Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FOOD CONTAMINATION, RADIOACTIVE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed1983

Preliminary observations on californium-252 behaviour in sea water, sediments and zooplankton.

We carried out radiotracer experiments on the behaviour of 252Cf in the marine environment. The particulate fraction of californium in sea water approached 45% after four days. Californium rapidly adsorbed onto marine coastal and deep-sea sediments with Kd values from 1.4 X 10(4) to greater than or equal to 1 X 10(5). The concentration of 252Cf in euphausiids reached near-equilibrium factors of 3 X 10(2) in water after one week; in contrast, the assimilation from food was very low. Excreted fecal pellets, molts and zooplankton carcasses are potentially important vectors for californium re-distribution in the oceans.

Animals↗
PubMed1983

Transfer of 226Ra, 210Pb and uranium from soil to garden produce: assessment of risk.

A study of gardens contaminated by uranium processing wastes was carried out in the town of Port Hope, Ontario, during the summer of 1976. Concentrations of 226Ra, 210Pb, and total uranium were measured in soils and in garden produce. Highest concentrations were found in root and stem vegetables and, for radium, also in leafy vegetables. Fruit generally showed the lowest values. Uptake was consistent with a linear dependence on soil concentration. Mean concentration factors of 1.1 X 10(-3), 0.37 X 10(-3), and 0.075 X 10(-3) were obtained for 226Ra, 210Pb, and uranium, respectively. The highest estimated dose to an individual who ingested produce from a contaminated garden was 68 mrem/yr to bone surface from 226Ra. The implications of these findings for other communities affected by nuclear fuel-cycle operations are discussed.

Food Contamination, Radioactive↗
PubMed1983

Age dependent concentration of 226Ra in human bone and some transfer factors from diet to human tissues.

The concentration of 226Ra in more than 1000 human bone samples, still born infants, fetuses, blood, mixed diet, drinking water and mineral water has been measured. An age dependence of 226Ra concentration in human bone could be demonstrated. Up to an age of 20 yr two maxima of 226Ra concentration in bone occur, coinciding with the increased velocity of skeleton growth. Normally, the main source for uptake of radium by man is food. In Germany the transfer factor from diet to bone is about 0.098. Compared with data from literature for other countries, mainly the U.S.A., the German value is higher by a factor of about 1.5. This difference may be due to the lower calcium uptake in Germany which leads to higher resorption of radium. Two methods for measuring natural radium concentrations is biological material and water samples are briefly described: a gamma-gamma-coincidence method for indirect measurement of 226Ra via the short lived 214Bi(RaC) and an alpha-spectrometric method for direct measurement of the alpha-emission of 226Ra.

Adolescent↗
PubMed1983

Iodine-129 in mule deer thyroids in the Rocky Mountain West.

Thyroids from mule deer (Odocoileus hemionus) were collected in New Mexico, Colorado, Wyoming and Idaho and 129I/127I atom ratios were determined. Iodine-129/127 atom ratios were significantly (P less than 0.005) different among states. Ratios in Wyoming and Idaho control thyroids were significantly (P less than 0.05) larger than ratios in New Mexico and Colorado. Fallout from past atmospheric nuclear tests at the Nevada Test Site is suggested as a possible explanation for the differences in ratios. Average 129I/127I ratios in thyroids of other large mammals collected 54 km west and 116 km northeast of the Idaho National Engineering Laboratory (INEL) in south eastern Idaho were up to 15 times those found in control thyroid samples from Idaho. Atmospheric effluents from the Idaho Chemical Processing Plant located on the INEL were likely responsible for the increased ratios in animals collected in the INEL vicinity. Although of no health consequence to the animals, 129I in deer thyroids may be a sensitive indicator of contaminants from nuclear fuel reprocessing plants and atmospheric nuclear tests or accidents.

Animals↗
PubMed1983

Iodine-129 uptake and effects of lifetime feeding in rats.

Irradiation of thyroid glands in rats at a dose rate of approximately 1 rad/day from continually ingested 129I resulted in no significant increase in thyroid tumors compared to controls, nor in other thyroidal effects, nor was there any difference in longevity between the two groups. Marked decreases in 131I uptake by thyroid glands of 129I-fed rats were observed, but these decreases reflected "blocking" of the thyroid by the large quantities of iodine required because of the low specific activity of 129I. In view of the lack of effects on the thyroid gland invoked by lifetime exposures to 129I, and considering the low specific activity of the radionuclide and the limited capacity of the thyroid gland for iodine, the hazard from 129I appears to be extremely limited.

Administration, Oral↗
PubMed1983

Levels of 226Ra, 210Pb and total U in fish near a Saskatchewan uranium mine and mill.

Radionuclide levels in fish from the Beaverlodge Lake area, Saskatchewan, Canada, varied significantly among lakes, species and tissues, but did not vary with fish sex or age. Fish from lakes affected by an operating uranium mine and mill had radionuclide levels one to two orders of magnitude above levels in fish from an uncontaminated control lake. Concentrations were greatest in white suckers, intermediate in lake whitefish, and low in lake trout. Skin and bone contained the highest radionuclide levels; levels in flesh were much lower. The mean ash-weight concentration of 226Ra in non-control, eviscerated, whole fish was 9.3, 1.8 and 0.8 pCi X g-1 in white suckers, lake whitefish and lake trout respectively. Mean 210Pb levels for those species were 4.0, 1.4 and 0.5 pCi X g-1, while U content was 96.8, 28.2 and 5.8 micrograms X g-1, respectively. Radium-226 content in forage fish ranged from 9.7-70 pCi X g-1. Lead-210 levels ranged from 3.9-55.0 pCi X g-1, while U levels ranged from 15-119 micrograms X g-1. Bioconcentration factors varied among sites, species and tissues. The primary radionuclide transfer pathway appears to be via sediments, either through direct contact or through food organisms. Bottom-feeding species had the highest radionuclide levels while piscivorous fish had the lowest levels. The internal dose rate to non-control fish are comparatively low; any effects are likely to occur at the genetic level.

Animals↗
PubMed1984

Rainsplash as a mechanism for soil contamination of plant surfaces.

We characterized the physical transport of soil, and therefore contaminants attached to the soil, onto vegetative surfaces due to rainsplash. Soil accumulation by tomato plants (Lycopersicon esculentum) was investigated as a function of soil particle size, rainstorm characteristics, foliage height, surface area and canopy cover of the plants. No soil particles greater than 105 micron in diameter were detected on the plants. Most of the soil was splashed no higher than 40 cm above the ground surface. Linear relationships were observed for concentrations of less than 53 micron soil on vegetation and certain rainfall characteristics. Data from this study, as well as ancillary calculations, provide evidence that a significant fraction of surficial contamination of foliage may be attributed to the rainsplash mechanism.

Food Contamination, Radioactive↗
PubMed1984

Plutonium contents of broadleaf vegetable crops grown near a nuclear fuel chemical separations facility.

Among agricultural crops, broadleaf vegetables are particularly prone to intercept and retain aerially released contaminants. The plutonium concentration of four broadleaf crops (broccoli, cabbage, lettuce and turnip greens) was determined, when grown in close proximity to a nuclear-fuel chemical-separations facility. Concentrations varied among species, apparently influenced by the crop morphology, with Pu concentrations increasing in the sequence: cabbage less than broccoli less than turnip greens less than lettuce. Washing of the crops significantly reduced the Pu concentration of lettuce, but had no effect on Pu concentration of broccoli and cabbage. The vast majority of Pu found in the crops was due to direct deposition of recently released Pu and resuspension of Pu-bearing soil particles, and was not due to root uptake. Resultant doses from consumption are small relative to the annual background dose.

Food Contamination, Radioactive↗
PubMed1984

Plutonium in Finnish Lapps--an estimate of the gastrointestinal absorption of plutonium by man based on a comparison of the plutonium content of Lapps and southern Finns.

The plutonium body burden of five male Lapps was determined through radiochemical analysis of bone, liver and lung samples, and compared with the body burden of male southern Finns. Tissue burdens of plutonium were found equal in the Lapps and southern Finns. The mean content of 239,240Pu in bone (ribs), liver and lung of the Lapps was 0.045, 0.42 and 0.033 pCi/kg wet wt (1.7, 15.5, 1.2 mBq/kg), respectively. The average body burden of plutonium in the Lapps was 1.1 pCi (41 mBq). The 137Cs, 90Sr, 210Po and 210Pb contents of tissue samples were analyzed to estimate the amount of reindeer tissue consumed by the Lapps studied. The 137Cs content in liver and lung of the Lapps was, on the average, 2160 and 1180 pCi/kg wet wt (79.9 and 43.7 Bq/kg), respectively. In southern Finns both liver and lung content of 137Cs was less than 50 pCi wet wt (less than 1.9 Bq/kg). For 210Po, the liver and lung values were 86.2 and 8.2 pCi/kg wet wt (3.2 and 0.3 Bq/kg) in the Lapps and 15.4 and 3.9 pCi/kg wet wt (0.6 and 0.1 Bq/kg) in southern Finns, respectively. The inhalation intake of 239,240Pu of male Lapps during the period 1954-1978 was about 13 pCi (0.48 Bq) and that of southern Finns about 18 pCi (0.67 Bq). The estimated values for dietary intake were 535 pCi (19.7 Bq) and 36 pCi (1.3 Bq), respectively. The fractional absorption factor of 239,240Pu from the GI tract of man was estimated to be (8-9) X 10(-4), which is somewhat higher than that presently suggested by the ICRP for soluble plutonium compounds (1 X 10(-4)).

Adult↗
PubMed1984

Field and greenhouse experiments on the fate of technetium in plants and soil.

The behavior of 95mTc in plants and in a Captina silt loam soil following a single application of the pertechnetate form of the radionuclide to bare soil was compared between field and greenhouse conditions. Over a period of approx. six months, the net uptake of 95mTc by plants from undisturbed, intact soil in the greenhouse was about a factor of 10 greater than that in the field. Sieving the soil through a 2-mm mesh screen before potting and then planting new grass further increased plant uptake of 95mTc by approx. a factor of 20 relative to the field. Uptake by new grass was increased even more by decreasing the pot size. Most of the 95mTc applied to soil in the field or the greenhouse remained in the top 4 cm of the profile. Soon following application to soil, pertechnetate was transformed, or otherwise immobilized, such that extractions with 0.01 M CaCl2 recovered only a portion of the 95mTc present in soil. The extractability of 95mTc from soil using CaCl2 decreased over time as did 95mTc concentrations in vegetation. The pertechnetate applied to soil appeared to be converted over time to a less soluble and therefore less bioavailable form.

Animal Feed↗
PubMed1984

Concentration of orally administered and chronically fed 95mTc in Japanese quail eggs.

A chronic feeding study using 95mTc incorporated into alfalfa and an acute study where 95mTc was amended to alfalfa showed that about 8.4% of ingested Tc was transferred to eggs. After 10 days of chronic feeding, 80% of the Tc was in yolk, 20% in albumin and less than 1% in shell and associated membranes. At necropsy, technetium concentrations in the three largest oocytes were nearly equal. The biological half-time for Tc was about one to two days in acute studies. Results from the chronic feeding study also indicated that Tc levels in albumin reach a maximum between three and five days while maximum yolk concentration is attained in about six to seven days. Albumin concentrations declined about 20-50% after Day 6.

Administration, Oral↗
PubMed1984

Nuclear fuel-cycle radionuclides in raptor castings: implications for environmental monitoring.

Our sampling results indicate that raptor castings (regurgitated material containing the nondigestible remains of prey) faithfully reflect the composition of known environmental gamma-emitting radionuclides. The castings are easily obtainable and provide a way to monitor for the presence of biologically available radionuclides. Raptor castings can also provide a useful adjunct to existing monitoring programs where small mammal burrowing into buried waste may occur.

Animals↗
PubMed1985

Transport of elements from soil to human diet: an alternative approach to pathway analysis.

Transport from soil to human dietary intake is conventionally treated by analyzing the various pathways through uptake by plant roots and transfer from animal feed into milk and meat. An alternative approach is proposed requiring only the average daily human ingestion of each element and its abundance in soil, both readily available for most elements. The two methods are compared quantitatively and give results consistent within a mean factor of four, which is roughly the standard deviation in estimates from the pathway analysis. Neither method gives consistently larger or smaller transfer rates. Each method has important advantages in some applications.

Animal Feed↗
PubMed1985

A field study of Ra accumulation in trout with assessment of radiation dose to man.

The purpose of this study was to determine the concentrations of 226Ra in edible fish from surface ponds near an open pit U mine. Because one reclamation plan for the U mine proposed formation of an artificial lake in the open pit, potential radiation dose to man from ingestion of fish needed to be investigated. Trout were collected from four existing ponds which varied in mean 226Ra concentration from 12-33 pCi/l. and in Ca concentration from 30-330 mg Ca/l. Radium and Ca accumulation in trout flesh, skin, fins and bone were measured. Geometric mean concentrations of 226Ra in trout flesh from four ponds ranged from 6.3-30 pCi/kg wet weight. The distribution of Ra in the trout body was similar to that of Ca. Of the total 226Ra in trout carcasses, 6% was in flesh, 25% was in skin, 28% was in fins, and 41% was in bone. Mean concentration factors for 226Ra in trout flesh from the four ponds ranged from 0.29-2.5. Bone concentration factors were up to 260 times higher than for flesh. Observed ratios (Ra/Ca in fish tissue divided by Ra/Ca in water) were used to normalize the differences in Ca availability among the locations. Observed ratios were higher in all tissues of fish which had been in the ponds for a longer time, indicating that 226Ra concentrations in fish may increase with continued exposure to the nuclide. The calculated dose equivalent commitment to human endosteal tissue ranged from 0.2-2 mrem per fish consumed, depending on the assumed dietary and environmental parameters. Neglecting the consumption of trout skin underestimated the ingestion dose from 226Ra by a factor of 5-10. Estimated annual dose equivalent rates to human endosteal tissue ranged from 1.0-83 mrem/yr for an individual who consumed one fish per week for a 50-yr period. The dose to man from ingestion of 226Ra in fish would not likely preclude the establishment of a recreational lake at this site.

Animals↗
PubMed1985

The origin of I in soil and the 129I problem.

It is widely believed that the I in soil is derived from the I in oceans by evaporating-atmospheric transport-washout by rain over land, rather than from the I in rock when the latter is weathered into soil. Since human I burdens are derived largely from soil by plant root uptake into food, this implies that the specific activity of 129I in the I of human thyroids will be the same as that in the oceans, whereas it would be similar to that in rock (much lower) if the I in soil were derived from weathering of rock as is the case for other heavy trace elements. The bases for the oceanic origin theory are analysed and found not to be in accord with modern data. Recent data shows no correlation between concentration of I in soil and proximity to oceans, which argues strongly against the oceanic origin theory. Some problems with long-distance atmospheric transport are pointed out. It is shown that the balance between I input to soil during soil formation by rock weathering and output from soil by erosion leaves little room for contributions from oceanic sources. It is concluded that only a small fraction of the I in soil is of oceanic origin. Most estimates of very long-term effects of 129I on human health are therefore several times too high.

Food Contamination, Radioactive↗
PubMed1985

Survey of radionuclides in foods, 1978-1982.

Samples from the U.S. Food and Drug Administration's total-diet, market-basket program, samples of imported foods, and samples collected near nuclear power plants were analyzed for radionuclides. Most radionuclides were below the limit of detection for a majority of the samples; however, data are reported for 3H, 90Sr and 137Cs in certain samples. Generally a downward trend is observed for 90Sr when data for the 5-yr period were compared. The total dietary intake of either 90Sr or 137Cs is well within Range I of the Federal Radiation Council (FRC) radiation protection guides for these radionuclides.

Adult↗
PubMed1985

Food-chain transfer of U-series radionuclides in a northern Saskatchewan aquatic system.

Levels of TotalU, 226Ra, and 210Pb in water, sediments, insects and fish were measured in a stream and a lake affected by U mill effluents and in three uncontaminated systems (one creek and two lakes). Radionuclide levels were significantly elevated in water, sediments and biota at contaminated sites. Radionuclide concentration declined with each successive trophic level due primarily to very low assimilation efficiency. Fish radionuclide concentrations varied with season but did not vary with age or year of sampling. Distribution coefficients were high; therefore, a large proportion of radionuclides entering the systems go to the solid phase. Organisms feeding on or near sediments had higher radionuclide levels than pelagic species. There is a potential for long-term cycling of radionuclides from sediments through food chains due to low flux and sedimentation rates. With the exception of water----insects and water----fish all transfer coefficients (TC) were low, usually less than one. Control TCs were greater than TCs in contaminated areas. Radium-226 and 210Pb TCs declined dramatically at the insect-fish level. Uranium uptake from water by insects and fish was much less than 226Ra or 210Pb uptake. Uptake from sediments was similar for all nuclides in insects but 210Pb sediment-fish TCs differed from 226Ra or U TCs. The critical pathway in the contaminated area was sediments----insects----forage fish----whitefish----man. Estimated internal dose rates to large fish in the contaminated area were 1-2 rad/y. Dose to humans from consumption of one fish serving per week for 1 y was 2% of the International Commission on Radiological Protection (ICRP) annual limit for the general public.

Animals↗
PubMed1985

The suitability of transfer coefficients used for stochastic calculations in radioecology.

In radioecology, stochastic calculations are used to an increasing extent. It is shown that transfer coefficients which are defined as concentration ratios are not suited for stochastic calculations, at least for essential elements and their antagonists. The reason is that essential elements are regulated in plants and animals whereby their concentrations vary within narrow limits, rather independent of the concentrations in the source compartment. For a more accurate description of the transfer of radionuclides, it is proposed to include the concentrations of the essential elements in the source and target compartments into the transfer equation which leads to the specific activity model. This model has already been proposed by Comar et al. in 1956. It seems to work accurately for the transfer into animals and their products as well as into plants. Examples of its applicability are presented and discussed. Furthermore stochastic calculations seem to be more reasonable with this model.

Animals↗