Faecal matter pollutes Cauvery in TN most

Faecal matter pollutes Cauvery in TN most

Contamination of surface water is a common phenomenon

Faecal matter pollutes Cauvery in TN most

The Cauvery as it flows through Hogenekal. Faecal contamination is high due to disposal of either untreated or partially treated municipal waste into the river.

The twin-pronged programme, “Monitoring of Indian National Aquatic Resources (MINARS) and Global Environmental Monitoring System (GEMS),” which in all studied the Cauvery water quality at 20 stations along its course in Tamil Nadu, is appalled by  the data.

The “overall analysis of the data reveals that the faecal contamination of surface water of the river is a common phenomenon due to the unhygienic anthropogenic activities and disposal of either untreated or partially treated municipal waste into the river systems directly or indirectly,” says the study.

The findings of the study form part of the latest annual report of the Tamil Nadu Pollution Control Board (2008-09), placed in the State Assembly on Monday.

Under the “MINARS” arm, water quality tested over a period of time at 16 places along the river course in the State, uniformly shows a value for the ‘pH’ range – a measure of how acid or alkaline a substance is, at above the standard norm of 7, indicating the water could be alkaline.

The “Biochemical Oxygen Demand (BOD),” against a tolerance limit of 3 mg/litre, is below that value at all those places. Only at the “Grand Anaicut” point upstream of Tiruchirappalli does the BOD figure shows a relatively healthy 2.78 mg/litre.

In general, the “designated best use (DBU)” for Cauvery waters at the above 16 stations presents a mixed picture. At five of those places, the water could at best be used for “outdoor bathing.” In the remaining places, the river could be a drinking water source only after “conventional treatment, followed by disinfection,” the study has emphasised.

The sampling for this study was done on a frequency prescribed by the Central Pollution Control Board and the analysis done at the “Advanced Environmental Laboratory,” Salem, the report said.

The analysis of water samples for quality in the Thamiraparani river—the other major river in Tamil Nadu further down south—was not very reassuring either. The level of ‘pH value’ monitored at seven stations along the river showed it varied from 6.69 to 7.01, against the prescribed norm of 6.5 to 8.5. The biochemical oxygen demand (BOD) level was also lower than the norm of 3 mg/litre, ranging from 1.0 to 2.7 mg/litre, the study has found.