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/lp/de-gruyter/comparative-investigation-of-river-water-quality-by-owqi-nsfwqi-and-bSiOGtK5Bt
- Publisher
- de Gruyter
- Copyright
- Copyright © 2016 by the
- ISSN
- 2083-4810
- eISSN
- 2083-4810
- DOI
- 10.1515/aep-2016-0005
- Publisher site
- See Article on Publisher Site
Abstract
Rivers are considered as one of the main resources of water supply for various applications such as agricultural, drinking and industrial purposes. Also, these resources are used as a place for discharge of sewages, industrial wastewater and agricultural drainage. Regarding the fact that each river has a certain capacity for acceptance of pollutants, nowadays qualitative and environmental investigations of these resources are proposed. In this study, qualitative investigation of the Talar river was done according to Oregon Water Quality Index (OWQI), National Sanitation Foundation Water Quality Index (NSFWQI) and Wilcox indicators during 20112012 years at upstream, midstream and downstream of the river in two periods of wet and dry seasons. According to the results of OWQI, all of the values at 3 stations and both periods are placed at very bad quality category and the water is not acceptable for drinking purposes. According to NSFWQI, the best condition was related to the upstream station at wet season period (58, medium quality) and the worst condition was related to the downstream in wet season period (46, very bad quality). Also the results of Wilcox showed that in both periods of wet season and dry season, the water quality is getting better from upstream station to the downstream station, and according to the index classification, the downstream water quality has shown good quality and it is suitable for agriculture. Introduction For proper application of water resources, communities, agricultural and industrial centers are usually constructed next to the rivers (Srinivas et al. 2013, Shamsai et al. 2006). Because of the increase of population, industrial development, increase of water salinity, pouring various organic and mineral pollutants into rivers as sewage and etc. Rivers are water bodies most vulnerable to pollution due to their role in transporting point and non-point discharges in their vast drainage basins (Boyacioglu 2014) and rivers are being contaminated and this contamination of water resources in most of the rivers around the world leads to serious threats to environment, agricultural products and human health (Jafarabadi 2012, Godghate et al. 2013). In many countries such as Iran, social and industrial developments changed the qualitative characteristics of the river water and leads to excessive pollution. Therefore, overall national planning and resource management in respect to water with emphasis on allocation of priorities among the different uses is necessary. It is not surprising that, due to the above factors, studying water quality is so much important to be carried out in order to keep our awareness and understanding of our environment (Abdul Hameed et al. 2010). Regarding apparent difference between limitation of water resources and daily increasing demand for these resources at communities, the emphasis is placed on continuous monitoring, control and treatment of surface waters. Therefore, continuous measurement and analysis of qualitative parameters of rivers are considered as the main issue for identification of water quality. While until now, limited studies of a few rivers have been done in Iran, nowadays in many developed countries, qualitative zoning of rivers have became a basic method for proper management of water resources (Cheraghi et al. 2007, Rahimi 2003). As a result, qualitative studies and zoning of rivers according to indicators of water quality standard, not only clear the qualitative conditions of the river water, it also leads to sustainable development and help to increase the productivity of the river (Mirmoshtaghi 2012, Bharti et al. 2011). By identifying those sections of the river where the water quality parameters are lower than the standard values, finding proper solutions for removing of these pollutants will become easier (Nazari et al. 2005, Eneji et al. 2012). Among the various indexes which are applicable for water quality zoning, NSFWQI was selected because of high precision, simplicity and availability of the required parameters (Shamsai et al. 2006, Zandbergen et al. 1988), and also OWQI index was selected and used because of being strict and having no weighting parameters which are involved in the index. In 2011, Mirmoshtaghi studied the water quality of the Sefidrood River by investigating 20 samples at 5 sampling stations according to NSFWQI index and compared the results with OWQI index. The results showed that maximum and minimum values of NSF were 57 and 32, respectively. And the average value of NSFWQI for Sefidrood River equals to 47.5, which classifies it as a bad region. Also, calculation of OWQI index showed the very bad quality of the Sefidrood River water during the study period (Mirmoshtaghi 2012). Shamsai in 2006 studied 3 quality indicators of OWQI, NSFWQI and BCWQI for qualitative zoning of the Karoon River and the Dez River during 3 years. The results obtained from comparing these indexes showed that NSFWQI is preferred because of direct involvement of measured parameters on structure of sub-index and total-index and also by considering the weight effect on sensitivity (Shamsai et al. 2006). A similar study was conducted by Curtis in 2001. He studied the OWQI calculation method and type of sampling from the Oregon River, by investigating parameters such as pH, total solids, fecal coliform, phosphate, dissolved oxygen, BOD5, nitrate and temperature. The results of that study showed that the OWQI index is a good indicator for zoning of the river. In another study, Cude showed the usefulness of the Oregon water quality index as a tool for water quality management. The Oregon water quality index is a single value which is representative of the water quality and obtained by combining the values of the eight above mentioned water quality variables (Cude 2001). In this study, the water quality index (WQI) was represented by three indexes of NSFWQI, OWQI and Wilcox to evaluate the spatial and temporal changes of surface water quality in the Talar River, the scores calculated were used for classifying the water quality and assessing the impacts of industrial and rapid urbanization on the overall water quality of the river. Material and Methods To determine the structure of surface waters quality indexes, the data prepared by measurement of water quality parameters are considered as base of the progress. Although, depending upon the kind of the index and its objectives, the parameters are different. These parameters are representative of the chemical, physical and biological characteristics of the water. The functions and relations that build the mathematical structure of the indexes affect these parameters and finally present the index as a single number (Liu et al. 2012). National Sanitation Foundation Water Quality Index (NSFWQI) NSFWQI is one of the most widely used indicators which comprises nine main parameters such as pH, total solids, fecal coliform, total phosphate, dissolved oxygen, BOD5, nitrate, turbidity and temperature. NSFWQI is obtained as below: NSFWQI= WiIi (1) In this equation, Ii is the quality of the ith parameter (a number between 0 and 100 read from the appropriate subindex graph) and Wi is the weight factor of the ith parameter (Badalians Gholikandi et al. 2012). After measuring the above characteristics, the sub-index of each of them is obtained from conversion curves. These curves convert the parameters into measures that range from zero to 100. To calculate the final index in this method, each sub-index obtained from the related curves is multiplied by weight factor, and the final index is obtained by the sum of them, according to Equation 1 (Ebrahimpur et al. 2012). For the calculation of NSFWQI and determination of Qi, the Wilcox Standard Graphs are used (Shamsai et al. 2006, Fabiano et al. 2008, Sanchez 2007). Classification of river pollution intensity and water description according to NSFWQI are presented in Table 1. Oregon Water Quality Index (OWQI) Generally, this index is used to assess water quality for recreational purposes. Simplicity, availability of required quality parameters, and the determination of sub-indexes by curve or analytical relations are some advantages of this approach. In this method, each of the eight parameters (as mentioned before) is no-weighting factor and has same effect on the final factor. Table 2 presents a water description according to the index numerical values. The final Oregon index is calculated by Equation 2; in this formula, n is the number of parameters Table 1. Classification of river pollution intensity according to NSFWQI index Calculated index 91100 7190 5170 2650 025 Class A B C D E Water Quality Condition Excellent Good Medium Bad Very Bad (n=8) and SIi is the value of parameter i (Ebrahimpur et al. 2012). This index is calculated by Equation 2: OWQI n i =1 1 SI 2 i (6) The standard graphs are used to calculate the SIi (Shamsai et al. 2006). Finally, the pollution and water quality of the river is assessed according to Table 3. Wilcox indicator Nowadays, this index is considered as a very common method for classifications of water for agricultural purposes. In this classification, two factors, Electrical Conductivity (EC) and Sodium Adsorption Ratio (SAR) are considered and each of them is divided into four sections which finally lead to the creation of totally 16 groups. The groups are classified as follows: (1) Very good water with EC less than 250 mohs/cm, it is in class C1S1. (2) Good water that is related to one of C2S1 or C2S2 groups. (3) Medium water that is related to one of C3S3, C3S2, C3S1, C2S3, C1S3 groups and is suitable for irrigation of lands with good drainage. (4) Unsuitable water for irrigation that is related to one of C4S3, C4S2, C1S4, C2S4, C3S4, C4S4, C4S4 groups (Saghi 2011), and as the index is greater the quality is lower (Rahmani 2008). Tables 3 and 4 show classification of water for agricultural purposes. Locations of sampling stations Location Map of the Talar River in Mazandaran province is shown in Fig. 1. For the determination of sampling stations along the river pathway, some issues including the discharge place of municipal and industrial wastewater, agricultural drainage and other sources of pollutants into the river, the qualitative effects of branches of river water and availability of Table 2. Average values of river water index according to OWQI index Numerical value 90100 8589 7084 6070 1059 Condition Excellent Good Medium Bad Very Bad Color Blue Green Yellow Orange Red Table 3. Agricultural water classification according to SAR SAR < 10 1018 1826 > 26 Classification S1 S2 S3 S4 Quality of Alkaline Low Medium High Very high Table 4. Agricultural water classification according to EC EC (mohs/cm) 100250 250750 7502250 > 2250 Classification C1 C2 C3 C4 Quality of the soil Low Medium High Very high Table 5. Locations of the stations Locations of Stations Station Pole-Sefid (Upstream) Shirgah (Middle stream) Kiakola (Downstream) Latitude 3998373 401878 4047543 Longitude 685267 669383 662205 The Average Height of the Basin (m) 637 253 6 The values of NSFWQI during two periods of dry and wet season are shown in Fig. 2. According to NSFWQI, none of the stations at all sampling months had a good or excellent water quality and at best conditions. Station No.1 which is less polluted and does not have any wastewater discharge during the two periods, has just a moderate quality. The reasons for this are natural low value of pH in the Talar River, irrigation of upstream agricultural lands and entry of chemical fertilizers, pesticides and manure into the stream (Banjaka et al. 2012). The values of OWQI during two periods of dry and wet season are shown in Fig. 3. The OWQI value at all of the stations in all sampling months was between 15 and 20 that is an indicator of "very bad" water quality hencethe Talar river water is not suitable for fishing and recreational purposes (Boskidisa et al. 2011). the stations were considered (Fataei et al. 2013). Locations of the stations are presented in Table 5. Under Study Parameters The variables studied in this research consist of nitrate, phosphate, total solids, pH, temperature, turbidity, fecal coliform, DO (Dissolved Oxygen) and BOD5. All of these parameters are measured according to the standard methods (APHA, 2005). Results and discussion Table 6 presents the average values of parameters during two periods of wet season and dry season at three zones of upstream, midstream and downstream, during six sampling months at three stations according to available standards. Table 6. Average results of parameters during periods of wet season and dry season Parameter DO (mg/L) BOD5 (mg/L) TS (mg/L) Turbidity (NTU) Temperature (°C) pH Fecal coliform (Colony/100ml) Nitrate (mg/L) Phosphate (mg/L) Wet season Upstream 7.31 0.5 3211 1022.11 -1.41 8.13 1047.16 5.11 0.113 Middle stream 8.05 0.78 2889.5 2398.66 2.33 8.15 2366.66 5.075 0.253 Downstream 4.183 0.583 2664.16 2260.83 4 8.13 2160 4.0 0.236 Upstream 8.96 0.65 1794.41 338.5 9.83 8.16 1585 3.73 0.173 Dry season Middle stream 9.16 1.31 747.16 715.83 16 8.05 3016.66 9.63 0.181 Downstream 5.45 6.11 1382.83 536.76 17.83 8.08 2466.66 7.51 0.205 Fig. 1. Location Map of the Talari River in Mazandaran province Fig. 2. NSFWQI changes trend in the Talar river Fig. 3. OWQI changes trend in the Talar River Comparison of OWQI and NSFWQI changes trend in various periods OWQI and NSFWQI changes trend in wet and dry seasons at various stations are shown in Figs 4 and 5. The comparison of OWQI and NSFWQI showed that NSFWQI is more suitable for the Talar river zoning, because it well shows the entering of pollution into the river along its pathway during sampling months. Also because of weighting parameters that are involved with NSFWQI, this index is distinct from OWQI. The study of Hooshmand in 2009 confirms this result that NSFWQI has a higher efficiency in comparison with OWQI (Hooshmand et al. 2009). Also, Fabiano in 2008 investigated the NSFWQI on the Macaco and the Kiocsada Rivers and the results of this study showed that NSFWQI is an acceptable indicator for zoning of the both studied rivers (Fabiano et al. 2008). Also, the study of Simeonov et al. in 2003 conducted on surface water quality of Northern Greece showed that by least treatment the water in this condition can be potable (Simeonov et al. 2003). Wilcox numerical value The amount of Wilcox indicator at study stations is presented in Table 7. According to Wilcox, in each period, the water pollution is decreased from upstream to downstream and conversely, water quality is increased because of EC and SAR reduction. Also, the water samples from the river in all sampling months and stations showed that the Talar river water is in S1 condition (low alkalinity) and C2C3 classes, according to SAR and EC, respectively. Generally, based on Wilcox the Talar river water is pretty suitable for agriculture in all sampling months and stations (Kowalkowski et al. 2007). Conclusions Population load and excess urban activity in the basin of this river, industrial activities, excessive consumption of chemical fertilizers and pesticides, discharge of rural, urban and industrial wastewater and also solid wastes into the river which have a continuous increasing trend are the main source of river pollution. So, human factor is the main cause of river pollution. Besides human factors, natural factors such as low rainfall, water consumption for agricultural and industrial purposes, development of agricultural lands at the expense of natural lands wastefulness and finally, increased physical and chemical pollution of the river that leads to Fig. 4. Comparison of OWQI and NSFWQI changes trend in wet season Fig. 5. Comparison of OWQI and NSFWQI changes trend in dry season Table 7. NSFWQI water quality index in two periods of wet and dry season Stations Up stream Middle stream Down stream Wet season Qualitative Condition Average Average Bad Index Value 58 51 46 Average Average Bad Dry season Qualitative Condition Index Value 55 52 50 natural disruption of its biological and bioavailability capacity. In this study, the river water quality is different for OWQI index and NSFWQI index. The reason for this can be due to the fact that OWQI is stricter than NSFWQI. According to OWQI, the DO, BOD5 and turbidity at station No.1 are at acceptable values of standards and there is no wastewater discharge into it, but, because of high nitrate and phosphate contents (due to the use of chemical fertilizers and pesticides at upstream), low pH and interactions between these parameters, station No.1 does not have a good quality water (Saha 2010). In terms of drinking purposes, water quality at station No.1 was better than in other stations and by least treatment and pH adjustments it can be potable. But water at other stations needs more advanced treatment to become acceptable for drinking purposes (Wongsupapa 2009). According to the studies which present the current conditions of the Talar River, three conclusions can be considered: Generally, it comes from the interpretations of the results based on NSFWQI that along the Talar river pathway from upstream station to the outlet of the Caspian Sea, the pollution load is increased and water quality is decreased. The NSFWQI value at upstream station was more than 50 and at down-stream station (in both periods) was less than 50, which is indicator of bad conditions. So, according to NSFWQI, the average quality of the Talar river water is moderate. Table 8. OWQI index in two periods of wet and dry season Stations Up stream Middle stream Down stream Wet season Qualitative Condition Very bad Very bad Very bad Index Value 18.62 18.42 17.89 Very bad Very bad Very bad Dry season Qualitative Condition Index Value 19.22 15.58 17.68 Table 9. Wilcox value at study stations in wet and dry seasons Station Upstream Middle stream Downstream Wet season Qualitative Index C3S1 C2S1 C2S1 Qualitative Condition Medium Good Good C3S1 C3S1 C2S1 Dry season Qualitative Index Qualitative Condition Medium Medium Good According to the results of the OWQI index experiments, the water quality of the river is in "very bad" condition so the Talar river water is not suitable for fishing and recreational purposes. Based on Wilcox index, the Talar river water is suitable for agricultural purposes in entire river and on every day of the year.
Journal
Archives of Environmental Protection – de Gruyter
Published: Mar 1, 2016