How borehole water hurts your health

Frustrated by poor public water supply, many Kenyans are increasingly drinking from salty boreholes.

Today, a borehole on site is a must-have for property buyers or renters in the country’s growing urban centres.

“You pay more for a flat connected to a borehole, but at least it assures you of constant water supply,” says Joseph Muteru of Tassia in Embakasi, Nairobi.

 The water, however, has a strong salty taste and is not good at quenching thirst, he says.

“We have to buy bottled water for drinking,” says the father of three.

Those who can’t afford bottled water have to make do with the salty water for drinking, cooking and other domestic uses.

Water is big business in Embakasi, and it is peddled from hand carts, motorbikes, private bowsers and recently the mushrooming mini water-refilling shops that are all over.

A refilled 10-litre bottle mainly from borehole water costs Sh90-Sh100.

“You can’t be sure this water is of good quality, with some leaving a whitish residue in containers,” says Muteru.

Water experts say removing salt from water is a complex process requiring expensive technology and cannot be entrusted to roadside kiosks.

Available data shows there are about 4,000 registered boreholes, as well as a similar number of unrecorded boreholes in Nairobi.

The data further shows Embakasi, Karen, Langata, Spring Valley, Upper Parklands, Muthaiga, Loresho and Kyuna have the highest concentration of boreholes in Nairobi.

In an earlier interview, Nahashon Muguna, the head of the Nairobi City Water and Sewerage Company, said meeting water demand in the capital is a major challenge.

“The water we are using was supposed to serve the population of the city only up to the year 2000,” said Muguna.

In 1990, it was estimated that about 90 per cent of urban Kenyans had access to clean water. But currently, only about half of the 4.5 million Nairobi residents have direct access to piped water.

This means that more than two million Nairobi residents are not assured of safe water, especially with the commodity being under rationing since 2016.

This largely explains the growing demand for boreholes in the city.

High demand for boreholes has also been recorded in Kiambu and Machakos counties, and adjacent urban areas of high volcanic soils, such as Kajiado, Ngong, Athi River, Kitengela, Ongata Rongai and Kitui.

Data collected by Nato Simiyu and Simeon Dulo for the University of Nairobi shows a dramatic spike in the number of boreholes sank after the year 2000.

The number of boreholes in Nairobi increased by 64 per cent between 2000 and 2013, and the trend has continued to rise.

A report published last year by a team from the Water Resources Authority, Kenya, University of Aberdeen, and the British Geological Survey, both of the UK, showed the number of borehole drilling applications in Nairobi jumped from about 40 in 2014 to over 180 per month by 2019.

In 2016, when Philip Muraguri at Jomo Kenyatta University of Agriculture and Technology (JKUAT) sampled borehole water from Kasarani, Dagoretti, Embakasi, Langata and Starehe areas, he reported high salt content levels.

Boreholes in Embakasi, Kasarani and Roysambu areas had the highest number of boreholes, with salt levels above safe limits as specified by the World Health Organisation (WHO) and the Kenya Bureau of Standards.

Salt and bacteria

Last year another team from JKUAT published a report indicating that all the borehole water in Umoja Innercore Estate in Nairobi is highly contaminated and unfit for human consumption.

The study published in the Journal of Water Resource and Protection had collected borehole water samples from hospitals, churches, residential apartments and a private school.

The water was tested at the university’s laboratory that is accredited by National Environmental Management Authority (Nema) and all samples declared not fit for human consumption.

While much of the contamination was bacterial, a significant number of samples had salt levels well above WHO recommended safety standards for drinking water.

The WHO in its current guidelines on salt in drinking water says while it is important for human health, if excessive, or above two grammes per day, it may be harmful.

The guidelines cite an experiment where mice fed on high-salt water had developed higher blood pressure and increased death rates due to stroke.

“Excessive salt intake seriously aggravates chronic congestive heart failure in humans, and ill effects due to high levels of sodium in drinking water have been documented,” says the WHO guidelines.

In September, a team of Kenyan, Japanese and Taiwanese scientists reported a possible link between consumption of salty water and hypertension among residents of Kajiado County.

The researchers from Kyoto University of Japan, the African Population and Health Research Centre, Nairobi, National Taiwan University, and the University of Eldoret found 70 per cent of their study population with dangerously high salt levels in their urine.

The team suggested consumption of salty drinking water and other factors, including unhealthy diets, smoking and alcohol and obesity, were responsible for high hypertension rates in the area.

More than a quarter of the study participants, or 26.2 per cent, were hypertensive. This was higher than the national average.

While obesity has been identified as a major factor in hypertension, researchers at the Kenya Medical Research Institute, the National Museums of Kenya, and several US and German universities have warned people of normal weight are not immune to salt-related rises in blood pressure.

The researchers, in a study published in January in the journal Science of the Total Environment found high levels of hypertension among the Daasanach pastoralists living on the shores of Lake Turkana.

The team had engaged 226 adults from the community and found high levels of hypertension and hyper-dilute urine. This was associated with drinking salty water from hand-dug wells, river beds and boreholes.

Hyper-dilute urine is an indication of altered kidney function, suggesting they may not be working properly and are a cause for medical worry.

The scientists, however, found a daily intake of milk protected them against hypertension and hyperdilute urine.