Goa’s Mandovi River, which flows past the state capital Panjim was found to be polluted with faecal coliform levels well beyond permissible limits at all the 22 sampling locations, the Goa State Pollution Control Board, in an interim report submitted before the Bombay High Court revealed.
The Pollution Control Board, which was tasked with conducting water quality sampling following reports of dead fish being found floating in one of the lakes that feed into the river, however revealed that the source of the pollution was yet to be established. Most Probable Number (MPN) is a unit used in microbiology to estimate the total number of living microorganisms in a given sample. 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. “In its future endeavour of identifying the point and non-point sources of wastewater/coliform contamination, the GSPCB is aiming to identify and contain the pollution from non-point sources. The high court instituted a suo motu public interest petition after the Mala Lake, located along the Rio de Ourem on the city’s eastern edge, became the latest water body to fall prey to contamination and neglect after hundreds of dead fish were found floating in the water in April this year. The lake, once sought to be promoted as a recreational and tourist destination, has been lying in neglect. Other parameters of the river water including pH levels, turbidity, dissolved oxygen, biological oxygen demand, presence of nitrates and nitrites were found to be within permissible limits.
Fecal coliform numbers ranged from 130 to 540 MPN/100 ml during high tide and 130 to 940 MPN/100 mL during low tide, according to the report. According to the Central Pollution Control Board (CPCB) norms the permissible limit for Faecal Coliform is 100 MPN/100ml. Based on the analysis reports of high tide samples, 22 out of 22 sampling points exceeded the permissible limit of 100 MPN/100mlThe highest faecal coliform reading was 540 MPN/100 ml, recorded at several sampling points: upstream from the Mandovi Bridge, near the Cruise Boats jetty, near Casino Majestic Pride, near Mid-point towards the mouth of River Mandovi (Downstream of anchored Casinos), and near Panaji, the report said. Based on the analysis reports of low tide samples, all 22 sampling points exceeded the permissible limit mid-point towards the mouth of River Mandovi and downstream of the anchored casinos, both recorded the highest numbers of 940 MPN/100ml.
“The same trend has also been reported in samples analysed during the pre-monsoon season,” the report also said. There appears to be a greater input of microbial load through non-point sources of sewage effluent runoff into the River Mandovi,” the Pollution Board said in its report adding that likely non-point sources of pollution into the Mandovi estuarine stretch along the Panaji city shore mainly are, Rio de Ourem (Ourem Creek), City market drainage, Santa Inez creek/canal, while along the opposite bank in Betim are the Betim Fishing jetty, Betim fish market and a few seasonal storm drains. State advocate general Devidas Pangam said that the state would assist the Goa State Pollution Control Board (GSPCB) in carrying out “surveys of various sources like various creeks discharges and drainages where we’ll be able to find out the real source of this pollution.”
