The industrial complex Neot Hovav, in Israel, is situated above an anaerobic fractured chalk aqui... more The industrial complex Neot Hovav, in Israel, is situated above an anaerobic fractured chalk aquitard, which is polluted by a wide variety of hazardous organic compounds. These include volatile and non-volatile, halogenated, organic compounds. In this study, we characterized the indigenous bacterial population in 17 boreholes of the groundwater environment, while observing the spatial variations in the population and structure as a function of distance from the polluting source. In addition, the de-halogenating potential of the microbial groundwater population was tested through a series of lab microcosm experiments, thus exemplifying the potential and limitations for bioremediation of the site. In all samples, the dominant phylum was Proteobacteria. In the production plant area, the non-obligatory organo-halide respiring bacteria (OHRB) Firmicutes Phylum was also detected in the polluted water, in abundancies of up to 16 %. Non-metric multidimensional scaling (NMDS) analysis of the...
Many of polybrominated organic compounds, used as flame retardant additives, belong to the group ... more Many of polybrominated organic compounds, used as flame retardant additives, belong to the group of persistent organic pollutants. Compound-specific isotope analysis is one of the potential analytical tools for investigating their fate in the environment. However, the isotope effects associated with transformations of brominated organic compounds are still poorly explored. In the present study, we investigated carbon and bromine isotope fractionation during degradation of tribromoneopentyl alcohol (TBNPA), one of the widely used flame retardant additives, in three different chemical processes: transformation in aqueous alkaline solution (pH 8); reductive dehalogenation by zero-valent iron nanoparticles (nZVI) in anoxic conditions; oxidative degradation by H2O2 in the presence of CuO nanoparticles (nCuO). Two-dimensional carbon-bromine isotope plots (δ(13)C/Δ(81)Br) for each reaction gave different process-dependent isotope slopes (Λ(C/Br)): 25.2 ± 2.5 for alkaline hydrolysis (pH 8); 3.8 ± 0.5 for debromination in the presence of nZVI in anoxic conditions; ∞ in the case of catalytic oxidation by H2O2 with nCuO. The obtained isotope effects for both elements were generally in agreement with the values expected for the suggested reaction mechanisms. The results of the present study support further applications of dual carbon-bromine isotope analysis as a tool for identification of reaction pathway during transformations of brominated organic compounds in the environment.
An extensive water and sediment monitoring network has been established during
the past two decad... more An extensive water and sediment monitoring network has been established during the past two decades in the Nahal Besor catchment of the northern Negev. Its primary purpose is to measure water and sediment fluxes at different hydrological scales and thus assist in understanding the complexity of sedimentary dynamics when these are assessed at the outlet of the trunk stream. Water and suspended sediment monitoring systems have been developed to provide discrete and continuous records, from which material fluxes have been calculated. The network involves 3 upland catchments— Nahal Eshtemoa, Nahal Sekher, and a sub-catchment of Nahal Bikhra—differing in size and/or rainfall regime. Suspended sediment rating curves for the small (0.66 km2 ) and medium-sized (112 km2 ) basins in the same physiographic province are nearparallel, but that of the small basin lies below, reflecting less availability of sediment that can be mobilized throughout the range of specific discharge. The rating curve of Nahal Sekher (170 km2 ) cuts across those of the Eshtemoa and Bikhra, reflecting the greater aridity of the Sekher, the southern part of which contributes some runoff and much sediment only during major flow events. It also reflects the importance of sand, less loess cover, and greater exposure of rock in the headwaters of the Sekher. The complexity of sediment response during individual events results from flushing that brings hysteresis to the relation between concentration of the suspension and water discharge. This is also used to show the progressive exhaustion of sediment sources during the passage of an individual event.
The industrial complex Neot Hovav, in Israel, is situated above an anaerobic fractured chalk aqui... more The industrial complex Neot Hovav, in Israel, is situated above an anaerobic fractured chalk aquitard, which is polluted by a wide variety of hazardous organic compounds. These include volatile and non-volatile, halogenated, organic compounds. In this study, we characterized the indigenous bacterial population in 17 boreholes of the groundwater environment, while observing the spatial variations in the population and structure as a function of distance from the polluting source. In addition, the de-halogenating potential of the microbial groundwater population was tested through a series of lab microcosm experiments, thus exemplifying the potential and limitations for bioremediation of the site. In all samples, the dominant phylum was Proteobacteria. In the production plant area, the non-obligatory organo-halide respiring bacteria (OHRB) Firmicutes Phylum was also detected in the polluted water, in abundancies of up to 16 %. Non-metric multidimensional scaling (NMDS) analysis of the...
Many of polybrominated organic compounds, used as flame retardant additives, belong to the group ... more Many of polybrominated organic compounds, used as flame retardant additives, belong to the group of persistent organic pollutants. Compound-specific isotope analysis is one of the potential analytical tools for investigating their fate in the environment. However, the isotope effects associated with transformations of brominated organic compounds are still poorly explored. In the present study, we investigated carbon and bromine isotope fractionation during degradation of tribromoneopentyl alcohol (TBNPA), one of the widely used flame retardant additives, in three different chemical processes: transformation in aqueous alkaline solution (pH 8); reductive dehalogenation by zero-valent iron nanoparticles (nZVI) in anoxic conditions; oxidative degradation by H2O2 in the presence of CuO nanoparticles (nCuO). Two-dimensional carbon-bromine isotope plots (δ(13)C/Δ(81)Br) for each reaction gave different process-dependent isotope slopes (Λ(C/Br)): 25.2 ± 2.5 for alkaline hydrolysis (pH 8); 3.8 ± 0.5 for debromination in the presence of nZVI in anoxic conditions; ∞ in the case of catalytic oxidation by H2O2 with nCuO. The obtained isotope effects for both elements were generally in agreement with the values expected for the suggested reaction mechanisms. The results of the present study support further applications of dual carbon-bromine isotope analysis as a tool for identification of reaction pathway during transformations of brominated organic compounds in the environment.
An extensive water and sediment monitoring network has been established during
the past two decad... more An extensive water and sediment monitoring network has been established during the past two decades in the Nahal Besor catchment of the northern Negev. Its primary purpose is to measure water and sediment fluxes at different hydrological scales and thus assist in understanding the complexity of sedimentary dynamics when these are assessed at the outlet of the trunk stream. Water and suspended sediment monitoring systems have been developed to provide discrete and continuous records, from which material fluxes have been calculated. The network involves 3 upland catchments— Nahal Eshtemoa, Nahal Sekher, and a sub-catchment of Nahal Bikhra—differing in size and/or rainfall regime. Suspended sediment rating curves for the small (0.66 km2 ) and medium-sized (112 km2 ) basins in the same physiographic province are nearparallel, but that of the small basin lies below, reflecting less availability of sediment that can be mobilized throughout the range of specific discharge. The rating curve of Nahal Sekher (170 km2 ) cuts across those of the Eshtemoa and Bikhra, reflecting the greater aridity of the Sekher, the southern part of which contributes some runoff and much sediment only during major flow events. It also reflects the importance of sand, less loess cover, and greater exposure of rock in the headwaters of the Sekher. The complexity of sediment response during individual events results from flushing that brings hysteresis to the relation between concentration of the suspension and water discharge. This is also used to show the progressive exhaustion of sediment sources during the passage of an individual event.
Uploads
Papers by noa balaban
the past two decades in the Nahal Besor catchment of the northern Negev. Its primary
purpose is to measure water and sediment fluxes at different hydrological scales and
thus assist in understanding the complexity of sedimentary dynamics when these are
assessed at the outlet of the trunk stream. Water and suspended sediment monitoring
systems have been developed to provide discrete and continuous records, from which
material fluxes have been calculated. The network involves 3 upland catchments—
Nahal Eshtemoa, Nahal Sekher, and a sub-catchment of Nahal Bikhra—differing in
size and/or rainfall regime. Suspended sediment rating curves for the small (0.66 km2
)
and medium-sized (112 km2
) basins in the same physiographic province are nearparallel,
but that of the small basin lies below, reflecting less availability of sediment
that can be mobilized throughout the range of specific discharge. The rating curve of
Nahal Sekher (170 km2
) cuts across those of the Eshtemoa and Bikhra, reflecting the
greater aridity of the Sekher, the southern part of which contributes some runoff and
much sediment only during major flow events. It also reflects the importance of sand,
less loess cover, and greater exposure of rock in the headwaters of the Sekher. The
complexity of sediment response during individual events results from flushing that
brings hysteresis to the relation between concentration of the suspension and water
discharge. This is also used to show the progressive exhaustion of sediment sources
during the passage of an individual event.
the past two decades in the Nahal Besor catchment of the northern Negev. Its primary
purpose is to measure water and sediment fluxes at different hydrological scales and
thus assist in understanding the complexity of sedimentary dynamics when these are
assessed at the outlet of the trunk stream. Water and suspended sediment monitoring
systems have been developed to provide discrete and continuous records, from which
material fluxes have been calculated. The network involves 3 upland catchments—
Nahal Eshtemoa, Nahal Sekher, and a sub-catchment of Nahal Bikhra—differing in
size and/or rainfall regime. Suspended sediment rating curves for the small (0.66 km2
)
and medium-sized (112 km2
) basins in the same physiographic province are nearparallel,
but that of the small basin lies below, reflecting less availability of sediment
that can be mobilized throughout the range of specific discharge. The rating curve of
Nahal Sekher (170 km2
) cuts across those of the Eshtemoa and Bikhra, reflecting the
greater aridity of the Sekher, the southern part of which contributes some runoff and
much sediment only during major flow events. It also reflects the importance of sand,
less loess cover, and greater exposure of rock in the headwaters of the Sekher. The
complexity of sediment response during individual events results from flushing that
brings hysteresis to the relation between concentration of the suspension and water
discharge. This is also used to show the progressive exhaustion of sediment sources
during the passage of an individual event.