Showing posts with label Heavy Metals. Show all posts
Showing posts with label Heavy Metals. Show all posts

Monday, 1 August 2022

Safer plant-based nanoparticles for combating antibiotic resistance in bacteria: A comprehensive review on its potential applications, recent advances, and future perspective

 Science of the Total Environment, 821, 153472. 2022


Background

Antibiotic resistance is one of the current threats to human health, forcing the use of drugs that are more noxious, costlier, and with low efficiency. There are several causes behind antibiotic resistance, including over-prescription of antibiotics in both humans and livestock. In this scenario, researchers are shifting to new alternatives to fight back this concerning situation.


Scope and approach

Nanoparticles have emerged as new tools that can be used to combat deadly bacterial infections directly or indirectly to overcome antibiotic resistance. Although nanoparticles are being used in the pharmaceutical industry, there is a constant concern about their toxicity toward human health because of the involvement of well-known toxic chemicals (i.e., sodium/potassium borohydride) making their use very risky for eukaryotic cells.


Key findings and conclusions

Multiple nanoparticle-based approaches to counter bacterial infections, providing crucial insight into the design of elements that play critical roles in the creation of antimicrobial nanotherapeutic drugs, are currently underway. In this context, plant-based nanoparticles will be less toxic than many other forms, which constitute promising candidates to avoid widespread damage to the microbiome associated with current practices. This article aims to review the actual knowledge on plant-based nanoparticle products for antibiotic resistance and the possible replacement of antibiotics to treat multidrug-resistant bacterial infections.

Monday, 10 January 2022

Assessment of the Ecological Risk from Heavy Metals in the Surface Sediment of River Surma, Bangladesh: Coupled Approach of Monte Carlo Simulation and Multi-Component Statistical Analysis

 Water 2022, 14(2), 180


River sediment can be used to measure the pollution level in natural water, as it serves as one of the vital environmental indicators. This study aims to assess heavy metal pollution namely Copper (Cu), Iron (Fe), Manganese (Mn), Zinc (Zn), Nickel (Ni), Lead (Pb), and Cadmium (Cd) in Surma River. Further, it compares potential ecological risk index values using Hakanson Risk Index (RI) and Monte Carlo Simulation (MCS) approach to evaluate the environmental risks caused by these heavy metals. in the study area. With obtained results, enrichment of individual heavy metals in the study area was found in the order of Ni > Pb > Cd > Mn > Cu > Zn. Also, variance in MCS index contributed by studied metals was in the order of Cd > Pb > Ni > Zn > Cu. None of the heavy metals, except Ni, showed moderate contamination of the sediment. Risk index values from RI and MCS provide valuable insights in the contamination profile of the river, indicating the studied river is currently under low ecological risk for the studied heavy metals. This study can be utilized to assess the susceptibility of the river sediment to heavy metal pollution near an urban core, and to have a better understanding of the contamination profile of a river.

Sunday, 9 October 2016

TOF-SIMS and FE-SEM/EDS to verify the heavy metal fractionation in serpentinite quarry soils

CATENA, 136, 2016, 30–43


This study aims at extensively defining serpentinite quarry soils and analysing their content and distribution of heavy metals using chemical sequential extraction. The association with the different geochemical phases of the soil was verified using TOF-SIMS and SEM-EDS techniques. Seven soils were chosen in two serpentinite quarries located in Moeche (M) and Silleda (C) (Galicia, northwest of Spain). The selected areas for soil sampling were: dump sites (M1, M2 and C1), rock extraction sites (M3, C2), and quarry boundaries (M4 and C3). The total soil concentration of Co, Cr, Ni, and V varied from 1472 to 7132, 1499 to 4309, 76 to 373, and 21 to 140 mg kg− 1, respectively. In all cases they exceed the maximum limit permitted in soils. After chemical sequential extraction it was found that the high content of Co, Cr, Ni, and V is associated with the residual fraction of the soils. In addition, Fe and Mn oxides have a high capacity for Co fixation, whereas Cr, Ni, and V are mainly associated with magnesium silicates. The fractions related to organic matter and the soluble or available forms are, respectively low and very low, not exceeding 2.5% in any of the soils. This association of the metals with magnesium silicates and Fe oxides, and the low content of metals bound to organic matter were identified by using the TOF-SIMS and SEM-EDS techniques. Both techniques confirmed and verified the results obtained during the chemical sequential extraction by checking the interaction of heavy metals with the different components of the soil.

Wednesday, 7 September 2016

Valorization of biosorbent obtained from a forestry waste: Competitive adsorption, desorption and transport of Cd, Cu, Ni, Pb and Zn

Ecotoxicology and Environmental Safety, 131(2016) 118–126


Bark from Pinus pinaster is one of the most abundant forestry wastes in Europe, and among the proposed technologies for its reutilization, the removal of heavy metals from wastewater has been gaining increasing attention. In this work, we have studied the performance of pine bark for heavy metal biosorption on competitive systems. Pb, Cu, Ni, Zn and Cd sorption and desorption at equilibrium were studied in batch experiments, whereas transport was studied in column experiments. Batch experiments were performed adding simultaneously different concentrations (0.08–3.15 mM) of two or more metals in solution to pine bark samples. Column experiments were performed with 10 mM solutions of two metals or a 5 mM solution of the five metals. In general, the results under competitive conditions were different to those obtained in monoelemental experiments. The multi-metal batch experiments showed the adsorption sequence Pb≈Cu>Cd>Zn>Ni for lower metal doses, Pb>Cu>Cd>Zn>Ni for intermediate doses, and Pb>Cu>Cd≈Zn≈Ni for high metal doses. Desorption followed the sequence Pb<Cd<Cu<Zn<Ni for the lowest metal doses, and Pb<Cu<Zn<Cd<Ni for the highest ones. The bi-metal batch experiments indicated that Cu and Pb suffered the highest retention, with high capacity to displace Cd, Ni and Zn from adsorption sites on pine bark. The transport experiments produced comparable results to those obtained in the batch experiments, with pine bark retention capacity following the sequence Pb>Cu>Zn>Cd>Ni. The presence of a second metal affected the transport of all the elements studied except Pb, and confirmed the strong influence of Pb and Cu on the retention of the other metals. These results can help to appropriately design decontamination systems using this forestry waste.

Monday, 5 September 2016

Competitive and non-competitive cadmium, copper and lead sorption/desorption on wheat straw affecting sustainability in vineyards

Journal of Cleaner Production


The novelty of this work lies on the consideration of wheat straw to retain Cu and other heavy metals in vineyards, in addition to its known potential to decrease erosion, thus facilitating the growth of new vine plants and contributing to sustainability in vineyard production. In this study we used batch-type experiments to investigate Cd, Cu and Pb competitive and non-competitive sorption/desorption on wheat straw. In non-competitive experiments, sorption sequence was Pb > Cd > Cu when the lowest molar concentrations (0.5 mmol L−1) were added, and Pb > Cu > Cd when the highest molar concentrations (6.0 mmol L−1) were added. Sorption curves indicated clearly higher sorption for Pb, lower initial sorption in the case of Cu, and certain trend to saturation of sorption sites for Cd. Data showed good adjustment to the Langmuir model just for Cd, whereas the Freundlich equation fitted well for all three metals. Desorption rates were low, in the order Pb < Cd < Cu. In the competitive experiment, the sorption sequence was Pb > Cu > Cd. The results indicate that competition clearly affected to Cd sorption, especially when the highest concentrations (6 mmol L−1) of the three heavy metals were added. The highest percentage of desorption in the competitive system corresponded to Cd, whereas Pb and Cu experienced clearly lower release. Comparing competitive and non-competitive experiments, Pb sorption was equivalent in the non-competitive and competitive trials, Cu sorption was slightly higher in the non-competitive than in the competitive experiment, and Cd sorption was clearly higher in the non-competitive trial. Percentage desorption decreased for Pb and for Cu in the competitive trial, whereas it was clearly higher for Cd in the competitive than in the non-competitive experiment. The overall results indicate that Pb, Cu and Cd can be retained by wheat straw (especially Cu and Pb), thus decreasing risks of pollution, which could be used to treat polluted waters, and could also give additional value to wheat straw mulching used to protect vineyards from erosion and Cu (and other heavy metals) pollution, thus contributing to sustainability in this productive sector.

Sunday, 22 November 2015

Metales pesados en suelos de pradera de A Pastoriza (NO España) tratados con purín de vacuno y fertilizantes NPK

Spanish Journal of Soil Science, 5 (2015) 154-164


En Galicia las praderas ocupan una gran extensión, siendo utilizadas principalmente para la alimentación del ganado vacuno destinado tanto a la producción de leche como de carne. Las granjas se manejan de manera intensiva, utilizando fertilizantes inorgánicos y purín de vacuno para aumentar la producción de pastos. Esta práctica puede aumentar el contenido de metales pesados en el suelo. En este trabajo se estudian las concentraciones totales y la distribución en profundidad de metales pesados y elementos afines (As, Cd, Cr, Cu, Mn, Ni, Pb y Zn) en dos suelos forestales (SN1, SN2) y en cinco praderas (P1-P5) fertilizadas con purín de vacuno y NPK en una zona con una gran vocación ganadera (A Pastoriza, Lugo). Se pretende conocer el grado de influencia de la fertilización sobre los niveles de estos elementos. Los suelos elegidos se desarrollaron a partir de pizarras (SN2, P4) y de cuarcitas de la Serie de Cándana (SN1, P1, P2, P3, P5). Los suelos forestales presentaron pH ácido (4,58-4,68), elevada saturación del complejo de cambio por Al (75-90%) y baja concentración de P disponible (4,78-11,96 mg kg-1); estos parámetros mejoran en los suelos de pradera como consecuencia de las enmiendas y fertilizantes aplicados, presentando un pH entre 5,17 y 7,02, una saturación de Al que varía entre 0,58-59,24% y P disponible entre 5,24 y 42,07 mg kg-1.En relación con los metales pesados, la profundidad de la muestra no afecta de modo significativo a su concentración total, pero sí el material de partida, presentando concentraciones más elevadas de Fe, As, Cu y Ni los suelos desarrollados sobre pizarras, posiblemente debido a la presencia de materiales piríticos. En la mayoría de los casos, los metales pesados estudiados presentan concentraciones totales inferiores a las establecidas como genéricas para suelos desarrollados sobre los respectivos materiales geológicos, y siempre son menores que los límites considerados fitotóxicos. La fertilización aplicada no parece tener una influencia significativa sobre los contenidos totales de estos elementos, con la excepción del Zn en la pradera P4, ya que los suelos naturales en muchos casos presentan valores similares e incluso superiores a los obtenidos en las parcelas fertilizadas.

Wednesday, 15 July 2015

Heavy metals in pastureland soils situated in A Pastoriza (NW Spain) treated with cattle slurry and NPK fertilizers

Spanish Journal of Soil Science, 5, 154-164 (2015)
DOI: 10.3232/SJSS.2015.V5.N2.05


In Galicia (NW Spain), pasturelands cover a broad extension and are mainly used to feed cattle. Farms are managed in an intensive manner, using cattle slurry and inorganic fertilizers to increase pasture production, but also increasing risks of heavy metal pollution. In this work we studied the influence of fertilization practices on total concentrations and in-depth distribution of heavy metals and related elements (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn) in two forest soils (SN1, SN2) and five pastureland soils (P1-P5) fertilized with cattle slurry and NPK, in a broadly exploded farmland area (A Pastoriza, Lugo). Soils SN2 and P4 were developed over slate, whereas soils SN1, P1, P2, P3 and P5 evolved on Candana quartzite. Forest soils presented acid pH (4.58-4.68), high Al saturation (75-90%), and low available P concentration (4.78-11.96 mg kg-1), whereas those parameters exhibited better scores in the pastureland soils, due to previous amendment and fertilization practices, thus giving pH 5.17-7.02, Al saturation 0.58-59.24%, and available P 5.24-42.07 mg kg-1. Regarding heavy metals, soil depth did not affect significantly to total concentrations, contrary to that happening with parent material, with higher As, Cu, Fe, and Ni concentrations found in soils over slate (possibly due to the presence of pyritic materials). In most cases, heavy metal total concentrations were lower than that considered as reference background levels for soils developed over each of the parent materials, and were always lower than that considered phyto-toxic. In this study, natural soils usually presented heavy metal total contents similar or even higher than that of the fertilized soils (unless Zn in the P4 pastureland), thus indicating that the spread doses of fertilizers did not influence significantly their concentration levels.