A Preliminary Evaluation of the DDT Contamination of Sediments in Lakes Natron and Bogoria (Eastern Rift Valley,Africa) |
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Authors: | Roberta Bettinetti Silvia Quadroni Giuseppe Crosa David Harper Jennifer Dickie Margaret Kyalo Kenneth Mavuti Silvana Galassi |
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Institution: | (1) Department of Chemical and Environmental Sciences, University of Insubria, Via Valleggio 11, 22100 Como, Italy;(2) Department of Biology, University of Milan, Via Celoria 26, 20133 Milan, Italy;(3) Department of Structural and Functional Biology, University of Insubria, Via Dunant 3, 21100 Varese, Italy;(4) Department of Biology, University of Leicester, Leicester, LE1 7RH, England, UK;(5) Department of Geography, University of Leicester, Leicester, LE1 7RH, England, UK;(6) School of Biological Sciences, University of Nairobi, 30197 00100 Nairobi, Kenya |
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Abstract: | Dichlorodiphenyltrichloroethane (DDT) is still used in Africa for the indoor control of malaria and it may represent a potential
hazard for wildlife. The littoral sediments of two alkaline-saline lakes, Natron (Tanzania) and Bogoria (Kenya), in the Eastern
Rift Valley, supporting large populations of lesser flamingos (Phoeniconaias minor), were analysed for DDT residues. Physical–chemical analyses (temperature, conductivity, pH and dissolved oxygen) were also
performed on the water of the two lakes and in the tributaries of Lake Natron, to evaluate the influence of the environmental
variables on pollutant occurrence. At Lake Natron, around 1 km from the sediment collection sites, tree leaves of Acacia tortilis were also collected. The main metabolite found in all sediment samples was pp’DDE, whilst equal concentrations of pp’DDT
and pp’DDE were measured in acacia leaves. The levels of DDTs measured in the sediments were within 5.9–30.9 ng g−1 d.w., reaching the maximum value in a tributary of Lake Natron. On the whole, the contamination of Lake Natron and Lake Bogoria
basins seems to be quite moderate. Nevertheless, the pp’DDE/pp’DDT ratio equals 1 in the Acacia tortilis leaves, which makes one suppose that the input of the parent compound was rather recent and could have been from aerial transport
or dust from relatively close-by old pesticides storage sites. |
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Keywords: | Obsolete contaminant pollution Soda lakes Sediments Acacia leaves Tanzania Kenya |
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