Application of the Water Quality Index as Simple Indicator of Watershed Pollution Jajrud River as a case study

Transcription

1 Application of the Water Quality Index as Simple Indicator of Watershed Pollution Jajrud River as a case study Mirzai. M. (MSc) Research Assistant of Water Energy research center Sharif Mirzai@sharif.ac.ir Received 27 May 2013; Revised 16November 2013; Accepted 15 January 2014; Published 24 April Science and Engineering Publishing Company Abstract: The purpose of this paper is using the water quality index (WQI) to help management actions in the Jajrud watershed in Tehran Iran, as a simple pollution indicator for human activities. In this research, the water quality of Jajrud River has been investigated for 9 years during The WQI was calculated by two methods: National sanitation foundation water quality index (WQINSF), Subjective water quality index (WQISUB). Water quality parameters which were used in this index are: Turbidity, Total phosphate, Total solids, Biochemical Oxygen Demand (BOD), nitrate, Fecal Coliform, ph, temperature, Dissolved Oxygen (DO). The amount of WQI was measured at ten stations along the river. Then its quality is categorized based on different conditions including excellent, good, average, bad and very bad. The results showed that water quality, except two stations, was average. Also the amount of the WQI was calculated by two methods are relatively convergent and approximate. Keywords: Water Quality Index; Jajrud River; Water Pollution; Tehran Introduction Different regions of the world are faced with different types of problems associated with the occurrence, use and control of water resources which may endanger the sustainable development of these resources. The surface water quality is a very sensitive issue. Anthropogenic influences as well as natural processes degrade surface waters and impair their use for drinking, industry, agriculture, recreation and other purposes due to the spatial and temporal variations in water chemistry, a monitoring program and representation and reliable estimation of the quality of surface waters are necessary. The WQI has been considered to give a criterion for surface water classification based on the use of standard parameters for water characterization (Bordalo and sava bordalo, 2007). This method facilitates to provide a simple and an apprehensible tool to conserve restore and monitor the water quality and consequent effects on the surrounded area by looking a single number and corresponding scale. (Cvetkovic, et al., 2011) (Akkoyunlu, et al., 2012). This index is a mathematical tool used to transform large quantities of water characterization data into a single number which represents the water quality level. The use of WQI is a single practice, which allows adequate classification of water quality. The calculation of WQI requires first a normalization step, where each parameter is transformed into a 0 100% scale, so that 100 represents the highest quality. The next step is to apply weighting factors that reflect the importance of each parameter as an indicator of the water quality. (Sanchez, Colmenarejo, Vicente, 2007). Developing a fuzzy inference system which considers different criteria and local conditions of the regions has been used to simplify and to predict quality of water bodies (H. J. J. Carbajal, 2012) (Mahapatra.s.s, 2011). Asadollahfardi et al. (2004) reviewed the WQI and used the WQI to define water quality of Karun River in Iran. Asadollahfardi (2009) applied the WQI in surface water in Tehran. Materials and Methods The Study Area Parts of Jajrud River, upstream of latian dam, Tehran, was selected for a case study in this research. Its area is 690 Km2, longitude 51 52ʹ to 51 55ʹ and latitude 35 45ʹ to 36 at the northwest of Tehran. This basin is one 42

2 Advances in Water Resource and Protection (AWRP) Volume 2, of the most important sources of drinking water of Tehran, and has a significant role in preventing floods. Studies show that due to the regionʹs proximity to Tehran, suitable climate, has experienced significant population changes and vegetation (Tehran s agricultural organization, 2002). Studies show that many tourists on weekends in the hot season, the skiing facilities in the winter, in the area attending. In addition, every year to maturity and harvest the gardens, seasonal migration takes place in the region (Water & Energy center of Sharif University report, 2003). The presence of tourists in the area, especially around rivers, Top of Form. The presence of tourists in the area, especially around rivers, river pollution and environmental problems in the basin is. Due to the mountainous region, and its relatively high slope and existence of the rock bed in residential areas around the river, the disposal of municipal wastewater is difficult. However, collecting wastewater is being done in Lavasan and Roodbar Ghasran Towns (Water & Energy center of Sharif University Report, 2003). The study area and sampling stations are shown in figure 1. These stations were selected according to the distribution of population centers and how branches of river are joined together. FIG.1. THE STUDY AREA AND LOCATION OF THE STATIONS Sampling and Monitoring Sampling schedule should cover both wet and dry seasons (Da. olahi, et al., 2012). Sampling of Jajrud Was collected seasonally between 2001 and 2008 by our research team Under the Institute of Water & Energy, Sharif university of Technology. Temperature, ph, Dissolved oxygen, Total dissolved solids (TDS) by portable devices based on standard method for water and wastewater tests is measured. (APHA, 1999) Laboratory analysis to identify; Total suspended solids (TSS), Ammonia nitrogen (NH4), Total phosphate ( TPO4), Biological oxygen demand (BOD5), Turbidity (NTU) Fecal Coliform (FC) is measured based on standard method. See Table 1. Station / parameter TABLE1. STATISTICAL SUMMARY OF WATER QUALITY DATA Before meygoon After meygoon Dab Hajiabad Pole lashkarak Before Saigon Polefasha m Ahar Galandoa k M SD M SD M SD M SD M SD M SD M SD M SD M SD M SD Tw ,3 5, FC ph , Turbidity TSS NO T PO BOD DO TDS NH M= Mean Value SD= Standard Deviation All values,except PH,in mg/l.turbidity in NTU.Bacteria expressed as MPN per100 ml Age 43

3 The WQI Calculation Water quality index was calculated in two ways; the first one was done by National Sanitation Foundation and parameters used including temperature, BOD5, Total Phosphate, Total Nitrate, Turbidity, Fecal Coliform, Total solids and DO. (Ott, 1978) This index is calculated by equation (1): n iw i i 1I WQI (1) n W 1 i 1 Where WQI is a number between 0 to 100 which 0 25 represents as very bad, as bad, as Medium, as Good and as excellent water quality. II is subindex of each parameter and is between zero to 100 also obtained from special curves. N is the number of water quality parameters for calculating the WQI and Wi is the weight factor for each parameter. This factor is between zero up to 1 and is identified considering the importance of each parameter in water quality. In the Second Method The WQI is subjective water quality index. To determine WQI sub the basic equation (2) is used i which is presented by Rodrique Zde Bascaron (Conesa Fdez Vitora, 1995); (2) Where K is a coefficient which its maximum is one for good appearance quality, and 25% for very contaminated appearance quality. Ci is the scale factor for each Parameter. Pi is the weight factor for each parameter. The extreme value for Pi is 4 and it is related to parameter which has the most degree of importance in aquatic such as DO and TSS. The least value is dedicated to parameters like ph and temperature that have the least degree of effect. Table 2 presents the suggested value for Ci and Pi to calculate WQI according to European standards (EU, 1975). Water quality parameters which were applied including temperature, ph, turbidity, TSS, NO3, TPO4, BOD5, DO, TSS and NH4. Table 2 shows categorizing the degree of water quality considering the calculated index by this method (Conesa Fdez Vitora, 1995). TABLE 2. PARAMETERS CONSIDERED FOR WQI CALCULATION Normalization factor(ci) Relative Parameter / Weight(pi) Analytical Value Ammonia nitrogen 3 <0.01 <0.05 <0.10 <0.20 <0.30 <0.40 <0.50 <0.75 < >1.25 BOD 5 3 <0.5 <2 <3 <4 <5 <6 <7 <8 <12 15 >15 Dissolved oxygen >7.0 >6.5 >6.0 >5.0 >4.0 >3.5 >3.0 > <1.0 Nitrates 2 <0.5 <2.0 <4.0 <6.0 <8.0 <10.0 <15.0 <20.0 < >100.0 ph Phosphorus (orthophosphate) 1 <0.16 <1.60 <3.20 <6.40 <9.60 <16.0 <32.0 <64.0 < >160.0 Solids: dissolved 2 <100 <500 <750 <1000 <1500 <2000 <3000 <5000 <10,000 20,000 >20,000 Solids:total 4 <250 <750 <1000 <1500 <2000 <3000 <5000 <8000 <12,000 20,000 >20,000 Temperature 1 21/16 22/15 24/14 26/12 28/10 30/5 32/0 36/ 2 40/ 4 45/ 6 >45/< 6 Turbidlty 2 <5 <10 <15 <20 <25 <30 <40 <60 < >100 Results and Discussion The statistical summary data during research in ten measurement stations in jajrud watershed is presented in Table 1. Parameter values measured at the stations indicated: the mean value of ph, at all stations during the measurement period are the same. The values of Fecal Coliform (FC), the stations of the population centers, significantly increase. This increase in FC after Maygoon town (Station 2) can be seen clearly. The upstream branches (ahar and Zayegan), stations 8 and 6, the turbidity is less. Total solids (TS) in station 9 (Galandoak) located in seasonal River kandrood is significantly increased. The amount of total Phosphate is also high on Galandoak 44

4 Advances in Water Resource and Protection (AWRP) Volume 2, station 9, and after Meygoon station 2. Variation of BOD5 is similar to phosphate in the river. The highest amount of nitrate Station 9 (located on the river kandrood) is obtained. Dissolved oxygen is high in the water because of high slope of the river. WQInsf and WQI sub in ten stations is presented in figure 2. Index values of WQIns are calculated at ten measurement stations except second station, between 50 and 70 are obtained. While the index values of WQI sub calculated for all stations in between 50 and 70 are obtained. The results from these two methods are closely related, and the trend is the same for all stations. Comparing these values of WQInsfand WQI sub with water quality categorizing, it is obvious that water quality (except second station) is average. Water quality index is affected by municipal wastewater of Meygoon to the river in the second station and is affected by seasonal Kandrood River at the upstream and carrying organic material and nutrient by sediment in the rainy season in the 9th station. Also the results are extracted by the two methods are approximate and similar. WQI value station wqi(nsf) wqi(sub) FIG.2.VARIATION OF WATER QUALITY INDEX FOR DIFFERENT SAMPLING STATIONS IN THE TWO METHODS Conclusion and Suggestions Monitoring the quality of the Jajrud River during 9 years shows that Meygoon and Fasham town which are located along the river and have effects on this river. These effects specially increase microbial contaminants in the water. Calculating WQI for categorizing water of the investigated river presents its importance. Based on the results of the two methods for calculating the index values, water quality in the river is in average condition. Of course, the second station is out of the range. In comparing the two methods, WQINSF is more usable and has fewer problems. The amount of this index has well convergent with WQIsub. References A. A. Bordalo, J. Sava Bordalo. The quest for safe drinking water: an example from guinea bissao. Water research. vol , A. Atilla and A. M.E. Pollution evaluation in streams using water quality indices: A case study from Turkey s Sapanca Lake Basin [Journal] // Ecological Indicators Vol American Public Health Association (APHA). Standard Method for the Examination of Waters and Wastewaters, 20th. APHA, Washington, DC. USA, Asadollahfard, G. Afshar, A, and Shakhastani,A.Review of water quality indices and its usage in National Sanitation of Water Quality indices in Karoon River, Journal of Sharif University, 27, Iran,2004 Asadollahfardi, G. Application of water quality indices to define surface water quality in Tehran, International Journal of Water, 5,51 67, 2009 C. Maja and C.F. Patricia Use of ecological indicators to assess the quality of Great Lakes coastal wetlands [Journal]// Ecological Indicators : Vol Conesa Fdez Vitora V.In: Methodological Guide for Environmental Impact Evaluation, 2nd ed, p.390. Mundi Prensa, Madrod, Dadolahi Sohrab A., Arjomand F. and Fadaei Nasab M. Water quality index as a simple indicator of watersheds pollution in southwestern part of Iran [Journal]// Water and Environment Journal Vols. DOI: / j x. E. Sanchez, M. F. Colmenarejo, J. Vicente. Use of the water quality index and dissolved oxygen deficit as simple indicators of watersheds pollution, Ecological indicators. vol , European Union (EU). Council directive 75/440/EEC of 16 june 1975 concerning the quality required of surface water intended for the abstraction of drinking water in the member state. official journal L198, 25/07/1975, ,

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