Saturday , 18 August 2018
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Faecal coliform in Goa’s seawater higher than permissible limits: Study

ABDUL WAHAB KHAN

PANAJI: There may not be a single river or beach in the state which is clean throughout its length according to a recent study by Goa State Pollution Control Board (GSPCB) which has found high level of faecal coliform in the water bodies throughout the year.

Under the central pollution control board sponsored national water monitoring programme the GSPCB measured water quality of rivers at 40 locations on 16 rivers, 10 beaches and among them 21 locations is non-complying to the water quality criteria with respect to faecal coliform and total coliform.

The presence of faecal coliform in aquatic environment indicates that the water has been contaminated with the faecal material of man or animals. When the levels are high, there is an elevated risk of waterborne diseases.

About half of the stretch monitored during the yearlong study of water in 16 rivers has high level of faecal coliform and organic pollution, measured in terms of biological oxygen demand (BOD). The decline in the quantity and quality of water flow has reduced the productivity of many terrestrial, aquatic, and coastal zone ecosystems and led to loss of biodiversity.

Similar is the situation of Goan beaches, the water quality data analysis found faecal coliform exceeds prescribed limit in all ten beaches- Tiracol, Miramar, Calangute, Morjim, Mobor, Baina, Galgibag, Colva, Vagator and Velsao.

According to the water quality criteria prescribed by the Central Pollution Control Board (CPCB), faecal coliform organism MPN/100-ml should be 30 or less on river water without conventional treatment but after disinfection. The data of the water quality analysis showed the faecal coliform in River Mapusa, River Mandovi, River Sal, and River Zuari which did not comply with the CPCB standard. The total coliform values in water samples of River Bicholim and River Valvanti was high throughout the year.

According to GSPCB annual report, the worst polluted water stretch is Mapusa river along the highway which counted the faecal coliform as high as 220000 in the month of December last year, which clearly indicates pollution load increases as the river receives sewage and effluents along its course. The dissolved oxygen level had also depleted five times in different seasons. Dissolved oxygen (DO) is the amount of free oxygen found in the water.

The Biochemical Oxygen Demand (BOD), one of the most important indicators of oxygen depletion in a water body, was observed more than 3 mg/L in River Mapusa in the month of February last year.

The analysis report of GSPCB found the level of faecal coliforms in range of 330-11000 MPN per ml at the five locations of River Mandovi which exceeded during the monsoon. The analysis indicates that water quality meets the desired criteria of various parameters except for the levels of faecal coliform in all six locations. The analysis further indicates that the level of pH at two locations i.e. near Hotel Miramar and IFFI Jetty, Panaji has also exceeded twice between July and October.

The highest recorded FC collected from river River Sal was 17000 MPN/per 100 ml at Panzarconi in Cuncolim in June last year and the level of BOD has also exceeded in the month of May and July in the same year at Mobor and at Orlim in April, similarly at Khareband in December. A high BOD in water means that the water has great amounts of micro-organisms, mainly aerobic bacteria. This fact is very common in areas contaminated with wastewater.

Similarly the FC level is almost the same in the samples collected from River Sinquerim, Talpona, and Bicholim.

The faecal coliform levels at the River Khandepar varies in different seasons with values exceeding as high as 2400 MPN/l in June and December while FC count in River Tiracol remained high between July and November from 1300-5400 MPN/l. The water samples collected from River Zuari at three locations near Borim Bridge, Madkai jetty and Cortalim showed faecal coliform in the range of 230MPN/100ml to 17000 MPN/100ml. The level rises in the month of July and August.

The report mentions that water samples collected from River Mandovi from five different locations has faecal coliform content from 790-4900 MPN per 100ml which went upto 7900 MPN/ml in the month of August and September.

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