Long-term stability of decontamination effect in recreational areas near the town Novozybkov, Bryansk Region, Russia.

In 1995 and 1997, experimental decontamination campaigns were carried out in two recreational areas, Novie Bobovichi and Guta-Muravinka, near the town of Novozybkov, Bryansk Region, Russia. These areas were strongly affected by the Chernobyl fallout in 1986. In order to examine the long-term stability of the clean-up procedures, a programme has been carried out to continuously monitor the radiological situation in and around the decontaminated areas. This follow-up program consists of regular (1-3 times per year) measurements of absorbed gamma-dose rate in air (DR) at reference indoor and outdoor locations, repeated DR measurements on a grid, and gamma-spectrometric analysis of soil and other environmental samples. Very similar dynamics of the Chernobyl-related DR, mostly attributed to radiocaesium decay, were found in all the locations. For the period under study (September 1995-May 2003), the half-lives (years) for the reduction in radiocaesium-dependent DR contribution due to contaminant migration (in the following termed 'DRM half-lives') were, respectively, 52+/-26, 57+/-23, 43+/-21, 46+/-15, and 80+/-56 for the following locations: untreated outdoors, treated outdoors, untreated indoors, treated indoors, and undisturbed forest-grassland plots outside the recreational areas. These relatively high values of the current DRM half-lives correspond very well with the results of soil core analyses, which showed no time-dependent changes in the mean mass depths of the (137)Cs distribution, neither at treated nor at undisturbed plots. The following signs of natural restoration of the disturbed forest-meadow ecosystems have been observed at treated areas: formation of a new litter layer, development of grassy spots, mushroom growths and new generations of pines and birches. The levels of the (137)Cs content in grass and mushrooms from treated plots were one or two orders of magnitude lower, than those registered in the samples from untreated areas. The follow-up study demonstrates the long-term stability and efficiency of the decontamination carried out. There are two main reasons for the sustainment of the effects: careful implementation of adequate clean-up procedures and natural strong fixation of radiocaesium in soil-associated matrices of the ecosystems.

Deposition of contaminant aerosol on human skin.

Over recent years, it has been established that deposition of various types of pollutant aerosols (e.g., radioactive) on human skin can have serious deleterious effects on health. However, only few investigations in the past have been devoted to measurement of deposition velocities on skin of particles of the potentially problematic sizes. An experimental programme has shown the deposition velocities on skin of particles in the ca. 0.5-5 microm AMAD range to be high and generally associated with great variations. A series of investigations have been made to identify some of the factors that lead to this variation. Part of the variation was found to be caused by differences between individuals, whereas another part was found to be related to environmental factors. The identification of major influences on skin contaminant deposition is important in estimating health effects as well as in identifying means for their reduction.

Requirements of future models for inhabited areas.

Models for inhabited areas are used in a variety of applications for accidental or continuous releases of radioactivity to atmosphere. Pathways of interest are external exposure from radioactive material in the cloud or deposited on indoor and outdoor surfaces and people, inhalation from the plume and from material resuspended from the ground. In developing a model for inhabited areas it is necessary to consider what the end users may need and ensure that the model is appropriate for the application; different levels of detail may be appropriate for different applications. This paper considers the main processes governing exposure in inhabited areas, commenting on the extent to which we understand them and how well current models reflect this understanding. It also identifies where the authors believe future modelling is needed and the key areas where the current inhabited area models could be improved.

Estimation of doses received in a dry-contaminated residential area in the Bryansk region, Russia, since the Chernobyl accident.

In nuclear preparedness, an essential requirement is the ability to adequately predict the likely consequences of a major accident situation. In this context it is very important to evaluate which contributions to dose are important, and which are not likely to have significance. As an example of this type of evaluation, a case study has been conducted to estimate the doses received over the first 17 years after the Chernobyl accident in a dry-contaminated residential area in the Bryansk region in Russia. Methodologies for estimation of doses received through nine different pathways, including contamination of streets, roofs, exterior walls, and landscape, are established, and best estimates are given for each of the dose contributions. Generally, contaminated soil areas were estimated to have given the highest dose contribution, but a number of other contributions to dose, e.g., from contaminated roofs and inhalation of contaminants during the passage of the contaminated plume, were of the same order of magnitude.

Reduction of external dose in a wet-contaminated housing area in the Bryansk Region, Russia.

An investigation of the feasibility of reducing the external dose rate in a recreational housing area located between the settlements of Guta and Muravinka, Bryansk Region, Russia, which had been contaminated by the Chernobyl accident more than a decade earlier was made. Removal of contaminated topsoil was carried out over an area of about 2000 m2, optimising the thickness of the removed layer according to an assessment of the vertical contaminant distribution. A layer of clean sand was applied to shield against radiation from residual contamination in the ground. Careful monitoring of dose rates in reference positions showed that this could reduce the dose rate outdoors by about a factor of 6. The replacement of a roof was found to reduce the dose rate considerably inside the house. A cost analysis of the operation is presented.

Measurement of contaminant removal from skin using a portable fluorescence scanning system.

The residence time of particulate contamination on the human body is a factor that has an important impact on the accuracy of exposure assessment in the aftermath of an accidental release of radionuclides to the atmosphere. Measurements of particle clearance from human skin were made using an illumination system to excite fluorescence in labelled silica particles and a CCD camera and image processing system to detect this fluorescence. The illumination system consists of high-intensity light emitting diodes (LEDS) of suitable wavelengths arranged on a portable stand. The physically small size of the LEDs allows them to be positioned close to the fluorescing surface, thus maximising the fluorescent signal that can be obtained. The limit of detection was found to be 50 microg of tracer particle per cm2. Experiments were carried out to determine the clearance rates of 10 microm and 3 microm particles from the skin. Results show that, in the absence of any mechanical rubbing of the skin, the clearance of particles from the skin followed an approximately exponential decay with a half-time of 1.5-7.8 h. Skin hairiness and degree of human movement were found, in addition to particle size, to have an important influence on particle fall-off rate.

Weathering of radiocaesium contamination on urban streets, walls and roofs.

Recent investigations in Russia have emphasised the significance of dose contributions from contamination on urban streets and roof pavings, and, typically to a lesser extent, walls in the urban environment. The crucial factor determining the magnitude of these contributions is the retention of the contamination by the different types of urban surface. Since the Chernobyl accident, a series of long-term field studies has been carried out on urban streets, walls and roofs, to examine the weathering processes of 137Cs on the various surface types. The derived time-functions are applied to estimate resultant long-term doses to inhabitants of an urban centre. The paper highlights the effect on caesium retention of surface material characteristics.

Radiation dose implications of airborne contaminant deposition to humans.

In nuclear accident consequence assessment, dose contributions from radionuclide deposition on the human body have in the past generally been either ignored or estimated on the basis of rather simple models. Recent experimental work has improved the state of knowledge of relevant processes and parameter ranges. The results presented in this paper represent a first approach to a detailed assessment of doses from radiopollutant deposition on the human body, based on contaminant-specific data. Both the dose to skin from beta-emitters and the whole-body dose from gamma-emitters on body surfaces were found to give potentially significant contributions to dose. Further, skin penetration of some contaminants could lead to significant internal doses.

Short rotation coppice for revaluation of contaminated land.

When dealing with large-scale environmental contamination, as following the Chernobyl accident, changed land use such that the products of the land are radiologically acceptable and sustain an economic return from the land is a potentially sustainable remediation option. In this paper, willow short rotation coppice (SRC) is evaluated on radiological, technical and economic grounds for W. European and Belarus site conditions. Radiocaesium uptake was studied in a newly established and existing SRC. Only for light-texture soils with low soil potassium should cultivation be restricted to soils with contamination levels below 100-370 kBq m-2 given the TFs on these soils (5 x 10(-4) and 2 x 10(-3) m2 kg-1) and considering the Belarus exemption limit for firewood (740 Bq kg-1). In the case of high wood contamination levels (> 1000 Bq kg-1), power plant personnel working in the vicinity of ash conveyers should be subjected to radiation protection measures. For appropriate soil conditions, potential SRC yields are high. In Belarus, most soils are sandy with a low water retention, for which yield estimates are too low to make production profitable without irrigation. The economic viability should be thoroughly calculated for the prevailing conditions. In W. Europe, SRC production or conversion is not profitable without price incentives. For Belarus, the profitability of SRC on the production side largely depends on crop yield and price of the delivered bio-fuel. Large-scale heat conversion systems seem the most profitable and revenue may be considerable. Electricity routes are usually unprofitable. It could be concluded that energy production from SRC is potentially a radiologically and economically sustainable land use option for contaminated agricultural land.

Decontamination in a Russian settlement.

Decontamination was carried out in an area with three houses in Novo Bobovichi, Bryansk region, Russia, in the autumn of 1995. It was demonstrated that significant reductions in the dose rate both indoor (DRF = 0.34) and outdoor (DRF = 0.20) can be achieved when a controlled cleaning is undertaken. This paper describes the decontamination work carried out and the results obtained. The roofs of the houses were swept and cleaned by special roof cleaning equipment. The soil around the houses was removed by hand while carefully monitoring the ground for residual contamination. By monitoring the decline in the dose rate during the different stages of the work the dose reducing effect of each action has been measured.

Residual neuromuscular block is a risk factor for postoperative pulmonary complications. A prospective, randomised, and blinded study of postoperative pulmonary complications after atracurium, vecuronium and pancuronium.

BACKGROUND: After anaesthesia involving pancuronium a high incidence of both residual neuromuscular block and postoperative pulmonary complications (POPC) has been reported. The aim of this study was to compare the incidence of POPC following the use of pancuronium, atracurium, and vecuronium, and to examine the effect of residual neuromuscular block on the incidence of POPC. METHODS: A total of 691 adult patients undergoing abdominal, gynaecological, or orthopaedic surgery under general anaesthesia were randomised to receive either pancuronium, atracurium, or vecuronium. Perioperatively, the response to train-of-four (TOF) nerve stimulation was evaluated manually. Postoperatively, the TOF ratios were measured mechanomyographically, and through a 6-day follow-up the patients were examined for pulmonary complications. RESULTS: The incidence of residual block, defined as a TOF ratio < 0.7, was significantly higher in the pancuronium group (59/226: 26%) than in the atracurium/vecuronium groups (24/450: 5.3%). In the pancuronium group, significantly more patients with residual block developed POPC (10/59: 16.9%) as compared to patients without residual block (8/167: 4.8%). In the atracurium/vecuronium groups, the incidence of POPC was not significantly different in patients with (1/24: 4.2%) or without (23/426: 5.4%) residual block. Multiple regression analysis indicated that abdominal surgery, age, long-lasting surgery, and a TOF ratio < 0.7 following the use of pancuronium were potential risk factors for the development of POPC. CONCLUSION: Postoperative residual block caused by pancuronium is a significant risk factor for development of POPC.

Bioactive substance accumulation and septic complications in a burn trauma patient: effect of perioperative blood transfusion?

Evidence has emerged that suggests adverse effects to perioperative homologous blood transfusion are related to the age of the blood products. Recently, time-dependent accumulation of bioactive substances in red cell suspensions, standard platelet concentrates and fresh frozen plasma during storage have been shown. The potential adverse effects of these bioactive substances were analysed in a burn trauma patient. A patient with 40 per cent second and third degree burn trauma without other injuries underwent a two-step transplantation operation. Samples for analyses of histamine, eosinophil cationic protein (ECP), eosinophil protein X (EPX), neutrophil myeloperoxidase (MPO) and interleukin 6 (IL-6) were drawn frequently from the patient before, during and after the operations, and from all transfused red cell, platelet and fresh frozen plasma units. Urine was sampled every hour during the first operation for analyses of ECP and EPX excretion. All analyses were performed by ELISA and RIA methods, and results compared to patient outcome. The patient received a total of 48 and 8 SAGM blood, 6 and 0 platelet and 12 and 4 fresh frozen plasma units at the two operations, respectively. Transfused products contained a total of 64.54 nmol and 17.50 nmol histamine, 115518 ng and 25764 ng ECP, 174457 ng and 38770 ng EPX, 6950915 ng and 1505125 ng MPO, and 14740 pg and 5600 pg IL-6 at the two operations, respectively. The accumulation of the substances in patient plasma correlated to postoperative septic reactions, without any disclosure of bacteraemia after the first operation, while the accumulation at the second operation correlated to the septic reaction and Pseudomonas aeruginosa infection. Time-dependent accumulation of bioactive substances in blood products during storage may be related to the development of post-transfusion adverse effects.

Health impacts of large releases of radionuclides. The fate and impact of radiocontaminants in urban areas.

The Chernobyl accident made it clear that the contaminants released after a severe nuclear accident may spread over large areas, and thereby form a significant external radiation hazard in areas of high population density. Since then, the weathering effects on the deposited radiocontaminants (essentially radiocaesium) have been followed on different types of surface in urban, suburban and industrial areas in order to enable an estimation of the long-term impact of such events. Analytical expressions have been derived for the typical behaviour of radiocaesium on the different surfaces, and dose measurements and calculations for different urban environments have pinpointed which surfaces generally contribute most to the dose and consequently are most important to clean. At this point, after nearly a decade, the dose rate from horizontal pavements has decreased by at least a factor of 10, whereas the dose rate from an area of soil or a roof has generally only been halved. The contamination on walls is the most persistent: it has only decreased by 10-20%.

The effect of succinylcholine on atracurium-induced neuromuscular block.

BACKGROUND: The interaction between prior succinylcholine and atracurium has been found only after full recovery of succinylcholine block. We investigated whether the effect of succinylcholine on atracurium block may depend on the level of recovery from succinylcholine. METHODS: Fifty patients in 4 groups received atracurium 0.2 mg/kg when first response (T1) in train-of-four (TOF) after succinylcholine 1 mg/kg had recovered to 5%, 25%, 75% or 100%. A control group received only atracurium. The following indices were compared: the time from injection of atracurium to maximum block (onset time) and to return of T1 to 25% (duration 25%), maximal depression of T1, time from 25% to 75% recovery of T1 (interval 25-75%) and time from injection of atracurium to a TOF ratio of 0.75 (duration TOF 0.75). RESULTS: Onset time was shorter, max T1 depression was greater and duration 25% increased the more succinylcholine recovery progressed. Neither interval 25-75% nor duration TOF 0.75 varied with the level of recovery from succinylcholine. The control group showed a shorter latency and onset time compared to the early (5%) recovery group and a longer onset time and less depressed T1 compared to the late (100%) recovery group. There was no difference between the control group and the early or late recovery groups, respectively for duration 25% or duration TOF 0.75. CONCLUSION: The effect of prior administration of succinylcholine on atracurium block depends on the state of recovery from succinylcholine and concerns both its potency, onset and duration characteristics.

The agreement between adductor pollicis mechanomyogram and first dorsal interosseous electromyogram. A pharmacodynamic study of rocuronium and vecuronium.

The agreement between evoked adductor pollicis mechanomyogram and first dorsal interosseous evoked electromyogram (EMG) was evaluated during a pharmacodynamic study of rocuronium and vecuronium. In the first place the effective doses of rocuronium producing 50% and 90% block (ED50 and ED90, respectively) were established in 32 neurolept anaesthetized patients from the adductor pollicis mechanomyogram and the first dorsal interosseous EMG area and amplitude. Secondly, limits of agreement between the two methods were evaluated from the mean difference between methods +/- 2 s.d. in 20 patients during onset of block following 2 x ED90 of rocuronium and vecuronium, and during recovery from the last supplementary dose of 1/2 x ED90. Limits of agreement show how much the EMG may be above or below the mechanomyogram. No differences were found between mechanomyographical and EMG based ED50 (0.20 mg kg-1) and ED90 (0.30-0.32 mg kg-1), respectively. The first EMG train-of-four (TOF) response overestimated block at 25% recovery and underestimated block at 75% and 90% recovery by only 3-7%. Limits of agreement suggested that the EMG may be 7-8% above or below the mechanomyogram during onset compared to 12-17% during recovery. The EMG TOF ratio lagged behind that of the mechanomyogram by 0.05 at TOF ratios below 0.50. No difference was found between methods at a TOF ratio of 0.75. Limits of agreement indicated that the EMG TOF ratio may be 0.12-0.15 above or below that of the mechanomyogram. Agreement between the amplitude and the area of the EMG were better than between the mechanomyogram and the EMG. Evaluation of the time courses of action showed that rocuronium had a faster onset of action than vecuronium (1.8 min compared to 2.8 min) while duration of action and reversal were similar. In conclusion, the first dorsal interosseous EMG amplitude and area can be used to assess rocuronium and vecuronium block.

Equine hoof function investigated by pressure transducers inside the hoof and accelerometers mounted on the first phalanx.

The dampening of hoof impact was investigated by measuring the accelerations transmitted through structures of the hoof in horses trotting freely on an asphalt tarmac. The hoof dampened the vibrations transmitted to the first phalanx. Shoeing decreased the viscous dampening and increased the median power frequency and the maximal amplitude of the vibrations transmitted to the first phalanx. The pressure inside the digital cushion of the foreleg was recorded. The pressure dropped during the stance phase, indicating expansion of the hoof. The expansion of the hoof was not produced by frog or sole weight bearing because this would have increased the intra-digital cushion pressure. The pressure theory of hoof function must presumably therefore be rejected. Shoeing the horses augmented the intra-digital cushion pressure drop and probably impaired the movements of the hoof wall.

Differential effect of pancuronium at the adductor pollicis, the first dorsal interosseous and the hypothenar muscles. An electromyographic and mechanomyographic dose-response study.

Cumulative dose-response curves were constructed from evoked compound electromyographic (EMG) recordings in man to compare the sensitivity to pancuronium of the adductor pollicis, the hypothenar and the first dorsal interosseous muscles. Also, the EMG and mechanomyography-based sensitivity of the adductor pollicis muscle were compared. The EMG and the mechanomyogram were evaluated in random sequence in each of 21 adult thiopental, fentanyl and diazepam anesthetized patients. The EMG-based ED50 were 36-38 micrograms.kg-1 with no differences between muscles. The EMG-based ED90 of the adductor pollicis and the hypothenar muscles were 62-65 micrograms.kg-1 compared to the 60 micrograms.kg-1 of the first dorsal interosseous muscle (P < 0.05). ED50 (34 micrograms.kg-1), and ED90 (56 micrograms.kg-1) obtained from the adductor pollicis mechanomyogram were significantly lower than those based on the EMG (P < 0.05). It is concluded that differences in sensitivity to pancuronium exist between the three muscles when evaluated from the EMG, and that the apparent sensitivity of a given muscle to a muscle relaxant may depend upon whether the response is evaluated using EMG or mechanomyography.

[Body height in a population of children in Greater Copenhagen 7 to 18 years of age in 1981 and 1985. The Osterbro child study]. / Højde hos en population af storkøbenhavnske børn i alderen 7-18 år, 1981 og 1985. Osterbro-undersøgelsens børneundersøgelse.

As part of the childrens' section of the Osterbro investigation, a quantity of standard health information concerning 736 boys and girls in 1981 and 892 in 1985 was collected. Review of these values revealed a significantly greater average height (greater than 3 cm) for boys in the age group 8-16 years and for girls aged 7-15 years than in previously published materials. The final height at about the age of 18 years for both girls and boys was not found to deviate significantly from previous results. The height/weight relationship remained unchanged. Current adjustments of the normal curves for childrens' growth should be made and/or an assessment of how well the subpopulation concerned is in agreement with the national average.

[Food composition and serum lipids in children]. / Kostsammensaetning og serum-lipider hos børn.

The composition of the diet is considered to be one of the factors which may be of significance in development of ischaemic heart disease. In order to investigate whether the composition of the diet has a greater influence on the cholesterol levels in children than in adults, af 24-hour dietary interview was carried out on 42 children aged 7-11 years who had previously been examined in the childrens' section of the Osterbro investigation. The children were selected in three groups with low, average and high serum cholesterol levels, respectively. The dietary content of energy-providing substances was compared with the cholesterol values measured. In addition, the composition of the diet in other respects was described and was found to contain, on an average, 40% fat, 14% protein and 42% carbohydrate (of which 14% was sugar). The cholesterol intake was 146 mg/1,000 Kcal. The sugar consumption was low as compared with the national average, approximately 62 g/day. The protein consumption was approximately 2 g per kg body-weight per day. The median total energy intake was 8,024 KJ for girls and 8,569 KJ for boys lower than the recommended daily values and corresponded to a low levels of physical activity. This investigation showed a definite linear connection between the fat energy percentage and the serum cholesterol (alpha = 5.26 p less than 0.005) and that intake of saturated fatty acids, in particular can be related to the cholesterol level (alpha = 2.88 and p less than 0.005). A significantly greater fat energy intake was demonstrated in girls (p less than 0.05) in the group with high serum cholesterol levels.(ABSTRACT TRUNCATED AT 250 WORDS)