The treatment of contaminated water is a pressing issue. As a solution it is proposed to use a biological engineering construction with the aquatic vegetation - a bioplato. The process of water purification takes place at the expense of the natural capacity of a number of living organisms and plants to transform and absorb contaminants [1]. The phytoremediation method helps to extract heavy metals from water and makes it suitable for consumption and use. However, in order to be most effective, it is necessary to choose the planting method and optimal environmental conditions. Therefore, several types of bioplato were created and tested during the experiment: with different planting methods (bare root, container grown) and in the presence of microorganisms (Pseudomonas fluorescens and Rhodococcus erythropolis).The contaminants were water-soluble salts of lead (II) acetate and cadmium chloride. Iris pseudacorus and Typha gracilis were selected for the experiment, as the plants are capable of significant heavy metals accumulation. The sampling was carried out according to GOST R 56237-2014 «Drinking water. Sampling at water preparation stations and pipeline distribution systems» and GOST 31861-2012 «Water. General requirements for sampling». The samples were analyzed using an atomic emission spectrometer with inductively bound plasma iCAP 6300 Duo.Studies have shown that the purification rate of plants in both planting methods is quite high - more than 92 %. In bare root samples, purification is more efficient (99% in the solutions with the cadmium ions concentration 20 times above the threshold limit value (TLV). The use of microorganisms contributed to the reduction of Pb2+ absorption by 18% in the bioplato with bare root planting method. However, a bioplato with container grown planting method in the presence of micro-organisms is 8,7% better at purifying water from Cd2+ ions
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Mercury in the modern world is a global pollutant entering the environment as a result of human activities. Currently, there are a large number of territories in the world whose soils and reservoirs contain mercury in quantities that pose a danger to human health and the environment. However, the methods that are traditionally proposed for remediation may pose a risk of secondary mercury contamination and/or negative health effects for those involved in cleaning. Phytoextraction of heavy metals from the soil environment is currently considered as one of the most promising non-invasive methods of reclamation. However, this approach has limited effectiveness for cleaning soils and reservoirs. Chemically reduced phytoextraction can increase the efficiency of this process both by converting less bioavailable mercury compounds into bioavailable fractions in the soil, and by increasing the rate of metal transfer in plants. The paper presents the results of a screening study of various chemical additives to enhance the phytoextraction of mercury with white creeping clover (Trifolium repens L.). The results obtained showed a good potential for reducing phytoextraction for the first time studied S-containing complexion, in which the monoethanolamine salt of dithiobiacetic acid was used as a sulfur-containing chelant (MEDBA).
The reported study was funded by MUCTR according to the research project No. 3-2020-039.
Heavy metals are among the most widespread pollutants in soil. Phytoextraction technology is used to solve the problem of multi-metal-contaminated soil. The efficiency of this process can be increased by introducing various amendments. A soil amendment is any material added to a soil to improve its physical properties, such as water retention, permeability, water infiltration, drainage, aeration, and structure. Some chemical amendments for enhanced phytoextraction, such as amino polycarboxylates chelators, can be hazardous to the environment and perform poorly at pH > 8. The effect of the potassium salt of hydroxyethylidene diphosphonic acid (K2HEDP), plant growth regulators (PGRs), and iron chelate alone and in combination on the phytoextraction by Trifolium repens L. seedlings of Cd, Ni, and Cu was studied in this work. K2HEDP works in a wider pH range. The results of this study confirmed that amino polycarboxylate chelators, with the sodium salt of ethylene diamine tetraacetic acid (Na2EDTA) as an example, have a pronounced negative effect on the growth and development (organ mass) of Trifolium repens L. seedlings. K2HEDP, proposed by the authors instead of Na2EDTA, produced a pronounced positive effect on plant growth and development, which was further enhanced by the use of PGRs and with iron chelates. However, it should be noted that K2HEDP showed significantly lower efficiency in trials on the Trifolium repens L. seedlings. The highest was the efficiency of K2HEDP with PGRs and iron chelates for the phytoextraction of Cd.
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