Is your borehole water safe?

With the city’s water supply proving to be unreliable, many developers are resorting to boreholes, but residents are complaining of discoloured teeth and clothes, writes ALLAN OLINGO.Living in Nairobi’s Umoja Estate, Mercy Onyango had to grapple with constant water shortage while catering for her family. Mercy had to spend a significant part of her salary to buy water, as the flat she was living in was not serviced by the City Council’s water pipeline.Mercy had to contend with this challenge for several months before she could find an apartment with regular water supply.She says: "I am glad the apartment I currently live in has a borehole, which has given us a constant supply of the precious commodity since I moved in here two years ago, even though we pay extra for the electricity used to pump the water."DEVELOPERS SINKING BOREHOLESTo counter the inefficiency of the Government in managing this scarce resource and ensuring it is accessible to all, many developers have resorted to allocating part of the construction capital to sinking boreholes.Harun Nyamboki, a developer with the Moke Gardens Estate, notes that the need for reliable, clean and affordable water drove him to sink a borehole instead of depending on the City Council’s water supply system. "Initial contacts with the Nairobi Water Company were unyielding, slow and expensive yet we required a reliable water supply in order to commence project implementation. And even when we eventually obtained a quotation, the cost was prohibitive yet there was no guarantee of supply," he says.Nyamboki adds that even though the borehole water project cost him Sh3.5 million, the reliability, cost-effectiveness and quality it brings to his tenants are among the advantages of having the borehole as compared to the City Council’s water service. According to Nyamboki, water is one of the scarce resources the Government should take seriously as it affects every aspect of development.Early this year, the Athi Water Services Board collaborated with the Nairobi Water and Sewerage Company in emergency measures that have included sinking various boreholes in various parts of Nairobi. However, some tenants complain of the hardness of the water, their teeth discolouring and in some cases rotting because of the mineral composition of the borehole water. Others even complain of white clothes discolouring after washing with some resorting to washing their clothes at their neighbours’ who have city council water. Borehole water also has a salty taste and in some cases, one can get stomach upsets after drinking it"While boreholes are very expensive to sink, pumping water is equally expensive. Borehole yields can also be quite poor as the quality of the borehole water is poor compared to the treated City Council water," explained Mr Gordon Misigo, the Chief Manager, Human Resource and Administration at Athi Water Services Board. With water shortages, most of the water supplied by vendors has a high chance of being contaminated with industrial effluent and raw sewage as most residents are unaware of their source, leave alone their handling.UNDERGROUND WATER DECLINE However, even with their guaranteed constant supply, the rapid drilling of boreholes in the city could be dangerous.According to National Environment Management Authority (Nema), the high number of boreholes is worrying, especially if the owners don’t adhere to the regulations governing the drilling of boreholes.Nema Communications Officer Jackline Marita says the agency had noted that many property owners have drilled boreholes close to each other yet the law requires them to be not less than 100 metres apart."To Nema, this is worrying and has caused some boreholes and wells to dry up. In the near future, we might be forced to drill deeper to get water," she says.Nema requires proponents who wish to sink boreholes to apply for an environmental impact assessment licence before commencing drilling. In 2009, the Water Resource Management, a government agency in charge of water resources, approximated that 18,500 boreholes had been sunk in the country. A World Bank report released the same year noted that the increased borehole sinking activity within Nairobi and its environs posed a threat of cave-ins, as the underneath structure gets weakened. "There is a possibility that major ground water depletion may reduce the capacity of the geological material underneath," says Amos Kigondu, a geological expert.According to the report, the number of boreholes in the city has been growing rapidly and stood at 2,250 in 2001. Data from Water Resources Management Authority, there are 16,000 boreholes in the country with 4,000 being in the Nairobi metropolis. The report further noted that the average depth and static ground water, which is permanent regardless of fluctuations in the water table, have been going down. In the 1950s, the ground water level was 80 metres deep, but by 1996, it was edging to 140 metres and experts warn it is receding further as everyone rushes to sink boreholes.The increased number of boreholes, especially in Nairobi, would also see the underground water decline at a faster rate, with an average water level decline of 1.8 metres a month.BOREHOLE WATER SAFETYThe World Bank report, however, notes that the natural quality of groundwater is good except for the presence of fluoride, which may result in dental and skeletal fluorosis, which leads to discolouring of teeth and weakening of bones. "Available chemical analyses show only the major elements, so there is as yet no proof that groundwater does not contain trace elements like selenium or arsenic," read the report.Hydrologists say flouride in borehole water can be harmful to humans and animals, depending on the concentration. Excess amounts of flouride can cause a condition known as "endemic dental flourosis" during the period of tooth formation. This condition leads to dark-brown staining of teeth. The flouride can be removed through a process called reverse osmosis.The Ministry of Water and Irrigation is in charge of checking the quality of borehole water, including the presence of certain chemicals before issuing a certificate indicating whether or not the water is fit for human consumption. Developers are supposed to get clearance on their boreholes based on World Health Organisation (WHO) and Kenya Bureau of Standards (Kebs) guidelines. The acceptable levels of flouride, for example, are 1.5mg per litre for WHO and 4mg per litre for Kebs. Nitrate levels should not exceed 45mg per litre as excesses cause blue baby syndrome, a heart condition in infants.High levels of magnesium in excess of 50mg per litre may cause diarrhoea in new users while levels of iron exceeding 0.3mg per litre are toxic to children. Sulphate gives the water an odour and an unpleasant taste. It is, however, not clear whether all developers obtain these certificates and whether tenants are aware of such requirements. According to the Word Bank report, the greatest concern of this underground water is the potential for pollution. The report notes that the upper aquifer is the most vulnerable to potential pollution from the land surface like solid waste, seepage from latrines, septic tanks, sewers and drains and infiltration from polluted streams. This, therefore, means boreholes in more congested estates like in Eastlands have a higher chance of pollution than those in less congested areas like Ngong’ or Karen.

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