Evaluating Radiological Dose Rates to NTS Plants
and Animals
NNSA evaluates the radiological dose to plants, aquatic animals, and
land animals on the NTS which may be exposed to radiation from past or
present site operations. This evaluation is done by using both current
and historical routine environmental monitoring data collected on the
NTS. DOE Standard 1153-2002, “A Graded Approach for Evaluating Radiation
Doses to Aquatic and Terrestrial Biota,” was developed by DOE’s
Biota
Dose Assessment Committee to assist in such evaluations at all DOE
sites.
The DOE has established dose limits for plants and wildlife. They are
the maximum dose rates that are expected to have no direct, observable
effect on plant or animal reproduction. These limits are:
Dose limit for plants = 1 rad/day
Dose limit for aquatic animals = 1 rad/day
Dose limit for land animals = 0.1 rad/day
Dose evaluations are based on the concentrations of radionuclides in
soil, water, and sediment of known contaminated habitats and on plant
and animal distributions within those habitats. Initial evaluations
indicate that plants and animals on the NTS are not expected to be
exposed to radiation doses harmful to their populations. However, the
initial dose evaluation conducted for plants and animals in the
contaminated area around Sedan, a legacy Plowshare site in northwest
Yucca Flat, indicated that further dose assessment is necessary.
Field collections of plants and animals and analysis of their tissues
for radionuclides are performed annually to augment the dose evaluation
results based on soil, water, and sediment concentration data. At Sedan,
plant samples have been collected and analyzed for radionuclides. The
results suggest that plants around Sedan receive doses less than the
upper limit of 1 rad/day.
Work continues on identifying and sampling plant and animal
populations in contaminated habitats of the NTS. The work goals are to
verify the dose evaluations based on existing soil, water, and sediment
data and identify those populations that may be receiving higher,
harmful dose rates.
The methods and results of NTS plant and animal dose evaluation
activities can be found in the most currently published
Nevada Test Site Environmental Report
[
PDF, 9 MB].
Refer to Radiological Monitoring of
Plants and Animals for more information
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