Removal of mercury (II) from the aquatic environment by phytoremediation

Abstract

A B S T R A C TPhytoremediation may be an alternative to traditional methods of removing heavy metals from the aquatic environment. In order to remove mercury at a concentration of 0.3 mg/L from Hoagland medium, two species of pleustophytes were used, namely Salvinia natans and Lemna minor. Some homogeneous cultures and another one mixed in a weight ratio of 2:1 were used. The physiological condition of the plants was controlled after 7, 14 and 21 d by evaluating biomass growth, analysing the changes in the amount of total protein and assimilation dyes. At the same time, the level of the mercury content in the base and plant tissues was controlled. The increase in biomass during plant exposure to mercury was up to 190% compared to baseline. Accumulation of mercury in plant tissues to 238.34 mg/kg d.m. , contributed to a significant reduction in its concentration in the medium. The bad condition of the plants led to an attempt to support phytoremediation by micro-organisms taking an active part in the transformation of mercury. For this purpose, epiphytic bacteria, accompanying S. natans, which are resistant to mercury at a concentrations of 0.3 mg/L, were isolated. Studies indicate the possibility of using the plants S. natans and L. minor to remove mercury compounds from the aquatic environment, while providing a basis to determine the principles of design and operation of Lemna ponds, especially when the process is simultaneously stimulated by those bacteria that are resistant to high concentrations of mercury.

Phytoremediation and Microorganisms-Assisted Phytoremediation of Mercury-Contaminated Soils: Challenges and Perspectives

“…The presence of bacteria enhanced phytoaccumulation relative to the uninoculated plants, by up to 650 and 320 mg Pb kg −1 and up to 7.5 and 2.4 mg Hg kg −1 in roots and shoots respectively [144]. Growth and Hg 2+ uptake capacities were improved in Salvinia natans and Lemna minor grown in aqueous solution containing 0.3 mg Hg(NO 3 ) 2 L −1 , by the presence of three strains of epiphytic bacteria [145]. Hg-resistant Enterobacter ludwigii and Klebsiella pneumoniae, isolated from of 37…”

“…The presence of bacteria enhanced phytoaccumulation relative to the uninoculated plants, by up to 650 and 320 mg Pb kg −1 and up to 7.5 and 2.4 mg Hg kg −1 in roots and shoots respectively [ 144 ]. Growth and Hg 2+ uptake capacities were improved in Salvinia natans and Lemna minor grown in aqueous solution containing 0.3 mg Hg(NO 3 ) 2 L −1 , by the presence of three strains of epiphytic bacteria [ 145 ]. Hg-resistant Enterobacter ludwigii and Klebsiella pneumoniae , isolated from Alternanthera sessilis and Cyperus esculentus , growing on a Hg-contaminated site individually stimulated growth, lowered proline, malondialdehyde content, and electron leakage in commercial Triticum aestivum seedlings under 75 μM HgCl 2 in hydroponics [ 146 ].…”

Bioremediation of mercury contaminated soil and water: A review

“…Hamzah et al (2015) found that the presence of bacteria increased phytoaccumulation of Hg in shoots (by up to 7.5 mg kg −1 ) in comparison to uninoculated plants. Sitarska et al (2016) reported on enhanced growth and Hg 2+ absorption capabilities of Salvinia natans and Lemna minor cultivated in a water solution comprising 0.3 mg L −1 Hg(NO 3 ) by three strains of epiphytic bacteria. Franchi et al (2017) examined a group of five Hg/As‐resistant bacteria in conjunction with thiosulphate, a fertiliser that acts as a metal mobilising agent.…”

“…Brevundimonas diminuta SF-S1-5 and Alcaligenes faecalis SF-S1-60, two heavy metal-resistant rhizobacteria, significantly assisted Scirpus mucronatus growth in sand soil contamined by a mixture of Pb (100 mg kg À1 ) and Hg (1 mg kg À1 ) Hamzah et al (2015). found that the presence of bacteria increased phytoaccumulation of Hg in shoots (by up to 7.5 mg kg À1 ) in comparison to uninoculated plants Sitarska et al (2016). reported on enhanced growth and Hg 2+ absorption capabilities of Salvinia natans and Lemna minor cultivated in a water solution comprising 0.3 mg L À1 Hg(NO 3 ) by three strains of epiphytic bacteria.…”

Phytoremediation of Heavy Metals by Salvinia natans in a Kashmir Himalayan RAMSAR Site

“…This technology is environment friendly and potentially cost-effective. The potential of aquatic macrophytes for heavy metal removal has been investigated and reviewed thoroughly (Ahmad et al 2014(Ahmad et al , 2015Devlin 1967;Ellis et al 1994;Kara et al 2003;Marques et al 2009;Rahman et al 2008;Rai 2005;Sharma and Gaur 1995;Sitarska et al 2015;Vymazal 1995). Ahmad et al (2014Ahmad et al ( , 2015 recently reported the heavy metal removal capability of Ceratophyllum demersum, Phragmites australis and Potamogeton natans in Hokersar wetland -an important Ramsar site in the Kashmir Himalaya, India.…”