Chromium(VI) Biosorption and Bioaccumulation by Live and Acid-Modified Biomass of a Novel Morganella morganii Isolate

Conventional methods of chromium removal are often insufficient for the remediation of chromium-contaminated natural environments, necessitating the development of alternative strategies. In this paper, we report the isolation of a novel Morganella morganii strain capable of reducing hexavalent chromium to its less-toxic and less-soluble trivalent form. Cr(VI) reduction by this strain was evaluated in both acidic environments and conditions reflecting natural freshwater sources. The isolate achieved equilibrium within 3 h and displayed a specific uptake rate of 24.30 ± 1.67 mg Cr(VI)/g biomass following HCl treatment. Without acid treatment, a reduction of over 90% was recorded within 72 h for an initial Cr(VI) concentration 20 mg/L, corresponding to a Cr(VI) removal capacity of 19.36 ± 1.89 mg/g. Absorption data of acid-treated STB5 biomass most closely followed the Toth and Langmuir models. FTIR results indicate that hydroxyl groups and extracellular or cell membrane polysaccharides may be potential adsorption sites for hexavalent chromium. Our results suggest that the isolate may be used in situ for treatment of polluted freshwater environments. Copyright © Taylor & Francis Group, LLC

Accumulation trends of metals and a metalloid in the freshwater crayfish Astacus leptodactylus from Lake Yeniçaǧa (Turkey)

This study aims to determine the extent of metal pollution in Lake Yeniçaǧa (Bolu, Turkey) by investigating the accumulation trends of five metals (Al, Cu, Fe, Ni and Zn) and a metalloid (As) in gills, exoskeleton, hepatopancreas and abdominal muscles of the freshwater crayfish Astacus leptodactylus. Principal component analysis (PCA), cluster analysis (CA), correlation analysis and analysis of variance (ANOVA) were utilised to determine the accumulation profiles of each element over four seasons. The greatest element accumulation was found to occur in the gills. All elements in exoskeletal tissue displayed positive correlations with each other, a similar trend was also observed in the hepatopancreas samples. Strong (r=0.868) and very strong (r=0.960) positive correlations were found between the accumulations of Al and Fe in gills and the exoskeleton, respectively. Correlations in tissue accumulation rates are discussed in the context of metabolic roles and impacts associated with the elements tested. Elemental compositions of Yeniçaǧa water and sediment samples were also investigated to determine whether the composition of the surrounding environment matches the metal accumulation trends of tissue samples. We demonstrate that, by the criteria set by the United States Environmental Protection Agency, Lake Yeniçaǧa is heavily polluted in terms of As and Ni. © 2013 Taylor & Francis

Morphological, anatomical, palynological, karyological and autecological characters of Centaurea amaena Boiss. & Balansa [Sect. Phalolepis (Centaurea/Asteraceae)]

Centaurea amaena Boiss. & Balansa included in the Phalolepis section of the Compositae (Asteraceae) family is an endemic species that is under critical risk of extinction. The morphological, anatomical, palynological, karyological and autecological features have been studied in this study. In accordance with the new observations, additional information was added to the previous description of the species, and the description was edited. Moreover, threat category of C. amaena has been updated according to International Union for Conservation of Nature criterions as CR B2ab(i,iii) (previously EN). Pollen grains are symmetric and isopolar, tricolporate. The somatic chromosome number is determined as 2n = 18 in C. amaena. The karyotype formula of this species consists of three median chromosome pairs and six submedian chromosome pairs. The physical and chemical properties of the soil in which the plant grows are, sandy-loam, weak acid, high organic matter