Efficiency of sodium phytate in the remediation of As, Mn, and Cu contamination in acid mine drainage using water hyacinth.

The accumulation and uptake efficiency of heavy metals, including As, Mn, and Cu, in water hyacinth (Eichhornia crassipes (Mart.) Solms) grown in synthetic acidic wastewater supplemented with sodium phytate (SP) was examined. Three treatments were studied using synthetic acidic wastewater containing 0.25, 5.0, and 1.0 mg/L of As, Mn, and Cu, respectively, (SM + heavy metals) and having pH in the range of 4-6, which comprised of (1) control treatments using SM + heavy metals at pH 4, 5, 6 without SP, and treatments using SM + heavy metals at pH 4, 5, 6 with SP: Cu (2) in a 1:3 M ratio and (3) a 1:6 M ratio. The translocation factor (TF < 1) indicated that plants had a lower capacity to transport heavy metals from the roots to the stems. The shoots of water hyacinth exhibited the highest capacity to absorb and store As in the pH 4-treatment with SP (SP:Cu1:3 mol), whereas the roots showed the greatest capacity at pH 4 without SP. The roots and shoots of the water hyacinth showed the greatest capacity to take up and store Mn in the pH 5-treatment with a 1:3 M ratio of SP:Cu. The roots showed the greatest capacity to take up and store Cu in the pH 6-treatment, and the shoots showed the highest capability in the pH 5-treatment with 1:3 M ratio of SP:Cu. Moreover, analysis of the chemical forms revealed that As accumulated in the arsenate form, whereas Mn accumulated in the divalent form.

The combination of phytoremediation and electrokinetics remediation technology on arsenic contaminated remediation in tailing storage facilities from gold mine.

This research aims to study the effects of combining Mott dwarf Napier grass cultivation and electrokinetic (EK) treatment on arsenic (As) mobility and remediation of As-contaminated mine tailings. Experimental groups were treated with 0, 1, 2, and 4 V/cm for 15 days-120 days. Groups treated with 1 and 2 V/cm electromagnetic field had better As remediation efficiency than the control group with no electromagnetic field treatment. However, electromagnetic field treatment at 4 V/cm inhibited plant growth and had an effect on As uptake in the form of solution at a low level. Plants in experimental group treated with 1 V/cm electromagnetic field for 90 days had significantly high As accumulation (7.69 ± 0.16 mg/kg) in their roots. Their relative growth rate was close to that of the control group with the highest biomass (15.09 ± 0.65 g) recorded on day 120. Mobility and accumulation of As and other elements in the plants were investigated using micro-X-ray fluorescence technique (Beamline BL6b). It was found that very low As concentrations could not be detected although energy emitted from its innermost electron shell (K alpha (Kα1&2) and K beta (Kß1)) were equal to 10.54 and 11.72 keV. In general, As accumulation in plants occurs primarily in the roots and stems, with greater accumulation around the cortex, epidermis, and xylem. This is similar to the patterns of iron and phosphate accumulation, which occurs through phosphate transporters. In addition, high aluminum mobility and accumulation were found in the stems and leaves of Mott dwarf Napier grass. However, As accumulation in the roots of Mott dwarf Napier grass was higher than in the stem and leaves.

Phytostabilization of arsenic and manganese in mine tailings using Pennisetum purpureum cv. Mott supplemented with cow manure and acacia wood-derived biochar.

The purpose of this research was to investigate the effects of cow manure and acacia wood-derived biochar on the immobilization of arsenic (As) and manganese (Mn) in contaminated mine tailings using Mott dwarf Napier grass (Pennisetum purpureum cv. Mott). Cow manure or acacia wood-derived biochar was separately mixed with mine tailings at rates of 1, 3, and 5% (w/w). Samples of mine tailings and plants were collected every 30 d during the 120-d period. The total As and Mn accumulation amounts in the plants were analyzed in both the underground (roots) and aboveground (stems and leaves) parts of the plants. The results revealed that cow manure and acacia wood-derived biochar can reduce the mobilization of As and Mn in mine tailings and thus reduce their uptake and accumulation in P. purpureum. Acacia wood-derived biochar was able to stabilize and immobilize As and Mn in mine tailings, allowing the metals to be taken up for plant utilization despite the lower plant growth (biomass and relative growth rates) than that obtained with added cow manure. The accumulation amounts of As in the aboveground and underground parts of P. purpureum grown in mine tailings with 5% BC application were 0.52 ± 0.05 mg kg-1 and 1.57 ± 0.1 mg kg-1, respectively, while the accumulation amounts of As in the aboveground and underground parts were 31 ± 1.08 mg kg-1 and 73.05 ± 2.60 mg kg-1, respectively. In other words, the percentage reductions in As and Mn uptake and accumulation in the aboveground and underground parts were 78.6% and 63.9% for As and 72.5% and 69.3% for Mn, respectively. The results of this study can be applied for the remediation of heavy metal-contaminated areas, especially gold mines and surrounding areas, as well as in other areas.

Effect of EDTA and NTA on cadmium distribution and translocation in Pennisetum purpureum Schum cv. Mott.

The primary objective of this research was to investigate the cadmium (Cd) distribution in Pennisetum purpurem (Napier grass) in the presence of 30 mg/L of Cd and different types and concentrations of chelating agents (ethylenediaminetetraacetic acid disodium dihydrate (EDTA), nitrilotriacetic acid (NTA), and EDTA-NTA mixtures). Plant samples were collected every 15 d during a 105-d experimental period. Accumulation of Cd in each part of the plant was determined using atomic absorption spectrometer (AAS), and the distribution of Cd was determined by laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) and synchrotron radiation micro X-ray fluorescence (SR-micro-XRF). The highest concentrations of Cd accumulation of 889 ± 53 mg kg-1 in the underground part (roots) and 265 ± 26 mg kg-1 in the aboveground part (stems and leaves) in the presence of 1:1 M ratio of Cd:EDTA after 30 d of exposure were observed. Plants grown in the presence of either NTA or EDTA-NTA mixtures showed significant lower Cd accumulation levels. The LA-ICP-MS analysis showed that Cd was primarily accumulated in the aboveground part (stems and leaves), especially in the xylem and intercalary meristem. In addition, translocation factor was very low. Thus, P. purpurem could be considered as a candidate plant for cadmium phytostabilization.

Effect of EDTA and NTA on Arsenic Bioaccumulation and Translocation Using Phytoremediation by Mimosa pudica L. from Contaminated Soils.

This study aimed to investigate the effects of Nitrilotriacetic acid (NTA) and Elthylenediaminetetraacetic acid (EDTA) on the bioaccumulation and translocation of arsenic (As) by Mimosa pudica L. using soils with 5 mg/kg of added As and NTA and EDTA concentrations of 50, 100, and 200 mg/kg. Soil and plant samples were collected every 30-120 days to analyze the As concentrations in the soil, underground part of the plants (root), and aboveground parts of the plants (shoots and leaves). The results showed that the plants with EDTA concentrations of 100 mg/kg had the highest As accumulation. At 120 days, M. pudica L. had a higher accumulation in the underground parts (29.71 mg/kg) than in the aboveground parts (6.32 mg/kg), with statistical significance (p < 0.05). The As translocation factor in the aboveground parts was less than 1, indicating As accumulation in the underground part only. With EDTA concentrations of 50 and 100 mg/kg, M. pudica L. had the highest bioaccumulation potential of As of 8.00 and 8.44, respectively. However, this research did not examine the reaction between As and any growth promoters. Further research should investigate the details of such a reaction at the molecular level, as well as explore how fertilizer factors might affect the As absorption of M. pudica L.