Faecal contamination of public water sources in informal settlements of Kisumu City, western Kenya Selpha Opisa, Maurice R. Odiere, Walter G. Z. O. Jura, Diana M. S. Karanja and Pauline N. M. Mwinzi ABSTRACT High levels of environmental contamination, often associated with improper waste and excreta management, are widespread among informal settlements within urban areas in developing countries. We determined the level of faecal contamination in domestic water sources and evaluated the potential contribution of these water sources to intestinal helminthiases in seven informal settlements of Kisumu City, western Kenya. Membrane filtration technique was used for enumeration of total and faecal (Escherichia coli) coliform bacteria in water samples collected from dams, rivers, springs and wells. Out of the 80 water sources sampled, 76 (95%) were highly contaminated with E coli. All water samples from unprotected wells (26) and 92.6% of samples from protected wells (25) were positive for E. coli. The highest and lowest E. coli densities were observed in samples from dams (3,800 ± 1,807 coliforms per 100 ml) and boreholes (419 ± 223 coliforms per 100 ml), respectively ( p ¼ 0.0321). Distance from pit latrines was negatively associated with E. coli coliform density for wells (r ¼À0.34, n ¼ 53, p ¼ 0.0142). Untreated well-water may not be suitable for human consumption, and its continued use constitutes a major health risk for the inhabitants of these informal settlements. Selpha Opisa Maurice R. Odiere (corresponding author) Diana M. S. Karanja Pauline N. M. Mwinzi Neglected Tropical Diseases Branch, Centre for Global Health Research, Kenya Medical Research Institute, P. O. Box 1578–40100, Kisumu, Kenya E-mail: modiere@kemricdc.org Selpha Opisa Walter G. Z. O. Jura Department of Zoology, Maseno University, P. O. Box 333–40105, Maseno, Kenya Key words | coliform, Escherichia coli, faecal contamination, informal settlement, slum, soil-transmitted helminths INTRODUCTION Rapid urbanization has been ongoing in many developing countries, including sub-Saharan Africa, where the urban population is expected to triple between 2010 and 2050 to >1.2 billion people (UN-HABITAT ). In Kenya, for instance, the proportion of the urban population nearly doubled between 1980 and 1998, increasing from 16 to 31% (World Bank ). Urbanization is often driven by per- ceived opportunities for improving the family status and for education. However, more often than not, urban areas cannot address the demands of an expanding population with strengthened infrastructure, resulting in extreme pov- erty (Arnaud ). New residences frequently found as informal settlements, often referred to as slums, where the density of population is high, and sanitation, availability of clean water, and health services are low (UN-HABITAT ; Patel & Burke ). The harsh reality is that these slums are home to about 70% of all urban residents in sub-Saharan Africa (United Nations ). In Kenya, rapid urbanization amid economic degradation has resulted in an increased proportion of people living in absolute poverty in the urban areas (CBS ), including slums of cities such as Kisumu where overcrowding and lack of adequate water and sanitation are a major challenge (UN-HABITAT ). Although an adequate supply of safe drinking water is universally recognized as a basic human need, millions of people in the developing world do not have ready access to an adequate and safe water supply. The spread of many infectious diseases including cholera, typhoid, hepatitis, polio, cryptosporidiosis, soil-transmitted helminths (STH) infections and schistosomiasis has been associated with human excreta and the lack of adequate personal and domestic hygiene. It is estimated that one-third of deaths in developing countries are caused by the consumption of 2674 © IWA Publishing 2012 Water Science & Technology | 66.12 | 2012 doi: 10.2166/wst.2012.503