SHILLONG, Feb 20: The rivers of Shillong are gasping for survival, the latest water quality index reveals.
The Umshyrpi near Shillong Law College has a pH level of 7.1, a dissolved oxygen level of 0.7 mg and a biochemical oxygen demand of 35.0 mg. The pH, DO and BOD at Umshyrpi are 7.4, 3.2 mg and 21 mg.
The Wah Umhrah at Demthring has a pH level of 7.4, DO of 1.2 mg and BOD of 30 mg. At Umkaliar, near the Shillong abattoir and Mawpdang Mawlai, the readings are 7.6, 4.5 mg and 12.5 mg, 7.4, 0.5 mg and 40 mg, and 7.1, 1.3 mg and 28 mg.
The Lunar River, a tributary of Lukha, has a recorded pH level of 2.9, DO of 6.8 mg and BOD of 2.7 mg.
The levels indicate the water quality of these rivers is not satisfactory.
BOD is the amount of dissolved oxygen expressed in milligrams of oxygen per litre of water, consumed by micro-organisms to decompose the organic matter present in water. Pristine waters have a value below 1 mg, moderately polluted waters between 2–8 mg and treated municipal sewage about 20 mg.
DO refers to the level of free, non-compound oxygen present in water or other liquids. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water.
pH is a measure of how acidic or basic the water is. A pH of 7 or less means that the river water is acidic while values above 7 are alkaline or basic.
Environmentalist and author HH Mohrmen expressed concern over the state of the rivers in the state. “Rivers in the state come under the autonomous district councils, but they do have neither funds nor power to rejuvenate the rivers. The responsibility is with the state government but it needs to have the will,” he said.
Environmentalist Naba Bhattacharjee said he had highlighted issues plaguing the rivers in a complaint with the National Green Tribunal in 2014. The matter is under appeal in the Supreme Court.
Earlier, Forest and Environment Minister James Sangma said he was optimistic about rejuvenating the rivers with proper intervention by the government.
The NGT had in 2019 imposed a fine of Rs 1 crore on the government for failing to comply with its orders to set up action plans for cleaning the rivers and managing solid waste disposal.
The Meghalaya State Rejuvenation Committee had prepared an action plan in 2019 for the rejuvenation of the Wah Umkhrah and the Umshyrpi. Approved by the Central Pollution Control Board, the action plan entailed responsibilities for various government departments and local urban bodies.
As Shillong does not have a municipal sewer network system, all homes and industries feed raw sullage and effluents without proper treatment directly into the rivers. Thousands of families living on the banks of the rivers extract this water for drinking and domestic purposes.
This cycle is posing a serious threat to the health of the city’s residents and also to the environment including soil and groundwater.
A river rejuvenation analysis done by Clear Water Dynamics had suggested river resizing works to avoid flooding along riverbanks, identification and design of storm water drain to avoid flooding in river catchment areas, design of sewer networks and interceptor chambers to avoid entry of sewer into rivers and construction of STPs to treat and divert treated water into the river.
Additional engineering work proposals included bank stabilisation and rainwater harvesting methods (recharge pits), riverfront development proposal – seating arrangements, kids play area, community gathering places, walking pathways, drinking water kiosk and bio-toilets.
A 2008 investigation report on the contamination of the Lukha by the Meghalaya State Pollution Control Board indicated that the river was polluted and had turned blue as its tributary, the Lunar was highly acidic and reacted with the limestone effluents causing the bluish tint in the river.
It was informed that there are 15 companies, including 10 cement factories that constitute the major polluting units in the state. Apart from these units, three ferro-alloy companies, a power plant and a brewery were also on the offenders’ list.
Seven of these cement companies are based in the limestone-rich Jaintia Hills districts. Three other cement companies, one each in East Khasi Hills, East Garo Hills and in Jaintia Hills district, have also been listed by the government as major polluting industries.