Determination of nitrate concentration and its risk assessment in bottled water in Iran

Bottled water is one of the sources of drinking water in many arid and semi-arid countries, including Iran. The greatest concern is the health effects of exposure to excessive nitrate concentrations in drinking water due to the development of methemoglobinemia in children. Therefore, the present study was aimed at determining the concentration of nitrate and its risk assessment in drinking water bottled in Iran. 71 different bottled water brands were identified in this study. The nitrate concentration in water samples was then measured using an Ion Chromatography No. 4110 in accordance Standard Methods for the Examination of Water and Wastewater. The hazard quotient (HQ) of nitrate was calculated using the formula based on input variables including nitrate concentration, water per capita, body weight and reference dose. The results showed that the concentration of nitrate in bottled water was in the range of 0.146–50.1 mg/L (average 10.55 mg/L) in one of which, the concentration of nitrate was higher than the WHO guideline. The mean EDI values for nitrate in different groups of infants, children, teenagers and adults were 0.0795, 0.5633, 0.3976 and 0.3186 mg/kg, respectively. The mean HQ values for nitrate in different groups of infants, children, teenagers and adults were 0.0528, 0.3737, 0.2638 and 0.2114, respectively. In general, the hazard quotient (HQ>1) for the population consuming bottled water, appropriate strategies should be considered in order to reduce the concentration of nitrate in bottled water.

infants, children, teenagers and adults were 0.0795, 0.5633, 0.3976 and 0.3186 mg/kg, respectively. The mean HQ values for nitrate in different groups of infants, children, teenagers and adults were 0.0528, 0.3737, 0.2638 and 0.2114, respectively. In general, the hazard quotient (HQ 4 1) for the population consuming bottled water, appropriate strategies should be considered in order to reduce the concentration of nitrate in bottled water.
& 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Bottled water quality and risk assessment More specific subject area Bottled water nitrate Type of data Tables  How data was acquired Bottled water brands tested were obtained from the Iranian Bottled water association. The nitrate concentration of the samples was measured using an Ion Chromatography No. 4110 in accordance with the method described in "Standard methods: For the examination water and wastewater, 22nd edn". Data format Raw, Analyzed Experimental factors 71 different brands of high-consumption bottled water in Iran were randomly selected Experimental features Determine the concentration level of nitrate Data source location Iran Data accessibility The data are available with this article

Value of the data
Bottled drinking water is one of the source of nitrate absorption into the body [1][2][3][4][5]. Noncarcinogenic problems occurred due to the exposure to methemoglobinemia nitrate and syndrome in humans, especially children. Therefore, the risk assessment of nitrate exposure can be helpful in the prevention of methemoglobinemia [6][7][8][9][10][11].
The results of the study indicated that the nitrate concentration in many brands of bottled water is lower than the standard limit, therefore, the consumption of bottled water does not create a threat to the health of consumers.
Based on risk assessment and data analysis, the highest percentage of HQ 41 was associated with the age group of children, thus the sensitivity should be applied to the selection of drinking water brands for this age group.

Data
The parameters used to calculate the nitrate risk assessment in bottled water are shown in Table 1. Nitrate concentration and nitrate estimated daily intake (EDI) and hazard quotient (HQ) for the four populations of bottled water consumers have been shown in Table 2.

Experimental design, materials and methods
In this study, 71 different brands of high-consumption bottled water in Iran were randomly selected, the nitrate concentration of all bottled water samples was measured using an Ion Chromatography No. 4110 in accordance with the method described in the book "Standard methods: For the examination water and wastewater, 22nd edn" [17][18][19][20][21][22]. Then, the health risks of exposure to nitrate in bottled water were assessed according to the classification conducted by Yousefi et al. [12]. for different age groups, which is determined by calculating the hazard quotient (to show non-carcinogenic effects) for different age groups based on the following equations. HQ values less than 1 indicate a non-cancerous effect of the population exposed to exposure. While, if this value is greater than 1, it indicates the occurrence probability of noncarcinogenic effects in the exposed population.
First, the daily nitrate consumption in bottled water was estimated according to Eq. (1) [12,14]: EDI: Estimation of daily nitrate consumption C f : Nitrate concentration in drinking water C d : Average daily drinking water intake B w : body weight Then, HQ risk contribution was calculated to predict non-carcinogenic risk of exposure to nitrate using Eq. (2): where, HQ is the risk of non-carcinogenic substances EDI: Estimated Daily intake (mg/kg d) RFD: Reference dose The reference dose for nitrate is 1.6 mg/kg d [14]