-23] and was compared with the reference dose (RfD)
of 0.372 µg/kg/day which is calculated on the basis of
maximum acceptable level of bromate (10 µg/L) in

Health Risk Assessment for Bromate (BrO–) Traces in Ozonated Indian Bottled Water 576 3
drinking water as per guide lines of US EPA, 1999. Here,
the water ingestion rate was set as 2 L·day–1 which is
similar to the upper-bound level of adult daily intake
recommended by US EPA [24]. 350 days for exposure
frequency [24]. 63.7 years for total exposure duration i.e.
the average all India life expectancy for both males and
females [25], 23250 days for average time [25] and 51.5
± 8.5 kg for body weight [26]. The hazard quotient (HQ)
and chemical toxicity risk (LADD) was calculated through
ingestion of bottled water by the following formula:
LADD
HQ RfD  (Equation (2))

kg dayi
CIREFLE
LADD gBW AT 
 
 (Equation (3))
where, Ci = Concentration of bromate in bottled water
(µg /L)
IR = Ingestion rate (L/day)
EF = Exposure frequency (days/year)
LE = Life expectancy (years)
AT = Average Time (days)
BW = Body Weight (kg)
RfD = Reference Dose (µg·kg–1·day–1)
LADD = lifetime average daily dose, (µg·kg–1·day–1)
2.4. Uncertainty Analysis and Statistical
Methods
To analyze the uncertainty on estimation of excess can-
cer risk and lifetime average daily dose (LADD), the
input distributions on exposure frequency and body wei-
ght were assumed as triangular distribution and normal
distribution respectively. Normality test for bromate (con-
centration) distribution was also tested by Shapiro-Wilk
‘W’ statistical method which is a semi-nonparametric
analysis of variance that detects a broad range of diffe-
rent types of normality in a sample of data (Origin Soft-
ware, Version 8.1). At 5% significant level, the calcu-
lated probability value (W) was found to be lower than
the tabulated value. This indicates that the bromate dis-
tribution can be assumed as a normal distribution. Inges-
tion rate of drinking water, total exposure duration and
averaging time were considered as constant input values
as given in Table 1.
3. Results and Discussions
3.1. Physico-Chemical Characteristics of Bottled
water
The physicochemical analyses of the bottled water sam-
ples are presented in Table 2. The pH of bottled water
was slightly alkaline and varied within narrow range of
7.1 - 7.3. TDS (Total Dissolved Solids) of water samples
were in the range of 150 - 170 mg/L. The concentration
of major ions in bottled water was observed to be far
below the permissible limits as per drinking water guide-
line of Bureau of Indian standard [27].
3.2. Bromide and Bromate Levels in Bottled
Water
The mean concentration of Br– and BrO3– in different
brands of packaged drinking water samples was found to
be 11.17 µg/L (range: 2 - 30 µg/L) and 28.13 µg/L (range:
6 - 65 µg/L) respectively. It was observed that, 45.16%
bottled water were above the acceptable limits as per
drinking water guidelines of US, EPA for bromate levels.
At present, the International Bottled Water Association
(IBWA) based on USEPA has set a self- regulatory limit
for bromate in bottled water of 10 µg/L whereas the
World Health Organization (WHO) have set a guideline
value of 25 µg/L which is under review and the proposed
new guideline value is 10 µg/L. The average ratio of
measured BrO3–/Br– was observed as 0.43 with the range
of 0.16 - 0.62, whereas, chemical kinetically, this ratio is
predicted to be 1.6 because it is derived that 62.5% (6.25
µg/L) of bromide in bottled water is needed to convert
into bromate upon ozonation to exceed the minimum con-
tamination level (10 µg/L). The formation of bromate in
bottled water was not found to be completely 100% in
opposition to predicted concentration. The actual forma-
tion of bromate ranged from 0.45% to 39.06% with mean
value of 25.86% against predicted concentration. Table 3
shows the measured bromide and bromate concentration,
their ratios and percentage formation of bromate in bot-
tled water of various regions of India and consequently
risks (excess Cancer risk and chemical toxicity risk) due
to ingestion. The reduction in bromate levels may be
because of not favoring the formation of intermediate
species as hypobromite (OBr–) at measured pH range of
bottled water. In the pH range of 7 - 8, only 1% - 10% of
hypobromous acid [HOBr]total (in the form of OBr-) takes
part in reactions with molecular ozone [7]. The oxidation
of hypobromous acid by ozone is very slow and therefore,
does not contribute significantly to bromate formation.
Moreover, the concentration of bromate is also depend-
ent on the amount of bromide in the source water, ozone
concentration and duration of contact.
3.3. Correlation Analysis
To establish a correlation of Bromide and bromate con-
tent in bottled water, Pearson coefficients of correlation
was used and showed a fairly high degree of correlation
with coefficient (r) = 0.78 with the intercept +2.17 and
slope +0.31. This implies that bromate content in bottled
water was very much influenced and controlled by bro-
mide content. Moreover, there are also some other
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Health Risk Assessment for Bromate (BrO3
–) Traces in Ozonated Indian Bottled Water
577
Table 1. Probability distribution of input parameters used to forecast excess cancer risk and LADD.
Input parameters Mean Value Standard Deviation Distribution References
Bromate levels (µg/l ) 11.16 7.24 Normal This study
IR (l/day) 2 - - US EPA, 1991
BW (kg) 51.5 8.5 Normal H.S. Dang et al. 1995
EF (days/year) 350 (180-365) - Trianguler US EPA, 1991
LE (Years) 63.7 - - HDR,India,2009
US EPA: United States, Environmental Protection Agency, EF: Exposure Frequency, LE: Life Expectancy, HDR: Human Development Report, BW: Body
Weight, IR: Ingestion Rate.
Table 2. Physiochemical characteristics of Indian bottled water samples.
Parameters pH TDS
(mg/L)
Hardness
(mg/L)
HCO3–
(mg/L)
Cl–
(mg/L)
NO3–
(mg/L)
SO4–
(mg/L)
Na+
(mg/L)
K+
(mg/L)
Mg++
(mg/L)
Ca++
(mg/L)
Range 7.1 - 7.3 150 - 17060 - 70 55 - 652.06 - 28.30.3 - 10.70.1 - 11.51 - 400.02 - 2.04 0.03 - 80.2 - 25
Table 3. Measured Bromide and Bromate concentration, their ratios and percentage formation of bromate in bottled water of
various regions of India and consequently r i sks (Excess Cancer risk and chemical toxicity risk) due to ingestion.
Chemical Risk
Bottled Water
code Locations
Measured
concentration of
Br–
(µg/L)
Measured
concentration of
BrO3–
(µg/L)
Measured BrO3–
concentration
/measured Br–
concentration
Percentage
formation
of measured BrO3–
against predicted
concentration (%)
Excess
Cancer
Risk
(× 10–4 ) LADD
(µg·kg–1·day–1)
HQ (Hazard
quotient)
BW-1 Mumbai 36 22 0.61 38.19 4.40 0.818 2.2
BW-2 Mumbai 11 4 0.36 22.72 0.80 0.149 0.4
BW-3 Mumbai 62 10 0.16 10.08 2.00 0.372 1
BW-4 Mumbai 32 12 0.37 23.43 2.40 0.446 1.2
BW-5 Mumbai 10 6 0.59 37.50 1.20 0.223 0.6
BW-6 Mumbai 10 5 0.50 31.25 1.00 0.186 0.5
BW-7 Mumbai 31 16 0.52 32.25 3.20 0.595 1.6
BW-8 Mumbai 59 13 0.22 13.77 2.60 0.484 1.3
BW-9 Mumbai 22 9 0.41 25.56 1.80 0.335 0.9
BW-10 Mumbai 53 24 0.43 27.12 4.80 0.855 2.3
BW-11 Mumbai 8 2 0.25 15.62 0.40 0.074 0.2
BW-12 Pune 16 10 0.62 39.06 2.00 0.372 1
BW-13 Bangalore 39 20 0.51 32.05 4.40 0.744 2
BW-14 Bangalore 17 6 0.35 22.05 1.20 0.223 0.6
BW-15 Bangalore 6 3 0.50 31.25 0.60 0.111 0.3
BW-16 Chennai 21 12 0.57 35.71 2.40 0.446 1.2
BW-17 Hyderabad 7 2 0.28 17.85 0.40 0.074 0.2
BW-18 Surat 39 8 0.20 12.82 1.60 0.298 0.8
BW-19 Surat 8 5 0.62 39.06 1.00 0.186 0.5
BW-20 Surat 35 9 0.26 16.07 1.80 0.335 0.9
BW-21 Surat 9 5 0.56 34.72 1.00 0.186 0.5
BW-22 Baroda 18 11 0.61 38.19 2.20 0.409 1.1
BW-23 Baroda 57 26 0.46 28.50 5.20 0.967 2.6
BW-24 Ahmadabad 33 9 0.27 17.04 1.80 0.335 0.9
BW-25 Jaipur 15 7 0.46 29.16 1.40 0.260 0.7
BW-26 Delhi 10 5 0.50 31.25 1.00 0.186 0.5
BW-27 Delhi 65 30 0.46 28.84 6.00 1.116 3
BW-28 Dehradun 29 14 0.48 30.17 2.80 0.521 1.4
BW-29 Shimla 38 17 0.45 27.96 3.40 0.632 1.7
BW-30 Allahabad 41 8 0.19 12.19 1.60 0.297 0.8
BW-31 Patna 35 16 0.46 28.57 3.20 0.595 1.6

Health Risk Assessment for Bromate (BrO–) Traces in Ozonated Indian Bottled Water 578 3
factors which can influence the concentration of bromide
in bottled water. Figure 2 showed a correlation analysis
of bromide & bromate concentration in bottled water.
3.4. Risk Assessment due to Oral Ingestion of
Bromate in Bottled Water
3.4.1. Individual Excess Cancer Risk
The present study determined the bromate concentration
in the bottled water of each area and estimated the indivi-
dual excess cancer risk. The individual excess cancer risk
due to ingestion of bromate in bottled water at an average
of 2 L/day over the lifetime expectancy of 63.7 years for
an Indian adult observed to be in the range of 4 × 10–5 - 6
× 10–4 with a mean value of 2.24 × 10–4 which showed
about one order of magnitude higher than the maximum
acceptable level (2 × 10–5) as per guide lines of US EPA.
In the worst case (95th percentile), the excess cancer risk
was expected to be about 6 per 10 thousand people which
is 30 times higher than the acceptable risk.
3.4.2. Chemical Toxicity Risk
To evaluate the chemical toxicity risk of bromate, the
lifetime average daily dose (LADD) of bromate through
ingestion was estimated at different percentile and com-
pared it with the reference dose (RfD) of 0.372 µg/kg/day
and thereby produced a hazard quotient. The life time
average daily dose (LADD) worked out to be 0.414
µg/kg/day as a mean with a range of 0.074 µg/kg/day -
1.116 µg/kg/day by considering the body weight as 51.5
± 8.5 kg of an adult Indian reference man. The mean of
hazard quotient (LADD/RfD) was also found to be
slightly greater than unity indicating that bromate in In-
dian bottled water is under alarming situation from the
chemical toxicity point of view. In the worst case based
on very conservative assumptions (at 95th percentile), the
exposure dose deter- mined to be 0.967 µg/kg/day which
is 2 - 3 times higher than RfD. The Basic statistical pa-
Figure 2. A correlation analysis of bromide & bromate
concentration i n bottled water.
rameters of bromide and bromate content in Indian bot-
tled water including risks (Excess Cancer risk and
chemical toxicity risk) at different percentiles (5th - 95th)
due to ingestion of bromated are presented in Table 4.
4. Conclusions
This study was carried out with a view to bring the awa-
reness of Indian centralized regulatory authorities who
have not recommended any acceptable limits in this
prospect. However, in developed countries like Europe
and America, the limits for bromate are well prescribed.
Lack of awareness in this respect has leaded to various
manufactures, which are using it without proper regula-
tion. There are limited methods currently available to re-
move bromate from water. The average exposure level of
bromate was comparatively high and the chemical toxic-
ity in turn is also presumed to be greater. Therefore, it is
suggested that either bromide (precursor of bromate)
Table 4. The Basic statistical parameters of bromide and bromate content in Indian bottled water including risks (Excess
Cancer risk and chemical toxicity risk) at different percentiles (5th - 95th) due to ingestion of bromate.
Mean Median Minimum MaximumRange5th
percentile
25th
Percentile
75th
Percentile
95th
percentile
Inter Quartile
Range (IQR)
Bromide (Br–) 28.13 29 6 65 59 7 10 39 62 29
Bromate (BrO3– ) 11.16 9 2 30 28 2 5 16 26 11
Excess Cancer Risk
(× 10–4) 2.24 1.84 0.40 6 5.6 0.40 1 3.2 5.20 2.20
Chemical Toxicity
risk (LADD) 0.414 0.335 0.074 1.116 1.0420.074 0.186 0.595 0.967 0.409
Hazard Quotient
(HQ) 1.113 0.90 0.2 3 2.8 0.2 0.5 1.6 2.6 1.2
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Health Risk Assessment for Bromate (BrO–) Traces in Ozonated Indian Bottled Water579
3
should be removed using different techniques like mem-
brane filtration, ion exchange, precipitation etc prior to
ozonolysis [28,29] or to restrict bromate formation dur-
ing the ozonation process by decreasing the pH to 6.8
[30]. Under low pH conditions, ozone appears less effec-
tive as an oxidant and the formation of unwanted bromi-
nated organic DBPs is also more favoured. Because of
the large number of factors that influence bromate pro-
duction, it will be necessary to optimize treatment by
balancing the advantages and disadvantages of various
measures on an individual basis for each water supply.
5. Acknowledgements
The authors sincerely acknowledge the guidance and
help provided by Dr. P. K. Sarkar, Head, HPD. Thanks
are also due to Shri H. S. Kushwaha, Director, H,S & E
Group, for constant encouragement.
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