and the
238 U
+ intensity was used with this correction factor to subtract the UH
+
contribution on
239 Pu+, the correction amounting to <2% of the total m/z 239 signal. Mass discrimination was 0.7–0.8% per m/z, and corrections were performed
using a factor determined based upon
238 U/
235 U measured externally for a natural U
standard (
38 U/
235 U ¼ 137.88). The UH+ and mass-discrimination corrected ICPMS
data were used to calculate
239+240 Pu activities and
240 Pu/
239 Pu atom ratios.
The accuracy of the ICPMS-based
239+240 Pu activity measurements were
assessed through preparation and analyses of two standard reference materials
produced from the US National Institute of Standards and Technology (NIST).
Seven aliquots of 1.0 g nominal mass were prepared for each of these materials
through the course of the study. For NIST 4353 (Rocky Flats Soil-1), a
239 +
240 Pu
activity of 8.3 Æ 1.4 Bq/kg was found; for NIST 4357 (Ocean Sediment), a
239 +
240
Pu activity of 10.7 Æ 0.9 Bq/kg was obtained. These compare well vs the certified
activities of 8.03 Æ 0.60 and 10.4 Æ 0.2 Bq/kg, respectively. Though these materials
are not certified for any Pu atom ratios, the
240 Pu/
239 Pu results obtained
(0.061 Æ 0.003 and 0.227 Æ 0.010 for 4353 and 4357, respectively) are concordant
with expected
240 Pu/
239 Pu in materials containing weapons-grade Pu (NIST 4353)
and Pu from latter Sellafield discharges (NIST 4357).
Monitoring of the radiochemoecological state of the Black Sea ecosystem was
carried out after the Chernobyl accident in the period between 1986 and 2011.
Materials for investigation were taken during expeditions as a rule on scientific
research vessels such as “Professor Vodyanitskiy” and “Academician
Kovalevskiy”, IBSS. Sampling of the bottom sediments was carried out by box
corers. Concentrations of the radionuclides of
90 Sr and
137 Cs were analyzed in the
following marine macrophytes: Ceramium virgatum, Cladophora spp., Cystoseira
Table 18.2 Interannual changes of average
90
Sr and
137
Cs concentrations in the sea water of the
North-western Black Sea before and after the Chernobyl nuclear power plant (ChNPP) accident
Period, year
Concentration
137
Cs Bq m
À3
9 0
Sr Concentration Bq m
À3
Before 26th of April 1986
14–15
15
After 26th of April 1986
143 Æ 43
28–53
1987
84 Æ 25
22 Æ 3
1988
79 Æ 24
24 Æ 6
1989
476 Æ 24
21 Æ 1
1989
76 Æ 1.3
21 Æ 1
1990
69 Æ 21
23 Æ 2
1991
31 Æ 9
No data
1992
36 Æ 11
20 Æ 1
1993
36 Æ 11
22.0
1994
27.7
27.3
1995
28 Æ 8
15.0
1998
24 Æ 6
2 0 Æ 4
2000
24 Æ 2
1 9 Æ 4
2011
14.9–16.8
6.7–32
18 Radioecology of the Black Sea
305
238 U
+ intensity was used with this correction factor to subtract the UH
+
contribution on
239 Pu+, the correction amounting to <2% of the total m/z 239 signal. Mass discrimination was 0.7–0.8% per m/z, and corrections were performed
using a factor determined based upon
238 U/
235 U measured externally for a natural U
standard (
38 U/
235 U ¼ 137.88). The UH+ and mass-discrimination corrected ICPMS
data were used to calculate
239+240 Pu activities and
240 Pu/
239 Pu atom ratios.
The accuracy of the ICPMS-based
239+240 Pu activity measurements were
assessed through preparation and analyses of two standard reference materials
produced from the US National Institute of Standards and Technology (NIST).
Seven aliquots of 1.0 g nominal mass were prepared for each of these materials
through the course of the study. For NIST 4353 (Rocky Flats Soil-1), a
239 +
240 Pu
activity of 8.3 Æ 1.4 Bq/kg was found; for NIST 4357 (Ocean Sediment), a
239 +
240
Pu activity of 10.7 Æ 0.9 Bq/kg was obtained. These compare well vs the certified
activities of 8.03 Æ 0.60 and 10.4 Æ 0.2 Bq/kg, respectively. Though these materials
are not certified for any Pu atom ratios, the
240 Pu/
239 Pu results obtained
(0.061 Æ 0.003 and 0.227 Æ 0.010 for 4353 and 4357, respectively) are concordant
with expected
240 Pu/
239 Pu in materials containing weapons-grade Pu (NIST 4353)
and Pu from latter Sellafield discharges (NIST 4357).
Monitoring of the radiochemoecological state of the Black Sea ecosystem was
carried out after the Chernobyl accident in the period between 1986 and 2011.
Materials for investigation were taken during expeditions as a rule on scientific
research vessels such as “Professor Vodyanitskiy” and “Academician
Kovalevskiy”, IBSS. Sampling of the bottom sediments was carried out by box
corers. Concentrations of the radionuclides of
90 Sr and
137 Cs were analyzed in the
following marine macrophytes: Ceramium virgatum, Cladophora spp., Cystoseira
Table 18.2 Interannual changes of average
90
Sr and
137
Cs concentrations in the sea water of the
North-western Black Sea before and after the Chernobyl nuclear power plant (ChNPP) accident
Period, year
Concentration
137
Cs Bq m
À3
9 0
Sr Concentration Bq m
À3
Before 26th of April 1986
14–15
15
After 26th of April 1986
143 Æ 43
28–53
1987
84 Æ 25
22 Æ 3
1988
79 Æ 24
24 Æ 6
1989
476 Æ 24
21 Æ 1
1989
76 Æ 1.3
21 Æ 1
1990
69 Æ 21
23 Æ 2
1991
31 Æ 9
No data
1992
36 Æ 11
20 Æ 1
1993
36 Æ 11
22.0
1994
27.7
27.3
1995
28 Æ 8
15.0
1998
24 Æ 6
2 0 Æ 4
2000
24 Æ 2
1 9 Æ 4
2011
14.9–16.8
6.7–32
18 Radioecology of the Black Sea
305