In Summary

Millions of Kenyans are at risk of serious bone defects and dental discolouration as a result of high levels of fluoride in their drinking water, researchers have warned.

Scientists say that most of Kenya’s underground water contains fluoride levels that are higher than the 1.5 milligrams per litre recommended by the World Health Organisation.

Fluoride is a chemical compound that occurs naturally on the earth’s crust. It is formed during rock formation and is a chemical ion of chlorine.

Millions of Kenyans are at risk of serious bone defects and dental discolouration as a result of high levels of fluoride in their drinking water, researchers have warned.

The risk is made worse by the fact that, as the rest of the world moves to treated and piped water systems, more than half of Kenyans (56 per cent) still rely on underground water, which the Kenya National Bureau of Statistics (KNBS) defines as, among others, water fetched from wells and boreholes.

Scientists say that most of Kenya’s underground water contains fluoride levels that are higher than the 1.5 milligrams per litre recommended by the World Health Organisation.

As a result, KNBS Principal Quality Assurance Officer, Mr Barrison Akolo, during a recent consultative forum in Nakuru, urged caution among consumers, saying that water derived from underground sources “tends to have higher levels of fluoride than that obtained from surface sources”.

Fluoride is a chemical compound that occurs naturally on the earth’s crust. It is formed during rock formation and is a chemical ion of chlorine.

Quantity differs

“All rocks have fluoride,” says Mr James Gichana, a water engineer, “but the quantity differs, depending on where the rock is located.

During water formation within the rocks, fluoride naturally becomes one of its components.

However, the quantity of fluoride in the water depends on the saturation of the chemical compound in the rock or layer.

So some have very high concentration while others have only small amounts.”

Two decades ago, the University of Nairobi’s Department of Dental Surgery and Faculty of Engineering conducted a study on the levels of fluoride in Kenyan waters.

The findings were startling, with exposure levels ranging between 5mg/l to 10mg/l.

The Kenya Society for Fluoride Research (KSFR), which corroborates the findings, further shows that 19 million Kenyans suffer from fluorosis, a condition that can affect the teeth or skeleton, depending on the length of time one has been exposed to water with a high concentration of fluoride, and their geographical location.

“As fluoride sediments in the body,” explains Mr Julius Kubai, a water engineer, “it begins to destroy parts of the body, especially the bony skeleton and teeth.”

Depending on the quantity of the fluoride, he adds, the effects may begin to show two years after one starts consuming water with high levels of fluoride.

Unfortunately, says Mr Kubai, the effects are only preventable, and cannot be reversed.

Dental fluorosis mainly affects children with developing teeth, although it affects adults as well.

Effects worse in children

“There is no cure for dental fluorosis, the condition of the damaged teeth cannot be restored,” he explains.

In adults, the teeth lose their white colour and develop yellowish spots within two years.

Mr Kubai says the effects are even worse in children, who can lose their teeth due to the weakening of the jaw.

In areas where the water has more than 10 milligrams of fluoride per litre, the adults’ whole teeth turn black and become fragile.

In severe cases, they sometimes chip.

Skeletal fluorosis, which in its acute stage causes total immobility, develops slowly and can take up to 30 years.

The skeletal bones develop outgrowths and become deformed.

This is common in areas where the fluoride content in the water exceeds 4 mg/l, like Nakuru, Naivasha and Baringo.

The effects of fluoride have social implications for those affected, notes Nakuru County Executive Member for the Environment, Water, Energy and Natural Resources, Mr Richard Rop.

“You often find people with the discoloured or black teeth covering their mouth while laughing in public.

It makes them self-conscious and uncomfortable, thus denying them a chance to socialise freely. It is not a nice feeling.”

Locked out of jobs

In fact, the effects go beyond socialising and affect one’s career.

There are people who get locked out of jobs whose main requirements are good physical condition and teeth, such as the army, police force, and reporting or anchoring on TV.

The KSFR notes that more than 80 per cent of the potential recruits who turn up for recruitment into the armed forces in central Kenya fail due to the bad condition of their teeth, which is attributable to fluoride.

Notably, the government and non-governmental organisations are the largest suppliers of underground water in both urban and rural areas.

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