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PubMed1982

137Cs concentrations in northern Alaskan Eskimos, 1962-79: effects of ecological, cultural and political factors.

Concentrations of worldwide fallout 137Cs were measured in the lichen-caribou-Eskimo food chain of northern Alaska during the period 1962-79. Pronounced inputs of fallout occurred after major nuclear weapons tests in the atmosphere and 137Cs was transmitted through the food chain to Eskimos with about a 2-yr delay due to environmental parameters. Caribou (Rangifer tarandus) meat sampled during spring harvest contained 4 times the 137Cs concentration of lichens obtained from their winter range. Calculated caribou meat ingestion rates of Anaktuvuk Pass Eskimos during winter ranged from approximately 1 kg/day in 1964 to 0.16 kg/day in 1977. Several environmental factors affected seasonal patterns and amounts of 137Cs transferred through the food chain. Maximum 137Cs concentrations of approximately 20 nCi/kg body weight in ESkimos occurred in 1964 and have now decreased to approximately 0.5 nCi/kg, largely because of cultural and political factors. Radiation doses from 137Cs body burdens during the study period ranged from 60 mrad/yr in 1962 to approximately 140 mrad/yr during the 1962-64 maxima and decreased to 8 mrad/yr in 1979.

Alaska↗
PubMed1982

Prediction of 90Sr body burdens and radiation dose in Anaktuvuk Pass Alaska Eskimos due to fallout.

Strontium-90 concentrations in skeletons of Eskimo residents of Anaktuvuk Pass. Alaska during 1954-79 were predicted from two models based on (1) Sr kinetics in human bond and (2) estimated annual 90Sr ingestion rates via caribou meat. Predicted skeletal burdens of adult Eskimos gradually increased through 1961 and then rapidly achieved maximal values during 1964-66, reflecting fallout 90Sr levels in caribou meat which contributed 80-97% of dietary 90Sr intake. Concentrations of 90Sr in male Eskimo bone samples were similar using either model. Predicted values in vertebrae of adult Eskimo males were slightly lower than values reported in New York City adults until 1980 and subsequently declined by 9% per yr, while samples from adults in New York City and San Francisco declined by 6 and 5%, respectively. Predicted skeletal burdens in Anaktuvuk Pass residents born in 1954 and 1959 achieved maxima in 1971 and 1974, respectively; concentration in children born in 1964 were still increasing in 1979 but had achieved a lower level than older age cohorts. Estimated radiation dose rates to adult skeletons during 1964-66 were 13-15 mrad/yr based on predicted vertebrae 90Sr concentrations. Those dose rates were less than or equal to 1% of recommended ICRP limits for general populations.

Adolescent↗
PubMed1982

Biokinetic behavior of technetium in the red abalone, Haliotis rufescens: a re-assessment.

The biokinetic behavior of 95mTc in the red abalone, Haliotis rufescens, is reviewed in light of recent experiments with other molluscs. Additional experimentation has confirmed that, when uptake is directly from labeled seawater, abalones exhibit concentration factors in excess of 100. Bivalve molluscs under the same experimental conditions have concentration factors that do not exceed 2. However, uptake and loss kinetics in the abalone cannot be described by a single compartment model as had been previously advanced. Assimilation of 95mTc by abalones following a single feeding of labeled macroalga, Nereocystis luetkeana, is approximately 45% and loss kinetics are similar to those observed following direct uptake from seawater.

Animals↗
PubMed1983

The relative importance of uptake and surface adherence in determining the radionuclide contents of subterranean crops.

The adherence of Pu-bearing particles to external surfaces of carrots, turnips, red potatoes, and sweet potatoes accounted for greater than or equal to 93% of their total Pu content. Uptake, which was measured as Pu content in peeled crops, accounted for less than or equal to 7%. Plutonium concentrations in most peeled crops were below background, and consequently, uptake could not be conclusively demonstrated. However, uptake accounted for most of the 137Cs, 40K, and 226Ra contents of subterranean crops. Concentration ratios for total radionuclide contents (i.e. surface adherence plus uptake) ranged from 3.9 X 10(1) for 40K, to 1.1 X 10(-2) for 239, 240Pu. Approximately 1.5 X 10(-3) pCi 239, 240Pu adhered per cm2 of subterranean crop surface per 1 pCi Pu/g of soil.

Cesium Radioisotopes↗
PubMed1983

The metabolism of tritium and water in the lactating dairy cow.

Two lactating Friesian cows received tritiated water (19 nCi of tritium per ml) to drink for 25 days. Urine and milk samples were collected and analyzed for tritium content. Plateau levels in milk water, and in milk fat, lactose and casein were reached in about 18 days. Tritium concentration in milk water and urine water was about 82% that in drinking water, indicating dilution with water from food and metabolic processes, and as a result of exchange through lungs and skin. At steady state, tritium activity in milk fat, lactose and casein was about 30, 28 and 15% of that in drinking water on a weight basis; at this time, about 1.5% of the daily ingested tritium appeared in one litre of milk in both animals. Comparison of the specific activity of the various milk constituents with the specific activity of the body water showed that the highest tritium incorporation occurred in lactose (0.58), followed by milk fat (0.36) and casein (0.27). Tritium incorporation in milk dry matter (0.45) is considerably higher than in most tissue components of several mammalian species after continuous ingestion of THO as reported in the literature. Tritium levels fell rapidly in milk and urine after the administration of THO was stopped, with half-times of around 4 days for the rapid components in all milk constituents. A slow component of 44 days, 225 days and 24 days half-time was found in milk water, milk fat and casein respectively.

Animals↗
PubMed1983

Deposition and retention of 141Ce and 134Cs aerosols on cool desert vegetation.

Deposition velocities and retention times were obtained for submicron aerosols of 141Ce and 13l4Cs deposited on two cool desert plant species, big sagebrush (Artemisia tridentata) and bottlebrush grass (Sitanion hystrix). Mean deposition velocities for sagebrush were 0.18 cm/s (141Ce) and 0.13 cm/s (134Cs). Mean deposition velocities for grass were 0.022 (141Ce) and 0.023 cm/s (134Cs). Species differences were significant (p less than 0.05), however, nuclide differences were not significant. The loss of activity on the vegetation consisted of two components. A rapid initial loss was found with effective half-times of approx. 1 d (1-8 d for 141Ce and 0.6 d for 134Cs) on sagebrush and approx. 2 d (2.8 d for 141Ce and 2.3 d for 134Cs) on grass. This was followed by a slower, long-term loss with effective half-times ranging from 11 d for 141Ce and 15 d for 134Cs on sagebrush to 9 d for 141 Ce and 11 d for 134Cs on grass.

Aerosols↗