Showing papers in "Journal of Radioanalytical and Nuclear Chemistry in 1995"

Natural radioactivity in Zambian building materials collected from Lusaka

Abstract: Samples of natural and manufactures building materials collected around Lusaka have been analyzed for natural radionuclides using γ-spectrometry. A simple comparison of the specific radioactivities of primordial radionuclides in these materials to the world averages for soil (25 Bq kg−1238U, 25 Bg kg−1232Th, 370 Bq kg−140K and 89 Bq kg−1 Raeq) shows that, of the nine types of samples analyzed, only burnt clay bricks (for238U,232Th and40K), cement roofing tiles (for238U), building and river sands (for232Th and40K) have greater activities than does soil. Radiological evaluation of specific radioactivities in these materials indicates that all materials meet the external γ-ray dose limitation of 1.5 mSv y−1, that is, all samples have a radium equivalent activity of less than 370 Bq kg−1.

Evidence for radon transport by carrier gas through faulted clays in Italy

Abstract: Extensive soil-gas surveys in sedimentary basins in Italy were performed to study the potential of some naturally occurring gases as indicators for concealed fracture zones, hydrocarbon and geothermal fluids. One conclusive result is a positive correlation between anomalously high values of radon and carbon dioxide in the soil-air over faults. The correlation coefficient for 1173 gas samples is 0.41. Statistically derived contourlines of Rn and CO2 anomalies show similar locations, shapes and directions. Fairly good Rn−CO2 coupling evidence appears even on a point-to-point analysis. Furthermore, it was recognized that the highest Rn values are in contrast to the low Ra content of the underlying clayey rocks and that conventional Rn transportation mechanisms seem to be inadequate for the clay sequences. All these facts strongly suggest that Rn is transported from the subsoil, through fault-linked pathways, by carrier gases of which CO2 could be one of the major components. The theory of geogas microbubbles is a possible explanation of the observed results. The carrier effect of ascending microbubbles can explain both the origin of soil-gas Rn anomaly and the Rn−CO2 coupling phenomenon.

Sorption of uranium and other heavy metals on hydroxyapatite

Abstract: The immobilization of UVI and PbII from aqueous solutions in a solid phase by interaction with calcium hydroxyapatite has been studied in batch experiments with increasing contact times. The results were compared with those previously found for CdII. All these elements are able to be efficiently immobilized by such a method. The sorbed quantities vary in the order Pb>U>Cd. The sorption mechanisms are element dependent. The dominant mechanisms are: dissolutionprecipitation with formation of an amorphous or microcrystalline phase for U, dissolution-precipitation with the formation of two new crystalline phases and with possible incorporation into the initial apatite for Pb, and intracrystalline diffusion and exchange for Cd.

“Multitracer” a new tracer technique — Its principle, features, and application

Abstract: We established “Multitracer”, a new versatile radiotracer technique, for simultaneous tracing of a number of elements in various chemical, environmental, and biological systems. Metal foil targets (typically Au, Ag, Ge, Cu and Fe) are irradiated with C, N, or O ions accelerated up to 135 MeV/nucleon by RIKEN Ring Cyclotron. Radiochemical procedures have been developed to remove the target material leaving the nuclides as Multitracer solutions containing various radionuclides of Be, Na, Mg, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Te, I, Ba, Ce, Pm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, W, Re, Os, Ir, Pt, and Hg. Multitracers enable efficient tracing of a number of elements, and comparison of their behavior under strictly identical experimental conditions. Such features will be demonstrated by means of an example of application to a model experiment for the study of removal mechanism of various elements from the ocean.

The measurement of the isotopic composition of plutonium in an Irish Sea sediment by mass spectrometry

Abstract: Samples from sediment cores, collected from a site close to the Sellafield outfall and dated using conventional γ- and α-spectrometry, have been analysed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Thermal Ionisation Mass Spectrometry (TIMS). This has provided information on the isotopic composition of plutonium in the liquid discharges from Sellafield; such information is not available using conventional α-spectrometry alone. There was very good agreement between the240Pu/239Pu ratios obtained by the two MS methods. More recent discharges have been characterised by a progressive decrease in the relative proportion of239Pu.

Improved separation method for determining actinides in soil samples

Abstract: Radionuclides have been identified as a significant source of contamination at many United States Department of Energy (DOE) sites. As a result, reliable and accurate methods to determine actinide content in environmental samples have become increasingly important. Therefore, an improved analytical scheme using a series of actinide-selective extraction chromatography (Tru-Spec™, Teva-Spec™) and ion-exchange (Diphonix™) resins was designed to satisfy the requirements of both alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). Alpha spectrometry required the sequential isolation of the actinides, whereas ICP-MS required only a group separation of the actinides. The separation schemes were designed to allow analysis of the actinides in soil, whether the soils were acid leached or totally dissolved through fusion. For those analytes present as contaminants (239/240Pu,241Am), the laboratory results agreed favorably with the accepted values for several reference soils. However, for the acid digestion procedure, the results for matrix constitutents (238U,234U,232Th) were quite low because the silicate matrix was not decomposed. The sodium hydroxide fusion technique described allowed accurate analysis of both matrix constituents and contaminants because a total dissolution was achieved.

Influence of geology and soil particle size on the surface-area/volume activity ratio for natural radionuclides

Abstract: The radioactive concentrations of226Ra,232Th,235U and40K in surface soil of the province of Caceres (Spain) were studied as a function of the geology and grain size. The activities of the four radionuclides in granitic and metamorphic soils have normal frequency distributions, with the mean value being significantly higher for the granitic soils than for the metamorphic soils. Sedimentary soils present asymmetric distributions, and their activities lie between the previous two types. The specific activities of the four radionuclides rises as the particle radius decreases. The equationAe=(P1/R)+P2 describes the dependence of the specific activityAe on radiusR, P1 andP2 being parameters that are related to the surface area and volume activities of the grains. The isotopes226Ra,232Th and235U accumulate with greater intensity on the surface of the grains than40K. This effect is more pronounced in granitic and sedimentary soils than in metamorphic soils.

Studies of radioactivity and heavy metals in phosphate fertilizer

Abstract: The enormous utilization of phosphate rock and super phosphate derived from it have the potential of being an important factor in the contamination of aquifers with alpha emitting radionuclides and heavy metals. Both rock phosphate and super phosphate contain substantial levels of natural uranium, amounting to hundreds of ppm. Our study has shown that whereas the uranium series in phosphate rock is nearly in secular equilibrium, in super phosphate the226Ra and its progeny are depleted by 60–70%. This is a result of the chemical processing of the rock phosphate. On the other hand the super phosphate is much more soluble and can be expected to release its radionuclides to the environment more rapidly than rock phosphate. The present study explores the release of radioisotopes and heavy metals from phosphate fertilizers. Extensive analytical use has been made of a germanium well-detector/Compton suppression system.

Elemental composition of lichens at Nahuel Huapi National Park, Patagonia, Argentina

Abstract: Five species of epiphytic lichens were sampled from urban and periurban areas of Bariloche, a non industrial city located on the East side of the Nahuel Huapi National Park, North-Western Patagonia, Argentina, and from pristine areas of the Park. Each individual lichen was analyzed using Instrumental Neutron Activation Analysis. The results of the analysis showed high concentrations of lithophile elements, with very good correlations among them. The relative concentration of these elements in all lichen species is in good agreement with the elemental composition of sediments collected in the Park. Elemental concentrations which are not related to detritical inputs are also presented.

Determination of organic, inorganic and particulate iodine in the coastal atmosphere of Japan

Abstract: A reliable method for the sampling and analysis of atmospheric iodine species was developed. The air filtering system consisted of a 0.4 μm Nuclepore® filter, 47 mm in diameter, for particulate collection followed by two, 47 mm in diameter, cellulose filters for inorganic iodine collection. The latter filters had been impregnated with 1N LiOH in a 10% glycerol-water mixture. The organic iodine was collected by two beds holding 0.2 g of fibriform activated charcoal produced from phenol resin. Supplementation of the charcoal with triethylendiamine (TEDA) enhanced the sorption ability for gaseous iodine. The filters were analyzed by neutron activation analysis. The background radioactivity could be reduced by using the fibriform activated charcoal due to the low content of impurities in the phenol resin. The background count for128I (443 keV) obtained from the fibriform activated charcoal was about one order of magnitude lower than that of the conventional granular one (plant origin). Approximate detection limits for particulate, inorganic and organic iodine were 1, 0.5 and 0.5 ng/m3, respectively, when 50 m3 of air was sampled by this system. The air was sampled at two locations along the coast of Ibaraki, Japan. The concentration ranges of particulate, inorganic and organic iodine were 0.3–3.4, 1.2–3.3 and 7.8–20.4 ng/m3, respectively. Almost 90% of the atmospheric iodine was in a gaseous form in which organic iodine was dominant.

Organic analyses of an actual and simulated mixed waste: Hanford's organic complexant waste revisited

Abstract: Reanalysis of the organics in a mixed waste, an organic complexant waste from the U. S. Department of Energy's Hanford Site, has yielded an 80.4% accounting of the waste's total organic content. In addition to several complexing and chelating agents (citrate, EDTA, HEDTA and NTA), 38 chelator/complexor fragments have been identified, compared to only 11 in the orginal analysis, all presumably formed via organic degradation. Moreover, a misidentification, methanetricarboxylic acid, has been re-identified as the chelator fragment N-(methylamine)imino- diacetic acid (MAIDA). A nonradioactive simulant of the actual waste, containing the parent organics (citrate, EDTA, HEDTA and NTA), was formulated and stored in the dark at ambient temperature for 90 days. Twenty chelator and complexor fragments were identified in the simulant, along with several carboxylic acids, confirming that myriad chelator and complexor fragments are formed via degradation of the parent organics. Moreover, their abundance in the simulant (60.9% of the organics identified) argues that the harsh chemistries of mixed wastes like Hanford's organic complexant waste are more than enough to cause organic degradation, even in the absence of radiation.

Trace element correlations with age and sex in human fingernails

Abstract: Concentrations of 17 elements in fingernails of 92 control individuals with ages ranging from 4 months to 93 years living in a relatively non-industrial environment were determined by instrumental neutron activation analysis (INAA). Statistical analysis demonstrated several different patterns of trace element correlation with age and sex. Bromine, Co, Cr, Fe, Na and Sb were found to be negatively correlated (p<0.05) with age, while Zn was positively correlated (p<0.05). Silver, Au, Se, and Zn concentrations were found to be higher in females than in males. Males had higher concentrations of Na and K than females. Significant interelement correlations were also observed. The age and sex variations observed should prove to be useful in the proper interpretation of elemental imbalances associated with degenerative neurological diseases, especially in view of recent reports that markers for AD have been detected in external tissue.

Determination of long-lived actinides in soil leachates by inductively coupled plasma-mass spectrometry

Abstract: Inductively coupled plasma-mass spectrometry (ICP-MS) was used to concurrently determine multiple long-lived (t1/2>104 y) actinide isotopes in soil leachates. Ultrasonic nebulization was found to maximize instrument sensitivity. Instrument detection limits for actinides in solution ranged from 50 mBq L−1 (239Pu) to 2μBq L−1 (235U). Hydride adducts of232Th and238U interfered with the determinations of233U and239Pu; thus, extraction chromatography was used to concentrate the analytes and separate uranium from the other actinides in advance of mass spectrometric determination. Alpha spectrometric determinations of230Th,239Pu, and the234U/238U activity ratio in soil leachates compared well with ICP-MS determinations; however, there were some small systematic differences (ca. 10%) between ICP-MS and α-spectrometric determinations of234U and238U activities. These differences were attributed to the use of different isotope dilution spikes for ICP-MS and α-spectrometry.

The use of element ratios to eliminate analytical bias in cold neutron prompt gamma-ray activation analysis

Abstract: Analytical bias due to neutron scattering and absorption in cold neutron prompt gamma-ray activation analysis (CNPGAA) is largely eliminated for homogeneous samples when element ratios are measured. Application of sensitivity ratios (measured relative to titanium) to the multielement analysis of the Allende meteorite increases both the speed and accuracy of the measurement. Greater measurement accuracy is achieved for some samples when ratios of element concentrations are reported. Problems are encountered when applying the ratio method to measurement of elements which deviate from 1/v behavior, and when gamma-ray attenuation or sample heterogeneity are significant.

Trace elements in Malaysian medicinal plants

Abstract: Elemental content of twenty medicinal plants used as tonic and for treatment of diabetes and simusitis were determined by INAA and XRF. Elemental determination was carried out in the raw samples, residues after boiling and the water soluble fractions. Samples were irradiated in TRIGA MkII reactor and counted using HPGe detector coupled to Personal Computer Analyzer (PCA) system. Bowen's Kale, NBS Pine Needles, NBS Citrus Leaves SRM were analysed to check the accuracy of the techniques used. Twenty elements were determined by both NAA and XRF. Arsenic was only detected inLabisia pothoina andDracontomelon dao with a concentrations of 0.40 mg/kg and 0.60 mg/kg respectively. Antimony was found in eleven samples with a concentration of <0.20 mg/kg. Al, Br, Ca, Cl, K, Mn, Na and Rb were detected in all samples whereas Mg and Zn were present in all samples exceptCinnamomum sp. Highest concentration of Br (190 mg/kg), Cl (11805 mg/kg), Co (0.50 mg/kg), Fe (1642 mg/kg), K (36788 mg/kg), Mn (325 mg/kg), Na (126 mg/kg), Rb (197 mg/kg), Sc (0.18 mg/kg) and Zn (3551 mg/kg) were observed in the tuber ofLasia aculeata. Less than 70% and 50% of the elements contained inCallicarpa longifolia andEurycoma longifolia were obtained respectively from water by boiling.

An investigation of radionuclide uptake into food crops grown in soils treated with bauxite mining residues

Abstract: Sandy soils of the coastal plain area of Western Australia have poor phosphorous retention capacity which leads to pollution of surface water bodies in the region. Application of bauxite mining residues (termed “red mud”) to vegetable and crops has been proposed as a solution to increase the phosphorous and water retention and thereby reduce the leaching of nutrients. The thorium and radium-226 concentrations in the “red mud” residues are in excess of 1 kBq/kg and 300 Bq/kg, respectively. Potentially, the use of these residues on agricultural land could result in increased levels of radionuclides in food crops grown in amended soils. The transfer of long-lived radionuclides of both the natural thorium and uranium series to a variety of vegetable crops grown under controlled conditions is investigated. The effects of varying the rates of application of “red mud” and phosphate fertilisers on radionuclide uptake are studied. It has been shown previously that fallout caesium-137 in sandy soils of the region transfers readily to food and grazing crops. Some of the parameters which influence that transfer are also examined.

Activation and tracer techniques for study of metallofullerenes

Abstract: Advantages and uniqueness of radiochemical techniques in fullerene studies are pointed out. Some experimental data are presented on metallofullerenes production yields, HPLC elution behaviors of Y, La, Gd containing fullerenes, encapsulation of a new metal in the carbon cage, stability of the carbon cage against recoil energy, and the distribution of metallofullerenes among various organs of rats.

A method for assessing and correcting coincidence summing effects for germanium detector efficiency calibrations

Abstract: The addition of54Mn and65Zn to a nine-radionuclide standard (containing241Am.,109Cd.57Co,139Ce,203Hg.113Sn,137Cs,88Y, and60Co) provides the capability to determine the extent of coincidence summing for gamma rays from88Y and60Co. A method for correcting the efficiency points at 1332 keV (60Co) and 1836 keV (88Y) for coincidence summing is presented.

A study on the association of two iodine isotopes, of natural127I and of the fission product129I, with soil components using a sequential extraction procedure

Abstract: Sequential extraction techniques have been utilized in order to investigate the degree of binding or association of natural iodine127I and the radioactive iodine isotope129I with soil components. The results indicate that only a small fraction of natural iodine (2.5–4%) but a large fraction of the recently added radioactive129I (38–49%) is water-soluble. The other forms of iodine which were determined for both iodine isotopes were exchangeable iodine, iodine bound to metal-oxides and iodine bound to organic matter.

Extraction behavior of uranium(VI), plutonium(IV) and some fission products with gamma pre-irradiatedn-dodecane solutions of N,N′-dihexyl substituted amides

Abstract: The extraction behavior of uranium(VI), plutonium(IV) and some fission products like zirconium(IV), ruthenium(III) and europium(III) from 3.5M nitric acid with γ-irradiated organic phase pre-equilibratedn-dodecane solutions of dihexyl derivatives of hexanamide (DHHA), octanamide (DHOA) and decanamide (DHDA) has been investigated as a function of absorbed dose upto 184·104 Gy. The results indicate that the extraction of uranium(VI) decreases gradually with dose upto 72·104 Gy and becomes almost constant thereafter, while, the extraction of plutonium(IV) decreases upto a dose of 20·104 Gy and then increases rapidly up to a dose of 82·104 Gy indicating synergistic effects of radiolytic products formed at higher doses. Extraction of zirconium(IV) increases gradually upto a dose of 72·104 Gy. Europium(III) does not get extracted with any of these amides in the entire dose range (0–184·104 Gy) studied, however, ruthenium shows insignificant increase in extraction with dose. The decrease inD values noticed in the case of plutonium and zirconium after the dose of 72·104 Gy which was attributed to the third phase formation and emulsification. Infrared studies confirm the final products of radiolysis as the respective amines and carboxylic acids. The degraded amide contents have been estimated by quantitative IR spectrophotometric technique. Extraction data obtained for uranium(VI) and plutonium(IV) with TBP/n-dodecane system have also been compared under similar experimental conditions.

Tracer experiments on the behavior of radioiodine in the soil-plant-atmosphere system

Abstract: In order to obtain information on the behavior of long-lived129I in the soil-plant-atmosphere system, two different experiments, transfer factors and volatilization of iodine, have been conducted by radiotracer techniques using125I. Soil-to-plant transfer factors varied very widely. Low values were found in tomato (0.0003) and rice (0.0019). The highest value for an edible part was seen in komatsuna,Brassica rapa L. (0.016), which is comparable to the IAEA recommended value of iodine for common crops (0.02). There was a tendency for older leaves to show higher concentrations than younger ones. The values for fruit, grain and beans were significantly lower than those for their leaves. Thus translocation of iodine with photosynthate from leaves into these plant organs was very small. Iodine in soil was found to be volatilized from the soil-rice plant system into the atmosphere as an organic iodine. Volatilization markedly decreased in the late cultivation period of rice plants.

Rapid determination of radium isotopes by alpha spectrometry

Abstract: An efficient analytical method for the determination of low-levels of226Ra and224Ra by alpha spectrometry is described. A cation exchange column was used to separate the analyte from other constituents in the sample (1–50 mL). After preconcentration and separation, the radium was electrodeposited onto a stainless steel disc from a solution of ammonium oxalate and hydrochloric acid. The electrodeposition was accomplished by the addition of platinum in microgram amounts. Linear responses were greater than two orders of magnitude. Detection limits of the procedure, taken as three times the standard deviation of several reagent blank analyses, were (1.8±0.3)×10−4 Bq and (2.9±0.3)×10−4 Bq for226Ra and224Ra, respectively. Recoveries of226Ra and224Ra ranged from 90% to 100% when samples of drinking water, well water, and dissolved bones were analyzed. Precision was calculated to be less than 5% for the determination of226Ra. Matrix effects were studied for salts of barium, magnesium, iron, and calcium.

226Ra and possible water contamination due to phosphate fertilizer production

Abstract: The raw material used in the production of fetilizers is phosphate ore containing various amounts of naturally radioactive elements. During phosphate ore processing, owing to chemical properties of radium, practically all226Ra gets incorporated into phosphogypsum and becomes the main source of radioactivity. This study was carried out in a fertilizer factory in central Croatia, which may represent a site of significant environmental contamination due to fertilizer production and phosphogypsum deposition in the area. The purpose of this paper was to determine whether ingestion of drinking water in this area poses a health risk for the inhabitants. The results of our study confirmed the occurrence of226Ra in elevated concentrations in the samples of trickling waters. However, concurrent analyses of drinking water indicated that the risk of adverse health effects for the population living in the vicinity of a phosphate fertilizer plant is negligible.

Uranium in phosphate rock and derivates

Abstract: It is well known that phosphate rock contains a small amount of uranium. During the production of phosphate fertilizers, most uranium present is found in the phosphate fraction. Uranium was determined in the 70–200 ppm range in the phosphate rock and the final products by nuclear and classical methods.

Extraction of uranium(VI) and plutonium(IV) with some high molecular weight aliphatic monoamides from nitric acid medium

Abstract: The extraction behavior of U(VI) and Pu(IV) with dioctyloctanamide (DOOA), dioctylethylhexanamide (DOEHA) and diisobutylethylhexanamide (DIBEHA) was investigated from nitric acid medium. With DOOA, U(VI) extraction is higher than that for Pu(IV) upto 5M HNO3 and the trend is reversed at higher acid concentrations. Extraction yield of U(VI) is higher than that for Pu(IV) in the case of DOEHA and DIBEHA. DIBEHA extraction of Pu(IV) is found to be very small. The lower value of the distribution ratio for Pu(IV) with branched amides was attributed to steric reasons. The possibility of using these amides for separation of U(VI) and Pu(IV) without valency adjustment was explored. Both U(VI) and Pu(IV) are extracted as their disolvates by DOOA and DOEHA.

Adsorption of Cs(I), Sr(II) and Co(II) on Al2O3

Abstract: The sorption of Cs(I), Sr(II) and Co(II) from aqueous solutions on alumina under various experimental conditions has been studied by batch techniques. Freundlich, Langmuir and Dubnin-Raduskevich equations have been used to interpret the sorption data. The values of various thermodynamic parameters have been determined. The sorption of Cs(I) and Sr(II) on alumina is exothermic in nature while that of Co(II) is an endothermic process. The ΔHo values for Cs(I), Sr(II) and Co(II) were−23.29 KJ/mol at 298K,−35.3 KJ/mol at 293 K and 13.49 KJ/mol at 293 K, respectively. Negative values of ΔGo show the spontaneity of the sorption processes; ΔGo values of Cs(I) and Sr(II) becomes less negative at higher temperatures while the ΔGo values of Co(II) become more negative with increasing temperature. At higher temperatures, less amounts of Cs(I) and Sr(II) and greater amounts of Co(II) are sorbed on alumina. The values of the mean free energies of sorption,E, for Sr(II) and Co(II) at various temperatures were within the range of 7–10 KJ/mol which show that these metals are sorbed on alumina predominantly by an ion-exchange process.

Preliminary investigations on7Be as a tracer in the study of environmental processes

Abstract: The usefulness of cosmogenic7Be as a tracer in a terrestrial environment has been investigated. Atmospheric fluxes and inventories of the radionuclide in grassland have been determined. Environmental behavior in connection with foliar interception and possibility of subsequent release has been studied.

Determination of129I and127I in environmental samples by neutron activation analysis (NAA) and inductively coupled plasma mass spectrometry (ICP-MS)

Abstract: In order to assess the levels and behavior of129I (half-life: 16×107 y) and127I (stable) in the environment, we have developed analytical procedures involving neutron activation analysis (NAA) Environmental samples collected around Tokaimura, Ibaraki Prefecture, Japan, have been analyzed using this method Ranges of129I and127I concentrations in surface soil were 09–180 mBq kg−1 and 1–60 mg kg−1, respectively Higher129I concentrations were found in soil samples collected from coniferous forests, suggesting a contribution from tree canopies in the deposition of this nuclide Most of the129I in soil, was found to be retained in the first 10 cm The129I/127I ratios in wheat fields were lower than those in rice paddy fields

222RN at Bermuda and Mauna Loa: Local and distant sources

Abstract: Continuous measurements of atmospheric222Rn were made for the past three years by the Environmental Measurements Laboratory (EML) at the Atmosphere/Ocean Chemistry Experiment site located at Tudor Hill, Bermuda and at the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory Mauna Loa Observatory. The222Rn analyzer is based on the two-filter tube method. At the Bermuda site, monthly median222Rn concentration range from ∼50 to 700 mBq m−3, and the concentrations vary seasonally, with a maximum in the winter and a minimum in the summer. The concentrations are significantly elevated when local winds traverse the island. At MLO, monthly median222Rn concentrations range from ∼ 100 mBq m−3 during the fall months to ∼ 400 mBq m−3 during the spring months. The springtime maximum values correspond to periods of rapid transport in the free troposphere from the Asian continent, corroborated by backward air mass trajectories. The222Rn data are also used to help decipher local daily upslope/downslope conditions present at MLO. This study illustrates the value of atmospheric222Rn monitoring, when screened through the filter of local meteorology, in studying the transport of continental air to the oceans, as well as the dynamics of local meteorological effects.

NAA and ICP-MS: A comparison between two methods for trace and ultra-trace element analysis

Abstract: NAA and ICP-MS are both highly sensitive methods for multi-element trace-and ultra-trace element determination. A comparison between analytical figures of merit of both methods is made. Both methods have specific advantages that put them beyond competition for certain applications. It is concluded that ICP-MS can replace NAA for many routine analyses. NAA remains essential as a highly reliable and accurate reference method.