PANAJI
All 44 water samples collected from the Mandovi estuary during the 2026 monsoon season exceeded permissible limits for faecal coliform bacteria, with the Goa State Pollution Control Board (GSPCB) identifying untreated sewage discharged through urban drains and nullahs as the primary source of contamination.
According to the Board’s interim report, the contamination was recorded at all 22 designated sampling locations across the estuary, raising concerns over the impact of untreated domestic wastewater on the river.
The findings also indicate that offshore casinos are not responsible for the contamination, with land-based sewage discharges emerging as the major concern.
The water-sampling exercise was conducted on August 24, 2026, during high- and low-tide cycles. All 44 samples exceeded the Central Pollution Control Board’s permissible limit of 100 MPN/100 ml for faecal coliforms. Counts ranged from 130 to 540 MPN/100 ml during high tide and rose to between 130 and 940 MPN/100 ml during low tide.
The highest count of 940 MPN/100 ml was recorded near the river mouth, along the Panaji shoreline and downstream of the anchored casinos. Elevated levels were also detected upstream of the Mandovi bridges and near the Cruise Boats Jetty.
The situation marks a deterioration from pre-monsoon sampling in June, when 16 of the 36 samples met the permissible limit during high tide. The Board attributed the deterioration partly to weaker monsoon conditions during June, July and August, which reduced the flushing of microbial pollutants towards the sea and allowed contamination from land-based runoff to accumulate in the estuary.
Despite the bacteriological contamination, the river’s physico-chemical parameters remained largely within acceptable limits. Dissolved oxygen ranged from 5.80 mg/l to 8.50 mg/l, above the CPCB baseline of 4 mg/l. Biochemical oxygen demand remained below detection limits at almost all locations, except for one reading of 2.1 mg/l near a casino vessel. Nitrate and nitrite levels also remained low.
Addressing the issue of offshore casinos, which was raised before the High Court, the GSPCB stated that the vessels were complying with wastewater-handling protocols. According to the report, sewage generated aboard the casinos is pumped into specialised sewage barges and transported to the sewage treatment plant at Patto in Panaji. The Board said it had verified inspection records, logbooks and payment records.
Instead, inspections identified St Inez Creek as a major source of pollution. A discharge of 10,000 to 15,000 litres per minute of dark, foul-smelling, organic-laden water was observed entering the Mandovi near Yoga Bridge, visibly discolouring a stretch of around 70 metres. Tidal currents carry the discharge both upstream and downstream.
Rua de Ourem Creek was found discharging more than 20,000 litres per minute near the old Patto Bridge, with an estimated 10 to 15 per cent of the flow comprising untreated domestic sewage. At Penha de França, a storm-drain canal was discharging around 100 litres per minute of mixed domestic wastewater and stormwater containing discarded plastic waste.
The GSPCB clarified that the findings are interim and form part of a three-season study mandated by the judiciary. Post-monsoon sampling at all 22 locations is scheduled for late October and November, with a comprehensive technical evaluation to be submitted before the High Court in December 2026.
High Court appraised of water quality status
The Goa State Pollution Control Board on Monday submitted to the High Court of Bombay at Goa that faecal coliform levels in the Mandovi river has remained consistently high despite the river’s overall water quality being assessed as good.
Advocate General Devidas Pangam, appearing for the State, said that the board had filed an interim report on the river’s water quality, which was taken on record by the Division Bench of Justice Valmiki Menezes and Justice Amit Jamsandekar.
“The report suggests the overall condition of the Mandovi river to be good, but the faecal contents are uniformly on the higher side,” the AG said as the Bench is hearing a PIL regarding pollution of Mala Lake and Mandovi River.
He said the Pollution Control Board was trying to identify the source of the faecal contamination and would conduct further surveys to trace the discharge entering the river.
“We have also decided to carry out further surveys and reports of various sources, like various creeks, discharges and drainages, where we will be able to find out the real source of this pollution,” Pangam said.
