Enhanced Accumulation of Copper and Lead in Amaranth (Amaranthus paniculatus), Indian Mustard (Brassica juncea) and Sunflower (Helianthus annuus)

Abstract

BackgroundSoil contamination by copper (Cu) and lead (Pb) is a widespread environmental problem. For phytoextraction to be successful and viable in environmental remediation, strategies that can improve plant uptake must be identified. In the present study we investigated the use of nitrogen (N) fertilizer as an efficient way to enhance accumulation of Cu and Pb from contaminated industrial soils into amaranth, Indian mustard and sunflower.Methods/Principal FindingsPlants were grown in a greenhouse and fertilized with N fertilizer at rates of 0, 190 and 380 mg kg−1 soil. Shoots, roots and total accumulation of Cu and Pb, transfer factor (TF), translocation index were assessed to evaluate the transport and translocation ability of tested plants. Addition of N fertilizer acidified the industrial soil and caused the pH to decrease to 5.5 from an initial pH of 6.9. Industrial soil amended with N fertilizer resulted in the highest accumulation of Pb and Cu (for Pb 10.1–15.5 mg kg−1, for Cu 11.6–16.8 mg kg−1) in the shoots, which was two to four folds higher relative to the concentration in roots in all the three plants used. Sunflower removed significantly higher Pb (50–54%) and Cu (34–38%) followed by amaranth and Indian mustard from industrial soils with the application of N fertilizer. The TF was <1 while the shoot and root concentration (SC/RC) ratios of Pb and Cu were between 1.3–4.3 and 1.8–3.8, respectively, regardless of plant species.ConclusionsSunflower is the best plant species to carry out phytoextraction of Pb and Cu. In contrast, Pb and Cu removal by Indian mustard and amaranth shows great potential as quick and short duration vegetable crops. The results suggest that the application of N fertilizer in contaminated industrial soil is an effective amendment for the phytoextraction of Pb and Cu from contaminated industrial soils.

Effects of Different Soil Amendments on Mixed Heavy Metals Contamination in Vetiver Grass

“…The findings show that application of higher levels of both N-fertilizer and EDTA are likely to enhance the accumulation of Cd in the shoots of Vetiver grass whereas the opposite was found with elemental S. Notwithstanding, the trend for Pb accumulation was in the following order of EDTA (25EDTA) > N-fertilizer >> elemental S among all treatments. The application of higher levels of EDTA and N-fertilizer could have probably increased Pb accumulation in the shoots of Vetiver grass, as similar trends have been reported previously by Nascimento et al (2006), Chiu et al (2006) and Rahman et al (2013). Although higher Pb accumulation was recorded with the application of N-fertilizer in the shoots, relatively all levels of N-fertilizer treatments displayed approximately similar accumulation of Pb.…”

Natural attenuation of toxic metal phytoavailability in 35-year-old sewage sludge-amended soil

“…Phytoremediation of soils is generally not viable for Pb because of its strong binding in soils and immobilization in roots of almost all plant species (Nanda Kumar et al 1995). Thus, studies have shown relatively low concentrations of Pb in aboveground tissues of amaranth and other crops grown on slightly Pbcontaminated soils (Mellem et al 2009;Rahman et al 2013). Most of the Pb measured in lettuce grown on heavily Pb-contaminated soil was determined by McBride et al (2013) to be due to contamination of leaf surfaces by soil particles rather than true uptake.…”

Nitrogen and phosphorus uptake efficiency in Indian mustard cultivated during three growth cycles in a copper contaminated soil treated with biochar

“…Nitrogen and P are very important plant macronutrients and their availability in soil as well as their interaction limits plant growth (GROOT et al, 2003). Studies about the effect of biochar on the availability of N in soil have generated many contradictory results varying from positive, negative and even no effect (CLOUGH et al, 2013;RAHMAN et al, 2013;NGUYEN et al, 2017). The same different outcomes are observed during the evaluation of the effects of biochar on plant N absorption (SAARNIO et al, 2013).…”