Removal of As, Cd, Pb, and Zn from contaminated soil by high biomass producing plants

Abstract

The uptake of As, Cd, Pb, and Zn and potential phytoremediation efficiency of five high biomass producing crops, white sweetclover (Melilotus alba L.), red clover (Trifolium pratense L.), curled mallow (Malva verticillata L.), safflower (Carthamus tinctorius L.) and hemp (Cannabis sativa L.) commonly used as grazing and/or energy crops was evaluated in both pot and field experiments at soils with different level of element contamination. In pot experiment the highest phytoremediation efficiency was demonstrated by C. tinctorius where 4.8% of Cd and 1.1% of Zn were removed from the moderately contaminated soil in one vegetation period when repeated harvest of aboveground biomass was performed. The removal of As and Pb was negligible for all the investigated plant species. At the highest element content in soil inhibition of plant growth due to the element phytotoxicity to plants was reported in most of cases. In the precise field experiment lower phytoremediation efficiency (biennial phytoremediation factors did not exceed 0.2% for Pb and Zn and 0.3% for Cd for C. tinctorius) was determined but yield suppress was not observed. Thus, free space for manipulation with element mobility in soil to increase element uptake by plants remains for further research.

Uptake of Pb, Zn and Cu by roots and shoots of fast growing plants grown in contaminated soil in Vietnam

“…No differences in uptake by shoots were observed for other three plant species. Tlustos et al (2006) showed that maximum uptake of Pb and Zn by shoots of high biomass-producing crops (sweet clover, red clover, curled mallow, safflower and hemp) to be 120 and 104 mg/m 2 , respectively. According to Dai et al (2007) …”

“…uptake per unit weight of plant roots and/or shoots. However, as demonstrated by Tlustos et al (2006) and Dai et al (2007), phytoremediation is a function of the plant assemblage of an area, and thus the remediation capacity should be evaluated as the uptake by all plants of a single species growing per unit area of land.…”

Malva: Food, Medicine and Chemistry

“…338 Out of four plants, M. verticillata was found to be good metal accumulator in average, and highets for both Cd and Pb. 339 Antimicrobial, antidiabetic, antibacterial Leaves methanolic and n-hexane extract were prepared.…”

Phytoremediation of heavy metals by Trifolium alexandrinum

“…An additional advantage of phytoextraction is that during this practice, plants cover the soil and thus, erosion and leaching are minimized (Jadia and Fulekar, 2009). For phytoremediation, two approaches are used: (1) The application of hyperaccumulators (such as Thlaspi caerulescens or Alyssum bertolonii) producing a relatively low amount of aboveground biomass but accumulating high amounts of one or more elements (2) The application of high biomass producing plants characterized by lower ability to accumulate target elements where total uptake of elements is comparable to that of hyperaccumulators due to high yield of above-ground biomass (Tlustos et al, 2006). Hyperaccumulators are defined as "plant species whose shoots contain > 100 mg Cd kg −1 , > 1000 mg Ni, Pb and Cu kg −1 or > 10000 mg Zn and Mn kg −1 (dry weight) when grown on metal rich soils" (Baker and Brooks, 1989).…”