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.”
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.”
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
|Severe brain damage (encephalopathy)
|Severe stomach cramps
|Damage to haemopoiesis (decreased haemoglobin synthesis)
|Reduced vitamin D metabolism
|Increased risk of hypertension in adulthood
Impaired nerve function – increased nerve conduction velocity
|Increased level of erythrocyte protoporphyrin
Decreased vitamin D metabolism
Decreased calcium homeostasis
Decreased growth (including puberty)
Impaired peripheral nerve function
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.
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.”
“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.”
“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.”
“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.”
“If not treated, lead poisoning is characterized by persistent vomiting, anaemia, encephalopathy, lethargy, delirium, convulsions, coma and death.”
“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.”