scholarly journals Periphytic Algae and Cyanobacteria from the Rio Doce Basin Respond Differently to Metals and Salinity, Showing Different Potential for Bioremediation

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2349
Author(s):  
Marcelo Pedrosa Gomes ◽  
Letícia Yoshie Kochi ◽  
Patrícia Lawane Freitas ◽  
Cleber Cunha Figueredo ◽  
Philippe Juneau

We have studied the isolated and combined effects of metals (Fe and Mn) and NaCl the on growth, physiology, and metal-uptake capacity of two photosynthetic periphytic species—Synechococcus elongatus (Cyanobacteria) and Chlorococcum infusionum (Chlorophyta)—isolated from an impacted area of the Rio Doce River (Brazil) after the Fundão dam collapse. The effective concentrations found to reduce 10 and 50% growth were 15.2 and 31.6 mg Fe l−1, and 2.5 and 7.9 mg Mn l−1 for S. elongatus and 53.9 and 61.6 mg Fe l−1, and 53.2 and 60.9 mg Mn l−1 for C. infusionum. Although the metal toxicity was related to oxidative stress, both species showed activation of antioxidant systems under phytotoxic concentrations of Fe and Mn. By binding large concentrations of metals on its cell surface and thus avoiding their entrance into the cells, C. infusionum presents greater resistance to Fe and Mn than S. elongatus. Under environmental realistic concentrations of Fe and Mn in river water from the Rio Doce Basin, S. elongatus and C. infusionum showed a metal removal efficiency of 42 and 65% and 53 and 79%, respectively after 96 h. These species were insensitive to increased NaCl concentrations which, in addition, did not disrupt the metal removal capacity of the species. Due to their salt and metal tolerance, S. elongatus and C. infusionum can be used for the remediation of waters contaminated with Fe and Mn.

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2153-2156 ◽  
Author(s):  
A. A. Pradhan ◽  
A. D. Levine

Binding of metal ions to extracellular components of microbial systems plays an important role in biosorption processes. Besides pH and temperature, type of anionic system and concentration of the metallic ions are some of the governing factors determining the maximum uptake capacity of the microbial system. Actinomycetes show an ability to selectively scavenge metals from aqueous systems. A biosorption system was tested using a bimetallic solution containing lead and copper. Uptake of Pb was observed to increase with concentration. Chloride ions had an inhibiting effect on the metal removal capacity of the actinomycetes system.


2019 ◽  
Vol 3 (1) ◽  
pp. 22 ◽  
Author(s):  
Andres Borgiallo ◽  
Ricardo Rojas

Layered double hydroxides (LDHs) present multiple applications due to their versatility and reactivity. Thus, Ca–Al LDHs with Friedel’s salt structure (HC) have been proposed as heavy metal scavengers due to their buffering capacity at basic pHs. Nevertheless, the control of the reactivity of LDHs such as HC is necessary to optimize their applications. Here, the reactivity of an HC prepared by a coprecipitation method was modified by its inclusion in calcium alginate (CaAlg) beads prepared by ionic gelation. The obtained beads (CaAlg/HC) showed good dispersion of the HC particles in the alginate matrix and were used to test the acid base reactivity and heavy metal uptake capacity compared with pure CaAlg beads and HC powder separately. The pH buffering capacity of CaAlg beads was enriched by the inclusion of HC that, in turn, was modulated in its reactivity. Thus, the HC dissolution times changed from mere seconds for the powder to tens of minutes when enclosed in the beads in a kinetic profile determined by the diffusive step. On the other hand, Cu2+ uptake capacity of CaAlg/HC beads combined the Cu(OH)2 precipitation capacity of HC with the complexation capacity of alginate, reaching good affinity and capacity for the obtained beads. Nevertheless, the precipitation of the hydroxide was produced outside the bead, which would induce the addition of an additional separation step to produce an acceptable Cu2+ elimination.


Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 598
Author(s):  
Muneeba Qurban ◽  
Cyrus Raza Mirza ◽  
Aqib Hassan Ali Khan ◽  
Walid Khalifa ◽  
Mustapha Boukendakdji ◽  
...  

The problem of metal-induced toxicity is proliferating with an increase in industrialization and urbanization. The buildup of metals results in severe environmental deterioration and harmful impacts on plant growth. In this study, we investigated the potential of two ornamental plants, Catharanthus roseus (L.) G.Don and Celosia argentea L., to tolerate and accumulate Ni, Cr, Cd, Pb, and Cu. These ornamental plants were grown in Hoagland’s nutrient solution containing metal loads (50 µM and 100 µM) alone and in combination with a synthetic chelator, ethylenediaminetetraacetic acid (EDTA) (2.5 mM). Plant growth and metal tolerance varied in both plant species for Ni, Cr, Cd, Pb, and Cu. C. roseus growth was better in treatments without EDTA, particularly in Ni, Cr, and Pb treatments, and Pb content increased in all parts of the plant. In contrast, Cd content decreased with EDTA addition. In C. argentea, the addition of EDTA resulted in improved plant biomass at both doses of Cu. In contrast, plant biomass reduced significantly in the case of Ni. In C. argentea, without EDTA, root length in Cd and Cu treatments was significantly lower than the control and other treatments. However, the addition of EDTA resulted in improved growth at both doses for Pb and Cu. Metal accumulation in C. argentea enhanced significantly with EDTA addition at both doses of Cu and Cd. Hence, it can be concluded that EDTA addition resulted in improved growth and better metal uptake than treatments without EDTA. Metal accumulation increased with EDTA addition compared to treatments without EDTA, particularly for Pb in C. roseus and Cu and Cd in C. argentea. Based on the present results, C. roseus showed a better ability to phytostabilize Cu, Cd, and Ni, while C. argentea worked better for Ni, Cd, Cu, and Pb.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1461
Author(s):  
Roberto Braglia ◽  
Lorenza Rugnini ◽  
Sara Malizia ◽  
Francesco Scuderi ◽  
Enrico Luigi Redi ◽  
...  

Increasing levels of freshwater contaminants, mainly due to anthropogenic activities, have resulted in a great deal of interest in finding new eco-friendly, cost-effective and efficient methods for remediating polluted waters. The aim of this work was to assess the feasibility of using a green microalga Desmodesmus sp., a cyanobacterium Nostoc sp. and a hemicryptophyte Ampelodesmos mauritanicus to bioremediate a water polluted with an excess of nutrients (nitrogen and phosphorus) and heavy metals (copper and nickel). We immediately determined that Nostoc sp. was sensitive to metal toxicity, and thus Desmodesmus sp. was chosen for sequential tests with A. mauritanicus. First, A. mauritanicus plants were grown in the ‘polluted’ culture medium for seven days and were, then, substituted by Desmodesmus sp. for a further seven days (14 days in total). Heavy metals were shown to negatively affect both the growth rates and nutrient removal capacity. The sequential approach resulted in high metal removal rates in the single metal solutions up to 74% for Cu and 85% for Ni, while, in the bi-metal solutions, the removal rates were lower and showed a bias for Cu uptake. Single species controls showed better outcomes; however, further studies are necessary to investigate the behavior of new species.


2016 ◽  
Vol 18 (2) ◽  
pp. 437-443 ◽  

<div> <p>Adsorption is one of the methods that can be used for metal removal. In this study five metals were used cadmium, chromium, lead, copper and Nickel (Cd, Cr, Pb, Cu, and Ni) over a concentration range from 0.8 to about 7 mg l<sup>-1</sup> for each metal. Adsorbents were prepared with increasing chitosan to bentonite ratio from 0 to 0.67 g chitosan/g bentonite. The study showed that adsorption of metals on plain bentonite and chitosan modified bentonite can fit well with Langmuir and Freundlich adsorption isotherms. Furthermore, the bentonite adsorption capacity will decrease with the increase of chitosan/bentonite ratio. This study concluded that bentonite is a good adsorbent. However, the applicability of bentonite as potential adsorbent may be limited by its physical properties such as slow settling rate and difficulty to use it as an adsorbent in adsorption columns. Despite the decrease of maximum theoretical adsorption capacity as a result of chitosan modification, the addition of small amount of chitosan can improve the physical characteristics of bentonite clay to be used as an adsorbent.&nbsp;</p> </div> <p>&nbsp;</p>


2016 ◽  
Vol 7 (4) ◽  
pp. 387-419 ◽  
Author(s):  
Renu ◽  
Madhu Agarwal ◽  
K. Singh

Heavy metals are discharged into water from various industries. They can be toxic or carcinogenic in nature and can cause severe problems for humans and aquatic ecosystems. Thus, the removal of heavy metals from wastewater is a serious problem. The adsorption process is widely used for the removal of heavy metals from wastewater because of its low cost, availability and eco-friendly nature. Both commercial adsorbents and bioadsorbents are used for the removal of heavy metals from wastewater, with high removal capacity. This review article aims to compile scattered information on the different adsorbents that are used for heavy metal removal and to provide information on the commercially available and natural bioadsorbents used for removal of chromium, cadmium and copper, in particular.


2014 ◽  
Vol 798-799 ◽  
pp. 622-627
Author(s):  
Wellington Siqueira Lima ◽  
José Vanderley Nascimento Silva ◽  
Aline Cadigna Lima Patrício ◽  
Guilherme Costa Oliveira ◽  
Meiry Glaúcia Freire Rodrigues

The problems caused by contamination of heavy metals generate a growing need to implement technologies to reduce or eliminate them. This work aims to evaluate the potential of gray clay, the process of removal of zinc and lead from synthetic effluents in finite bath system. The clay was characterized by: X-ray diffraction, X-ray Spectroscopy Energy Dispersive and Physical Adsorption of Nitrogen. The tests were performed finite bath following a 22 factorial design, with the variables: pH and initial concentrations of metal. The clays were evaluated for their removal capacity and rate of metal removal. After the characterization and evaluation, it was found that the gray clay comprises clay of the groups of kaolinite and mica. The results of the factorial design shown that the adsorption of the metals zinc and lead can be developed with good percentage of removal.


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