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A study was conducted to assess possible risks of copper contamination in fish
farmed in copper mining areas of Zambia. Nine fish farms were selected within and
around Kitwe district for the study. The farms drew water from different sources –
dam, river and spring. Five types of samples were sampled, i.e. soil, sediment, plant,
fish and water at each farm. Three fish ponds were sampled at each farm. Copper
determination in each sample was carried out using Atomic Absorption
Spectrophotometer (AAS). The results revealed that there were significant
differences between farms receiving water from different sources with respect to
copper concentration in soils, sediment, plant and fish but not in water. The soil and
sediment samples taken from around Mindolo Dam had the highest concentration of
copper, while those taken from around Kafue River had the lowest copper
concentration. The mean copper concentrations in soil and sediment samples taken
from around Mindolo Dam were 91.09 and 41.71 ppm while those from around
Garneton spring were 30.36 and 36.47 ppm and around Kafue River were 13.55 and
24.43 ppm respectively. From the three sources of water the mean copper levels in
plant, fish and water samples ranged from 13.93 to 26.12, 8.68 to 13.25 and 0.14 to
0.39 ppm respectively. Furthermore, farms receiving water from same sources
differed significantly with respect copper concentration in soil, plant, sediment and
fish, but not in water. From the results it can be concluded that the relatively high
levels of copper in soils and sediments from Mindolo Dam and Garneton Spring
were due to their natural presence there and had not been deposited from anywhere
else. The relatively much higher levels of copper observed in fish than in water mayii
be attributed to the build up of mineral in the fish with time. More studies are needed
to establish the origin of copper in and around the fish ponds in the study area. |
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