The main sources of water in the State are from the Bay of Bengal, from lakes like Chilika and Ansupa, from 11 rivers such as: Mahanadi, Subarnarekha, Baitarani, Rushikulya, Budhabalanga, Brahmani, Salandi, Kathajodi, Birupa, Kusabhadra, Daya and many rivulets. The water sources include ground water, tanks, ponds, open wells and tubewells.
The quality of water depends on the quantity of harmful elements present in it. Water may be polluted either from natural sources or human sources. The natural elements which cause water pollution are gases, soil, minerals, humus materials, waste created by animals and other living organisms present in water. During rain, surface water with soil, mud and humus enter into the river, tanks and other water bodies. The inorganic minerals like sodium, potassium, calcium, magnesium and heavy metals like iron, manganese, lead, mercury, chromium, cadmium, nickel, cobalt, beryllium when present above the permissible limit are harmful for drinking. Ground water containing fluoride above 0.15 mg/litre at Begunia in Khurda district, in six villages (Dergaon, Jutiki, Behal, Sargiguda, Kirojhote and Kandhamal) of G.P. Karlakata of Block Boden Nuapada district causes diseases like florosis, bone and teeth defornation, in both human beings and animals.
The human sources of water pollution are due to the following reasons: a) Discharge of domestic effluents, b) discharge of sewage, c) industrial effluent, d) mining operations, e) agricultural effluents and f) man-made water pollutions.
In urban areas people use about 335 litres of water daily for different domestic purposes. About 70-80 percent of this water drains out to the nearby ponds, tanks or rivers through the drains or nalas of the municipality, thereby pollute water. Municipal sewage is considered to be the main pollutant of water. Most of the sewage receives no treatment before discharge in all the cities of Orissa. The cities like Bhubaneswar, Cuttack, Rourkela, Sambalpur and Berhampur generate approximately 10,7.5,6,3 and 5 lakh litres of sewage effluents respectively everyday. These effluents are discharged into the river Mahanadi and Kathajodi in Cuttack, Kuakhai and Daya in Bhubaneswar, Brahmani in Rourkela, Mahabadi at Sambalpur and Rushikulya at Berhampur. The effluents contain heavy metals like lead, chromium, cadmium, zinc, mercury and harmful bacteria & viruses.
The paper industries in Orissa generally discharge effluents to the rivers like Rushikulya, Mahanadi, Kolab and Budhabalanga. These effluents contain high amount of carbonate, bi-carbonates and heavy metals of Fe, Mn, Zn and Cu which cause pollution of drinking water. Discharge of effluents from smelter plants to water bodies cause fluoride pollution in Angul. Fly ash effluents from captive power plants contain chromium, lead, cadmium and iron. These effluents discharged to the nearby water bodies pollute the water. The river Nandira at Talcher is said to be dead due to discharge of fly ash effluents into the river. Press mud effluents from sugar mills contain heavy metals like Iron, Manganese, Copper and Zinc. The effluents from chlorine plant containing high chloride and SAR value cause chloride and sodium toxicity to the river Rushikulya. The Phosphatic Fertilizer Industry discharges effluent containing Nitric, Sulphuric and Phosphatic acids to the joining mouth of the river Mahanadi into the Bay of Bengal. Discharge of hexavalent chromium from chromite mines of Sukinda pollutes
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