High human exposure to cobalt and other metals in Katanga, a mining area of the Democratic Republic of Congo.
OBJECTIVE
The human health impact of the historic and current mining and processing of non-ferrous metals in the African Copperbelt is not known. This study assessed the exposure to metals in the population of Katanga, in the south east of the Democratic Republic of Congo, using biomonitoring.


METHODS
Seventeen metals (including Cd, Co, Cu, Pb, U) and non-metals (including As) were measured by ICP-MS in urine spot samples from 351 subjects (32% women), aged 2-74 yr (mean 33 yr). Forty subjects (controls) lived 400 km outside the mining area; 311 subjects lived in the mining area, either very close (< 3 km) (n=179; 6 communities) or moderately close (3-10 km) (n=132; 4 communities) to mines or smelting plants.


RESULTS
For all metals (except Ni) urinary concentrations were significantly higher in subjects from the mining area than in control subjects. In subjects living very close to mines or smelting plants, the geometric means (25th-75th percentile) of urinary concentrations, expressed as microg/g creatinine, were 17.8 (10.9-29.0) for As, 0.75 (0.38-1.16) for Cd, 15.7 (5.27-43.2) for Co, 17.1 (8.44-43.2) for Cu, 3.17 (1.47-5.49) for Pb and 0.028 (0.013-0.065) for U, these values being significantly higher than those of subjects living 3-10 km from mines or industrial operations. Urinary Co concentrations were markedly elevated, exceeding 15 microg/g creatinine in 53% of the subjects, and even 87% of children (<14 yr), living very close to the mining areas. Urinary As was also high (79% above 10 microg/g creatinine in subjects living very close to the mining areas). Compared with background values from the US general population, subjects living very close to areas of mining or refining had 4-, 43-, 5- and 4-fold higher urinary concentrations of Cd, Co, Pb and U, respectively.


CONCLUSIONS
This first biomonitoring study of metal exposure in the African Copperbelt reveals a substantial exposure to several metals, especially in children. The urinary Co concentrations found in this population are the highest ever reported for a general population. The pathways of exposure and health significance of these findings need to be further investigated.
Banza
Célestin Lubaba Nkulu
CL
Unité de Toxicologie et Environnement, Ecole de Santé Publique, Université de Lubumbashi, Democratic Republic of Congo.
Nawrot
Tim S
TS
Haufroid
Vincent
V
Decrée
Sophie
S
De Putter
Thierry
T
Smolders
Erik
E
Kabyla
Benjamin Ilunga
BI
Luboya
Oscar Numbi
ON
Ilunga
Augustin Ndala
AN
Mutombo
Alain Mwanza
AM
Nemery
Benoit
B
D000293:Adolescent; D000328:Adult; D000368:Aged; D001151:Arsenic / Q000652:urine; D002648:Child; D002675:Child, Preschool; D003035:Cobalt / Q000652:urine*; D004781:Environmental Exposure / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D019216:Metals, Heavy / Q000652:urine; D008875:Middle Aged; D008906:Mining; D055815:Young Adult
D004785:Environmental Pollutants; D019216:Metals, Heavy; D003035:Cobalt; D001151:Arsenic