Levels of lead and other metals in citrus alongside a motor road

The present study investigates the accumulation of Pb, Cu, Mn and Zn in leaves of Citrus limon (L.) Burm picked up from a field situated near a busy road. Samples were collected at different distances of 1-500 m from the road. Washed and unwashed foliage of citrus were analyzed by AA. Differences between washed and unwashed samples were found only for lead which indicated a significant reduction in concentration in all distances that come up to 52.35%, the differences evidence that this metal mainly reaches leaves by aerial deposition. Lead concentration in leaves of citrus with regard to distance from the roads decreases rapidly with increasing distance. Lead levels were higher than typical background concentrations. These concentrations indicated that lead pollution on a local scale is caused by emissions from motor vehicles that are still using leaded gasoline, that is, the only source of contamination known in this place. The content of the other metals did not present significant differences between washed and unwashed samples and the concentrations are not a function of the distance from the load.