Assessment of Water Quality of Subarnarekha River In Balasore Region , Odisha , India

The present study was carried out to determine the water quality status of Subarnarekha River at Balasore region during pre-project period as Kirtania Port is proposed in this area. River water samples were analysed for physico-chemical parameters by following standard methods (APHA 1985) and the results showed their variations as follows: pH 7.3-7.8,Temperature 26.7-28.20C, Electrical Conductivity 392-514 μ mho ,Total suspended solids 118-148 mg/l, Total dissolved solids 241-285 mg/l, Alkalinity 27.3-42 mg/l, Total Hardness 64.63-114.06 mg/l, Calcium 24.6-32 mg/l, Magnesium 9.72-13.8 mg/l, Dissolved Oxygen 4.6-5.3 mg/l, Biochemical oxygen demand 1.1-3.39 mg/l, Chemical oxygen demand 53-147 mg/l, Nitrates 0.4-1.06 mg/l, Phosphates 0.86-2.4 mg/l, Sulphates 113-143 mg/l, Chlorides 26.32-36.63 mg/l, Iron 0.224-0.464 mg/l, Chromium 0.008-0.016 mg/l. The analysed physico-chemical parameters were almost not exceeded the maximum permissible limit of Indian standards (IS: 10500). After physico-chemical analysis, water quality index (WQI) was established from twelve important various physiochemical parameters by following weighted arithmetic index method. The calculated water quality index indicates that the quality of water was good and hence fit for use.


INTRODUCTION
Freshwater resources are under severe and increasing environmental stress.At a global level, two thirds of the withdrawals are used for agriculture and one fourth for industry.By the end of the century, withdrawals for agriculture have increased slightly whereas industrial withdrawals have probably doubled (World watch Institute, 1999).In India, the major 14 rivers i.e.Ganga, Yamuna, Godavari, Gomti, Kosi, Cauvery, Ravi, Sone, Chenab, Jhelum, Narmada, Mahi, Tapti and Krishna receive heavy flux of sewage, industrial effluents, domestic and agricultural wastes which consists of substances varying from simple nutrient to highly toxic hazardous chemicals.Most of the large rivers of the world are nothing but open sewers fit only to take urban wastes, half burnt bodies, poisonous pesticides and industrial effluents etc. many of our lakes, including Dal and Nagin of Kashmir have severally polluted with foul odour , silt deposits and get chocked due to excessive algal growths (Kaur, 2005).Ports are major hubs of economic activity and potential sources of pollution (National Research and Development Centre (NRDC), 2005).Gupta et al. (2002) suggested that deterioration of surface water quality may occur during both the construction and operation phases of ports.Subarnarekha basin is the smallest of the 14 major river basins of India draining an area of 19,296 square kilometres and covering hardly 0.6 percent of India's land surface, yet it is an important inter-State river flowing through one of the most important industrial belt and mineralrich areas of India..The river in its upper and middle reaches remains more or less as a stagnant pool, often highly charged with pollutants, particularly during dry periods as has been observed in the study based on the water quality data collected by the Bihar State Pollution Control Board (Priyadarshi, N, 1998(Priyadarshi, N, , 2004)).Subarnarekha is the lifeline of tribal communities and fishing communities, residing on the riverbanks and their life and livelihood is affected by the river's pollution.The basin therefore needs careful environmental management planning to protect its continued existence.A few studies have been undertaken to investigate the pollution of the Subarnarekha River towards its eastern and coastal sides (Mishra et al 1994, Senapati andSahu, 1996;Panda et al., 2006).The water quality of Subarnarekha River in Balasore region is also in threat because Government of Odisha has proposed Subarnarekha Port or Kirtania Port near the mouth of the Subarnarekha River at Chaumukh in Balasore district of the Odisha coast.The port has been awarded to Chennai-based Creative Port Development Limited (CPDL) to build and operate (http://en.wikipedia.org/wiki/Kirtania_port).If the port will come then anthropogenic activities will be increased which directly influence the water qualities of the river and the life of the people residing there to a greater extent.Hence, in present study the water quality assessment of river Subarnarekha in the coastal belt of Balasore during pre-projects period was done .This study can also be used as reference to monitor the water quality status of the Subarnarekha River during ongoing projects and post-projects scenario.

Sampling Locations
The sampling locations were selected randomly by considering the population, location and source.Water samples were collected from the locations along the route of the Subarnarekha River basin in Balasore district.The sampling locations were Rajghat, Jamkunda, Asti, Bhusandeshwar, Chaumukh and Chaumukh muhana which are described below (Table -1).

Physico-Chemical Analysis
Standard procedures as described by APHA (1985) was followed for the Sample collections, stabilization and transportation to the laboratory as well as storage.Water samples were analysed for eighteen parameters to determine the overall quality with respect to Temperature, pH, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Total Hardness, Calcium, Magnesium Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), Electrical Conductivity (EC), Chloride, Sulphate , Total Alkalinity, Chemical Oxygen Demand (COD),

Fig. 1: Map showing sampling locations (Source-Google Maps / Subarnarekha River)
Fluoride, Iron, Chromium and Nitrate-Nitrogen .The water samples were analysed for various parameters in the laboratory of P.G Department of Environmental Science, Fakir Mohan University, Balasore, Odisha during the period of March to July, 2013.In general, the standard methods recommended by APHA (1985) was adopted for determination of various physico-chemical parameters.

Water Quality Index
Calculating of water quality index is to turn complex water quality data into information that is understandable and useable by the public.Therefore, water Quality Index (WQI) is a very useful and efficient method which can provide a simple indicator of water quality and it is based on some very important parameters.
In current study, Water Quality Index (WQI) was calculated by using the Weighted Arithmetic Index method as described by Cude, C. 2001.In this model, different water quality components are multiplied by a weighting factor and are then aggregated using simple arithmetic mean.
For assessing the quality of water in this study, firstly, the quality rating scale (Qi) for each parameter was calculated by using the following equation; Where, Qi = Quality rating of ith parameter for a total of n water quality parameters Vactual = Actual value of the water quality parameter obtained from laboratory analysis Videal = Ideal value of that water quality parameter can be obtained from the standard Tables.Videal for pH = 7 and for other parameters it is equalling to zero, but for DO Videal = 14.6 mg/L Vstandard = Recommended WHO standard of the water quality parameter.
Then, after calculating the quality rating scale (Qi), the Relative (unit) weight (Wi) was calculated by a value inversely proportional to the recommended standard (Si) for the corresponding parameter using the following expression; Wi = 1/ Si Where, Wi = Relative (unit) weight for nth parameter Si= Standard permissible value for nth parameter I = Proportionality constant.
That means, the Relative (unit) weight (WI) to various water Quality parameters are inversely proportional to the recommended standards for the corresponding parameters.
Finally, the overall WQI was calculated by aggregating the quality rating with the unit weight linearly by using the following equation: Where, Qi = Quality rating Wi = Relative weight In general, WQI is defined for a specific and intended use of water.In this study the WQI was considered for human consumption or uses and the maximum permissible WQI for the drinking water was taken as 100 score.
Chemical analysis of water gives a concept about its physical and chemical composition by some numerical values but for estimating exact quality of water, its better to depend on water quality index which gives the idea of quality of drinking water.
The rating of WQI is shown below.

WQI level
Water Quality Rating

pH
Most natural waters are generally alkaline due to presence of sufficient quantities of carbonates.pH has no direct adverse effects on health, however a lower value below 4 will produce sour taste; and higher value above 8.5 ,an alkaline taste.In present study, it was found that the pH value ranged between 7.3 at sampling station-5 to 7.8 at sampling station-6.All the pH values represents alkaline nature of river water samples were within the permissible limit as per IS: 10500.

Temperature
Arise in temperature of the water leads to the speeding up of the chemical reactions in water, reduces the solubility of gases and amplifies the tastes and odours.Water in the temperature range of 7 0 C to 11 0 C has a pleasant taste and is refreshing .At higher temperature with less dissolved gases the water becomes tasteless and even does not quench the thirst.In present study, the values of temperature were ranged between 26.70 0 C at sampling station-3 to 28.20 0 C at sampling station-6.

Conductivity
As most of the salts in the water are present in the ionic forms, capable of conducting current, therefore, conductivity is a good and rapid measure of the total dissolved solids.It has got no health significance as such.In present study, the values of Electrical conductivity were ranged between 392 µ mho at sampling station-3 to 514 µ mho at sampling station-4.

Total Suspended Solids
IS acceptable limit for total solids is 500 mg/L and tolerable limit is 3000 mg/L of dissolved limits. .In present study the Total Suspended Solids (TSS) values ranged between 118 mg/l at sampling station-1 to 148 mg/l at sampling station-6.

Total Dissolved Solids
In natural waters dissolved solids are composed mainly of carbonates, bicarbonates, chlorides, sulphates, phosphates, and nitrates of calcium, magnesium, sodium, potassium, iron and manganese, etc.In present study, the Total Dissolved Solids (TDS) values ranged between 241 mg/l at sampling station-4 to 285 mg/l at sampling station-6.All the TDS values of river water samples were within the permissible limit as per IS: 10500.

Alkalinity
Alkalinity in natural waters is due to free hydroxyl ions and hydrolysis of salts formed by weak acids and strong bases.In present study, the Total Alkalinity values ranged between 27.30 mg/l at sampling station-5 to 42.30 mg/l at sampling station-1.All the Total Alkalinity values of river water samples in study area were within the permissible limit as per IS: 10500 .

Total Hardness
The total hardness of water is defined as the sum of calcium and magnesium concentrations, both expressed as calcium carbonate, in mg/L.Based on present investigation, hardness varied from 64.63 mg/l at sampling station-3 to 114.06 mg/l at sampling station-1.The permissible limit of Hardness for drinking water is 300 mg/l (IS 10500).Hence, all the hardness values of river water samples in study area were within the permissible limit.
to 147 mg/l at sampling station-6 in the study area, where as the prescribed limit for COD is 250 mg/l (IS 10500).Hence, all the COD values of river water samples were within the permissible limit.

Nitrates
Presence of high concentration of nitrates is an indication of pollution.Concentration of nitrates above 45 mg/L cause a disease methemoglobinemia.In present investigation, Nitrate was ranged from 0.40 mg/l at sampling station-6 to 1.06 mg/l at sampling station-3 in the study area, where as the prescribed limit for Nitrate is 45 mg/l (IS 10500).Hence all the Nitrate values of river water samples were within the permissible limit.