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Project

Blootstelling aan metalen en congenitale misvormingen in de Katangese kopergordel

The (former) province of Katanga has been the site of mining and mineral processing for many decades, with considerably increased activity since about the year 2000. This has led to substantial pollution of the environment and, hence, concern for the health of the population. Very high values of toxic metals have previously been reported for the general population of Katanga but, so far, the impact on public health is largely unknown. There have been anecdotal reports of an increased number of congenital malformations among children from mineworkers; however, epidemiological studies to investigate the health impact of metal pollution on the population have not been published in this region. We aimed to contribute to the evaluation of the possible impact of metal pollution on congenital malformations in the southern Katanga using three different types of studies: an epidemiological investigation (called KMC study for “Katanga Malformations Congénitales”) that represents the main study, descriptive studies of specific clinical conditions, and an analysis of toxicologically relevant data obtained from the main study.

The KMC study, described in chapter 2, was a case-control study in which we included, between March 1, 2013, and Feb 28, 2015, 138 newborns with visible birth defects (cases) and 108 healthy neonates born in the same maternity ward (controls) in Lubumbashi. Mothers were interviewed about potentially relevant exposures, including their partners’ jobs. Various trace metals were measured by inductively coupled-plasma mass spectrometry in maternal urine, maternal blood, umbilical cord blood, placental tissue, and surface dust at home. Those data were analysed using multivariable logistic regressions. We found that being a case was significantly associated with having a father with a mining-related job (about five-fold higher risk) or a mother with a paid job outside their house (almost three-fold higher risk). Mothers of cases were less likely to have taken vitamins during pregnancy. In general, no significant differences were found in toxic metal concentrations between cases and controls, but a doubling of Mn at the fetal side of the placenta was associated with an increased risk of birth defects, as was a doubling of cord blood Zn.

The clinical reports, described in chapter 3, included a case of agnathia otocephaly, a series of three cases of holoprosencephaly, and one case of Cornelia de Lange syndrome, conditions that had not been previously described in DR Congo. Among these cases, some neonates or their mothers had evidence of very high metal exposure, and the fathers of 3 of the 5 cases had a mining-related job.

In the toxicological analysis, described in chapter 4, we showed that among the participants of the KMC study, cobalt concentrations in umbilical cord blood were 40% higher than in maternal blood. The health consequences of high intrauterine exposure to cobalt are unknown, and the KMC study did not show an association between cobalt and congenital anomalies in Katanga. Nevertheless, the high levels of cobalt we observed in neonates and pregnant women of childbearing age may have negative effects.

Based on our previous documentations of high exposure to trace metals in people living close to mining and on the findings of this dissertation, we conclude that fathers’ mining jobs may have played a role in the occurrence of birth defects in neonates of the former province of Katanga. Legislation enforcement and advocacy are warranted to protect the population in this polluted area.

Datum:6 nov 2017 →  25 mrt 2022
Trefwoorden:Keywords: Katanga, cobalt, human health
Disciplines:Maatschappelijke gezondheidszorg, Gezondheidswetenschappen, Publieke medische diensten, Microbiologie, Systeembiologie, Laboratoriumgeneeskunde
Project type:PhD project