Zambia Copper belt lead contamination

•Kabwe is the second largest city in Zambia with a

population of 300,000.

•In 1902 lead was discovered in the mine

•Ore veins with lead concentrations up to 20% have

been mined deep into the earth.

•The mine closed in 1994

•The government failed to address the potential danger

of lead

•The city has been left with hazardous concentrations

of lead in the soil and water.

•Wide spread soil contamination

•Highly contaminated mine waste dumps simply left

once the mine closed

• Smelters emitted dust particles that settled over

a 20 km circumference and became buried in the

soil.

• The local canal became contaminated with lead

which lead further ground contamination during

flood events

• High concentrations of lead found in soils

• levels of lead right next to the smelter measured

245,000 parts per million (ppm)

• Levels in a local township ranged from 7,000 ppm

to 38,000 ppm

• Lead content of soil in residential areas should

not be more than 400 parts per million

• Industrial and agricultural sites

• Lead is one of the potent neurotoxins in the world

• In total 200,000 people were affected by the

contamination

• Some children were found to have more than 200µg/dl

• Symptoms of acute poisoning occur at levels above

20µg/dl

• Levels above 70µg/dl are considered a medical

emergency

•Removal of 39,000 m3 of mine waste

•Removal of 51000 m3 of dredged sediments

•Contaminated soil removed to a depth of 30cm.

•Liming of soil

•Planting a vegetation cover

•Demolition of defunct plant infrastructure

Solution ImplementedSolution Implemented

Alternative Solutions•Vitrification

•Capping

•Soil washing

•Relocate neighbourhoods

•Improve public awareness and education

programme