Concentrations of heavy metals in roadside soils, plants, and landsnails from the West Bank, Palestine

Concentrations of Cu, Cd, Pb and Zn were determined in roadside soil, plant and landsnail samples along Nablus-Ramallah main road in the West Bank. Average concentrations (mug.g(-1), dry weight) of the four metals in soil samples were, Cu: 23.8, Zn: 128.3, Cd: 0.45 and Pb: 149.9. These values were higher than those found in soil samples collected from control sites. Metals in roadside plant samples were within normal levels although plants from control sites were found to have slightly less metals. Different parts of a plant (roots, stem & leaves) were found to accumulate metals in different concentrations. The average concentration (mug.g(-1)) of metals in different plant parts were: Cu: < 5.2, Cd: < 1.0, Pb: < 2.19 and Zn: < 5.18. Average concentrations (mug.g(-1)) of metals in the three roadside snails were ranging between 121-132 for Cu, 18-27 for Cd, 21-24 for Pb and 43-69 for Zn. Snails were found to magnify Cd to serious levels (> 30-50 times higher than in plants and soils). Lead in snails was about 10 times higher than that in giant leaves and much less than that in roadside soils. Other metals in snails did not show abnormal concentrations.