SURFACE WATER QUALITY IN KENYA’S URBAN ENVIRONMENT: A CASE STUDY OF GITHURAI, NAIROBI, KENYA

Abstract

Safe, clean drinking water and sanitation facilities are key to economic development and public health in Kenya. Rapid urbanization and population growth mean worsening conditions for millions of Kenyans, especially the poorest. Sanitation is one of the greatest problems especially in the informal settlements where 60% of the people in the urban centers reside. In fact, 50% of all preventable illnesses in Kenya are water, sanitation and hygiene related. This study was done to establish the level of indicator water quality parameters, and establish water borne disease prevalence in Githurai and adjacent communities. Water samples were collected from 6 points distributed uniformly along Kiu River in Githurai. Using standard methods, the samples were analyzed  for Dissolved Oxygen (DO), BOD, TSS and TDS in the JKUAT environmental laboratory. A survey was also done in Githurai, Kahawa Sukari and Kahawa Wendani to establish the prevalence of water borne diseases. Data was collected from local medical clinics and Ruiru District Public Health Office. Randomly selected individuals were also interviewed to establish the frequency of visits to health facilities. The study revealed that dissolved oxygen in surface water was between 1.5 and 8.5 mg/L while biochemical oxygen demand (BOD) was between 200 and 400 mg/L. This was much higher than NEMA standards for surface water which  demand that  the BOD  of any effluents to be discharged into surface water  should be less than 30 mg/L.  Total suspended solids (TSS)  varied from 900 to 950 mg/L. NEMA allows domestic water not to have TSS of more than 30 mg/L. Total dissolved solids  (TDS) were in the range of 3000 to 9000 mg/L compared to a maximum of 1200 mg/L which  is allowed by NEMA. Surface water in Githurai is highly polluted and poses public health risks.  Some 30-40% of all patients visiting hospitals in the study area suffered from diarrheal diseases and the average resident in Githurai was treated for water borne diseases once every three months. Therefore, an urgent intervention is required to clean up Kiu River and stop further contamination of the river.