Seasonal Variation of the Concentration of Trihalomethanes in the Drinking Water in the City of Kumanova Bujar H. Durmishi1*, Arianit A. Reka, Murtezan Ismaili, Agim Shabani 1
Department of Chemistry, Faculty of Natural-Mathematical Sciences, State University of Tetova, Str. Ilindeni, n.n. 1200 Tetova, Macedonia *corresponding author: 389 72 702 868 e–mail:
[email protected]
Abstract Trihalomethanes (THMs), being the main byproducts of the water disinfection process, have been a great concern for over three decades for the scientific and wider community for their carcinogenic properties. The aim of this paper is to determine the presence of THMs in the drinking water of the city of Kumanova in the spring season and comparing their presence with the regulations within the Republic of Macedonia (as per the recommendations of EU and WHO). UV-VIS spectrophotometry was used as a method in order to determine the presence of THMs – a method based on Fujiwara’s reaction. THMs were determined in five various sample points during the months of March, April and May of 2011. Results have shown that the concentration of THMs in the drinking water of Kumanova is within the recommended values of EU, WHO and the Government regulations. Results show that the average concentration of THMs is 33.29 9.21 g/L. These results are the first of this kind for the city of Kumanova. The aim of this paper is also the prevention of health issues caused by the presence of THMs in drinking water.
Keywords: drinking water, health, trihalomethanes, UV-VIS spectrophotometry.
1. INTRODUCTION Water is the main factor for the existence of life in our planet. Water is used for various purposes, such as drinking, cooking, maintaining proper hygiene etc., thus controlling the water quality is necessary in order to gather information about the level of contamination. Drinking water should be of high quality, it should meet the standards for daily usage and should not bear the potential of health risk. Water with such qualities is often limited, thus water is used from lakes, underground waters as well as artificially accumulated waters that initially must undergo treatment (cleaning and disinfection). The treatment process of drinking water used in households consists of: accumulation of water in water reservoirs, water aeration, coagulation, flocculation and precipitation, filtration and disinfection [1]. During usage, water in households and industry is contaminated with inorganic, organic and other contaminants, and as such it returns to our environment. Furthermore, water is also contaminated by the usage of agricultural products. Today, water that is considered drinkable should be subject to physical and chemical analysis; this also includes water from natural sources, such as wells. Treatment is done with physical and chemical methods such as: filtration, disinfection with chemicals and ultraviolet 1
radiation. These methods have significantly increased the amount of accessible drinkable water for human consumption and at the same time have managed to reduce potential diseases. In order to eliminate bacteria, viruses and microorganisms that can cause various diseases amongst humans and animals, drinking water is treated with chlorine or similar disinfectants [2]. However, during the disinfection process, the organic matter present in water reacts with chlorine and bromine which results in byproducts. These byproducts are hazardous and impose hazardous cancerogenic concerns for the human health. These byproducts are divided in two main groups: haloacetic acids (HAA) and trihalomethanes (THM). In 1974 it was discovered that THMs are the main byproducts that are formed in the disinfected drinking water. These are a group of compounds that are formed when chlorine reacts with broken down organic matter and vegetation. The main THM-s formed in such way are chloroform (CHCl3), dibromomethyl (CHBr2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3) [3], [4]. It is scientifically proven that THMs are carcinogenic to animals and humans. Studies have shown that acute toxic doses of chloroform can cause depression of the central nervous system and cardiac effects. A study conducted by the California Department of Health found that women exposed to high levels of chlorinated byproducts have a 17.5% risk of miscarriage, while women who had less exposure to THMs have a lower risk, 9.5%. Because of the negative health impact, the US Environmental Protection Agency (US EPA) recommends that concentrations of THMs shall not exceed a value of 100 µg / L in tap water to customers [5]. Of particular importance is the study of the impact of various factors on the formation of THMs. Some of those factors are: pH, temperature, contact time, concentration of chlorides, natural organic matter, residual chlorine, bromide concentration etc. [6, 7, 8]. Each factor has a special effect on the formation of THMs. For example, increasing the pH and the contact time greatly increases the formation of THMs; increasing the temperature the reaction becomes much faster as well as the consumption of chlorine, which increases the formation of THMs [9]. As total THMs formed are in proportion to the amount of organic matter in the drinking water source, total THMs changes (their concentration) indicate changes in the quality of drinking water. The measurement of THMs in the right time is a valuable tool in monitoring the quality of drinking water, which also enables adjustments and improvements in the treatment process. THMs are analyzed in laboratories by using various gas-chromatographic methods. The most widely used method to determine the THMs is the EPA 502, a method with which THMs are analyzed by sweep and trap/detection - electrolytic conductivity. Chromatographic methods such as GC-MS PT, HS-GC-MS and GC-PT are very expensive and require longer time for analysis and processing of results. Therefore, as a method for quantifying the THMs, we have utilized the method of UV-VIS spectrophotometry, which requires inexpensive instruments and reagents, and shorter term analysis and processing of results.
2. MATERIALS AND METHODS 2.1. Drinking water in the city of Kumanova
2
The city of Kumanova and the Likova municipality are supplied with water from the Likova dam, which is the oldest dam in the entire territory of the Republic of Macedonia. Likova dam was built in 1958 and its located 2 miles west of the same village, at an altitude of 478 m (Fig. 1). River Likova is rich in water and its basin is 110 km2, while the altitude ranges from 450 to 1350 m, with an average altitude of 1070 m.
Fig. 1. Likova dam - system I
River Likova’s greater flow is during the spring season, whereas the flow levels drop during summer and autumn when the region needs irrigation of arable land and potable water supply in the region. Table 1. Some data in regards to the Likova accumulations Volume of accumulation 1 500 000 m3 Used volume 1 300 000 m3 Length of accumulation 1 480 m Width of accumulation 120 m
Due to the high demand for quality water, 14 years later a second dam was built about 5 km west of Lake Likova, Gllazhnja locality (Fig. 2). The length of the dam is 344 m concrete wall with a width of 4 m and a height of 84 m. The Gllazhnja reservoir supplies water to 13 settlements and a part to the city of Kumanova. Table 2. Some data in regards to the Gllazhnja accumulation Volume of accumulation 24 075 870 m3 Usage volume 22 160 000 m3 Length of accumulation 3162 m Width of accumulation 320 m Surface 96.5 ha
3
Fig. 2. Likova dam - system II (Gllazhnja area)
2.2. Working methodology The methodology involves collecting samples, their preparation and measuring. Experimental measurements were performed at the laboratories of the State University of Tetova. 2.2.1. Water sampling The sampling method has a great impact on the results of the analysis obtained. Thus sampling is defined by international recommendations. Water samples are placed in clean glass containers, which are initially rinsed 2-3 times with the water that is about to be tested. The container is closed with glass lid. In order not to confuse the samples, all the containers are labeled with date, the type of water, sample site, time and the name of the person collecting the sample. Prior to collecting the sample the water needs to flow for about 10 min. The time from collecting the sample and analyzing it should be as short as possible. Samples with high pollution should be analyzed within 12 hours, the ones with lower pollution within 24 hours, while non-polluted waters within 72 hours. During this time, the samples should be stored in a dark place and at a temperature of 3-4 °C to avoid possible changes as a result of the activity of microorganisms present in water. 2.2.2. Sample points, instruments and reagents Samples were collected from five sampling points of the city of Kumanova: K1 (Sinan Tatar Pasha Mosque), K2 (Fontana city center), K3 (Str. Dr. Ribar), K4 (Cafeteria Elib) and K5 (Str. Boris Kidriç). Drinking water samples from five sampling points are analyzed each week in the months March, April and May 2011 for the determination of THMs while using UV-Vis spectrophotometer (Ultrospec). The following reagents were used: pentane, pyridine, 50% solution of NaOH, chloroform, bromoform and methanol. 4
2.2.4. Determination of THMs The determination of the concentration of THMs in drinking water was performed with the method of UV-VIS spectrophotometry, a method that is highly sensitive and precise. With this method you can determine the total THMs in drinking water at 10 to 600 ppb (µg/L) as chloroform. This method relies mainly on the basis of chemical reaction Fujivar-s, where THMs with the respective reagent transform to a pink colored compound that absorbs in accordance with the Beer law made at wavelength 525 nm. The determination of THM-s is made with UV-VIS spectrophotometric method as described in scientific literature [10]. With this method, ten mL of pentane were added in a normal dish containing 1L of drinking water to be analyzed. The dish was shaken for about 3 minutes and then was left still until the two separate layers were visible. The pentane layer was then removed and was added to a test tube containing 2 mL of NaOH 50% and 3 mL of pyridine. The test tube was placed in a water bath at 45°C for 30 minutes in order to relieve the evaporation of pentane. Afterwards, the bath temperature was increased twice, at 55°C for 45 minutes and at 95°C for another 45 minutes. After this, 2 mL of the pyridine layer (with a pink color) were removed and after the refrigeration was transferred to a 1 cm glass civet and the absor-bance in 525 nm was measured (Fig 3).
Fig. 3. UV/VIS Absorption spectrum of THMs, = 50 g/L
For the preparation of the calibration curve, 1 mL bromoform and 1 mL chloroform all together were added to 1000 mL of methanol. Total concentration of THMs in this solution was 4.37 mg/mL, and this was the initial standard solution of THMs. Standard solution with concentrations 25, 50, 70, 100 and 125 g were prepared for the calibration curve by diluting the initial solution 4.37 mL/mL of THMs, where each solution is diluted with distilled water to the volume of 1 L (Fig. 4). These solutions were processed the same way as the drinking water samples.
5
0.08
Mars 2011
A
0.06
0.04
0.02
0.00 0
20
40
60
80
100
120
140
g/L Fig. 4. Calibration curve for determination of THMs, March 2011
3. RESULTS AND DISCUSSIONS Results of this study are presented in Table 4 and Figure 5. These values are compared with state regulations of Macedonia, the WHO and the EU (Table 3). Table 3. Standards/Recommendations for THM-s (mg/L) Compound WHO USEPA Health Canada (1993) (2001) (2001) * chloroform 0.200 0.000 – * dibromomethyl 0.060 0.060 – * dibromochloromethane 0.100 0.000 – * bromoform 0.100 0.000 – Total trihalomethanes (THM/OBSH 0.080 0.100 ** )≤1 *
Aus-ZR (2000) – – – – 0.250
UK (2000) – – – – 0.100
UE (2001) – – – – 0.100
The max target level of water pollution The sum of THM levels shall not exceed 1.
**
The variation of THMs has changed during the above months within the values 21.15 – 47.83 g/L. The lowest value was in March at sample point K1, while the highest values are at sample point K3 (May). The average values in March, April and May were: 22.91, 32.88 and 44.10 g/L respectively. The lowest average was 31.90 g/L at sample point K2, while the highest average observed was 36.56 g/L at sample point K3. The average value for the season, with a standard deviation was observed 33.29 9.21 g/L, which is below the allowed values of 6
the state regulations. Compared to the parallel research of the drinking water in the city of Tetova, it can be concluded that during the spring season the city of Kumanova has higher values of THMs [11, 12]. This is due to the fact that the water in the Kumanova region has a higher content of organic matter. The results provided in this paper are the first of their kind for the city of Kumanova. Table 4. Experimental results of THM-s (µg/L) and statistics Sample points / Month
March
April
May
K1
21.150
31.280
43.260
K2
22.410
32.670
42.680
K3
25.320
36.520
47.830
K4
23.040
34.530
41.450
K5
22.630
29.380
45.260
Min
21.150
29.380
41.450
Max
25.320
36.520
47.830
Median
22.630
32.670
43.260
Average
22.910
32.876
44.096
1.521
2.776
2.500
114.550
164.380
220.480
5
5
5
Stan. Dev. Sum N
60 50 40 30 20 10 0 K1
K2 Mars
K3 Prill
K4
K5
Maj
Fig. 5. Seasonal variation of THMs in g/L
7
5. CONCLUSIONS Based on the above mentioned results it can be concluded that: The spring variations of THMs have been within the state regulation limits during the time this research was conducted and it does not impose a health risk to the population of this region. The THM values are higher in the summer season, their monitoring is an imperative in order to ensure that the water is safe for use. Thus actions for reducing THMs are required, but should not negatively affect the water disinfection process. We recommend that the relevant authorities take appropriate actions to prevent and keep the THMs concentrations within limits, especially in the hot months when their values are much higher, as long term consumption can cause health problems. We recommend that continuous monitoring of THMs is established in order to have a better picture of their impact on the health of the citizens in the region.
6. ACKNOWLEDGMENT It is a pleasure as well as obligation to thank Prof. Dr. Hysen Reci, whose suggestions, directions and fruitful discussions contributed considerably upon the experimental part of this work. We express gratitude to Mr. Bujamin Durmishi and Mr. Sc. Nagip Zendeli for their financial contributions for reagents for determination of THMs. In particular we would like to thank Mr. Sc. Arianit A. Reka for his support provided during the translation and the proofreading of this article into the English language.
LITERATURE 1. Dr. sc. Bardha Korça (2002), “Analiza kimike e ujit”, WUS Austria, Prishtinë, 95. 2. Camel, V. & Bermond, A. (1998). The use of ozone and associated oxidation processes in drinkingwater treatment. Water Research, 32, 3208-3222. 3. Cragle, D.L.; Shy, C.M.; Struba, R.J.; Siff, E.J., (1985). A casecontrol study of colon cancer and water chlorinated in North Carolina. Water Chlorination: Chemistry, Environmental Impact and Health Effects. Chelsea. MI: Lewis Publishers Inc., Vol. 5, pp. 53. 4. Nikolaou A., Lekkas T., Golfinopoulos S. and Kostopoulou M. (2002a), Application of different analytical methods for determination of volatile chlorination by-products in drinking water, Talanta, 56, 717-726. 5. Elshorbagy, W., (2000), “Kinetics of THM Species in Finished Water”, J. Water Resour. Plng. and Mgmt., ASCE, 126 (1), 21-28. 6. Singer P.C. (1994), Control of disinfection by-products in drinking water, J. Env. Engineer., 120, 727. 7. Singer, P.C. (1999). Humic substances as precursors for potentially harmfull disinfection by-products. 8. Zazouli, M.A., Nasseri, S., Mahvi, A.H., Mesdaghinia, A.R., Younecian, M., Gholami, M., (2007a). Determination of Hydrophobic and Hydrophilic Fractions of Natural Organic Matter in Raw Water of Jalalieh and Tehranspars Water Treatment Plants (Tehran). J.Applied .Sci., 7 (18): 2651-2655. 9. Golfinopoulos S.K., Xilourgidis N.K., Kostopoulou M.N. and Lekkas T.D. (1998) Use of a multiple regression for predicting trihalomethane formation, Water Research, 32(9), 2821-2829.
8
10. Huang J, Smith R, Gary C (1984), Spectrophotometric Determination of Total Trihalomethanes in Finished Waters. Journal AWWA, Vol. 76 Iss. 4, 168-171. 11. Durmishi H. Bujar, D. Vezi, M. Ismaili, A. Shabani, Sh. Abduli (2012), Seasonal Variation of Trihalomethanes Concentration in Tetova's Drinking Water (Part B), World Journal of Applied Environmental Chemistry, Volume 1, Issue 2: 42-52. 12. Bujar H. Durmishi (2013), “The study of the trihalomethanes (THMs) content variation with advanced analytical methods in the drinking water in the city of Tetova” – Disertation, University of Tirana, 77-78.
9
