health impact of lead

“As part of our commitment to respect human rights and to a comprehensive approach, we will also undertake appropriate due diligence throughout the lifecycle of mining operations. Where we have caused or contributed to adverse human rights impacts we will contribute to their remediation as appropriate.”

Group Human Rights Policy, Anglo American

Scale and effects of lead poisoning

The scientific consensus is that there is no safe level of lead in the blood. Even at very low blood lead levels (BLLs), lead causes neurodevelopmental and clinical and sub-clinical effects, some of which are irreversible. Chronic exposure has an exacerbating effect. According to the United States Centers for Disease Control and Prevention (CDC), a BLL of 3.5 µg/dL is the reference level above which public health actions and medical monitoring should be initiated. If elevated BLLs are not reduced, children face the risk of life-long, irreversible damage and exacerbation of harm they have already suffered.

“Unlike many other metals, such as iron and zinc, lead performs no useful function in the human body – it only causes harm.”

WHO (2015), Lead exposure in African Children

the effects

The effects of lead poisoning range from behavioural issues to brain damage and death in severe cases.

The lead ingested by children is absorbed into their bones and, in the case of girls, is later released during pregnancy. It is known to cross the placenta, resulting in the unborn child being supplied the same concentration of lead as the mother. Not only does this risk harming the unborn baby, but lead causes pregnant women to have a higher risk of pre-eclampsia; gestational hypertension, miscarriage and pregnancy loss.

Very young children (0-5) are the worst affected. They ingest dust, which is all around them, when they suck their fingers. Many children develop an addiction to lead, which can taste sweet, leading them to eat contaminated soil.

Various studies have found that in the most affected townships of Kabwe around half of the children up to 5 years old have a BLL higher than 45μg/dl, and some have BLLs above 100ug/dl, which could easily prove fatal.

Tens of thousands of children in Kabwe have been poisoned and will have sustained serious and lifelong neurological and physical damage. These health risks will have seriously detrimental effects throughout their lives while materially impacting the town and its residents. The scale of lead contamination in Kabwe has been known for decades.

Clinical effects in children	Blood lead in µg/dL
Death	> 100
Severe brain damage (encephalopathy) Kidney damage Severe anaemia	100
Severe stomach cramps	50
Damage to haemopoiesis (decreased haemoglobin synthesis)	40
Reduced vitamin D metabolism	30
Increased risk of hypertension in adulthood Impaired nerve function – increased nerve conduction velocity	20
Increased level of erythrocyte protoporphyrin Decreased vitamin D metabolism Decreased calcium homeostasis Developmental toxicity Hearing impairment Decreased growth (including puberty) Impaired peripheral nerve function Transplacental transfer Reduced IQ Behaviour problems	20-10

Historic awareness of the issue in Kabwe

The claimants allege that the risk of environmental poisoning from lead mines to the wider community, including the impact on children, was known from as early as the late 1800s.

1893

In 1893, a report was produced by a committee convened by the New South Wales government to inquire into lead poisoning in Broken Hill in Australia, the Mine’s namesake. The committee was appointed to investigate the extent of lead poisoning among workers and the local community surrounding the Broken Hill site. The report concluded that the exposure to lead fumes from the smelters had caused an impact on the health of the local population and found that children were also impacted.

1969

From 1969 and into the early 1970s, Dr Ian Lawrence was a doctor at the Mine. Dr Lawrence stated that he took around 500 blood samples from children under the age of five attending the Township Clinic in 1969-70, virtually all of which exceeded safe BLLs. Many results were severe enough to cause serious brain damage and death. Dr Lawrence detailed these findings in a report he submitted to the Mine’s Chief Medical Officer.

1970

In 1970, once Anglo was alerted to Dr Lawrence’s findings, the Company commissioned Professor Lane and a Dr King from the University of Manchester, UK to investigate the veracity of Dr Lawrence’s claims and produce a report of their findings.

1971

In 1971, prompted by the deaths of eight Kabwe children from suspected lead poisoning, Dr A.R.L Clark from the London School of Hygiene and Tropical Medicine initiated an investigation into lead-related risks facing the communities surrounding the Mine.

1973

Between 1973 and 1974, Clark surveyed the BLLs of children and found these to be significantly elevated across the communities of Kasanda, Chowa and Makululu. In Kasanda, mean BLLs were reported between 42ug/dL to 104 ug/dL, peaking at two years of age (with a mean 20 times the current CDC limit of 3.5ug/dL). In Chowa mean BLLs ranged between 30ug/dL to 70ug/dL, whilst Makululu showed a mean range from 20ug/dL to a high peak of 83ug/dL.

2015

Almost 40 years later, in 2015, John Yabe and his colleagues investigated BLLs in children under the age of 7 years in villages around the Mine – the results were strikingly similar. All of the children sampled had BLLs exceeding 5ug/dL. Sampling further showed mean BLLs of 82.2ug/dL in Kasanda, 57.1ug/dL in Makululu, and 39 ug/dL in Chowa. Despite the intervening decades, the persistent and widespread nature of the lead pollution in Kabwe was evident, as children continued to present with lead levels described as being, “among the highest in the world”.

2018

In 2018, Bose O’Reilly et al. similarly sought to analyse the health impact of lead exposure on children in Kabwe. Looking at BLL sampling data between 2003 and 2015, they found that over 95% of children living in the most aﬀected villages had BLLs greater than 10 µg/dL. Approximately half of those children had BLLs greater than 45 µg/dL.

2020

In 2020, Yabe and others published an additional study examining the extent of lead poisoning in Kabwe. In addition to reporting high BLLs amongst children, the study also recorded high BLLs in women residing in Kabwe, reaching concentrations of up to 86 ug/dL. For women of childbearing age, increased BLLs have been linked with incidences of preeclampsia and hypertension, in addition to posing a risk of peri- and postnatal exposure to the foetus and young child.

The experts on lead poisoning

The scientific consensus is that there is no safe level of lead in blood:

“Kabwe has extensive lead contaminated soil and children in Kabwe ingest and inhale high quantities of this toxic dust.”
– Bose-O’Reilly, 2018
“Childhood Pb poisoning in Zambia’s Kabwe mining town is among the highest in the world, especially in children under the age of 3 years. Lead exposure among children is associated with developmental abnormalities including impaired cognitive function, reduced intelligence, impaired hearing and reduced stature.”
– Yabe et al., 2015
“Lead has been shown to affect virtually every organ and system in the body…the most sensitive effects of lead appear to be neurological (particularly in children), hematological, and cardiovascular.”
– Agency for Toxic Substances and Disease Registry
“Lead poisoning has devastating effects on neurodevelopment, such as mental retardation and lowering of intelligence quotient (IQ) in children, which may further result in poor school performance, lower tertiary education attainment, behavioural disorders and poor lifetime earnings.”
– WHO, 2018; Dapul and Laraque, 2014; Miranda et al., 2007; Canfield et al., 2003; Lidsky and Schneider, 2003
“If not treated, lead poisoning is characterized by persistent vomiting, anaemia, encephalopathy, lethargy, delirium, convulsions, coma and death.”
– WHO, 2018; Flora et al., 2012; Pearce, 2007
“After recovery from their lead poisoning…children made an extremely poor record in competition with their fellows. Their difficulties were in relation to both the intellectual and the emotional spheres.”
– Byers & Lord, 1943