* Gh.R. Jahed Khaniki 1 , H. Dehghani, A.H. Mahvi 1 ., L. Rafati 2 and F. Tavanfar
3
1 Department of Environmental health Engineering, School of Public Health, Medical Sciences/University of Tehran, Iran
2
MS Student in Department of Environmental health Engineering, School of Public Health, Medical Sciences/University of Tehran, and Hamadan Health Center, Iran
3 Hamadan Health Center, Iran
Abstract:
Nitrate (NO
3
‾) and nitrite (NO
2
‾) are naturally occurring ions that are ubiquitous in the environment. Both are products of the oxidation of nitrogen (which comprises roughly
78% of the atmosphere) by micro-organisms in plants, soil or water and, to a lesser extent, by electrical discharges such as lightning. After a period of time, the nitrates seep into the water table. This is a concern primarily for those whose household water source is a well, rather than their city. Nitrates have no color and no odor in water. Nitrates can cause cancer in humans, when consumed over a long period of time. The objective of this study is investigation and determination of nitrite and nitrate in ground water sources of
Hamadan province, Iran. 280 samples of water were examined for nitrate and nitrite at during six months from February to September, 2007 at the eight cities of Hamadan
Province (Hamadan, Malayer, Nahavand, Asadabad, Razan, Bahar, Kabudarahang and
Toyserkan). Nitrate and nitrite ions were analyzed by UV- Spectrophotometer, DR- 5000.
The results showed that the mean and standard deviation of nitrate and nitrite contents in water samples were 16.39 ± 14.05 mgL
-1
and 0.038 ± 0.056 mgL
-1
, respectively.
10 samples of water from five cities (Malayer, Razan, Bahar, Kabudarahang and Toyserkan) had more than the maximum acceptable concentration (MAC) for nitrate in drinking water. It was concluded that nitrate contents in drinking water can be higher than standard level in some areas and it can be a public health concern for people who consume contaminated water. Water resources control management can be important at these areas and it needs to apply some actions to reduce or remove nitrate from drinking water.
Nitrate (NO
3
‾) and nitrite (NO
2
‾) ions are hazardous materials that naturally occur in ground water. They are ubiquitous in the environment. Both are products of the oxidation of nitrogen (which comprises roughly 78% of the atmosphere) by micro-organisms in plants, soil or water and, to a lesser extent, by electrical discharges such as lightning. All rainfall and ground water aquifers contain some nitrate-nitrogen. Nitrate accumulates in agricultural watersheds where farmers spread organic fertilizers and animal manures on cropland. Nitrogen can leach through the soil to groundwater and then flow to recharge or private wells. Sources of nitrate that can enter in well include fertilizers, septic systems, animal feedlots, industrial waste, and food processing waste. Activities near the well can potentially contaminate the water supply. Nitrate and nitrite have some hazards for human. The primary health hazard from drinking water with nitrate-nitrogen occurs when nitrate is transformed to nitrite in the digestive system (Robillard et al., 2006). The nitrite oxidizes iron in the hemoglobin of the red blood cells to form methemoglobin, which
1

lacks the oxygen-carrying ability of hemoglobin. This creates the condition known as methemoglobinemia that blood iron in hemoglobin (Fe++) reduced to its oxidized form,
Fe+++ (Beatson, 1978). It is unable to release oxygen to body tissues because of its high dissociation constant (Adam., 1980). In 1982, 96 cases of methemoglobinaemia were reported. Nitrate levels in drinking water were above 100 mg L
-1
in 93% of cases and between 40 and 100 mgL -1 in the remaining 7% (WHO., 1985) .
Hamadan is one of the 30 provinces of Iran in the west north. The province of Hamadan covers an area of 19,546 km² and it has a population of approximately 1.7 million people.
The major cities of Hamadan province are Hamadan, Toyserkan, Nahavand, Malayer,
Asad Abad, Bahar, Razan, Kabudrahang. The most of drinking water is supplied from ground water resources. Two environmental contaminants such as nitrate and nitrite can enter to water resources at this areas. Some studies of nitrate and nitrite in water had previously been conducted in Iran. For example, Mahvi et al, 2005 reported from Ahvaz;
Mohammadian Fazli and Sadeghi, 2003 reported from Zanjan; Farshad and Imandel,
2002 reported from Tehran; Shams Khorram abadi, 2001 reported from Khoram abad.
The province of Hamadan was selected for this study because there is no whole information available on nitrate and nitrate in ground water sources. The purpose of the present study was thus to determine the concentrations of nitrate and nitrite in ground water sources of Hamadan province, Iran and to compare the nitrate and nitrite contents with standards levels.
Sample collection: A total of 280 water samples from ground water of Hamadan province were randomly collected from eight areas (Hamadan, Malayer, Nahavand,
Asadabad, Razan, Bahar, Kabudarahang and Toyserkan) over a period of six months during the spring and summer seasons (from February to September) of the year 2007.
All samples were collected in 1000 ml polythene bottles and carried to the laboratory.
Sample storage and preparation: water samples were stored in 1000 ml polythene bottles for up to 24 hours at 4ºC. Before analysis, the sample warmed to room temperature and it adjusted the pH to 7 with 5.0 N sodium hydroxide standard solution.
The test result for volume additions were corrected by dividing the total volume (acid
/base/ sample) by the original sample volume and multiplying the test result by this factor.
Sample analyzation. At first , for determination of nitrate, a square sample cell was filled with 10 mL of water sample. The contents of one NitraVer 5 Nitrate Reagent Powder
Pillow added with sample. The cell was vigorously for one minute. An amber color will develop after five minutes if nitrate was present. Then, the prepared sample was wiped and inserted it into the cell holder with the fill line facing the user. Also, for determination of nitrite, a square sample cell was filled with 10 mL of water sample. The contents of one NitriVer 3 Nitrite Reagent Powder Pillow added to prepared sample and were completely dissolved. A pink color will develop if nitrite is present. After twenty minutes, the prepared sample was wiped and inserted it into the cell holder with the fill line facing the user.
Nitrate and nitrate measurement . Nitrate and nitrate were measured using a HACH-
DR 5000 UV-Vis Spectrophotometer, USA colorimeter using the cadmium reduction
2

method (Method 8039) at 500 nm and diazotization method (Method 8507) at 507 nm, respectively. The standard solution method and blank preparation was done for determination of nitrate and nitrite in samples. All the recoveries of the nitrate and nitrite were studied over 95% and the concentration of the nitrate and nitrite are expressed in mg
L
-1
NO
3
-
N and NO
2
-
N, respectively.
Statistical analysis. All statistical analyses were performed using the software SPSS, version 11.5. Analysis of variance ANOVA was employed after logarithmic conversion when necessary to detect significant differences among means. A probability level of p<0.05 was considered statistically significant.
Nitrate and nitrite concentrations obtained from this study are summarized in table 1.
Water samples from Kaboudarahang and Malayer city had high content of nitrate and nitrite, respectively. The highest content of nitrate was showed 120.12 mg L
-1 in only one sample. Also, nitrate content was low in water samples of Hamadan city. Among the most collected water samples, Malayer city contained more nitrite about 0.73 mg L
-1
, whereas the Bahar city contained lower nitrite about 0.027 mg L -1 . The mean and standard deviation of nitrate and nitrite content in groundwater samples were 16.39±14.5 and 0.038±0.056 mg L
-1
, respectively.
The nitrate concentrations in 3.57% of samples (10 water samples) were higher the regulatory limits set for human consumption and 270 of samples (96.43%) were below the federal regulatory limits set for human consumption. The maximum acceptable concentration (MAC) for nitrate in drinking water is 45 mg L
-1
. Also, the concentration of nitrite should not exceed 3.2 mg L
-1
.
Table 1. Nitrate and nitrite contents in groundwater sources of Hamadan province (mg L -1 )
______________________________________________________________________________________
City No. of Sample Nitrate
(Mean± SD)
Nitrite
(Mean± SD)
______________________________________________________________________________________
Hamadan 40 10.39± 5.82 0.030± 0.049
Malayer 50 20.19±13.57 0.05± 0.11
Nahavand 45 11.21± 5.69 0.035 ±0.041
Asadabad 32
9.78± 6.3 0.030 ±0.021
Razan 24 18.33± 21.74 0.040 ±0.019
Bahar 36 *
16.69± 10.87 0.027± 0.03
Kabudarahang 30 * 25.79 ±23.36 0.047± 0.036
Toyserkan
Total
23
280
18.80± 12.81
16.39 ±14.05
0.014 ±0.034
0.038± 0.056
_____________________________________________________________________________________
* p< 0.05
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In present study, nitrate levels in municipal water supplies of Hamadan province are generally less than 16.39 mg L
-1
and 96.43 % of samples had less than standard levels.
Only 10 of 280 samples (3.57%) had nitrate above standard levels. The Cities of Malayer
(4 of 50 samples), Kabudarahang (3 of 30 samples), Toyserkan (1 of 23 samples), Bahar
(1 of 36 samples) and Razan (1 of 24 samples) had a nitrate concentration greater than 45 mg L -1 . Also, nitrite levels in the water supplies of all municipalities were below 0.03 mg
L
-1
. The highest level of nitrite was 0.73 mg L
-1
.
In a survey of groundwater supplies in Bahar city in Hamadan province of Iran in 2006 , nitrate levels in 30% of samples at 135 wells in an agriculture area were high than 44 mg
L
-1.
The maximum value recorded at was 75 mg L
-1
(Jalali and Kollahchi., 2005).
Farshad and Imandel in 2002 reported that nitrate and nitrite in water at among 300 large- complexes located in the outskirts of Tehran have 51.96 mg L
-1
and 5.9 mg L
-1
, respectively and they were above WHO specified limits and the safety standards established by national guidelines.
Miranzadeh et al (2006) investigated the nitrate levels in 66 samples of water wells and
288 samples of water distribution network of Kashan city. They showed that the mean concentration of nitrate in water wells and water distribution network were 13.2-15.4 mg
L
-1 and 17 mg L
-1
. Also, Mahvi et al (2005) studied agricultural activities impact on groundwater nitrate pollution. They investigated 42 water wells in Andimeshk and Susa plains in north of Khozestan-Iran. They demonstrated that all of the groundwater samples have nitrate concentration below the EPA MCL (44.27 mg L
-1
) and WHO guideline (50 mg L
-1
).
Gheysari et al (2007) assessed nitrate pollution of groundwater in south east of Isfahan region. They reported that some areas show the concentration of nitrate more than US-
EPA standards, especially in South-East of the region. The highest nitrate concentrations in the polluted area were 189.1 and 248.3 mg L
-1
and were identified to have high concentration of Nitrate between 80-90 %. The Nitrate pollution averages were 76.9 to
93.1 mg L
-1
. Also, Sadeghi and Fazli (2005) surveyed total nitrate and nitrite contents in drinking water resources (wells) in Zanjan City. Nitrate and nitrite concentrations in some drinking water wells were undesirable and some of the wells were exposed to the contamination.
In a survey in an agricultural area of Canada (New Brunswick), nitrate concentrations in approximately 20% of the 300 wells sampled exceeded 44 mg L -1 (Ecobichon et al.,
1985). In an another environment survey of groundwater in Canada, 60% of wells (450 samples in 125 locations) were found to have nitrate levels exceeding 45 mg L
-1
. The maximum recorded concentration was 182 mg L
-1
. The increased population and intensive agricultural can be reason for this contamination (Liebscher et al., 1992). Also, nitrate levels in Canadian municipal water supplies are generally less than 5 mg/L and only one of 59 (1.7%) had a nitrate concentration greater than 45 mg L
-1
. In this survey, nitrite levels in the water supplies of most municipalities were below 0.03 mg L -1 , the highest level reported being 0.3 mg L
-1
(Environment New Brunswick., 1983).
It was concluded that nitrate contents in ground water sources for drinking water supply in Hamadan province can be higher than standard level in some areas and it can be a public health concern for people who consume contaminated water. Water resources control management can be important at these areas and it needs to apply some actions to reduce or remove nitrate from drinking water. It is necessary to monitor nitrate and nitrite
4

in water. Therefore, domestic wells near potential point sources of contamination, such as livestock facilities or sewage disposal areas, should be tested at least once a year to monitor changes in nitrate concentration. Also, all drinking water supplies should be checked at least every two or three years to assure that significant increases in nitrate and nitrite are not occurring. Three methods such as distillation, reverse osmosis, and ion exchange are can be applied for removing nitrate from drinking water.
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Scientific and Research Journal of Faiz, 10 (2): 39-45.
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College of Agricultural Sciences, U.S. Department of Agriculture, and Pennsylvania
Counties Cooperating. resources.cas.psu.edu/WaterResources/pdfs/nitrate.pdf
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