Phytoextraction from Chromium-Contaminated Soil Using Moso Bamboo in Mediterranean Conditions

Abstract

An experimentation has been carried out in simulated Mediterranean and tropical laboratory conditions aimed to show the Moso bamboo capability of phytoextraction chromium from contaminated soil. Electronic microscopy supported the analyses performed on soil and on the different plant tissues. A preliminary test on the bamboo has been carried out in laboratory evaluating his growth with irrigation in Mediterranean conditions (600 mm/year) and tropical conditions (1.800 mm/year). A test of the bamboo tolerance of was also carried out by measuring his growth with irrigation with a solution of 100 mg Cr/l, reporting not significant damages to the plant tissues. Subsequently chromium phytoextraction was tested highlighting that bamboo removes Cr from soil with a percentage ranging from 43% (600 mm/year) to 47.4% (1.800 mm/year) of the total content in soil. Lastly, the distribution of chromium in the different fragments of the bamboo plants has been performed. It has been shown that approx. 69% of chromium, in Mediterranean conditions, was in the rhizomes and approx. 68% in tropical conditions. A slightly higher tendency to chromium translocation to leaves has been shown in tropical conditions than in Mediterranean conditions.

Phytoextraction of Cr(VI)-Contaminated Soil by Phyllostachys pubescens: A Case Study

“…The interpolation curve was linear in the four cases: h = 3.39 (weeks) + 53.56 with R 2 > 0.99 for Pot 1; h = 3.16 (weeks) + 51.18 with R 2 = 0.9964 for Pot 2; h = 5.933 (weeks) + 91.302 with R 2 = 0.996 for Pot 3; and h = 5.854 (weeks) + 90.057 with R 2 > 0.99 for Pot 4. For both climate cases, the growth rate g r was lower than that in the previous experiment [11], where the growth rate g r was 4.56 cm/week for Pots 1 and 2 and 8.45 cm/week for Pots 3 and 4. The total elongation, similar in both pots for each irrigation rate, also seems to be lower than that observed in natural conditions for MB [50,51].…”

“…The interpolation curve for Pot 3 was h = 162.48e 0.0056 (weeks) with R² = 0.9672; the same curve for Pot 4 was h = 160.34e 0.0061 (weeks) with R² = 0.9514 (Figure 5). In both cases, there was an increase in plant tolerance compared to that in the previous experiment [11], probably due to the higher volume of biomass developed [53][54][55][56]. The administration of Cr induced significant changes in tissue morphological parameters after the fifth or sixth week.…”

“…Chromium is required as a nutrient for human metabolism with consumption of 100 µg daily, but excessive exposure to Cr(VI) has toxic effects on human health, particularly on the respiratory system [6][7][8][9][10]. Chromium represents a wide concern in soil contamination, including in Italy [11].…”

“…On the basis of our previous work [11], wherein an experimental study was carried out in the laboratory to evaluate MB's tolerance and capacity for Cr phytoextraction and was developed in three stages.…”

“…To evaluate MB's tolerance in Cr-contaminated soils; To quantify its long-term Cr phytoextraction capacity; To evaluate the migration capacity of Cr within the plant; To assess the difference in the Cr content in plant sections as a function of different phytoextraction timings. On the basis of our previous work [11], wherein an experimental study was carrie out in the laboratory to evaluate MB's tolerance and capacity for Cr phytoextraction an was developed in three stages.…”