Tree Bark as Bio-Indicator of Air Pollution in an Arid Environment : Application Of Tree Bark As Bio-Indicator Of Air Pollution In An Arid Zone Environment Evidence From Developing Country

Ten different species of trees from 3 sampling zones were taken in Yobe State, north east, Nigeria. The bark and the soil around these trees were analysed for heavy metals: Zinc, Lead, Iron, Manganese, Chromium, Cobalt and Nickel, employing atomic absorption spectrophotometry. The results of the analysis indicate various concentration levels and different sources of the heavy metals of interest. All the values obtained correlate well with the anthropogenic sources and are within the acceptable limits. The statistical comparison of the values between the bark and soil shows correlation at P < 0.01 and significant difference at p < 0.05. the study demonstrates the suitability of some of the trees as a good bioindicator.