Mandovi River Shows Widespread Faecal Coliform Contamination

An interim report submitted by the Goa State Pollution Control Board (GSPCB) to the Bombay High Court revealed that all 22 sampling locations in the Mandovi River — which runs past Goa’s capital Panaji — exceeded the Central Pollution Control Board’s permissible limit of 100 Most Probable Number (MPN)/100 ml for faecal coliform bacteria. Measurements ranged from 130 MPN/100 ml to 940 MPN/100 ml, with higher concentrations recorded during low tide.

Hindustan TimesThe Indian Express

The investigation was prompted by reports of massive fish die-offs in Mala Lake, a water body feeding the river, earlier this year. The High Court of Bombay at Goa initiated a suo motu public-interest petition to address the contamination and later expanded the petition’s scope to include the Mandovi estuary.

The Indian Express

Sampling conducted on August 24 covered 22 sites from the IFFI jetty (downstream) to the Mandovi bridges (upstream). While pH, turbidity, dissolved oxygen, biochemical oxygen demand, nitrate and nitrite levels remained within CPCB limits, faecal coliform counts consistently surpassed the 100 MPN threshold. The report noted a pronounced rise in bacterial load at low tide, likely due to downstream flow and weaker monsoon flushing. Non-point sources identified include Rio de Ourem, city-market drainage, St Inez creek, and, on the opposite bank, Betim fishing jetty, Betim fish market, and seasonal storm drains.

The Indian ExpressHindustan Times

It added that future efforts will focus on pinpointing and containing non-point sewage runoff. State Advocate General Pangam reiterated the board’s commitment to assist in source-identification surveys.

Hindustan Times

• “Faecal coliform numbers ranged from 130 to 540 MPN [most probable number]/100 ml during high tide and 130 to 940 MPN/100 ml during low tide. Based on the analysis reports of high tide samples, 22 out of 22 sampling points exceeded the permissible limit of 100 MPN/100 ml…” — Goa’s Mandovi

The Indian Express

• “Based on the analysis of low tide samples, all 22 sampling points exceeded the permissible limit…A comparative analysis of tidal conditions indicates that faecal coliform contamination is significantly higher during low tide times in comparison to those during high tide times. The same trend has also been reported in samples analysed during the pre-monsoon season.” — The Indian Express It

The Indian Express