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Water Monitoring - Onsite Radiological
NSTec monitors annually a network of wells, a containment pond
system for tritiated water, sewage lagoons, and springs on the NTS for the presence of tritium,
gamma-emitting man-made radionuclides, and gross alpha and beta
radioactivity.
The
onsite wells
[
PDF, 15 MB] include drinking water supply wells, non-potable water supply wells,
and monitoring wells. Monitoring wells are historic nuclear testing-related
wells that are now used to monitor groundwater. Annual monitoring results from
drinking water wells indicate that subsurface nuclear testing has not impacted
the NTS drinking water supply network.
A few of the NTS monitoring wells have very low but detectable
levels of tritium and these wells are located within 0.6 miles of
underground nuclear test sites. Their tritium levels are all less than
3% of the drinking water standard of 20,000 pico-Curies per liter.
Tritium monitoring indicates that migration of radionuclides from
underground test areas has not been significant.
Gross alpha and beta radioactivity is detectable in most onsite
groundwater samples and likely represents the presence of
naturally-occurring radionuclides since there is a general lack of
corresponding detectable man-made radionuclides in the water samples.
Detectable levels of gross alpha and beta radioactivity in the drinking
water wells are all below the EPA limits for drinking water.
No man-made gamma-emitting radionuclides have been detected in
drinking water wells or monitoring wells on the NTS. Naturally-occurring
radium-226 and radium-228 have been detected in several water supply wells
at levels below EPA drinking water standards.
The detailed methods and results of onsite radiological monitoring of
groundwater can be found in Chapter 4 of the most recently published
Nevada Test Site Environmental Report
[
PDF, 15 MB].
The
onsite surface waters
[ PDF,
15 MB] sampled for the presence of tritium, gamma-emitting man-made radionuclides,
and gross alpha and beta radioactivity include a containment pond system, sewage
lagoons, and natural springs.
A system of 5 containment ponds were constructed to collect and hold
water discharged from E Tunnel in Area 12 where nuclear testing was
conducted in the past. The water is perched groundwater that has
percolated through fractures in the tunnel system. Tritium concentrations in the E Tunnel effluent waters are elevated,
but they are lower than the limit allowed under state permit.
Concentrations of Sr-90, Cs-137, Pu-238, Pu-239+240 and Am-241 are also elevated.
The containment ponds are fenced and posted with radiological warning
signs. Because the ponds are available to wildlife, game animals on the
NTS are monitored (see Biota Monitoring).
Onsite sewage lagoons are monitored annually for tritium and
other radionuclides. No detectable levels of tritium or other
radionuclides have been found.
Radiological monitoring results for onsite surface waters can be
found in Chapter 4 of the most recently published
Nevada Test Site Environmental Report
[
PDF, 15 MB].
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