STATISTICAL COMPARISON OF THE GEOCHEMISTRY OF VOLCANIC BEDROCKS AND SOILS FROM PODOCONIOSIS-ASSOCIATED REGIONS ON THE AFRICAN CONTINENT
Using both descriptive and multivariate statistics, we analyzed ten major oxides of the bedrock of four rift locations (Cape Verde Islands, East African Rift, Mid-African Rift, Red Sea Rift) on the African continent. The Hawaiian Islands were included as a control group since they are not known to have cases of podoconiosis. Descriptive analyses showed separation of each of the African locations into two geochemically distinct populations, one of which had no counterpart in the Hawaiian Islands. Principle component analysis also indicated a geochemically unique population within the African locations. Separation of the populations is most influenced by K2O, MgO, Na2O and SiO2. We propose that the unique African population, which is high in alkali, magnesium and silicon, is responsible for the irritant particles associated with podoconiosis. We also propose that a comparison of soil samples from Ethiopia (a known podoconiosis hotspot) will show the same statistical separation of geochemical populations between podoconiosis-endemic and non-endemic locations.