International Journal of Chemical Studies 2020; SP-8(5): 261-267 P-ISSN: 2349–8528 E-ISSN: 2321–4902 www.chemijournal.com Assessment of water quality status of river Kopili, IJCS 2020; SP-8(5): 261-267 © 2020 IJCS in Karbi Anglong district of Assam using water Received: 15-07-2020 Accepted: 19-08-2020 quality index Dipanka Nath Department of Aquatic Dipanka Nath, Rajdeep Dutta, Sarada Kanta Bhagabati, Raktim Sarmah, Environment Management, College of Fisheries, Assam Agricultural Hemanta Pokhrel, Abdul Malik Ahmed and Lawonu Prasad Mudoi University, Raha, Nagaon, Assam, India DOI: https://doi.org/10.22271/chemi.2020.v8.i5e.10629 Rajdeep Dutta Department of Aquatic Abstract Environment Management, College River Kopili, regarded as one of the most important Southern bank tributaries of the mighty river of Fisheries, Assam Agricultural Brahmaputra, is facing a tremendous pollution threat from its riparian areas, especially in its upper University, Raha, Nagaon, Assam, stretches due to anthropogenic activities. The Central Pollution Control Board (CPCB) in one of its report India has placed the Kopili river in 4th rank among the 56 most polluted river of North-East region. The results of the present study showed that water quality index [1] of the river ranges from poor to unsuitable quality Sarada Kanta Bhagabati Department of Aquatic of water for drinking in almost all the five sampling stations. The water quality found to be deteriorated Environment Management, College during winter season with an average WQI value of 81.88 as compared to pre-monsoon and monsoon of Fisheries, Assam Agricultural season with an average value of 67.13 and 80.12 respectively. According to the water quality index, University, Raha, Nagaon, Assam, station 4 and 5 are recorded to be the most polluted stations among the study area. Thus, all the above India analysis showed that the riverine ecosystem is moderately polluted, which may degrade further if proper management of the riverine ecosystem is not initiated timely, which is the need of the hour to sustain the Raktim Sarmah environmental integrity of the river Kopili. Department of Aquatic Environment Management, College of Fisheries, Assam Agricultural Keywords: Kopili river, Brahmaputra, environmental integrity, water quality index University, Raha, Nagaon, Assam, India Introduction Hemanta Pokhrel River is a lotic ecosystem flowing under the influence of gravity and confluence into the sea Department of Aquatic and some into lakes. Rivers are regarded as one of the most important resources in the world Environment Management, College as well as in India in particular. Rivers are important pathways for the flow of energy, matter of Fisheries, Assam Agricultural and organisms through the landscape [2]. Rivers also play a major role in assimilation or University, Raha, Nagaon, Assam, India transportation of the municipal and industrial wastewater discharges continuously or occasionally or seasonally. Most of the ancient civilizations grew along the banks of the rivers. Abdul Malik Ahmed The water quality of a river is the composite of several interrelated compounds, which are Department of Aquatic [3] Environment Management, College subjected to local and temporal variations and also affected by the volume of water flow . [4] of Fisheries, Assam Agricultural Surface water resources are more vulnerable to pollution than ground water resources University, Raha, Nagaon, Assam, especially in developing countries where the heavy industrialization, increasing urbanization, India and adaptation of modern agricultural practices play an important role in improving the living [5] Lawonu Prasad Mudoi standard but at the same time cause severe environmental damage , and declining quality of [6] Department of Aquatic life for many people . Water pollution affects their physico-chemical characteristics and Environment Management, College microbiological quality [7]. Therefore, constant monitoring of a river system is required to of Fisheries, Assam Agricultural evaluate the effects of environmental factors on water quality for proper utilization and University, Raha, Nagaon, Assam, India sustainable development of the resources. Water Quality Indices (WQI) provides a single value to the water quality of a source on the basis of one or the other system which translates the list of constituents and their concentrations present in a sample into a single value. The application of WQI helps to [8] understand the overall water quality status of individual sampling stations at a certain time Corresponding Author: and its suitability for various beneficial uses. The concept of indices to represent gradation in Dipanka Nath water quality was first proposed by [9], since then numerous water quality indices have been Department of Aquatic Environment Management, College formulated that can easily evaluate the overall water quality of an area promptly and of Fisheries, Assam Agricultural efficiently. The general WQI developed by [1] has undergone much improved modification University, Raha, Nagaon, Assam, suitable for a different purpose. India ~ 261 ~ International Journal of Chemical Studies http://www.chemijournal.com th Study area Where Qi is the quality rating of i water quality parameter Kopili is an inter-state river of North-East India flows through for a total of n quality parameter, Wi is the unit weight of nth the states of Meghalaya and Assam. Kopili originates from water quality parameter. The quality rating Qi is calculated the south-western slope of the Shillong peak and flows using the equation: through southern Assam before its confluence with Brahmaputra. The geographical co-ordinates range of Kopili Qi= [(Vactual-Videal)/(Vstandard-Videal)] ×100 basin extends from longitude 91-930 E and latitude 25-270 N. th The basin covers a total geographical area of 13,55,600 Where Vactual is the actual amount of n parameter present, hectares. Its basin is bound by the Jayanti Hills in the West Videal is the ideal value of the parameter [Vi = 0, except for pH and the South Cacher and Mikir Hills in the East. Kharkor, (Vi = 7) and DO (Vi = 14.6 mg/l)], Myntriang, Dinar, Longsom, Amring, Umrong, Longku and Vstandard is the standard permissible value for the nth water Langkri are its major tributaries in its upper reaches. Diyung. quality parameter. Jamuna, Umkhen-Borapani, Killing, Umtrew/Digaru, Kolong Unit weight (Wi) is calculated using the formula etc. are its major tributaries in down stretch at Assam. The Wi = 1/Si river flows for a total length of about 290 kilometers and has a catchment area of 16,420 square kilometers (6,340 sq. miles). Where 1 is the constant of proportionality. The water quality status (WQS) according to WQI is shown in Table 1. Materials and methods Water samples were collected from five (5) different sampling Results and Discussions sites viz. Dharma Nagar, 8 Kilo (S1), Kopili Dam (S2), 29 Water Quality Parameters Kilo (Inside NEPCO Power Station) (S3), Panimur (S4) and All the physical and chemical water quality parameters Borowasling (S5) on monthly interval over a period of one recorded at various sites of Kopili river during pre-monsoon, year, i.e. January 2019 to December 2019 (Fig. 1). monsoon and winter is shown in the table 2. Various physico-chemical parameters of water were assessed pH value expresses the intensity of the acidic or basic by following standard protocols of [10, 11]. A set of nine most characters of water. The average pH values for pre-monsoon, important water quality parameters like pH, turbidity, monsoon and winter was found to be 4.62 ± 0.37, 4.07 ± 0.83 dissolved oxygen, total alkalinity, total hardness, total and 3.69 ± 0.38 respectively. Highly acidic pH was recorded dissolved solids, electric conductivity, biological oxygen during the study period which may be due to the impact of demand (BOD3) and chemical oxygen demand (COD) are unauthorized coal mining in the upper stretch of the river. selected to calculate the water quality index (WQI) of Kopili Coal have high concentration of pyrites which in presence of river at Karbi-Anglong district of state Assam. Calculation of water and oxygen undergo oxidation to produce sulphuric WQI was carried out by following the ‘weighted arithmetic acid thereby increasing the acidity of the water. According to index method’ [1] using the following equation: [12, 13] an ideal pH for fish culture practice ranged between 6.5 [14] WQI = ∑WiQi ∕ ∑Wi to 9. According to the acidic pH death point for fish is 4. Fig 1: Map showing the study area Turbidity is the presence or absence of clay silt, dissolved NTU (±0.83) and 3.06-4.19 NTU (±0.43) during pre- organic and inorganic matter, turbid water received from the monsoon, monsoon and winter respectively. Turbidity was catchment area, plankton and other microscopic organisms. found to be maximum in the month of October 2019 which Observed turbidity value of Kopili river in Karbi-Anglong may be due to the bursting of hydroelectric dam of the river, district ranged between 0.41-1.46 NTU (±0.37), 1.45-3.72 which may carry a huge amount of sediment load from the ~ 262 ~ International Journal of Chemical Studies http://www.chemijournal.com catchment areas. A nephelometer turbidity reading of 20-30 season respectively, which is under the standard limit of NTU is considered as suitable for fish culture [15]. So, it can be ICMR (300 µS/cm). The increased in EC values of water assumed that the river water is not conducive for fisheries indicates that there is a source of dissolved ions in the point of view. vicinity. Higher the value of dissolved solids, greater the The amount of oxygen which is dissolved in a water body is number of ions in water. Increasing levels of conductivity is known as dissolved oxygen (DO). The mean DO values the products of decomposition and mineralization of organic ranged from minimum 7.25 mg/L (±0.36) during monsoon materials.