KARACHI: A recent study has shown high levels of fecal contamination and rare presence of chlorine in the piped water being supplied to Orangi Town.
The study published in the Bulletin of Environment, Pharmacology and Life Sciences, an online journal of the Academy for Environment and Life Sciences, India, was conducted at the Institute of Environmental Studies of Karachi University.
Only nine samples out of 46 were found fit for human consumption.
The samples of piped water were collected from various parts of Orangi Town and tested for bacteriological and physico-chemical analyses.
“Chlorine was found only in nine samples which reflect the presence of organisms of public health importance. Most critical were the high levels of total coliforms count (TCC), total fecal coliform count (TFC) and TFS (total fecal streptococci count), which were present in very high numbers as compared to the WHO guidelines, according to which there should be zero presence of these organisms in water,” says the study.
The mean level of TCC, TFC and TFS were found to be: 1734/per 100ml, 1155.196/per 100ml and 5.043/per 100ml.
The chlorine values ranged from zero to 0.25mg/l (in all the samples) while mean chlorine values of all the samples was 0.038mg/l.
“The occurrence of coliform organisms shows biological contamination of drinking water. Drinking water contaminated with such microbes can cause ailments, such as cholera, diarrhoea, typhoid, nausea and even death.
“These effects may be more severe for adults, newborns and children with immune deficiencies,” the study says.
The possible sources of such micro-organisms included effluent from septic systems, storm water run-off, untreated sewage of domestic or wild animal fecal substance and infiltration, it points out.
At many locations, the study says, open drainage channels were found (in the locality) through which sewage seeped and contaminated freshwater.
“Often, the Karachi Water and Sewerage Board officials argued that chlorine level is adequate at pumping stations. However, it seems, chlorine is being consumed during distribution because of heavy organic contamination from the sewerage network,” the study says.
It found physico-chemical characteristics of water samples well within limits except sulfate, which was higher than the WHO guidelines and the National Standard for Drinking Water Quality.
“The mean value of sulfate was 296.15mg/l and varied between 222mg/l and 375mg/l. The highest desirable limit for sulfate is in drinking water set by the WHO is 250mg/l. The sulfate presence in drinking water can cause noticeable difference in water taste while very high levels can cause a laxative effect,” it says.
Dr Moazzam Ali Khan, a senior university teacher, who supervised the study, said the presence of coliform organisms in water was mainly due to poor hygienic conditions prevailing in the area, which had been found due to poor water and sewerage infrastructure.
Both these systems, he said, were obsolete and needed immediate revamping.
“Hundreds of organisms are found in water and it is not humanly possible to examine all. Hence, drinking water is generally tested for total coliforms, total fecal coliforms and total streptococci, which indicate presence of disease-causing organisms in water,” he said while explaining the results of bacterial examination.
There should be continuous monitoring of chlorine and organisms (of public health importance found in drinking water) so as to maintain the residual chlorine of 0.2mg/l to 0.5mg/l at consumer level and zero presence of pathogens, he suggested.
Students who participated in the research were: Aamir Alamgir, Omm-e-Hany, S. Shahid Shaukat, Khalid Mahmood, Anusha Ahmed, Saira Ali, Kanza Riaz, Hina Abidi, Shaheryar Ahmed and Mannal Ghori.
Published in Dawn, January 15th, 2016