Atmospheric heavy metal pollution in Aqaba city, Jordan, using Phoenix dactylifera L. leaves

The leaves of date palms (Phoenix dactylifera L.) were evaluated as biomonitors of heavy metal contamination in the city of Aqaba, Jordan. The concentrations of iron (Fe), lead (Pb), zinc (Zn), copper (Cu), nickel (Ni), and chromium (Cr) were determined using a flame atomic absorption spectrophotometer. Samples of unwashed leaves for testing were collected from different locations with different degrees of metal pollution (urban, suburban, industrial, highway, and rural sites). Separate leaves were taken from outside the city to be used as a control sample. Samples collected from industrial areas were found to have high contents of all metals except for nickel, copper, and lead, which were found at high concentrations in the samples collected from highway sites. Significant correlations between the heavy metal concentrations in date palm trees in unwashed leave samples were obtained. The principle component analysis (PCA) along with correlation analysis provide significant information about the origin of heavy metals in palm tree samples.