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Table RD-17.  Activity Concentrations of Radionuclides Measured by Alpha Spectroscopy
in Lake Carlsbad Sediment Samples Collected during 1998 – 2000

See CEMRC 2000 Report "Radiological and non-radiological constituents in surface water and sediments at selected reservoirs"
for descriptions of locations and methods of data collection.
Download pdf file


Isotope Collection Date and Sampling Depth
March 17, 1998 (1 m depth) March 17, 1998 (1 m depth)
Activity Concentration
(mBq g-1)		 aSD
(mBq g-1)		 bMDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC B(mBq g-1)
241Am 4.23E-02 7.30E-03 1.33E-02 5.47E-02 8.31E-03 1.23E-02
238Pu <MDC

 

 1.80E-02 <MDC

 

 1.50E-02
239Pu 1.13E-01 1.15E-02 1.99E-02 1.43E-01 1.19E-02 1.04E-02
228Th 1.90E+01 5.28E-01 2.22E-01 2.71E+01 6.68E-01 2.69E-01
230Th 2.17E+01 5.71E-01 2.01E-01 3.22E+01 7.44E-01 2.24E-01
232Th 1.70E+01 4.93E-01 1.75E-01 2.69E+01 6.62E-01 2.07E-01
234U 3.66E+01 1.13E+00 3.46E-01 4.40E+01 1.27E+00 2.08E-01
235U 1.70E+00 2.56E-01 3.10E-01 2.31E+00 3.00E-01 2.87E-01
238U 2.79E+01 9.50E-01 3.33E-01 3.36E+01 1.06E+00 2.44E-01
Isotope March 19, 1998 (2 m depth) March 19, 1998 (3 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 3.20E-02 6.44E-03 1.20E-02 5.26E-02 7.57E-03 1.27E-02
238Pu <MDC

 

 2.21E-02 <MDC

 

 1.89E-02
239Pu 8.97E-02 1.04E-02 1.49E-02 1.48E-01 1.25E-02 1.30E-02
228Th 2.25E+01 6.19E-01 3.31E-01 2.16E+01 5.88E-01 2.83E-01
230Th 2.45E+01 6.47E-01 2.15E-01 2.54E+01 6.46E-01 2.24E-01
232Th 1.96E+01 5.64E-01 1.78E-01 2.23E+01 5.96E-01 1.63E-01
234U 3.51E+01 1.08E+00 2.45E-01 4.93E+01 1.39E+00 2.33E-01
235U 1.47E+00 2.35E-01 3.40E-01 2.24E+00 2.99E-01 2.90E-01
238U 2.56E+01 8.83E-01 2.54E-01 3.29E+01 1.06E+00 2.70E-01
Isotope August 19, 1998 (1 m depth) August 19, 1998 (3 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 3.98E-02 7.67E-03 1.38E-02 5.31E-02 7.91E-03 1.16E-02
238Pu <MDC

 

 2.70E-02 <MDC

 

 1.75E-02
239Pu 1.17E-01 1.25E-02 1.86E-02 1.63E-01 1.30E-02 1.21E-02
228Th 1.77E+01 5.00E-01 2.81E-01 2.01E+01 5.46E-01 2.67E-01
230Th 1.99E+01 5.34E-01 2.27E-01 2.60E+01 6.33E-01 1.82E-01
232Th 1.72E+01 4.88E-01 1.91E-01 1.97E+01 5.34E-01 1.74E-01
234U 4.19E+01 1.21E+00 2.26E-01 5.23E+01 1.57E+00 2.93E-01
235U 2.44E+00 3.02E-01 2.28E-01 2.14E+00 3.14E-01 3.14E-01
238U 2.71E+01 9.10E-01 2.29E-01 3.45E+01 1.19E+00 3.49E-01
Isotope August 19, 1998 (3 m depth) August 19, 1998 (4 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 3.17E-02 6.23E-03 1.10E-02 3.98E-02 7.72E-03 1.49E-02
238Pu <MDC

 

 1.60E-02 <MDC

 

 1.89E-02
239Pu 1.06E-01 1.08E-02 1.14E-02 1.48E-01 1.29E-02 1.41E-02
228Th 1.80E+01 5.19E-01 2.50E-01 2.88E+01 8.72E-01 3.87E-01
230Th 2.15E+01 5.74E-01 2.09E-01 3.21E+01 9.26E-01 3.14E-01
232Th 1.80E+01 5.17E-01 2.53E-01 2.74E+01 8.43E-01 2.12E-01
234U 3.72E+01 1.24E+00 2.98E-01 5.14E+01 1.56E+00 3.46E-01
235U 1.40E+00 2.48E-01 3.22E-01 2.23E+00 3.22E-01 3.06E-01
238U 2.74E+01 1.02E+00 2.81E-01 3.76E+01 1.26E+00 3.18E-01
Isotope June 30, 1999 (3 m depth) June 30, 1999 (2 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 4.16E-02 9.63E-03 2.12E-02 7.93E-02 1.12E-02 1.66E-02
238Pu <MDC

 

 1.18E-02 <MDC

 

 2.71E-02
239Pu 1.83E-01 1.44E-02 1.90E-02 2.83E-01 1.94E-02 1.88E-02
228Th 2.05E+01 7.19E-01 3.54E-01 2.01E+01 7.18E-01 3.51E-01
230Th 2.58E+01 8.17E-01 2.87E-01 2.24E+01 7.60E-01 3.23E-01
232Th 2.18E+01 7.40E-01 2.28E-01 2.08E+01 7.26E-01 2.13E-01
234U 4.52E+01 9.22E-01 1.95E-01 4.09E+01 8.83E-01 1.99E-01
235U 1.80E+00 1.97E-01 2.02E-01 1.57E+00 1.86E-01 1.84E-01
238U 3.06E+01 7.14E-01 2.38E-01 2.93E+01 7.11E-01 1.72E-01
Isotope June 30, 1999 (3 m depth) June 30, 1999 (3 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 3.93E-02 7.43E-03 1.35E-02 5.56E-02 7.79E-03 1.34E-02
238Pu <MDC

 

 1.85E-02 <MDC

 

 1.63E-02
239Pu 1.26E-01 1.18E-02 1.27E-02 1.66E-01 1.36E-02 1.17E-02
228Th 1.83E+01 6.75E-01 3.76E-01 2.52E+01 8.05E-01 3.39E-01
230Th 2.26E+01 7.56E-01 3.08E-01 3.03E+01 8.94E-01 3.16E-01
232Th 1.68E+01 6.38E-01 1.87E-01 2.52E+01 8.02E-01 2.36E-01
234U 4.22E+01 9.14E-01 2.68E-01 4.62E+01 1.06E+00 1.68E-01
235U 1.54E+00 1.87E-01 2.32E-01 2.07E+00 2.37E-01 2.34E-01
238U 3.03E+01 7.36E-01

2.58E-01

 3.33E+01 8.56E-01 2.00E-01
Isotope May 24, 2000 (3 m depth) May 24, 2000 (3 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 7.00E-02 1.01E-02 1.87E-02 4.47E-02 8.20E-03 1.67E-02
238Pu <MDC

 

 1.89E-02 <MDC

 

 1.58E-02
239Pu 1.68E-01 1.32E-02 1.35E-02 1.21E-01 1.12E-02 1.49E-02
228Th 2.38E+01 6.90E-01 3.70E-01 2.59E+01 7.06E-01 3.55E-01
230Th 2.90E+01 7.68E-01 2.47E-01 3.10E+01 7.77E-01 2.28E-01
232Th 2.41E+01 6.88E-01 2.81E-01 2.52E+01 6.87E-01 1.92E-01
234U 5.17E+01 1.38E+00 3.46E-01 4.54E+01 1.50E+00 2.75E-01
235U 2.19E+00 2.88E-01 3.08E-01 2.18E+00 3.28E-01 2.82E-01
238U 3.54E+01 1.27E+00 2.57E-01 3.52E+01 1.27E+00 2.78E-01
Isotope May 24, 2000 (3 m depth) May 24, 2000 (3 m depth)
Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)		 Activity Concentration
(mBq g-1)		 SD
(mBq g-1)		 MDC
(mBq g-1)
241Am 2.74E-02 7.94E-03 1.95E-02 6.62E-02 1.14E-02 2.17E-02
238Pu <MDC

 

 1.26E-02 <MDC

 

 1.77E-02
239Pu 8.99E-02 1.01E-02 1.68E-02 1.60E-01 1.33E-02 1.48E-02
228Th 1.96E+01 6.16E-01 3.61E-01 2.05E+01 6.05E-01 3.51E-01
230Th 2.34E+01 6.75E-01 2.70E-01 2.31E+01 6.41E-01 2.39E-01
232Th 1.96E+01 6.07E-01 1.84E-01 1.82E+01 5.56E-01 1.49E-01
234U 4.03E+01 1.38E+00 3.07E-01 4.98E+01 1.62E+00 3.70E-01
235U 2.15E+00 3.26E-01 3.00E-01 2.29E+00 3.42E-01 3.28E-01
238U 3.05E+01 1.15E+00 2.70E-01 3.24E+01 1.22E+00 3.40E-01
aSD=One standard deviation of the radioanalytical uncertainty
bMDC=Minimum Detectable Concentration