A recent study by the Goa State Pollution Control Board (GSPCB) has revealed that almost all the rivers, lakes and ponds in the state are polluted. The pollution, if unchecked, might soon make the waters in different types of water bodies unfit for human use. According to the GSPCB report, the pollution was being caused by the presence of faecal coliform bacteria on account of the disposal of untreated/partially treated domestic sewage and open defecation. The GSPCB arrived at the conclusion after checking the water quality with respect to indicators such as biochemical oxygen demand (BOD), dissolved oxygen (DO), which is the amount of free oxygen found in water, faecal matter of humans or other animals (faecal coliform) and total dissolved solids (TDS). The level of faecal coliform in the River Sal was in the range of 13,000-54,000 MPN (most probable number) per 100 ml with dissolved oxygen level, the highest in the state. As far as River Mandovi was concerned, the presence of faecal coliform was in the range of 330-11,000 MPN per 100 ml at six sites. Similar findings were recorded in other rivers, the Zuari, Chapora, Bicholim, Mhadei, Kushawati Mapusa and others. The faecal coliform presence was 54,000 MPN/100 ml in the Saipem Lake, which is the highest. High pollution was also recorded in the Carambolim, Rai and Curtorim lakes.
The permissible limit set up the Central Pollution Control Board (CPCB) for presence of faecal coliform should be 30 or less MPN/100 ml in river waters. The main reason for high content of faecal coliform in the water bodies was open defecation. A soon-to-be-released report by the Goa State Urban Development Agency on defecation sites has identified at least 177 spots in 124 municipal wards which are used by people as open defecation grounds. Most of these spots are open fields and spaces or slums along the water bodies. Among the 14 municipal bodies in the state Margao, Mapusa, Bicholim, Mormugao, Ponda, Valpoi, Canacona, Sankhali and Quepem were leading in areas of open defecation areas and accounted for 50 to 80 per cent of the wards. The survey was carried out by municipal bodies to provide data on the problem of open defecation.
Though coliform bacteria are not pathogenic (disease causing) organisms they are mildly infectious. If large numbers of coliforms are found in water, there is a high probability that other pathogenic bacteria or organisms might be present. There is also possibility of spread of waterborne pathogenic diseases that might coincide with faecal coliform contamination, such as ear infections, dysentery, typhoid fever, viral and bacterial gastroenteritis and hepatitis A. Studies have revealed that untreated organic matter containing faecal coliform could be harmful to the environment. The aerobic decomposition of faecal coliform can reduce dissolved oxygen levels if discharged into rivers or waterways, which would reduce the oxygen level enough to kill fish and other aquatic life.
The state authorities need to ensure that faecal coliform was removed or contained in the rivers and lakes by the use of chlorine and other disinfectant chemicals. However, these chemicals kill not only faecal coliform and disease bacteria but also the bacteria essential to the proper balance of the aquatic environment, endangering the survival of species dependent on those bacteria. While dealing with the situation there is need to ensure there was no ‘overdose’ of any chemical that could threaten aquatic organisms.
The government and local bodies need to provide treated, bacteria-free potable water to every household. There is also a need to create awareness among the people living in the areas along these water bodies to adopt safety measures against potential health hazards. The public should be made aware that faecal coliform could usually be inhibited by boiling water or by treating with chlorine and the need for washing thoroughly with soap after contact with contaminated water, which would help prevent infections. While chlorination is the most widely used method of disinfection, recent studies have raised concerns about the reaction of chlorine with organic matter in water, which could result in the formation of suspect carcinogenic compounds. The focus of the authorities should be on preventing open defecation for which every house should be provided with toilets. As water from various rivers was being used for filtration and supply of potable water to people, it should be a priority of the state authorities to cleanse the water bodies of the pollutants and prevent further pollution. That would cut down the cost of filtration. Stopping pollution in rivers and other water bodies was a must for guaranteeing good health of the people.