Background
“We are acutely aware of the deep and lasting effects of our history as an industry. I would even go as far as arguing that we are one of the very few industries that has had to reckon with the legacies of our past in a real and progressive way. While our progress is encouraging, we are still not where we need to be”
In an October 2020 speech, Mark Cutifani, CEO Anglo American plc.
Background to the Case
Since 1999, AASA has been a wholly-owned subsidiary of London-based Anglo American Plc. There is no suggestion that AA Plc is legally responsible. However, as the present head office company of the group it has the power and a moral and ethical responsibility to make amends for the public health scandal caused by the historical human rights abuses of the group, from which the group profited.
In South Africa, the court system enables the victims to benefit from the South African class action procedure, as well as attorneys and counsel experienced in running this type of complex class action litigation against a well-resourced defendant, and third-party litigation funding for their legal costs and experts’ fees, etc.
Fig. 5. Concentrations of Zn (A, B), Cd (C, D) and Pb (E, F) in two contaminated samples of topsoil from the Kabwe area, treated with humate (HU), triple superphosphate (TSP) and a mixture of TSP and humate. The concentrations are presented in % relative to untreated samples. Untreated and treated samples were digested with aqua regia (total concentration), in an acidified solution of glycine (gastric accessible metals) and in a mixture of DTPA and TEA (plant available metals). The experimental results indicate that the concentrations of plant-available Pb and, to a lesser degree, also Cd decrease in the TSP- and in the TSP and humate-treated samples compared with untreated samples. The addition of only humate does not affect the plant availability of Zn. The gastric accessibility of Zn, Cd and Pb is not affected by addition of phosphate or humate solutions.
Environmental Issues
High contamination of soils as a result of base metal ore smelting during 1904–1984 is a major problem faced by the local population of this area today. The contents of Pb in the soils of the Kabwe Town reach 2.6 wt%, and those of Zn attain a maximum of 3 wt%, but on an average do not exceed 0.5 wt% (Tembo et al., 2006). High contents of Pb werealso found in agricultural products, particularly in rape (Brassica napus), which is an important crop grown in the local vegetable gardens (ZCCM-IH, 1996, 2002). High concentrations of Pb in soils, consumption of contaminated vegetables and inhalation/ingestion of dust enriched in Pb and other contaminants has resulted in high blood Pb levels of people living in the most affected areas of the Kabwe settlements. According to the standards issued by the World Health Organization (WHO, 2007), the maximum permissible value for the lead concentration in human blood is 10 μg/dl for children. In 1994, altogether 866 people living in the Kabwe Town were tested for blood Pb and the mean values ranged from 13.1 to 45 μg/dl for adults (Herzman, 1995). The highest blood Pb values were found in the youngest group of the population (age 6–16 years; 17.7 to 52 μg/dl). This is ascribed to the fact that children are generally shorter, closer to the contaminated ground and therefore tend to inhale and digest larger volumes of contaminated dust particles, particularly when playing outdoors. In addition to the decommissioned Pb-Zn smelter, the ferromanganese smelters are still in operation in Kabwe and old tailings, slag deposits and residues left from base metal leaching represent potential sources for metalliferous dust re-suspension.
Conclusions
Monitoring of the regional extent of topsoil contamination has shown that emissions from the abandoned Pb-Zn smelter play a major role in the large-scale pollution of the local environment. However, resuspended dust from other sources (tailing ponds, slag deposits) and emissions from the active ferromanganese smelter also probably participate in the pollution. Strong contamination of the topsoil was found especially in for Pb and Zn. The concentrations of both elements exceed Canadian soil quality limits in several Kabwe Town districts. The distribution in the topsoil of the other monitored elements (Cu, Fe, Mn, Cr, Ni), d by both anthropogenic and geogenic factors.
The tests undertaken demonstrated the very high gastric accessibility of Pb and Cd in the topsoils. However, the tolerable daily intake (TDI) values calculated for a child weighing 10 kg, using the humantoxic maximum permissible levels, are exceeded for a large number of the studied samples only for Pb.
The results of plant-availability studies of PHE in the topsoil showed that a significant proportion of the contaminants are present in a plantavailable fraction. To suppress the plant availability of Pb, Zn and Cd, the samples of strongly contaminated topsoil were treated with phosphate or humate solution. Application of phosphate showed that the plant availability of Pb and Cd decreased significantly. The plantavailability of Zn was not affected by the phosphate treatment.
Based on these results, a range of measures has been formulated and suggested to improve the quality of the Kabwe environment. These include, for example, proposals to restrict the free movement of people and, in particular, children in the former technological grounds. Dust control can be achieved by planting greenery and sprinkling water on dusty roads, particularly in the dry season (May–October). Special attention should be paid to playgrounds and lawns adjacent to schools. These areas should be covered with uncontaminated soil and grass. Rehabilitation of these areas should be treated as a priority. The efficiency of these measures should be controlled by long-term monitoring of the amounts of lead in the blood of the population living in vulnerable areas, especially children and pregnant women. The amounts of plant-accessible Pb and Cd in heavily polluted soils can be reduced by phosphate amendment and the content of toxic elements in vegetables grown in phosphate-treated grounds should also be monitored regularly to verify the efficiency of phosphate treatment.
Supplementary data to this article can be found online at
https:// doi.org/10.1016/j.gexplo.2018.11.018.