Panaji: Around 28-kilometre stretch of the state’s largest river Zuari from Curchorem to Marcaim has been identified by the Goa State Pollution Control Board (GSPCB) as a badly polluted stretch due to household sewage, which is directly discharged into the river body.
The Central Pollution Control Board (CPCB) has classified River Zuari (28-km stretch from Curchorem to Marcaim) under Priority V, with BOD (biochemical oxygen demand) level ranging between 3.2 and 5.1 mg/l, which makes the river unfit for bathing. This classification by the CPCB is based on the report from GSPCB.
The GSPCB conducted source identification studies in January and February 2019 and observed individual households along the banks of the river in Marcaim, Adpai, Kaswada, Borim, Loutolim, Zamboli and Cortalim directly discharging untreated sewage into a nullah connecting the river.
The GSPCB had also monitored the water quality of River Zuari, which is the longest river of the state, at three locations of Panchawadi, Borim bridge and Marcaim jetty and found presence of faecal coliform above the desired levels of 500 MPN (most probable number) /100 ml in all three seasons. However, during the physical survey, the GSPCB did not find any industrial outfalls from Verna industrial units contributing to the pollution in this stretch.
The GSPCB has expressed concern over the levels of faecal coliform (FC), which exceeds the prescribed limits, while the biochemical oxygen demand levels, a key indicator of organic pollution, and dissolved oxygen meet the prescribed statutory requirement.
According to analysis, the pollution starts rising during high tide with faecal coliform rising as high as 720, and during low tide, the FC varies from 0.00 to 2520, with an average of 367.50. The BOD level in Zuari during pre-monsoon period remains low and varies from 0.08 to 2.13 mg/l with an average of 1.03 mg/l and post monsoon the BOD values range from 0.80 to 4.71 mg/l, with an average of 2.57 mg/l. The BOD level increases during high tide and decreases during low tide.
In September 2018, the National Green Tribunal (NGT) had directed all the state governments, including Goa to prepare an action plan within two months for making all polluted river stretches fit at least for bathing purposes (that is BOD < 3 mg/l and FC < 500 MPN/100 ml) within six months from the date of finalisation of the action plan.
The River Rejuvenation Committee, which has been formed as per NGT direction, in its proposed action report for Zuari river, has asked the fisheries and panchayat departments to provide toilet facilities for fishing jetty at Cortalim in six months and establish toilets at the jetty in a year.
The report said it is the responsibility of the village panchayats to improve and upgrade the existing solid waste management facility including collection system and erection of material recovery facilities/ storage shed for non-biodegradable waste in the village panchayats of Savordem, Panchwadi, Shiroda, Borim, Wadi-Talaulim, Durbhat, Bandora, Marcaim, Neura, St Lawrence (Agasaim), St Andre (Velha), Siridao-Pale, Curchorem-Kakora, Macasona, Curtorim, Rachol, Cortalim -Quelossim, Sancoale villages located along the banks of River Zuari.
The underground sewerage scheme is in progress for Ponda municipal area including Curti, Bandora, Kavlem, Undir and area close to Kapleshwari nullah, which further joins the Zuari river. Three sewage treatment plants are proposed at Curti, Kavlem and Bandora of capacity 8MLD, 15MLD and 15MLD, respectively, which will be ready within a year.