Owino Uhuru slum: Why lead poisoning therapy was halted

On July 16, the High Court in Mombasa rendered a landmark judgement when it ordered the State and two private companies to pay Sh1.3 billion to the residents of Owino Uhuru slum after they were exposed to lead poisoning.

The residents had gone to court in 2016 seeking to be compensated for the debilitating effects of the toxic metal as well as for the deaths of their loved ones.

As the trial progressed, experts demonstrated that lead poisoning was widespread and recommended that they undergo chelation therapy, which is a delicate and complicated medical procedure used to remove metals from the body.

When lead, mercury, iron and arsenic build up in the body, they can lead to chronic health problems that result in death. To remove the metals, doctors use special drugs that can either be swallowed or administered through an intravenous tube.

Once the drug has attached to the metal, it is excreted from the body through urine.

The court heard that on May 8, 2015, then acting Mombasa Director of Health Services Shem Patta said out of 50 victims, 16 would require close monitoring because they had the lead in their blood that was above the levels deemed safe by the World Health Organisation.

"Those determined to have high levels of poisoning will be treated through chelation therapy with close monitoring and tests between the treatments," said Dr Patta.

Patta disclosed that the procedures would be done by doctors and nurses from the national and county governments in Nairobi and Mombasa.

"Out of 50 samples, 11 showed lead levels above normal, which would require treatment," said Patta, adding that four children aged between seven and nine were also tested for lead poisoning and only one, aged eight, required treatment.

According to the medic, many of the residents had been exposed to lead contamination, but they did not suffer from life-threatening conditions. 

This was attributed to short exposure period and living further from the smelting plant that recycled used lead-acid batteries.

An earlier 2009 report compiled by Chief Government Chemist George Kakuta had indicated that blood samples from three children had lead levels exceeding the WHO's recommended 10 micrograms per decilitre (10ug/100ml).

One of the children, 12-year-old Catherine Auma, was found to have a blood lead level of 12ug/100ml, while Moses Odhiambo and Daniel Bazil, both aged 10, had lead levels of 17ug/100ml and 23ug/100ml, respectively.

Patta told the court that according to the WHO, lead levels of between 45-70µg/100ml in children was considered dangerous and required chelation therapy and monitoring.

The doctor said the 2015 tests among children, on average, showed levels of 45µg/100ml while those in adults went up to 80µg/100ml.

"Anything from 80µg/100ml to 100µg/100ml requires treatment with close follow up."

Medical complications

Patta also noted that there was no safe blood level of lead, with numbers as low as 5µg/100ml considered to dangerous enough to cause medical complications.

The doctor said that tests on residents targeted kidney and liver functions, adding that these organs, along with the brain, were often damaged by prolonged exposure to lead.

"Symptoms cannot solely be used as a manifestation of toxicity levels given there are people with high levels of poisoning but who manifest little or no symptoms."

According to the July 16 judgement, the chelation treatments were conducted for three months before being abandoned.

A 2015 report by Mombasa Health Executive Binti Omar disclosed that a joint health team was administering preliminary treatment to the poisoned residents by giving zinc, iron, and calcium tablets, which were aimed at strengthening their bones and immune systems.

But the treatment was terminated after it was determined that the residents were still living in a contaminated environment.

"Further analyses of the cases show that residents are still exposed to poisoning. We are extending the screening across 200 metres from the factory," said Omar.

On February 25, 2018, a team of experts reported that they had detected lingering contamination after conducting tests in the slum.

Victor Ochola, a radiographer who led the team, disclosed that three out of 18 residents showed abnormally high lead levels in their blood.

"Anything above 5µg/100ml needs to be investigated," said Dr Ochola, adding that one of the victims was a child with 8µg/100ml, and who had developed bone problems and could not walk.

The two other victims were an adult man and woman.

Ochola said the informal settlement was heavily contaminated, adding that the health effects would last for a long time given that lead has a half-life of 53,000 years and does not biodegrade.

The half-life of lead in adult human blood, however, has been estimated as 28 days, between 30-45 days in soft tissue, and 25-30 years in bones.

Ochola said it is difficult to eradicate the heavy metal from the soil, and that it easily enters the food chain through stormwater and other forms of effluent.