Genetic disorders in mice exposed to radiation in the vicinity of the Chernobyl nuclear power station.

Induced reciprocal translocations in spermatocytes of mice, either caught or exposed at the site, were observed at all levels of radioactive contamination around the Chernobyl nuclear power station. The frequency of reciprocal translocations was relatively low and increased linearly with increasing dose rate. Among 74 male mice exposed as early embryos, four reciprocal translocation heterozygotes were found. Furthermore, an increase in embryonic mortality and frequency of abnormal sperm heads was observed after termination of exposure, but these decreased rapidly with post-exposure time.     

污染预警综述及对放射性污染预警的启示

在分析目前环境污染中的地下水污染、土壤重金属污染等方面的预警系统和具体模型的基础之上,对污染预警系统产生的效果进行了评价,并以已有的污染预警模型的特点为指导,对放射性污染预警模型的建立提出了合理的建议,期望促进放射性污染预警模型的研究和完善。     

Long-term decline of 137Cs concentration in honey in the second decade after the Chernobyl accident

In the years 2001-2004 the (137)Cs activity was investigated in a total of 336 samples of different varieties of honey harvested in the Liguria Region of Northern Italy. Our purpose was to define (a) residual radioactive contamination following the Chernobyl accident and (137)Cs long-term decline, (b) correlation between (137)Cs activity and different honey varieties, and (c) correlation between (137)Cs activity and the prevailing geomorphological configuration in the collection areas. The mean (137)Cs specific activity was 4.33+/-5.04 S.D. Bq/kg. Chestnut honey showed higher levels of radioactive contamination, which were ascribed to the extensive, superficial and deep, root apparatus of the tree. Honey samples from acidic argillite soils, which withhold radionuclides after deposition and slowly release them to plants, also showed higher (137)Cs activity. Long-term decline was calculated at 456 days, a value lower than those published from different food sources in the years following the accident. The rate of long-term decline decreases with time.     

Interception, retention and translocation under greenhouse conditions of radiocaesium and radiostrontium from a simulated accidental source.

The behaviour of radioactive aerosols released from a severely damaged nuclear reactor and deposited on cereals was simulated under controlled conditions. 137Cs- and 90Sr-labelled aerosols were generated by volatilisation at high temperature of an artificially spiked pellet of depleted UO2. After cooling and maturation the aerosols were allowed to deposit on spring wheat (Triticum aestivum L. var. Arbon) cultures grown on lysimeters under greenhouse conditions. At the time of contamination the wheat plants were at different stages of development, from early vegetative growth (two leaves) until nearly mature (end of flowering). The estimated interception coefficient (micro) amounted to 13.1 m2 kg(-1); such a high value may be explained by the experimental conditions that created an over-saturated atmosphere during the contamination process and wet leaf surfaces. The first simulated rain, applied 6 days after the contamination, removed four times more 137Cs (54%+/-12 of the intercepted radionuclides) than 90Sr (15%+/-20) from the aerial parts. At harvest approximately 2% of the Sr and less than 1% of the Cs initially intercepted by the aerial parts is recovered for plants contaminated during the early development stages. A significantly higher proportion of the intercepted activity is still present for plants contaminated in the late development stages. The translocation to grains (TLF) increases when deposit occurs closer to the mature stage of the plant. The initial decrease of TLF values that we observed for strontium contamination in the earliest development stages is most probably due to the contribution of root uptake. Ploughing and re-sowing after the first rain, applied as a countermeasure reduced the 137Cs content in leaves and stems at harvest approximately 3 times but had no effect on the 90Sr content in vegetative organs. It reduced the 137Cs-contamination level in edible parts (grain) by a factor of 2 compared to the unploughed control, but doubled the 90Sr content.     

A robotic cutting tool for contaminated structure maintenance and decommissioning

With the global dependency on fossil fuels being undermined by growing prices and environmental concerns, nuclear power is returning as a solution for energy demands, however the increased cost of maintaining and updating ageing plants could render them nuclear alternative counter-economic. The development of tools specifically targeted at the maintenance field is vital to ensure the longevity and safety of existing power plants.This paper proposes a robotic tool capable of remotely cutting composite material structures. With design and engineering focused on the safety of the operator and automation, the proposed machine presents sufficient flexibility to be utilised in both maintenance and decommissioning of structures with low to medium levels of radioactive contamination.     

Relationship between heavy fuel oil phytotoxicity and polycyclic aromatic hydrocarbon contamination in Salicornia fragilis

Greenhouse experiments were carried out to study the effects of heavy fuel oil contamination on the growth and the development of Salicornia fragilis Ball and Tutin, a salt-marsh edible species. Plants were sampled in spring at the "Aber du Conquet" (Finistère, France), and artificially exposed by coating shoot sections with N degrees 6 fuel oil or by mixing it in their substratum. The impact of petroleum on plant development was followed by phytotoxicity assessments and PAH shoots assays. The plants exhibited visual symptoms of stress, i.e. chlorosis, yellowing, growth reduction and perturbations in developmental parameters. The contamination of plants by shoot coating appeared to be less than through soil. Moreover, the increase of the degree of pollution induced more marked effects on plants, likely because of the physical effects of fuel. However, bioaccumulation of PAHs in shoot tissues was also found to be significant, even at very low levels of contamination, and highly related to the conditions of exposure to oil. The strong relationships between the PAH contents of Salicornia plants and growth reduction suggest a chemical toxicity of fuel oil, compounds like PAHs being known to inhibit physiological processes in plants.     

Airborne radioactive materials and plants: A review

Airborne radioactive materials readily contaminate plant surfaces and thus are incorporated into the food chains. Most of the nuclear fission products and naturally occurring radionuclides in the air are carried on solid particles ranging in size from a few submicrons to several millimetres in diameter. Of many available mechanisms, rainfall plays a dominant role in the deposition and removal of radioactive particles from plants. Mechanisms for the deposition of submicron particles, which carry significant amounts of radioactivity, are still not very well understood. Available information on the physicochemical aspects of the retention of radionuclides by plants is inadequate in explaining radionuclide uptake and desorbability. Much of the work reported so far has been carried out on selected fission products only. There is a dearth of data pertaining to naturally occurring radionuclides, especially ²²²Rn and its daughters, significant amounts of which are released to the environment during uranium mining and milling operations. Radiation damage in plants is difficult to detect except at levels of contamination thousands of times higher than those attained in most real life situations. Existing reports give conflicting accounts of the damage induced by low-level radiation in plants.The literature data discussed in this review are presented as basic information needed for the conduct and interpretation of useful research.     

Heavy metal and pesticide content in commonly prescribed individual raw Chinese Herbal Medicines

Heavy metal and pesticide contamination has previously been reported in Chinese Herbal Medicines (CHMs), in some cases at potentially toxic levels. This study was conducted to determine general patterns and toxicological significance of heavy metal and pesticide contamination in a broad sample of raw CHMs. Three-hundred-thirty-four samples representing 126 species of CHMs were collected throughout China and examined for arsenic, cadmium, chromium, lead, and mercury. Of the total, 294 samples representing 112 species were also tested for 162 pesticides. At least 1 metal was detected in all 334 samples (100%) and 115 samples (34%) had detectable levels of all metals. Forty-two different pesticides were detected in 108 samples (36.7%), with 1 to 9 pesticides per sample. Contaminant levels were compared to toxicological reference values in the context of different exposure scenarios. According to a likely scenario of CHM consumption, only 3 samples (1%) with heavy metals and 14 samples (5%) with pesticides were found with concentrations that could contribute to elevated background levels of contaminant exposure. According to the most conservative scenario of CHM consumption, 231 samples (69%) with heavy metals and 81 samples (28%) with pesticides had contaminants that could contribute to elevated levels of exposure. Wild collected plants had higher contaminant levels than cultivated samples. Cadmium, chromium, lead, and chlorpyrifos contamination showed weak correlations with geographic location. Based on our assumptions of the likely mode of consumption of raw CHMs, the vast majority (95%) of the 334 samples in this study contained levels of heavy metals or pesticides that would be of negligible concern. However, given the number of samples with detectable contaminants and the range between the more likely and more conservative scenarios of contaminant exposure, more research and monitoring of heavy metals (especially cadmium and chromium) and pesticide residues (especially chlorpyrifos) in raw CHMs are advised.     

Soil migration, plant uptake and volatilisation of radio-selenium from a contaminated water table

The properties of (79)Se make it of likely potential importance in safety studies for geological disposal of radioactive wastes. Despite a substantial literature on toxic and nutritional aspects of selenium in the environment little consideration has been given to the behaviour of radioactive selenium and its potential transfer from a radioactive waste repository to the biosphere. Column experiments (15 x 50 cm), using a sandy loam soil, indicated that the upwards migration of (75)Se (as a surrogate for (79)Se) from a contaminated water table was dependent upon the redox status of the soil. Low redox conditions within the water table strongly limited upwards (75)Se soil migration, presumably due to the immobilisation of reduced Se species. Under natural conditions, (79)Se from a radioactive waste repository is therefore likely to accumulate at considerable depth. As a consequence, its absence from the rooting zone is likely to limit its transfer into plants. Nevertheless, the column experiments indicated that when an overlap between roots and soil contamination occurs, uptake into the plant is observed. Quantification of (75)Se volatilisation from the column surfaces suggested that this is a significant pathway by which (79)Se may move either directly from soil to the atmosphere, or from soil to plants and then to the atmosphere.     

Radioactive contamination of the Balchug (Upper Yenisey) floodplain, Russia in relation to sedimentation processes and geomorphology

The radioactive contamination of a riverine floodplain, heavily influenced by discharges from Krasnoyarsk-26, has been studied with respect to sedimentation processes and the geomorphology of the Upper Yenisey floodplain. The study was effected by implementation of a regime of in situ observations and measurements, sampling, and the interpretation of satellite images. The results of the study indicate that on the Balchug Bypass Floodplain, radionuclide contamination is primarily influenced by the thickness of the deposited sediments, and the area can be considered as two depositional environments. The Balchug floodplain area was contaminated due to sedimentation of radionuclide-contaminated alluvium, whose depositional regime significantly changed after the construction of a hydroelectric power station in 1967. Contamination levels are lower on the upstream part of the floodplain where sediment depth is less than 0.2-0.3 m, and this contamination started to accumulate in 1967, while the downstream part of the floodplain, exhibiting deeper deposits, displays higher levels of radionuclide contamination because radionuclides began to deposit here in 1958 when the Krasnoyarsk-26 Mining and Chemical Combine (KMCC) commenced operation. Radionuclide contamination of the floodplain is also related to the elevation of the floodplain, higher regions of the floodplain typically having lower contamination than low-lying areas, which tend to be frequently inundated with sediments being deposited during such inundations. Local relief, its orientation, and vegetation cover have also combined to form sediment traps with significantly higher radionuclide contamination. Lithological analysis combined with radiometric assay indicates a total 137Cs floodplain inventory of 33.7 GBq.     

Distribution of selected anthropogenic radionuclides (137Cs, 238Pu, (239,240)Pu and 241Am) in marine sediments with emphasis on the Spitsbergen-Bear Island area

Measurements of anthropogenic radionuclides in marine sediments can provide good estimates of past and present radioactive contamination of the marine environment. The Barents Sea is one of the world's richest ocean areas, and it is therefore of major interest for Norwegian fisheries to document the levels of radioactive contamination of this and adjacent ocean areas. In this study, concentrations of 137Cs, 238Pu, (239,240)Pu and 241Am were measured in marine sediments collected mainly in the Spitsbergen-Bear Island region. Additional samples collected in the deep Norwegian Sea and near the Greenland ice-edge have been included for comparison. The highest radionuclide levels were found near Spitsbergen, reaching over 50% higher than in adjacent areas. Determinations of the mineral content and particle size distribution indicate a relation between the content of clay minerals and radionuclide levels. The present study confirms earlier observations of elevated levels of 137Cs in sediments in the Spitsbergen-Bear Island area and documents elevated levels of 238Pu, (239,240)Pu and 241Am in these sediments. Using an exponential curve fit based on determinations of unsupported 210Pb in sediment cores, sedimentation rates of 0.28, 0.05 and 0.26 cm year(-1) were calculated at locations south of Spitsbergen, near the Greenland ice-edge and in the deep Norwegian Sea, respectively.     

Evidence for alternative exhaled elimination profiles of disinfection by-products and potential markers of airway responses to swimming in a chlorinated pool environment

Chlorine-based disinfectants protect pool water from pathogen contamination but produce potentially harmful halogenated disinfection by-products (DBPs). This study characterized the bioaccumulation and elimination of exhaled DBPs post-swimming and investigated changes in exhaled breath profiles associated with chlorinated pool exposure. Nineteen participants provided alveolar-enriched breath samples prior to and 5, 90, 300, 510, and 600 minutes post-swimming. Known DBPs associated with chlorinated water were quantitated by thermal desorption-gas chromatography-mass spectrometry. Two distinct exhaled DBP elimination profiles were observed. Most participants (84%) reported peak concentrations immediately post-swimming that reduced exponentially. A sub-group exhibited a previously unobserved and delayed washout profile with peak levels at 90 minutes post-exposure. Metabolomic investigations tentatively identified two candidate biomarkers associated with swimming pool exposure, demonstrating an upregulation in the hours after exposure. These data demonstrated a hitherto undescribed exhaled DBP elimination profile in a small number of participants which contrasts previous findings of uniform accumulation and exponential elimination. This sub-group which exhibited delayed peak-exhaled concentrations suggests the uptake, processing, and immediate elimination of DBPs are not ubiquitous across individuals as previously understood. Additionally, non-targeted metabolomics highlighted extended buildup of compounds tentatively associated with swimming in a chlorinated pool environment that may indicate airway responses to DBP exposure.     

Elemental mercury contamination survey in a chlor-alkali plant by the use of transplanted Spanish moss,Tillandsia usneoides (L.)

Atmospheric Hg⁰ contamination and the potential risk of occupational exposure were evaluated in a chlor-alkali facility by the use of transplanted Tillandsia usneoides. This plant species was selected since it presents some features that makes it useful for air monitoring purposes. After short-term exposure (15 days), control plants showed a mean concentration of 0.2 μg Hg.g⁻¹ whereas Hg values in transplants ranged from 1 to 10 400 μg.g⁻¹. This latter value was observed near an elemental Hg spillage. Even after exposure to toxic conditions plant metabolism was still operative, allowing the transplant technique to be employed to assess both Hg taken up through the stomata and Hg associated with particles deposited on the biomonitor.     

32P-postlabeling detection of DNA adducts in fish from chemically contaminated waterways

Fish were collected from sites in the chemically-contaminated Buffalo River, New York, and the Detroit River, Michigan. The sediments of these rivers have high levels of chemical contaminants, including polycyclic aromatic hydrocarbons (PAHs), and fish from these locations have high prevalences of liver cancer. To determine chemical-DNA interactions and a possible role for chemicals as a cause of the observed tumors, DNA was isolated from livers and was enzymatically digested to normal and adducted nucleotides. The DNA digests were enriched for hydrophobic, bulky adducts, either by preparative reverse phase high pressure liquid chromatography, or by selective nuclease P1 dephosphorylation of normal nucleotides. DNA-chemical adducts were then quantitated by 32P-postlabeling analysis. Regardless of the adduct enrichment procedure, the chromatograms derived from DNA of fish from polluted areas showed a diffuse, diagonal radioactive zone consisting, at least in part, of multiple overlapping discrete adduct spots. The behavior of the adducts in the diagonal radioactive zone and of their unlabeled precursors is consistent with their identification as nucleotide adducts of a variety of bulky, hydrophobic, aromatic genotoxic compounds. Analysis of bile demonstrated recent exposure to multi-ringed aromatic compounds.     

Quantum dot transport in soil, plants, and insects

Environmental risk assessment of nanomaterials requires information not only on their toxicity to non-target organisms, but also on their potential exposure pathways. Here we report on the transport and fate of quantum dots (QDs) in the total environment: from soils, through their uptake into plants, to their passage through insects following ingestion. Our QDs are nanoparticles with an average particle size of 6.5 nm. Breakthrough curves obtained with CdTe/mercaptopropionic acid QDs applied to columns of top soil from a New Zealand organic apple orchard, a Hastings silt loam, showed there to be preferential flow through the soil's macropores. Yet the effluent recovery of QDs was just 60%, even after several pore volumes, indicating that about 40% of the influent QDs were filtered and retained by the soil column via some unknown exchange/adsorption/sequestration mechanism. Glycine-, mercaptosuccinic acid-, cysteine-, and amine-conjugated CdSe/ZnS QDs were visibly transported to a limited extent in the vasculature of ryegrass (Lolium perenne), onion (Allium cepa) and chrysanthemum (Chrysanthemum sp.) plants when cut stems were placed in aqueous QD solutions. However, they were not seen to be taken up at all by rooted whole plants of ryegrass, onion, or Arabidopsis thaliana placed in these solutions. Leafroller (Lepidoptera: Tortricidae) larvae fed with these QDs for two or four days, showed fluorescence along the entire gut, in their frass (larval feces), and, at a lower intensity, in their haemolymph. Fluorescent QDs were also observed and elevated cadmium levels detected inside the bodies of adult moths that had been fed QDs as larvae. These results suggest that exposure scenarios for QDs in the total environment could be quite complex and variable in each environmental domain.     

Characterization of the frequency and nature of bleed air contamination events in commercial aircraft

Contamination of the bleed air used to pressurize and ventilate aircraft cabins is of concern due to the potential health and safety hazards for passengers and crew. Databases from the Federal Aviation Administration, NASA, and other sources were examined in detail to determine the frequency of bleed air contamination incidents. The frequency was examined on an aircraft model basis with the intent of identifying aircraft make and models with elevated frequencies of contamination events. The reported results herein may help investigators to focus future studies of bleed air contamination incidents on smaller number of aircrafts. Incident frequency was normalized by the number of aircraft, number of flights, and flight hours for each model to account for the large variations in the number of aircraft of different models. The focus of the study was on aircraft models that are currently in service and are used by major airlines in the United States. Incidents examined in this study include those related to smoke, oil odors, fumes, and any symptom that might be related to exposure to such contamination, reported by crew members, between 2007 and 2012, for US‐based carriers for domestic flights and all international flights that either originated or terminated in the US. In addition to the reported frequency of incidents for different aircraft models, the analysis attempted to identify propulsion engines and auxiliary power units associated with aircrafts that had higher frequencies of incidents. While substantial variations were found in frequency of incidents, it was found that the contamination events were widely distributed across nearly all common models of aircraft.     

The significance of Cd in hair: Influence of the level of intake and the external contamination in the rat

A standardized procedure in the rat was used to study the deposition of Cd in newly grown hair and its relation to ingested Cd. The internal deposition and the absorption in the intestine were evaluated using ¹⁰⁹Cd and ^115mCd as radiotracers. Stable Cd was supplied at different levels with the drinking water and analysed in hair, and in some cases also in the liver and the kidneys, by flameless atomic absorption spectrometry. It was demonstrated by the tracer that the internal deposition is proportional to the amount ingested. The time of exposure and the body burden had no influence. The external contamination with stable Cd was very high in animals kept conventionally, but can be reduced by using metabolic cages. It was, however, not possible to appreciably isolate the “background level”, i.e. Cd was also found in hair of “unexposed” animals kept in metabolic cages. A significant increase above “background” could only be achieved at a Cd intake of > 1 mg/d. Following a prolonged period of exposure, levels of Cd newly deposited in hair were reduced to background levels, within a few days, in spite of very high Cd concentrations in the liver and kidneys of these animals. It is concluded that the internal deposition of Cd in hair is proportional to the amount absorbed, and that it is largely masked by the external contamination and the relatively high “background” level; the internal deposition only reflects intake. The body burden or the Cd accumulated in specific organs has no influence on the deposition of Cd in hair.     

Uptake and release of polynuclear aromatic hydrocarbons by short-necked clams (Tapes japonica)

We studied the uptake and release of polynuclear aromatic hydrocarbons (PNAHs) by shortnecked clams (Tapes japonica) under the following conditions: exposure to PNAHs dissolved in artificial sea water, in the sediments and in natural sea water. Nine PNAHs, i.e. anthracene, pyrene, benz(a)anthracene, benzo(e)pyrene, benzo(b)flouranthene, benzo(a)pyrene, benzo(g,h,i)perylene, dibenz(a,h)anthracene and 3-methylcholanthrene, were dissolved in artificial sea water at a concentration of 10 ppb each. Index clams were placed in PNAH containing sea water for 7 days and then transferred into the clean artificial sea water for release. Maximal uptake of these substances ranged from 150 to 560 ppb and the release rate (half life) was 4–8 days. While six PNAHs were accumulated by the clams from the sediments during the 7-day exposure, levels of accumulated PNAHs were positively correlated to the PNAH concentrations in the sediments. High accumulation of pyrene, benzo(e)pyrene and benzo(b)fluoranthene were found and their levels in the sediments were correspondingly high. The levels of PNAHs fell to initial levels after the 14-day exposure to the PNAH free sea water. In the PNAH-uptake experiments conducted in the sea, pyrene 14 times the initial amount was accumulated in clams, while the other six compounds were accumulated at 3–8 times. All the PNAH amounts in the clams were determined by HPLC with a fluorescence detector. The results suggest that PNAHs are readily accumulated in clams and these PNAHs in the clams may be a useful biological indicator of PNAH contamination.