Spatial distribution of heavy metals in soil with distance from Tazama pipeline through the Mikumi National Park, Tanzania

A total concentration of six studied heavy metals Arsenic (As), Lead (Pb), Chromium(Cr), Mercury (Hg) Cadmium (Cd) and Copper (Cu) were measured in soil across distances from TAZAMA pipeline in transects which have incidences of oil spillage and those which have no history of oil spillage. All studied heavy metals were detected in the study area. As, Pb and Cr were detected in both transects, that is, with oils spills and those with no history of oil spillage to a distance of 0-35 m from the edge of the pipeline, with higher mean concentration in transects with oil spillage compared to those with none. From 50-200 m away from the pipeline these four metals were detected in transects with oil spillage only. Hg and Cd were detected in transects with history of oil spillage only. Cu was detected in all transects and at all ranges of distance. Concentration of studied heavy metals decreased with increased distance from the edge of the pipeline in both transects to all directions. The decrease was statistically significant in transects with oil spillage and insignificant with transects of no history of oil spillage.