The stability and partitioning of inorganic mercury (Hg2+) in natural waters was tested under different storage conditions. The experiments were carried out by spiking labelled Hg2+ to natural concentrations (from 3 to 13 ng L−1) in marine, coastal lagoon, lake, river, and rain waters. Hg2+ was labelled with high specific activity 197Hg. The experiments tested the dissolved and particulate-bound fractions in 10 to 13 days time trends under different storage conditions, namely temperature, natural and preserved by acidification, and container materials (Teflon, borosilicate glass and polyethylene). The concentration of labelled Hg2+ in non-preserved waters decreased significantly depending on the type of water and the storage conditions. In the case of marine and lake waters it was stable over a period of 10 days, whereas in the case of river and lagoon waters 20% of labelled Hg was lost. The partitioning of labelled Hg2+ between the solid and dissolved fractions during the storage period varied with the type of water and the storage conditions. For short term storage periods (1 day after labelled Hg2+ spiking) a significant amount of Hg2+ was transferred to particulates, ranging from 40 to 70%, with refrigerated samples reaching equilibrium more slowly. The labelled Hg2+ in water samples preserved by 1% HCl addition was stable at room temperature (20 °C) and in a refrigerator (5 °C) when stored in Teflon and borosilicate glass, but significant losses were observed when stored in polyethylene.
COBISS.SI-ID: 26615335
This article presents a novel systematic approach to the fabrication of highly functionalized, silica (SiO2) nanoparticles used for the adsorption of heavy-metal ions (Hg2+, Pb2+, Cd2+, Zn2+). Almost monodispersed silica (SiO2) nanoparticles with narrow particle size distributions of around 85 ± 5 nm were formed using the Stöber process. The prepared SiO2 nanoparticles were successfully surface-treated during a one-step procedure by the covalent attachment of mercaptopropyl groups onto the surfaces of the SiO2 nanoparticles. A FTIR spectra analysis confirmed that the binding of the mercaptosilane molecules onto the surface of the silica nanoparticles mediated the Si–O–Si and –SH vibrations. TEM/EDXS micrographs indicated the almost monodispersed and spherical morphology of the prepared product with strong signals of Si and S, thus implying that the coating procedure involving the mercapto groups onto the silica surface had been successfully accomplished. The final results for the heavy-metal (Hg2+, Pb2+, Cd2+, Zn2+) adsorption showed the strongest affinity within the following sequence Hg2+ (99.9%) ) Pb2+ (55.9%) ) Cd2+ (50.2%) ) Zn2+ (4%). Adsorption equilibrium was achieved after 1 h for all the analyzed samples.
COBISS.SI-ID: 17236758
The net toxicity of different forms of mercury, in the long-term during their transformation processes, leads to the selection of resistant bacterial cells and this result in community tolerance which is pollution induced. Accordingly, based on profiles of a bacterial community structure, analysis of Hg resistant culturable bacteria and quantification of merA genes, we assessed development of pollution induced community tolerance in a mercury-polluted gradient in the Idrijca River. TTGE analysis did not show effects of mercury pollution to bacterial community diversity, while quantification of merA genes showed that merA genes can be correlated precisely (R2 = 0.83) with the total concentration of mercury in the biofilm microbial communities in the pollution gradient.
COBISS.SI-ID: 3029839