DOE/ORO/2327 Oak Ridge Reservation Annual Site Environmental ...

Oak Ridge Reservation
revealed that neither is located in the groundwater discharge zone for the 7000/Bearden Creek Watershed
Discharge Area.
Spring/seep BC-01 was sampled during the wet season in March 2009, but could not be sampled
during the dry season due to the lack of water flow from the spring/seep.
No radionuclides were detected in BC-01. Iron and aluminum were detected at concentrations greater
than reference standards in 2009. These metals are most likely sorbed onto suspended solids in the
groundwater samples collected contributing to the exceedance of the reference standards. Other metals
were detected at low concentrations in groundwater samples collected from this discharge area in 2009
and results are provided in the 2009 Environmental Monitoring Results (DOE 2009).
Detection limits for the semi-volatile organic compounds (atrazine, benzo(a)pyrene,
hexachlorobenzene, and pentachlorophenol) exceeded reference standards. No volatile organic
compounds were detected in BC-01.
East End Discharge Area Exit Pathway Results
Well 923 was sampled in April and August 2009. Wells EE-01 and ED-02 were sampled in March
and August 2009. No radiological constituents were present above reference standards in samples
collected from East End Discharge Area monitoring points, however low concentrations of gross beta
activity were detected in the samples collected from EE-01, EE-02, and well 923. Additionally, low
concentrations of 214 Bi and 214 Pb were detected in EE-02.
Iron, manganese, and aluminum exceeded reference standards in EE-01 and EE-02, and iron and
manganese exceeded reference standards in well 923. A statistically significant historical increase in
manganese is observable in the EE-01 data set. It is likely that iron, manganese, and aluminum are sorbed
onto suspended solids in the groundwater samples collected contributing to the exceedance of the
reference standards. Other metals were detected at low concentrations in groundwater samples collected
from East End Discharge Area in 2009; these results can be viewed in the 2009 Environmental
Monitoring Results (DOE 2009).
Detection limits for several undetected semi-volatile organic compounds (atrazine, benzo(a)pyrene,
hexachlorobenzene, and pentachlorophenol) exceeded reference standards. Bis(2-ethylhexyl) phthalate
was detected in one sample collected from well 923. Plastic well casing materials used in the construction
of the well may explain the presence of the phthalate in the sample. A low estimated concentration of
bis(2-ethylhexyl) phthalate was also detected in a sample collected from EE-01 during 2009. No other
organic compounds were detected in samples collected from the East End Discharge Area.
Northwestern Discharge Area Exit Pathway Results
Wells 807 and 808 were added to the Northwest Discharge Area Exit Pathway in 2009. These wells
are located down gradient of many of the facilities located in the ORNL Main Campus. They are also
located near the water gap through Haw Ridge and are used to monitor a localized groundwater exit
pathway from the ORNL Main Campus into Melton Valley.
Wells 807 and 808 were sampled in April and August 2009 as was well 531. Well 535 was sampled
in early June and September 2009 due to continued access restrictions associated with construction
activities related to ORNL campus upgrades.
No radiological parameters exceeded their reference standards at any Northwestern Discharge Area
monitoring point in 2009. However, gross beta activity was detected in low concentrations in well 531
and 214 Bi, 214 Pb, and 3 H were detected in well 535. Gross beta activity, total radioactive strontium, 3 H, and
214 40
Bi were detected in well 807 while gross beta activity and K were detected in low concentrations in
well 808.
Iron and aluminum concentrations exceeded reference standards in well 531. However, statistical
analyses of historical data for both metals exhibit statistically significant decreasing trends in
concentrations. Iron, manganese, and aluminum also exceeded reference standards in well 535, and
analyses of historical data for iron and manganese exhibit statistically significant increasing trends at
well 535. Additionally, iron and manganese exceeded reference standards in well 807 with historical
5-78 Oak Ridge National Laboratory