Laboratory tests for the phytoextraction of heavy metals from polluted harbor sediments using aquatic plants

The aim of this study was to investigate the concentrations and pollution levels of heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons in marine sediments from the Leghorn Harbor (Italy) on the Mediterranean Sea. The phytoextraction capacity of three aquatic plants Salvinia natans, Vallisneria spiralis, and Cabomba aquatica was also tested in the removal of lead and copper, present in high concentration in these sediments. The average detectable concentrations of metals accumulated by the plants in the studied area were as follows: >3.328±0.032mg/kg dry weight (DW) of Pb and 2.641±0.014mg/kg DW of Cu for S. natans, >3.107±0.034g/kg DW for V. spiralis, and >2.400±0.029mg/kg DW for C. aquatica. The occurrence of pesticides was also analyzed in the sediment sample by gas chromatography coupled with mass spectrometry (GC/MS). Due to its metal and organic compound accumulation patterns, S. natans is a potential candidate in phytoextraction strategies

Biodegradation studies of polylactic acid copolymers

Medium molecular weight copolymers were synthesized by the condensation of L-lactic acid (LA), terephthalic acid (TPA) and 1,3-propanediol (PDO). The obtained copolymers were characterized for acid value, hydroxyl value and number average molecular weight. Also, the biodegradation behavior by different fungal species (A spergillus niger, A spergillu s versicolor, A lternaría altern a ta and P enicilliu m ) was performed. The degree of biodegradation was examined by weight loss. It was observed that the biodegradation of copolymer with higher quantity of lactic acid was faster and more effective than the biodegradation of copolymer with smaller quantity of lactic acid

Nitrones: not only extraordinary spin traps, but also good nitric oxide sources in vivo

Free radicals are involved in the development of reperfusion injuries. Using a spin trap, the intensity of such lesions can be reduced. Nitrones (effective in vivo spin traps) were tried in this work as in vivo nitric oxide donors. Nitrite and nitrate concentration values (rabbit blood) were used as biomarkers of nitric oxide production. Most nitrones did not increase plasma concentrations of nitrite and nitrate; on the contrary, reduced plasma concentrations of these indicators were noted. However, glyoxal isopropyldinitrone, in a dose of 50 mg kg–1, was highly effective in increasing nitric oxide production. In the same time, nitrones do not react with hepatic homogenates, proving that the release of nitric oxide takes place in the tissues and is not related to hepatic metabolism. Before using nitrones in vivo, they were tested in vitro for the ability to release nitric oxide following a reaction with the hydroxyl radical

Application of immobilized waste brewery yeast cells for Cd2+ removal. Equilibrium and kinetics

In this investigation, the removal of Cd2+ by a brewery waste biomass in immobilized (Ca alginate beads) form was studied. The removal process was conducted at room temperature under batch conditions (magnetic stirring) using different initial cadmium concentrations. The equilibrium of biosorption was reached in 150 min for all employed initial concentrations. The maximum biosorption capacity was calculated to be 5.96 mg Cd2+ g-1 yeast for an initial Cd2+ concentration of 169 mg L-1. Langmuir and Freundlich adsorption isotherms were used to correlate the equilibrium adsorption data. Based on the correlation coefficients, it was concluded that the Langmuir isotherm is more suitable for describing the equilibrium data of cadmium biosorption. In addition, first and pseudo-second order kinetic models were applied to describe the biosorption process. The kinetic parameters for the pseudo-second order kinetics were determined

Comparative Studies of the Phytoextraction Capacity of Five Aquatic Plants in Heavy Metal Contaminated Water

The uptake capacity of the aquatic plants (Salvinia natans Kunth., Eichhornia crassipes Mart., Lemna minor L., Elodea canadensisMichx., Pistia stratiotes L.) was analyzed in phytoextraction of Cu2+, Zn2+, and Cd2+. It was attend to study the plants capacity comparatively using mono and multimetallic systems. In particular, the chlorophyll, protein and carotenoids contents were studied during heavy metals uptake, in order to observe the stress effect on plants. The results obtained for the monometallic system showed that Salvinia natans Kunth. accumulated the highest quantity of Cu2+ (4.72 mg/g), Zn2+ (2.23 mg/g) and Cd2+ (1.90 mg/g). The leaves of Lemna minor L. accumulated the highest concentration of Cu2+ (10.80 mg/g) and Cd2+ (2.78 mg/g) in multimetallic system. The water lettuce (Pistia stratiotes L.) translocated the highest quantity of Zn2+ in its roots (4.80 mg/g). The chlorophyll andthe carotenoids levels decreased under the stress of heavy metals in both systems, while protein content increased under the influence of Cu2+ and Cd2+, but decreased for Zn2+. The studied hydrophytes proved to be useful in the uptake of heavy metals in monometallic system and much more effective in the multimetallic system and showed great potential for further applications in the industrial and commercial wastewater treatments

Nitrones: not only extraordinary spin traps, but also good nitric oxide sources in vivo

Free radicals are involved in the development of reperfusion injuries. Using a spin trap, the intensity of such lesions can be reduced. Nitrones (effective in vivo spin traps) were tried in this work as in vivo nitric oxide donors. Nitrite and nitrate concentration values (rabbit blood) were used as biomarkers of nitric oxide production. Most nitrones did not increase plasma concentrations of nitrite and nitrate; on the contrary, reduced plasma concentrations of these indicators were noted. However, glyoxal isopropyldinitrone, in a dose of 50 mg kg-1, was highly effective in increasing nitric oxide production. At the same time, nitrones do not react with hepatic homogenates, proving that the release of nitric oxide takes place in the tissues and is not related to hepatic metabolism. Before using nitrones in vivo, they were tested in vitro for the ability to release nitric oxide following a reaction with the hydroxyl radical