Phytoremediation of Lead: From Fundamentals to Application

Lead (Pb) is one of most widely studied heavy metals in respect to plant responses and accumulation potential in tissues, but scientific opinion on the use of plants in phytoremediation of Pb-contaminated soil and wastewater is sometimes controversial. Therefore, the aim of the present review was to analyze recent information on phytoremediation of lead, emphasizing possible problems related to use of various experimental systems. After a brief review of Pb tolerance and uptake by plants, an analysis of Pb accumulation in various experimental systems was performed. It is evident that the use of plant material from natural metal-contaminated habitats cannot give reliable results due to possible aerial contamination. Similarly, while hydroponic cultivation system has been frequently used for Pb accumulation experiments, it is that that extrapolation of results obtained in hydroponic experiments can be misleading and cannot be used for estimation of Pb accumulation capacity. Sometimes, experiments in tissue culture are employed for assessment of Pb accumulation, but the degree of generalization of the obtained results is limited by the possible interaction of Pb with medium components, as well as the dependence of the results on the type of explants. Soil-based experimental systems seems to be the most reliable for evaluation of Pb accumulation potential in plants. In contrast to chemically-assisted Pb phytoremediation systems, which have several problems of practical nature, microbially-assisted systems combined with co-cropping seem to be the most perspective for practical use.