A one-year study of the total air-borne14C effluents from two Swedish light-water reactors,one boiling water- and one pressurized water reactor

The results of a one-year study of the total air-borne¹⁴C effluents from two Swedish light-water reactors, one boiling water reactor (BWR) at Forsmark and one pressurized water reactor (PWR) at Ringhals, are presented. Air emitted from the stacks has been collected continuously over two-week periods and the¹⁴C content in the samples has been analysed using accelerator mass spectrometry (AMS). The¹⁴C activity concentration in the air issuing from the stack of the PWR varied between 2 and 1132 Bq/m³ with a mean value of 200 Bq/m³, while from the BWR the activity concentration varied between 4 and 146 Bq/m³, with a mean value of 95 Bq/m³. The corresponding¹⁴C release rate was 0.27 TBq/GW_el·year for the PWR and 0.48 TBq/GW_el·year for the BWR. During the same period of time, for comparison, the¹⁴C activity in continuously collected air from the stack of the PWR was also measured by liquid scintillation counting. In most cases the results of these measurements were in fair agreement with the corresponding AMS results.     

Temporal variations of iodine-127, potassium-40 and technetium-99 concentrations in Fucus serratus in the English Channel

The trends of¹²⁷I,⁴⁰K, and⁹⁹Tc levels were measured for several years inFucus serratus collected in 3 different Channel coastal stations. The results demonstrated cyclic seasonal variations of the levels, with maximum values in winter and minimum values in summer (ranging between 2 and 3). Ash levels evolved with a similar cycle, which allowed to estimate that the cycle thus observed was related to the alga biological activity and not to the releases. Trends of⁹⁹Tc levels were more complex. At Roscoff, a station little exposed to the releases, levels varied with the same annual cycle as natural elements. At Herquemoulin, a station close to the release point, the trend was mainly related to the released activities with a delay of about 1 year. At Wimereux, a distant station more strongly affected by sea currents, the cycle appeared in 1983 and 1984 but was hidden in 1985 and 1986 by the arrival of waters more strongly labelled because of the larger releases that occurred in 1985 (26 TBq), instead of 12 TBq in 1983 and 1984.     

Radionuclides in whole diets of people living near the Sellafield nuclear complex, UK

The British Nuclear Fuels Limited (BNFL) complex (Sellafield) in Cumbria discharges into the atmosphere, under authorization by the Environment Agency (and previously, the Ministry of Agriculture, Fisheries and Food (MAFF), radioactive waste consisting of gases, mists and dusts. As part of MAFF's radiological surveillance programme, the intake of radionuclides via food ingestion by members of the public living near this nuclear installation is routinely assessed from measurements made on local food and environmental samples and by using computer models simulating the dispersion and incorporation of radioactivity into foodstuffs. In this study, the individual diets of adults and children living near the Sellafield complex and those from a control group were assessed for their radionuclide content. The participants were selected via a food survey questionnaire which was aimed at identifying those who consume home grown fruits and vegetables or derive these from local sources. The diets were collected over a one-week period in August 1995 and following radiochemical analyses of the diets for^239+240Pu,¹³⁷Cs,⁹⁰Sr,¹⁴C, and¹²⁹I, the doses received by the participants from these nuclides were extrapolated over a one-year period and compared to doses calculated from food surveillance data and to doses predicted using the MAFF food-chain computer model.     

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

Samples from sediment cores, collected from a site close to the Sellafield outfall and dated using conventional - and -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 -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.     

Radioisotopes of thirteen elements in intertidal coastal and estuarine sediments in the Irish Sea

A survey has been carried out of⁴⁰K,⁶⁰Co,⁹⁹Tc,¹⁰⁶Ru,¹²⁵Sb,¹²⁹I,¹³⁴Cs,¹³⁷Cs,¹⁵⁴Eu,²²⁶Ra,²²⁸Ra,²³⁷Np,²³⁸Pu,^239,240Pu,²⁴¹Pu,²⁴¹Am,²⁴²Cm, and^243,244Cm activities in sediments from the Irish Sea. Several of these radionuclides were measured independently at two separate laboratories to enable the intercomparison of the results produced. The comprehensive data set generated allows the present spatial distributions of these radionuclides in coastal sediments to be examined in relation to sediment textural characteristics and by comparison with earlier survey, enables the temporal trends in their activities to be determined. In general all artificial radionuclides showed lower activities in sediments in response to falling discharges from Sellafield and relationships with either grain size, distance from Sellafield or both. Isotope ratios were similar to cumulative weighted activity ratios rather than present day values due to sediment mixing. Pu levels supplied evidence for the lag in response of sediment deposits with increasing distance from Sellafield due to sediment transport.     

Distribution and behaviour of99Tc,237Np,239,240Pu,and241Am in the coastal and estuarine sediments of the Irish Sea

Intertidal coastal and estuarine sediments from 24 sites in the Irish Sea have been analyzed for⁹⁹Tc,²³⁷Np,²³⁸Pu,^239,240Pu and²⁴¹Am. The²³⁷Np activity and²³⁹Pu/²⁴⁰Pu ratio were measured simultaneously by ICP-MS, and⁹⁹Tc was determined by HR-ICP-MS which is ten times more sensitive than Q-ICP-MS.The activities of⁹⁹Tc,²³⁷Np,^239,240Pu and²⁴¹Am were distributed over a wide range of 1.5–70.5, 0.01–13.3, 2.3–1589, 2.6–1894 Bq/kg, respectively. Activities of these radionuclides decreased exponentially with distance from the Sellafield source. The²⁴¹Am/^239,240Pu and²³⁷Np/^239,240Pu ratios were almost constant with distance from the Sellafield. This result suggests that the distribution and behavior of Np and Pu are controlled by complicated factors such as the influence of transport, the variation with time of Np/Pu ratio in the Sellafield discharges and sedimentary mixing processes in the Irish Sea.     

Polar Metabolites of the Tropical Green Seaweed Caulerpa taxifolia Which Is Spreading in the Mediterranean Sea: Glycoglycerolipids and Stable Enols (α\=Keto Esters)

Examination of the polar components of the green seaweed Caulerpa taxifolia (Vahl ) C. Agardh , which is heavily spreading in the northeastern Mediterranean, led to two families of compounds. The new (2R)-3-O-β-D -galactopyranosyl-1-O-[(7Z,10Z,13Z)-hexadeca-7,10,13-trienoyl]-2-O-[(9Z,12Z,15Z)-octadeca-1,12,15-trienoyl]-sn-glycerol ( 2 ) was isolated in low abundance, like the analogues 1 and 3 already known from freshwater cyanobacteria. The acyl positions in 1 – 3 were determined by enzymatic methods and the absolute configuration from the O-galactosylglycerol obtained upon alcaline methanolysis. More abundant were the (4-hydroxyphenyl)- and (3,4-dihydroxyphenyl)pyruvic acid methyl esters, occurring in the enol (Z) forms 13a and 14a accompanied by very minor (E) forms 13b and 14b . The latter became predominant on UV irradiation of 13a or 14a , allowing the determination of the C=C configuration of these isolatable, stable enols from ¹H,¹³C NMR couplings (larger H−C(3)/C(1) coupling constant in the (E) than in the (Z) isomer). Contrary to literature implications, the O-galactosylglycerolipids 1 – 3 lack any cholinergic or histaminergic activity; similarly, enols (= α-keto esters) 13 and 14 or terpenoids of this seaweed were also devoid of such biological activities (see Table).     

Thermodynamic Properties of Aqueous Solution of 2-Isopropoxyethanol at 25°C

Excess enthalpy, excess isobaric heat capacity, density, and speed of sound for aqueous 2-isopropoxyethanol solutions were measured at 25°C. The density was also measured at 20°C. The excess enthalpy was –800 J-mol^–1 at the minimum (mole fraction alcohol, x = 0.2), showing that the hydrogen bonds formed between unlike molecules are stronger than those in both pure liquid states. The excess volume also was large and negative, more than –1.2 cm³-mol^–1 at the minimum (x = 0.35). Excess isentropic and isothermal compressibilities are extremely negative. These results suggest that breaking the hydrogen bond network in water and forming the stronger hydrogen bonds between unlike molecules reduces the volume of the solution and makes the solution less compressible. The excess isobaric heat capacity is positive and large, up to 10 J-K^–1-mol^–1 and shows anomalous behavior in the neighborhood of x = 0.15.     

Thermochemical investigations of associated solutions. 13. Calculation of anthracene-chlorobutane association parameters from measured solubility data

Experimental solubilities are reported for anthracene dissolved in binary solvent mixtures containing 1-chlorobutane with n-hexane, n-heptane, n-octane, cyclohexane, methylcyclohexane and isooctane at 25°C. Results of these measurements, combined with estimates for the excess Gibbs free energy of the binary solvents, are used to evaluate the equilibrium constant for a presumed anthracene-chlorobutane molecular complex from the Extended Nearly Ideal Binary Solvent model. A single equilibrium constant was needed to describe the experimental data to within an average deviation of about 0.7%. The calculated association constant varied slightly with inert hydrocarbon cosolvent, the values ranging from K _AC ^ϕ =2.5 for isooctane to K _AC ^ϕ =6.0 for the cyclohexane cosolvent.     

Study of molecular interaction in binary liquid mixtures of ethyl acetoacetate with chloroform and dimethylsulphoxide using excess acoustic parameters and spectroscopic methods

Densities and ultrasonic velocities were measured for binary liquid mixtures of ethyl acetoacetate (EAA) with chloroform (CHCl₃) and dimethylsulphoxide (DMSO) over the entire composition range. These experimental values were used to calculate the adiabatic compressibility (βs), intermolecular free length (L_f), excess molar volume (V^E), excess adiabatic compressibility (β_s^E) and excess intermolecular free length (L_f^E) for the liquid mixtures under consideration. In all the excess parameters, a positive deviation was observed in CHCl₃–EAA binary mixture, whereas a slight negative deviation was found for EAA–DMSO binary liquid mixture. These deviations were explained in terms of molecular interactions between like and unlike molecules and further affirmed by UV–Vis spectroscopic measurements in terms of polar and non-polar environment in the close proximity of solvatochromic dye. Fourier transform infrared spectroscopy (FT-IR) and proton-nuclear magnetic resonance (H¹ NMR) measurements have also been done to explain the molecular interaction in the binary liquid mixtures.     

The benzoyl ion. Thermochemistry and kinetic energy release

The thermochemistry of benzoyl ion formation from a variety of sources has been examined by using the measured kinetic energy release for metastable ions to estimate the excess energy of the activated complex. A correlation is observed between this estimated excess energy and literature values of the heat of formation of the benzoyl ion. From this relationship and the observed correlation between the uncorrected heat of formation and the difference between the appearance potential of [C6H5CO]⁺ and the ionization potential of the parent compound, the large range of reported values for ΔHf[C6H5CO]⁺ is seen to be due, at least in part, to variation in the kinetic shift with the critical energy of the reaction. With the exception of the ion generated from trifluoroacetophenone and possibly that from benzaldehyde, the fragmenting [C7H5O]⁺ ions are shown, from kinetic energy release data, to be structurally identical. The approach adopted here may have general merit in improving or testing the accuracy of thermochemical data based on appearance potential measurements.     

Assessment of a Radiochemical Method Using 14C-Labeled N-Ethylmaleimide as a Reagent for Sulfhydryl Determination with Assays on β-Lactoglobulin and Insulin

A radiochemical method using ¹⁴C-labeled N-ethylmaleimide (NEM-¹⁴C) as a reagent for sulfhydryl determination is reassessed and described in detail. The method is based on the activity of ¹⁴C-labeled S-succinyl-L-cysteine (III-¹⁴C) recovered from the controlled hydrolysis of the NEM-¹⁴C treated sulfhydryl-containing peptide and the correlation between III-¹⁴C and SH content established with glutathione. It is simple, accurate and highly sensitive and is not affected by disulfide group as indicated by experiments with insulin. Good result is obtained from tests with β-lactoglobulin. It gives a value of 1.94 mole SH per mole protein, which is close to that generally accepted.     

Radioactive 129I in surface water of the Celtic Sea

Relatively large amounts of radioactive iodine ¹²⁹I (T _1/2  = 15.7 Ma) have been documented in seawater such as the English Channel, the Irish Sea and the North Sea. Data on the concentration of the iodine isotopes in waters of the Celtic Sea are missing. Aiming to provide first ¹²⁹I data in the Celtic Sea and compare them with levels in the other close-by seawater bodies, surface seawater samples were analyzed for the determination of ¹²⁷I and ¹²⁹I concentrations. The results revealed a high level of ¹²⁹I in these waters and suggest strong influence by liquid discharges from La Hague and Sellafield reprocessing facilities. ¹²⁷I concentrations are rather constant while the ¹²⁹I/¹²⁷I ratio reaches up to 2.8 × 10^?8 (ranging from 10^?10 to 10^?8), which is 2–4 orders of magnitude higher than pre-nuclear era natural level. Transport of ¹²⁹I to the Celtic Sea is difficult to depict accurately since available data are sparse. Most likely, however, that discharges originated from La Hague may have more influence on the Celtic Sea ¹²⁹I concentrations than the Sellafield. Comprehensive surface water and depth profiles ¹²⁹I data will be needed in the future for assessment of environmental impact in the region.     

Photosynthesis of oxygen in the forest ecosystem and its albedo as major factors of prevention of current civilization from the oxygen and freshwater disaster

The interrelation between the resource-forming and environment-forming functions of the phytosphere, on the one hand, and their consumption by the current civilization, on the other hand, is considered. It was shown that the world technogenic consumption of oxygen in excess of its influx to the atmosphere is 10¹⁰ t per annum, the globe average vegetation cover has gradually passed from forest to steppe, and the critical movement from steppe to desert is going now. The ecological-economic harmonization of the consumption of the environment-and resource-forming functions of the forest is needed.     

Excess Molar Volumes and Excess Partial Molar Volumes of Triethylene Glycol Monoethyl Ether–n-Alcohol Mixtures at 25°C

We have measured excess molar volumes V^E _m of binary mixtures of triethylene glycol monoethyl ether with methanol, ethanol, 1-propanol, 1-pentanol, and 1-hexanol over the full range of compositions at 25°C. The measurements were carried out with a continuous-dilution dilatometer. The excess molar volumes V^E _m are negative over the entire range of composition for the systems triethylene glycol monoethyl ether + methanol, + ethanol, and + 1-propanol and positive for the remaining systems, triethylene glycol monoethyl ether + 1-pentanol, and + 1-hexanol. The excess V^E _m increases in the positive direction with increasing chain length of the n-alcohol. The measured excess volumes have been compared to our previous published data with an effort to assess the effects of replacing methyl by ethyl groups and of inserting oxyethylene groups. The results have been used to estimate the excess partial molar volumes V^E _m,i of the components. The behavior of V^E _m and V^E _m,i with composition and the number of carbon atoms in the alcohol molecule is discussed.     

Densities and Viscosities of the Ternary Mixture (Benzene + 1-Propanol + Ethyl Acetate) at 298.15 K

Abstract

Densities and viscosities of the ternary mixture (benzene + 1-propanol + ethyl acetate) and the corresponding binary mixtures (benzene + 1-propanol, benzene + ethyl acetate and 1-propanol + ethyl acetate) have been measured at the temperature 298.15 K. From these measurements excess volumes, V^E , excess viscosities, η^E, and excess Gibbs energies of activation for viscous flow, G*^E , have been determined. The equation of Redlich-Kister has been used for fitting the excess properties of binary mixtures. The excess properties of the ternary system were fitted to Cibulka's equation.     

Technetium-99 in Fucusand seawater samples in the Finnish coastal area of the Baltic Sea, 1999

Liquid discharges of ⁹⁹Tc from the Sellafield nuclear facilities increased largely in the mid 90"s. These releases are transported to the Nordic sea areas by the ocean currents. Results of the ⁹⁹Tc activities along the Norwegian coastal areas and in the North Sea have been reported but then again, the spreading of ⁹⁹Tc into Baltic Sea has not been studied thoroughly. Fucus vesiculosus and seawater samples were collected in the summer 1999 from the Finnish coastal areas for measuring ⁹⁹Tc in the Baltic Sea area. A modified analytical method for measuring ⁹⁹Tc in the environmental samples was developed at that time. The method based on extraction chromatography and liquid scintillation measurement of ⁹⁹Tc. The ⁹⁹Tc concentration in the Fucus vesiculosus in the Finnish coast of the Baltic Sea varied from 1.6 to 11.6 Bq/kg (dry weight) being highest at the most northern sampling sites. These values were considerable lower than those in the Danish and Norwegian coasts. The variation in the concentrations observed are probably due to biological factors. The ⁹⁹Tc concentration in the Baltic Sea water studied was below 0.2 Bq/m³.     

Measurements of99Tc,137Cs,237Np, Pu isotopes and241Am in sediment cores from intertidal coastal and estuarine regions in the Irish Sea

Long-lived radionuclides,⁹⁹Tc,¹³⁷Cs,²³⁷Np, Pu isotopes and²⁴¹Am were determined in the long sediment cores collected from nine intertidal sites around the west Cumbria of the Irish Sea, UK. The inventories of all nuclides measured varied considerably among the sampling sites, but generally their inventories decreased with increasing distance from Sellafield. Furthermore, the inventory ratios with respect to relationship with distance from Sellafield enabled comparison of transport behavior of⁹⁹Tc,¹³⁷Cs,²³⁷Np and²⁴¹Am compared with^239,240Pu. As a consequence, the apparent fractional rate of solution transport to the intertidal sediment was found to increase as follows:⁹⁹Tc>¹³⁷Cs>²³⁷Np>^239,240Pu≥²⁴¹Am.     

Excess enthalpies of mixtures containing n-heptane,methanol and methyl tert-butyl ether (MTBE)

Molar excess enthalpies H ^E have been measured for the binary mixtures MTBE+methanol, MTBE+n-heptane and methanol+n-heptane using a quasi-isothermal flow calorimeter. The measurements have been performed at atmospheric pressure and at 25 and 40°C for all the mixtures and for MTBE+methanol also at 50°C. The experimental results for MTBE methanol and MTBE+n-heptane are compared with those calculated using the NRTL equation.Communicated at the Festsymposium celebrating Dr. Henry V. Kehiaian's 60^th birthday, Clermont-Ferrand, France, 17–18 May 1990