comparison of lead uptake by four seedling species (acer cappadocicum, fraxinus excelsior, thuja orientalis and cupressus arizonica)

the phytoremediation capability in pb removal from the contaminated soils by three native seedlings species (acer cappadocicum, fraxinus excelsior and thuja orientalis) and one exotic species (cupressus arizonica) were compared. the seedlings were grown in pb contaminated soils at 0, 100, 200, 300, 400 and 500 mg kg-1 concentrations for 6 months (mar 21 to sept. 22, 2015), after which the biomass allocation and pb accumulation in tissues of root, stem, and leaf were assessed. the results showed that the higher pb levels (400 and 500 mg kg-1 soil) caused significant reduction in growth in all species, but this inhibition was less marked in the two conifer (t. orientalis and c. arizonica) compared to the two broad-leaf seedlings (a. cappadocicum and f. excelsior). pb concentration in different tissues of seedlings increased with its increase in the soil. further, pb accumulation in the conifers was twice higher than that of the broad-leave species. therefore, this study suggests that the two conifer species (p. orientalis and c. arizonica) can be used for phytoremediation, although further research is needed to make a final decision.