Phycoremediation of contaminated water by cadmium (Cd) using two cyanobacterial strains (Trichormus variabilis and Nostoc muscorum)

Abstract

Background Water pollution with heavy metals is a severe dilemma that concerns the whole world related to its risk to natural ecosystems and human health. The main objective was to evaluate the removal efficiency of Cd of various concentrations from contaminated aqueous solution by use of two cyanobacterial strains (Nostoc muscorum and Trichormus variabilis). For this purpose, a specially designed laboratory pilot-scale experiment was conducted using these two cyanobacterial strains on four different initial concentrations of Cd (0, 0.5, 1.0 and 2.0 mg L−1) for 21 days. Results N. muscorum was more efficient than T. variabilis for removing Cd (II), with the optimum value of residual Cd of 0.033 mg L−1 achieved by N. muscorum after 21 days with initial concentration of 0.5 mg L−1, translating to removal efficiency of 93.4%, while the residual Cd (II) achieved by T. variabilis under the same conditions was 0.054 mg L−1 (89.13% removal efficiency). Algal growth parameters and photosynthetic pigments were estimated for both cyanobacterial strains throughout the incubation period. Conclusions High Cd concentration had a more toxic impact on algal growth. The outcomes of this study will help to produce treated water that could be reused in agrarian activities.

Process optimization and modeling of Cd2+ biosorption onto the free and immobilized Turbinaria ornata using Box–Behnken experimental design

“…Table 5 provides a comparison of the removal efficiency (percentage) of Cd 2+ ions in this study to that determined in other studies published in the literature 14 , 60 , 69 – 74 . The Cd 2+ elimination efficiency achieved in this study was much higher than that described for other biosorbents.…”

Cyanoremediation of heavy metals (As(v), Cd(ii), Cr(vi), Pb(ii)) by live cyanobacteria (Anabaena variabilis, and Synechocystis sp.): an eco-sustainable technology

“…This may be attributed to the ease with which Cd( ii ) and As( v ) can damage the protein structures. 31 El-Hameed et al 38 used cyanobacteria T. variabilis and N. muscorum and showed that these two cyanobacteria under Cd( ii ) contamination exhibited a reduction in chlorophyll and carotenoid production after 14 days.…”

Degradation and remediation of environmental pollutants by algae

“…The researchers found that eukaryotic microalgae and cyanobacteria can be used as antidotes to treat radionuclide contaminated wastewater, and they have great potential to accumulate radionuclides as nutrients for their intracellular metabolism. For example, Coccomyxa actinabiotis isolated from radioactive wastewater may tolerate a wide range of radiation doses up to 20kGy [66]. Similarly, studies by Rivasseau et al have shown that the algae has almost 100% removal of 137Cs from radioactive contaminated wastewater with an initial Cs concentration of 67Bq/L [66].…”

“…For example, Coccomyxa actinabiotis isolated from radioactive wastewater may tolerate a wide range of radiation doses up to 20kGy [66]. Similarly, studies by Rivasseau et al have shown that the algae has almost 100% removal of 137Cs from radioactive contaminated wastewater with an initial Cs concentration of 67Bq/L [66]. In addition, Fukuda et al reported that nearly 188 species of aquatic plants and microalgae were widely used to 137Cs, 125I and 85Sr from the water environment during the Fukushima nuclear power plant accident [67].…”