Removal of silver nanoparticles using phytoremediation method

This paper presents on removal of silver nanoparticles using phytoremediation. In this study, floating macrophyte (Pistia stratiotes) was used for phytoremediation of silver nanoparticles. This study investigated the performance of Pistia stratiotes in the removal of silver nanoparticles using phytoremediation method. The silver nanoparticles were green synthesized by using Muntingia calabura sp. leaves as reducing and stabilizing agent. The silver nanoparticles were successful synthesized as a peak appeared at wavelength 450 nm by UV-Vis spectrophotometer, while Pistia stratiotes had been acclimatized in tank at laboratory. Similar size of Pistia stratiotes had been employed for investigation. Each selected Pistia stratiotes was placed in 5 L bottles water containing different concentration (0.5 ppm, 1.0 ppm, 2.0 ppm and 3.0 ppm) of silver nanoparticles. This study was evaluated using UV-Vis spectrophotometer for five days. The results showed that the highest removal was achieved 69.88% at concentration of 0.5 ppm. This percentage removal relatively decreased up to 55.61% as concentration increase at 3.0 ppm. These results prescribed that phytoremediation of silver nanoparticles by Pistia stratiotes can be considered to apply and implement in water environment for AgNPs removal.

Uptake Prediction of Eight Potentially Toxic Elements by Pistia stratiotes L. Grown in the Al-Sero Drain (South Nile Delta, Egypt): A Biomonitoring Approach

The potential to utilise the free-floating macrophyte Pistia stratiotes L. to survey contamination of the Al-Sero Drain in the South Nile Delta, Egypt, by eight potentially toxic elements (PTEs) was investigated in this study. This study considered the absorption of eight PTEs (Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn), and the evaluated P. stratiotes were located in three sampling locations along the Al-Sero Drain, with sampling conducted in both monospecific and homogenous P. stratiotes. Samples of both types of P. stratiotes and water were collected on a monthly basis between May 2013 and April 2014 at each location, utilising three randomly chosen 0.5 × 0.5 m quadrats. Regression models were designed to predict the concentration of the PTEs within the plant’s shoot and root systems. Elevated water Fe levels were correlated with a rise in shoot system Fe concentration, whereas higher Ni concentrations in the water led to a higher Ni concentration within the root system. The latter was also true for Pb. Water Cu levels had a negative association with the Cu concentration within the P. stratiotes shoot system. Raised Fe levels were also correlated with a diminished Fe level within the roots. For all PTEs, P. stratiotes was characterised by a bioconcentration factor of more than 1.0, and for the majority by a translocation factor of less than 1.0. The goodness of fit for most of the designed models, as indicated by high R2 values and low mean averaged errors, demonstrated the associations between actual and predicted PTE concentrations. Any disparity between measured and predicted parameters failed to reach significance with Student t-tests, reinforcing the predictive abilities of the designed models. Thus, these novel models have potential value for the prediction of PTE uptake by P. stratiotes macrophytes inhabiting the Al-Sero Drain. Furthermore, the macrophyte’s constituents indicate the long-term impact of water contamination; this supports the potential future use of P. stratiotes for biomonitoring the majority of the PTEs evaluated in this study.

Involvement of a unique chemodosimeter in selective estimation of noxious cyanide in common water hyacinth (Eichhornia crassipes): An environmental refinement

A naphthaldehyde-pyridoxal conjugated chemodosimeter (NPLC) was developed and employed for the sensitive and selective detection and estimation of cyanide in common water hyacinth (Eichhornia crassipes), a free floating macrophyte used...

Uptake, Growth, and Pigment Changes in Lemna minor L. Exposed to Environmental Concentrations of Cylindrospermopsin

Cylindrospermopsin (CYN)-producing cyanobacterial blooms such as Raphidiopsis, Aphanizomenon, Anabaena, Umezakia, and Lyngbya spp. are occurring more commonly and frequently worldwide. CYN is an environmentally stable extracellular toxin, which inhibits protein synthesis, and, therefore, can potentially affect a wide variety of aquatic biota. Submerged and floating macrophytes, as primary producers in oligotrophic habitats, are at risk of exposure and information on the effects of CYN exposure at environmentally relevant concentrations is limited. In the present study, we investigated CYN uptake in the floating macrophyte Lemna minor with exposure to reported environmental concentrations. The effects were evaluated in terms of bioaccumulation, relative plant growth, and number of fronds per day. Variations in the concentrations and ratios of the chlorophylls as stress markers and carotenoids as markers of oxidative stress defense were measured. With exposure to 25 μg/L, L. minor could remove 43% of CYN within 24 h but CYN was not bioaccumulated. Generally, the pigment concentrations were elevated with exposure to 0.025, 0.25, and 2.5 μg/L CYN after 24 h, but normalized quickly thereafter. Changes in relative plant growth were observed with exposure to 0.25 and 2.5 μg/L CYN. Adverse effects were seen with these environmentally realistic concentrations within 24 h; however, L. minor successfully recovered within the next 48–96 h.

Climatic Niche Shift during Azolla filiculoides Invasion and Its Potential Distribution under Future Scenarios

In order to prevent future biological invasions, it is crucial to know non-native species distributions. We evaluated the potential global distribution of Azolla filiculoides, a free-floating macrophyte native to the Americas by using species distribution models and niche equivalency tests to analyze the degree of niche overlap between the native and invaded ranges of the species. The models were projected under two future emission scenarios, three global circulation models and two time periods. Our results indicate a possible niche shift between the distribution ranges of the species, indicating that A. filiculoides can adapt to novel environmental conditions derived from climatic differences during the invasion process. Our models also show that the future potential distribution of A. filiculoides will decrease globally, although the species could colonize new vulnerable regions where it is currently absent. We highlight that species occurrence records in the invaded area are necessary to generate accurate models, which will, in turn, improve our ability to predict potential invasion risk areas.