Index name

Water Pollution Index (modified)

Scientist who Developed Index: Name, Institute; Year; First Reference;

DRAGANA MILIJAŠEVIĆ, ANA MILANOVIĆ, JOVANA BRANKOV and M. RADOVANOVIĆ
Geographical Institute “Jovan Cvijić”, Serbian Academy of Science and Arts, 11000 Belgrade, Serbia
2011
Milijašević D., A. Milanović, J. Brankov, M. Radovanović 2011. Water quality assessment of the Borska reka river using the WPI (Water Pollution Index) method. – Archive of Biological Science, 63: 819-824.

Abstract (Summary):

Water Pollution Index Modified – The Borska Reka river (47 km long, 373 km2 of basin area) is located in eastern Serbia and it is the biggest tributary of the river Veliki Timok. It is also one of the most polluted watercourses in Serbia. Using the data of the Republic Hydrometeorological Service of Serbia, the paper analyzes water pollution using the combined physical-chemical WPI index (Water Pollution Index Modified) over two periods: 1993-1996 and 2006-2009. The analysis of parameters showed significantly increased values of heavy metals (especially iron and manganese) which are indicators of inorganic pollution (primarily because of mining), but also increased values of organic pollution indicators (Biological Oxygen Demand-BOD5, ammonium, coliform germs), as the result of uncontrolled domestic wastewater discharge.

Keywords: The Borska Reka river, WPI (water pollution index), mining, copper, iron, manganese, BOD5.

Introduction

Water Pollution Index Modified

Much research has been devoted to the study of the influence of mining and the mining industry on the quality and pollution of surface waters. This problem is partly presented in the papers which examine environmental changes caused by mining, with special analysis of hydrological changes (Schrek, 1998, Razo et al., 2004, Rigina, 2002). Some theoretical research has considered the possible ways of solving the conflict between mining and its impact on the environment by defining adequate regulations (Bridge, 2000, Adler et al., 2007). Also, there are many papers and publications which analyze the water quality of certain water bodies (rivers and lakes) in large mine basins (Ashton et al., 2001, Rosner, 1998, Holopainen et al., 2003, Oli´as et al., 2004, Milentijević et al., 2010). The aforementioned research is mainly based on the sampling method and chemical analysis of parameters or satelliteimage interpretation. The mining development in eastern Serbia started in the first half of the 5th millennium BC, as verified by the archeological site “Rudna Glava” which is noted in scientific literature as the center of early European copper metallurgy. The copper mining mine “Bor” began in 1904 and was funded by foreign capital. However, after World War II, it became state property and is now the established company “RTB Bor Group”. Metal production has increased in time and produces large quantities of waste products and therefore creates complex ecological problems. The written data have indicated that the environmental state in the town of Bor and its surroundings has been recorded in certain ways since 1908 when an area of 1250 ha was covered with dangerous substances (Stanković, 2004). Today, old-fashioned technologies which produce a large quantity of solid and liquid waste are mainly used in the mines. Besides the constant watercourse pollution by the wastewaters discharge, there are sometimes very dangerous accidents through flotation dams breaking. The Borska Reka basin is located in eastern Serbia. It covers 373 km2, which is about 8% of the total river basin of the Veliki Timok river. This river is to the left of the Veliki Timok into which it empties at the place Vražogrnac, and is the biggest tributary. It springs from the eastern slopes of the Veliki Krš and Mali Krš mountains (1148 m altitude) and it is 47 km long. Running towards the mouth, it receives several tributaries, among which are the Kriveljska river, Belorečka river, Slatinska river etc. The Slatinska river is taken as an extension of the Borska Reka river. The average annual discharge is about 3.22 m3/s, the lowest is in August (1.65 m3/s), аnd the highest is in February (4.90 m3/s). Water Pollution Index Modified – The Borska Reka river is one of the most polluted watercourses in Serbia; it is an out of water class river and without any traces of life. The basic pollution source in the Borska Reka basin is the mining-industrial complex “Bor” and untreated communal wastewaters. Numerous researchers study the problem of water quality and pollution in this river basin in the framework of environmental state analysis (Lekovski et al., 1997, Lekovski and Miljković, 1997, Jenić and Mitrović, 1992) or water course quality (Ristić and Ristić, 1991).

Uses and Limitation:

It has wide application and it is used as the indicator of the quality of sea (Filatov. et al., 2005) and river water (Lylko et al., 2001), as well as of drinking water (Nikoladis et al., 2008).

Categorization Table

The quality class according to WPI (lyulko et al. 2000, milijašević et al. 2011)

Standards Required

The standard threshold values for all parameters are specific for each country, given as national legislative (oFFiCial gazette RS 74/2011), which should minimize the bias caused by ecological and geographical differences.

Variables Selection

The following parameters are taken into consideration: dissolved O₂, pH, suspended sediments, BOD₅, nitrites, orthophosphates, ammonium, metals (Fe, Mn, Hg, Cu, Pb, Cd), sulfates and coliform germs.

Calculation of Water Pollution Index Modified:

The Water Pollution Index Modified is calculated as the sum of the ratio of the measured annual average value Ai and the standard threshold values T for each parameter, divided by the number of used parameters (n):

\(\)

\begin{eqnarray*}
WPI=\sum_{n=1}^{n} \ \frac{A_{i}}{T} X \frac{1}{n}
\end{eqnarray*}

Case Studies based on Water Pollution Index Modified

Case Study 1

Water quality and status assessment of water bodies could be based on a large number of various parameters, including physical, chemical, hydromorphological, microbiological and biological. Often it is difficult to interpret the results of water status assessment when numerous quality elements are analysed, since each may indicate different quality class. The Water Pollution Index Modified (WPI) overcomes this problem by providing a single assessment score. Previously, WPI was calculated using physical and chemical parameters combined with microbiological parameters. Biological quality elements are recommended by the EU Water Framework Directive (WFD) as obligatory for the assessment of ecological status of water bodies. For the first time in this study, the index was modified to include also biological parameters. Sampling and field measurements were done in 2007–2011, at three sites on the Sava River in the Belgrade region. According to the obtained WPI values, the river was assessed as polluted in 2007, moderately polluted for the period 2008–2010 and slightly polluted (“pure”) in 2011. This result shows an overall improvement of the water quality during the period of examinations. Our study demonstrates that the WPI could be effectively used as a metric for ecological assessment according to the requirements of the WFD. It should be further elaborated to provide type- and stressor-specific assessment system.

Case Study 2

The Timok River (202 km long, 4547 km2 basin area) is located in East Serbia. It is a right tributary of the Danube River and one of the most polluted watercourses in Serbia. On the basis of the data provided by the Republic Hydrometeorological Service of Serbia, the paper presents an analysis of water quality and pollution using the combined physico-chemical WPI index (Water Pollution Index) calculated for two periods – 1993–96 and 2006–2009 at four hydrological stations: Zaječar-Gamzigrad (Crni Timok River), Zaječar (Beli Timok River), Rgotina (Borska Reka River) and Čokonjar (Timok River). The following parameters were taken into consideration: dissolved O2, O2 saturation, pH, suspended sediments, Five Day Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (CODMn), nitrites, nitrates, orthophosphates, ammonium, metals (Cu, Fe, Mn, Hg, Ni, Zn, Cd), sulphates and coliform germs. The average WPI values were calculated for the observed periods based on the comparison of the annual average values of the listed parameters and defined standard values for the I water quality class (according to the Regulation on the Hygienic Acceptability of Potable Water of the Republic of Serbia). The highest pollution degree was recorded in the Borska Reka River, where heavy metal levels (especially manganese and iron) were significantly increased. These metals are indicators of inorganic pollution (primarily caused by copper mining). Also, increased values of the organic pollution indicators (ammonium, coliform germs, Five-Day Biological Oxygen Demand – BOD5) in the Borska Reka and the Timok rivers are the result of uncontrolled domestic wastewater discharge.

References

Brankov, Jovana, Milijašević, Dragana, Milanović, Ana (2012). The assessment of the surface water quality using the water pollution index: a case study of the Timok river (the Danube river basin), Serbia. Archives of Environmental Protection, 38 (1), 49-61.

Popović, Nataša Z., Đuknić, Jelena A., Čanak Atlagić, Jelena Ž., Raković, Maja J., Marinković, Nikola S., Tubić, Bojana P., Paunović, Momir M. (2016). Application of the Water Pollution Index in the Assessment of the Ecological Status of Rivers: a Case Study of the Sava River, Serbia. Acta zool. bulg., 68 (1), 97-102.