Use of phytoremediation techniques for elimination of lead from polluted soils

The effect of chelating agent – EDTA (ethylene-diamine-tetra-acetic acid) was used for induced phytoextraction to increase intensity of lead transfer from roots to aboveground parts of garden pea. Pot experiments with contaminated soil substrata (50 mg Pb.kg-1 and 100 mg Pb.kg-1) were established for experimental purposes in growth chamber. The results showed that application of 5 and 10 mmol EDTA.kg-1 to experimental variants with 100 mg Pb.kg-1 doubled the increase of lead uptake by pea roots in comparison with variants without EDTA addition, which was statistically confirmed. Intensive lead transfer was observed from roots to aboveground parts of pea after application of 5 and 10 mmol EDTA.kg-1 in variant with 50 mg Pb.kg-1 (40-fold increase), as well as in variant with 100 mg Pb.kg-1 (17-fold increase). The results showed that induced phytoextraction can improve the mobility of lead from soil to plant roots. Application of 5 mmol EDTA.kg-1 resulted to 40-fold increase of lead transfer to green plant parts, despite the fact, that garden pea does not belong to conventional metal hyperaccumulating plant species. Following the results, pea could be used for decontamination of arable soil. The optimal EDTA concentration seems to be 5 mmol.kg-1. Therefore, application of 10 mmol EDTA.kg-1 decreased root mass about 55%, which resulted to decrease the intensity of lead uptake.

Hysteresis of heavy metals uptake induced in Taraxacum officinale by thiuram

Dandelion (Taraxacum officinale) yields active substances frequently used in herbal medicinal preparations. Its plantations are exposed to fungal plagues which pose a threat to herbal crops. The aim of this study was to evaluate the long time effects of a fungicide thiuram on dandelion growth and photosynthesis. Additionally, the manganese, iron, copper, zinc, cadmium, and lead uptake and transport were also investigated. Plants were cultivated under greenhouse conditions by the pot method in a universal flowering soil. The elements content in soil and plants were determined by the HR-CS FAAS spectrometer. Thiuram concentrations were established by the HPLC. Those analyses showed that almost 80% of thiuram decomposed within two weeks of its application. The photosynthesis indicators suggested, that plants were in good conditions and the fungicide supplementation facilitated plant growth. The latter could be prompted by thiuram acting as a sulfur rich chemical micro fertilizer. The hypothesis, that thiuram significantly affects heavy metals interactions in dandelion was proved by the one-way analysis of variance. Notable, metals uptake did not completely recover after fungicide decomposition for all investigated elements except iron We suggest to define this chemically induced, time-dependent heavy metals migrations in the soil–plant system as hysteresis of heavy metals uptake.

Effects of Lead on Growth and Mineral Nutrition of Wheat (Triticum Aestivum L.) As Influenced by Manure and Lime

A pot experiment was conducted to evaluate the effects of four levels of lead (50, 100, 150 and 200 mg/kg) treatment on wheat (Triticum aestivum L.) and its amelioration by cowdung, poultry litter and lime. The lengths, fresh and dry weights of shoot and root decreased with increasing level of lead as well as the macronutrients compared to the control. The maximum reduction was observed in the pots treated with 200 mg/kg lead. The highest reduction in macronutrient content was also observed in 200 mg/kg Pb treated pot whereas N, P, K, Ca and Mg concentration was reduced by 0.41, 0.019, 1.15, 0.38 and 0.071% for shoot and 0.512, 0.071, 0.17, 0.51 and 0.122% for root, respectively. Lead concentration in roots and shoots increased with increasing level of lead treatment compared to the control. Cowdung was shown to be most effective, followed by poultry litter and lime. This particular organic manure had considerably greater decreasing impacts in lead uptake by wheat crops. Cowdung treated pots increased fresh and dry weight by 14.56 and 13.28% for grain, 7.58 and 7.08% for shoot and 2.41 and 2.06% for root compared to pot treated with 100 mg/kg lead. J. Biodivers. Conserv. Bioresour. Manag. 2020, 6(2): 69-76

Concomitant oral intake of purified clinoptilolite tuff (G-PUR) reduces enteral lead uptake in healthy humans

Lead exposure can cause substantial organ damage. Enteral lead absorption may be reduced by concomitant intake of clinoptilolite tuff, a zeolite from natural sources. This study aimed to assess the effect of purified clinoptilolite tuff (G-PUR) on enteral lead uptake in adults using stable lead isotope 204Pb as a tracer. In this randomized, placebo-controlled, double-blind, parallel-group study, 42 healthy participants were randomized to receive oral G-PUR 2.0 g, 2 * 2.0 g, or placebo, together with 2.5 µg of 204Pb in water. The enrichment of 204Pb caused by the tracer in blood and urine was measured by mass spectrometry. G-PUR was well tolerated. The mean maximum 204Pb enrichment of 0.505% of total blood lead was significantly higher (p < 0.0001) in the placebo group compared to G-PUR 2.0 g (0.073%) or G-PUR 2 * 2.0 g (0.057%) group. Normalized 204Pb AUC0-192 was 86.5, 11.9, and 8.5% * h without and with G-PUR 2.0 g, and G-PUR 2 * 2.0 g, respectively (p < 0.0001 vs. placebo). This smaller 204Pb exposure was paralleled by a reduced urinary excretion in subjects receiving G-PUR. Concomitant oral intake of purified clinoptilolite tuff reduced enteral uptake of 204Pb in healthy humans by approximately 90%. The reduced bioavailability is demonstrable by a decrease of 204Pb tracer enrichment in blood and urine.Trial registration: clinicaltrials.gov identifier: NCT04138693, registered 24/10/2019.

Determination Of Interactions Of Ferrihydrite-Humic Acid-Pb(II) System

Ferrihydrite often precipitates with humic acid in natural ways, affecting the fate of lead ions, the stabilization of humic acid and the aging process of ferrihydrite. A series of 2-line ferrihydrite-humic (Fh-HA) acid with varying C loadings has been prepared, the morphology and surface properties of Fh-HA organo-minerals have been characterized, the adsorption property of Pb ions onto Fh-HA has been studied. The results indicated a strong interference of HA to ferrihydrite. 2-line Fh dominated mineral phase in all samples, but with increasing C/Fe molar ratios the crystallinity gradually weakened, particles became smaller and SSA decreased significantly. The data of Mössbauer spectra confirmed C loading changed the unit structure of ferrihydrite. Fh-HA performed good adsorption properties to Pb(Ⅱ): high efficiency and big capacity, especially Fh-HA_2.0. pH had great effect on Lead uptake, the pH change not only affects the amounts of competitive ions in solutions, but also the dissociation and protonation of functional groups on the surface of Fh-HA. Sorption kinetics can be well modeled by a pseudo-second order model, and the process was controlled by film and intraparticle adsorption simultaneously. The adsorption isotherms can be well described by Freundlich isotherm model. The careful determination of Fe 2p, O 1s and Pb 4f spectra before and after lead adsorption showed mononuclear bidentate or binuclear bidentate ligands occurring on Fh-HA surface, forming stable inner-sphere complex. By comparison of Mössbauer spectra and TEM images, it revealed a slower evolution of iron oxide/oxyhydroxide phases in Fh-HA-Pb system compared to pure ferrihydrite with aging time, ferrihydrite transformed to a combination of ferrihydrite, goethite and hematite phases. in this study, the determination of C-Fe interaction, Pb fate influenced by Fh-HA and transformation of ferrihydrite would have a great implication to application of Fh-HA precipitates in remediation for soil or groundwater polluted by heavy metals.

PENGARUH ABU TERBANG BATUBARA TERHADAP SIFAT KIMIA TANAH DAN SERAPAN TIMBAL (Pb) OLEH TANAMAN AKAR WANGI (Vetiveria zizanioides L.)

Coal fly ash is a soil amendment that can be used to improve soil productivity because coal fly ash contains essential nutrients needed by plants. However, coal fly ash also contains heavy metals. This study was at a time to explore the effect of coal fly ash on soil chemical properties and lead uptake by vetiver plant (Vetiveria zizanioides L.). Treatments tested were applications of six proportion levels (0, 2.5, 5., 10, 15, and 30% by weight). The seven treatments were arranged in a completely randomized design with three replicates. The result showed that the coal fly ash had a significant effect on soil pH, total-P, total-N, total-K and Pb. The value of the Pb translocation factor from the roots to the shoot of the vetiver plant was relatively low, so that the vetiver plant was not suitable for use in phytoextraction of Pb from Pb-contaminated soil.

Adsorption of Aqueous Using Granular Adsorbents from Accanthospermum hispendum DC

Granular activated carbons have been important adsorbents for the decontamination of aqueous environmental contaminants. Acanthospermum hispidum weed represents a ready available source of low-cost adsorbents in sub-Saharan Africa that has barely been paid attention. The effects of pH, contact time, concentration, adsorbent dosage, particle size and temperature on the adsorptive removal of Pb (II) from aqueous solutions over activated carbon granules from the thorns of Accanthospermum hispindum (AC-T) were for the first time investigated and compared with those of the leaves (L), the sodium hydroxide modified thorns (NaOH-T) and regular thorns (T) of this plant. These adsorbents were characterised by the surface charge analysis, scanning electron microscopy (SEM) and the Attenuated Total Reflectance Fourier Transform infrared (ATR FTIR) spectroscopy. The SEM revealed a wafer-like appearance for the AC-T with a large distribution of open pores. The adsorption data of lead uptake onto the adsorbents were examined using two pseudo-order kinetic schemes and three isotherm models. To fully understand the adsorption capacities of the adsorbents, batch desorption recoveries were studied. The FTIR depicted the various functionalities responsible for the adsorption. Adsorption over AC-T was found to agree with pseudo second-order kinetic scheme, the Langmuir and Freundlich isotherm. This material exhibited the highest adsorption capacity. The order of reusability of the adsorbents is T < AC-T < NaOH-T.