The geochemical behaviors of dissolved (<0.4 mm), low molecular weight (<10 kDa) and colloidal (10 kDa- 0.4 mm) 210Po in surface waters from the Jiulongjiang estuary were examined and the input/removal rates of ...The geochemical behaviors of dissolved (<0.4 mm), low molecular weight (<10 kDa) and colloidal (10 kDa- 0.4 mm) 210Po in surface waters from the Jiulongjiang estuary were examined and the input/removal rates of different 210Po species were estimated. Both dissolved and low molecular weight 210Po were considerably removed during estuarine mixing. However, colloidal 210Po was removed only at low salinity regions (S <15) but had input behavior at high salin-ity surface waters (S >15). The input/removal rates of three species indicate that 210Po was removed rapidly in the Jiu-longjiang estuary. The discrepancy of input/removal rates between 210Po species suggests different geochemical be-havior and a dynamic transformation between 210Po species. Low molecular weight 210Po may be more appropriate for characterizing the 210Po behavior in estuary zone than the traditional dissolved 210Po.展开更多
The method based on solvent parameters(mass,cycle of acidification, and autodeposition time), combined with response surface methodology(RSM) modeling and optimization, has been developed for maximizing ^(210)Po activ...The method based on solvent parameters(mass,cycle of acidification, and autodeposition time), combined with response surface methodology(RSM) modeling and optimization, has been developed for maximizing ^(210)Po activity in tea samples, as observed by an alpha spectrometer. RSM based on 3-factor and 5-level composite center design was used to obtain the optimal combination of solvent conditions. As solvent parameters for ^(210)Po activity, different masses(0.5, 0.75, 1, 1.5, and 2 g), different cycles of acidification(2, 3, 4, 5, and 6 times), and different autodeposition times(2, 3, 4, 5, and 6 h) were studied. The 3D response surface plot and the contour plot derived from the mathematical models were used to determine the optimal conditions. According to the obtained results, the experimental value of ^(210)Po activity was in good agreement(R^2=0.96) with the value predicted by the model. We found a favorable effect of mass on the ^(210)Po activity(p\0.05).展开更多
üIn this study, we aimed to determine the accumulations of ^(210) Po and ^(210) Pb in soil and lichen samples in K? prü bas??. The K? prü bas?? district is home to the largest uranium deposits in Turkey...üIn this study, we aimed to determine the accumulations of ^(210) Po and ^(210) Pb in soil and lichen samples in K? prü bas??. The K? prü bas?? district is home to the largest uranium deposits in Turkey. To date, there has been no study recorded in the literature related to ^(210) Po and ^(210) Pb depositions in lichens in K? prü bas??. Six different lichen species(Cladonia convoluta, Parmelina tiliacea, Physcia stellaris, Pleurosticta acetabulum, Xanthoparmelia conspersa, and Xanthoria parietina) as well as soil samples were collected from seven sampling locations around K? prü bas??. Lichens were used as biomonitors for ^(210) Po and ^(210) Pb deposition. The ^(210) Po and ^(210) Pb activity concentrations were measured in all the samples by alpha spectrometry. The activity concentrations in the lichen samples ranged from 64 to 577 Bq kg^(-1) with an average of 266 Bq kg^(-1) for ^(210) Po and from 78 to 565 Bq kg^(-1) with an average of 333 Bq kg^(-1) for ^(210) Pb. The activity ratios of ^(210) Po/ ^(210) Pb ranged from 0.80 to 1.99. In the lichen species,the mean ^(210) Po activity values varied from 154 Bq kg^(-1) in Pleurosticta acetabulum to 390 Bq kg^(-1) in Xanthoparmelia conspersa. The range of the mean ^(210) Pb activity was between 153 Bq kg^(-1) in Cladonia convoluta and 378 Bq kg^(-1) in Parmelina tiliacea. In the soil samples, ^(210) Po and ^(210) Pb activity concentrations were ranged from14 to 1268 Bq kg^(-1) and from 19 to 1113 Bq kg^(-1),respectively. While the values of ^(210) Po and ^(210) Pb measured in the lichen samples are comparable with those of the literature, the results of ^(210) Po and ^(210) Pb in the soil taken from the uranium mine are higher than the results of the literature studies.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.40076024)the 10th Five-Year Plan of COMRA(Grant Nos.DY 105-02-4,DY 105-02-01 and DY 105-01-04-11).
文摘The geochemical behaviors of dissolved (<0.4 mm), low molecular weight (<10 kDa) and colloidal (10 kDa- 0.4 mm) 210Po in surface waters from the Jiulongjiang estuary were examined and the input/removal rates of different 210Po species were estimated. Both dissolved and low molecular weight 210Po were considerably removed during estuarine mixing. However, colloidal 210Po was removed only at low salinity regions (S <15) but had input behavior at high salin-ity surface waters (S >15). The input/removal rates of three species indicate that 210Po was removed rapidly in the Jiu-longjiang estuary. The discrepancy of input/removal rates between 210Po species suggests different geochemical be-havior and a dynamic transformation between 210Po species. Low molecular weight 210Po may be more appropriate for characterizing the 210Po behavior in estuary zone than the traditional dissolved 210Po.
文摘The method based on solvent parameters(mass,cycle of acidification, and autodeposition time), combined with response surface methodology(RSM) modeling and optimization, has been developed for maximizing ^(210)Po activity in tea samples, as observed by an alpha spectrometer. RSM based on 3-factor and 5-level composite center design was used to obtain the optimal combination of solvent conditions. As solvent parameters for ^(210)Po activity, different masses(0.5, 0.75, 1, 1.5, and 2 g), different cycles of acidification(2, 3, 4, 5, and 6 times), and different autodeposition times(2, 3, 4, 5, and 6 h) were studied. The 3D response surface plot and the contour plot derived from the mathematical models were used to determine the optimal conditions. According to the obtained results, the experimental value of ^(210)Po activity was in good agreement(R^2=0.96) with the value predicted by the model. We found a favorable effect of mass on the ^(210)Po activity(p\0.05).
基金supported by Manisa Celal Bayar University,Scientific Research Projects Coordination Unit(No.2012/118)
文摘üIn this study, we aimed to determine the accumulations of ^(210) Po and ^(210) Pb in soil and lichen samples in K? prü bas??. The K? prü bas?? district is home to the largest uranium deposits in Turkey. To date, there has been no study recorded in the literature related to ^(210) Po and ^(210) Pb depositions in lichens in K? prü bas??. Six different lichen species(Cladonia convoluta, Parmelina tiliacea, Physcia stellaris, Pleurosticta acetabulum, Xanthoparmelia conspersa, and Xanthoria parietina) as well as soil samples were collected from seven sampling locations around K? prü bas??. Lichens were used as biomonitors for ^(210) Po and ^(210) Pb deposition. The ^(210) Po and ^(210) Pb activity concentrations were measured in all the samples by alpha spectrometry. The activity concentrations in the lichen samples ranged from 64 to 577 Bq kg^(-1) with an average of 266 Bq kg^(-1) for ^(210) Po and from 78 to 565 Bq kg^(-1) with an average of 333 Bq kg^(-1) for ^(210) Pb. The activity ratios of ^(210) Po/ ^(210) Pb ranged from 0.80 to 1.99. In the lichen species,the mean ^(210) Po activity values varied from 154 Bq kg^(-1) in Pleurosticta acetabulum to 390 Bq kg^(-1) in Xanthoparmelia conspersa. The range of the mean ^(210) Pb activity was between 153 Bq kg^(-1) in Cladonia convoluta and 378 Bq kg^(-1) in Parmelina tiliacea. In the soil samples, ^(210) Po and ^(210) Pb activity concentrations were ranged from14 to 1268 Bq kg^(-1) and from 19 to 1113 Bq kg^(-1),respectively. While the values of ^(210) Po and ^(210) Pb measured in the lichen samples are comparable with those of the literature, the results of ^(210) Po and ^(210) Pb in the soil taken from the uranium mine are higher than the results of the literature studies.
