IGCP/SIDA Project 594, Annual Workshop, Windhoek, Namibia, 2012
Pathways of exposure to cobalt in
populations living in Katanga, D.R. Congo
C. Banza Lubaba Nkulu1, K. Cheyns2, J. Ngoy
Asosa1, L. Kabamba Ngombe1, A. Mutombo Mwanza1,
V. Haufroid3, Th. De Putter4, O. Luboya Numbi1,
B. Kabyla Ilunga1, C. Muleka Kimpanga1,
B. Nemery5, E. Smolders2
1. Unité de Toxicologie et Environnement, Ecole de Santé Publique,
Université de Lubumbashi, Lubumbashi, D.R. Congo
2. Division of Soil and Water Management,Department of Earth and
Environmental Sciences, KU Leuven, Leuven, Belgium
3. Laboratoire de Toxicologie Industrielle et Médecine du Travail, U.C.
Louvain, Brussels, Belgium
4. Geology, Royal Museum for Central Africa, Tervuren, Belgium
5. Occupational, Environmental and Insurance Medicine, Department of
Public Health, KU Leuven, Leuven, Belgium
“African copperbelt”
Kamin
a
10°0’0’’
S
Lika
si
Kipus
hi
26°0’0’’
E
Lubumbas
hi
28°0’0’’
E
12°0’0’’
S
Background
• Evidence of high exposure to several metals (Co,
Cu, As, U, …) in the population of south Katanga
• Evidence of higher exposure in subjects living very
close (< 3 km) to mines or smelting plants
Aims
Main pathways of exposure ?
– Air
– Dust
– Water
– Diet (staple foods, vegetables, fish,
meat, ...)
– Work
IGCP/SIDA Project 594, Annual
Workshop, Kitwe, Zambia, 2011
• Preliminary data
– Concentrations of metals in urine of adults
and children
– Concentration of metals in environmental
samples (drinking water, indoor + outdoor
dust, fish, chickens)
in three areas (Likasi & Lake Changalele)
Likasi and Lake Changalele
A Control
– 2 villages : Misisi-Sando (along river Lufira),
Kidimudilo
B Likasi
– 2 urban areas in vicinity of metallurgical plants:
Q. Shituru, Q. Panda
C Lake Changalele (receives effluents
from metallurgical plants in Likasi):
– 3 villages close to Lake Changalele (high fish
consumption): Kansalabwe, Shinangwa, Kibangu
KIBANGU
KANSALABWE
SHITURU
SHINANGWA
PANDA
R PANDA
KIDIMUDILO
MISISI-SANDO
R. LUFIRA
URINE
Kapolowe-Gare: Panda and Lufira rivers jonction
Fish
Shinangwa 2009
Food
Air pollution
Likasi 2006
IGCP/SIDA Project 594, Annual
Workshop, Kitwe, Zambia, 2011
• Preliminary conclusions
–Main source of exposure to metals
appears to be dust
–Fish may also be a significant
source
–Contribution of vegetables needs to
be assessed
IGCP/SIDA Project 594, Annual
Workshop, Windhoek, Namibia, 2012
• Additional data & further analysis re. Co
– Concentration of metals in food items (maize
flour, locally grown vegetables, ...)
– Food questionnaire (quantity/quality)
– Additional locations
• 1 urban area in Lubumbashi (Q. Kabecha) close to
a copper/cobalt processing plant
• 1 rural area close to a cobalt mine (Shamitumba)
• 2 control locations outside Copperbelt (Kamina,
Mbuji-Mayi)
Sampling
• Volunteers – convenience sampling (family
clusters: adults + children)
– Simple questionnaire (age, residence, …)
– Food questionnaire (1 per household)
– Spot sample of urine (avoiding contamination)
•
•
•
•
Soil dust samples (outdoor + indoor)
Drinking water
Chickens (liver, kidney) + Fish
Kitchen gardens (soil, vegetables) + maize
flour
Analytical methods
•
•
•
•
•
Urine
Water
Animal tissues
Vegetables
Soil & dust
oven dried, acid destruction
 Analysis by ICP-MS (Inductively Coupled
Plasma Mass Spectrometry)
Estimation of intake of Co
• Dietary intake based on
– food questionnaire (average data)
– concentrations of Co in collected samples
• Dust intake based on
– estimate from literature
– concentrations of Co in indoor + outdoor dust
Estimated adult dietary intake
Cereals (g/day)
Vegetables
(g/day)
Meat (g/day)
Water (mL/day)
Dust (g/day)
Fish (g/day)
Control area
Lakeside area
Polluted area
n=6
n=9
n=15
610 (50)
620 (26)
610 (47)
25 (11)
0.6 (11)
1500 (500)
28 (14)
0.1 (0.2)
1500 (500)
23 (17)
0.5 (0.5)
1500 (500)
0.1 (0.05)
0.1 (0.05)
0.1 (0.05)
4.1 (1.0)
3.1 (0.8)
2.5 (1.6)
Fraction of total
Maize flour
100 %
Cassava leaves
25 %
Sweet potato leaves
25 %
Other leafy vegetables
20 %
Fruit vegetables
15 %
Beans
5%
Fruit
5%
Other vegetables
5%
Meat (muscle)
80 %
Meat (liver)
10 %
Meat (kidney)
10 %
Drinking water
100 %
Indoordust
33 %
Outdoordust
67 %
Fish
100 %
Average Co concentrations (µg/g dry wt)
Control + Lakeside areas Polluted areas
Maize flour
Cassava leaves
Sweet potato leaves
Other leafy vegetables
Fruit vegetables
Beans
Fruit
0.05 (0.05)
0.4 (0.5)
n=12
n=14
1.5 (2.3)
12 (8.1)
n=8
n=16
1.1 (0.98)
6.7 (4.2)
n=9
n=32
1.2 (1.6)
46 (73)
n=54
n=52
0.58 (0.55)
12 (10)
n=19
n=14
0.84 (1.35)
22 (32)
n=15
n=11
0.58 (0.52)
-
n=3
Other vegetables
0.45 (0.49)
4.7 (4.8)
n=16
n=15
Average Co concentrations (µg/g dry wt)
Control + Lakeside area
Polluted area
0.38 (0.23)
-
Meat (muscle)
n=4
-
0.59
Meat (liver)
n=1
-
0.11
Meat (kidney)
n=1
Drinking water (µg/L)
Indoor dust
Outdoor dust
Soil
Fish
<0.001
0.012 (0.007)
n=4
n=5
11 (12)
440 (600)
n=26
n=33
11 (14)
290 (360)
n=26
n=33
20 (11)
132 (185)
n=5
n=21
0.34 (0.61)
6.2 (12)
n=44
n=54
-
Urinary Co concentrations (µg/g creatinine)
Adults
(≥14 years)
Children
(<14 years)
KAMINA
6.0 (8.3) [n=13]
3.4 (1.5) [n=9]
MISISI
2.3 (1.5) [n=7]
5.2 (3.4) [n=3]
MBUJI MAYI
2.7 (2.2) [n=26]
4.2 (4.9) [n=6]
SANDO
9.8 (9.3) [n=10]
8.2 (4.9) [n=7]
KANSALABWE
15 (16) [n=25]
14 [n=1]
KIBANGU
16 (14) [n=11]
21 (9.4) [n=6]
SHINANGWA
12 (10) [n=11]
13 (9.7) [n=6]
KABECHA
16 (27) [n=17]
20 (17) [n=8]
LIKASI PANDA
12 (8) [n=21]
13 (7.4) [n=7]
LIKASI SHITURU
23 (22) [n=28]
56 (32) [n=9]
SHAMITUMBA
25 (24) [n=13]
99 (120) [n=9]
Location
Control area
Lakeside area
Polluted area
Estimated Co intake (µg/day) – Adults
55
99
635
62
65
170
79
509
593
62
553
60
Adults
(A)
Co urine (µg/g creatinine)
50
40
30
20
10
0
0
200
400
600
Co intake (µg/day)
800
1000
Estimated Co intake (µg/day) – Children
29
46
352
36
34
34
37
416
313
33
340
250
(B)
Co urine (µg/g creatinine)
Children
200
150
100
50
0
0
100
200
300
400
Co intake (µg/day)
500
600
Conclusions
• Good (but not perfect) relation between estimated
Co intake and urinary concentration of Co
– Lower bioavailability of Co in dust?
– Incorrect estimate of quantity of dust intake?
• Main contributory sources of Co:
– Control areas: ~90% maize flour + vegetables
– Lakeside areas: ~25% fish
– Polluted areas: vegetables and dust
(dust especially in children)
• Further analyses are planned for other metals