Swedish Plants Research Articles

Cs-137 in fuels and ash products from biofuel power plants in Sweden

The activity concentrations of Cs-137 in peat, wood chips and ash products from 13 Swedish district heating plants have been investigated during the winter seasons of 1986/87, 1988/89, 1989/90 and 1990/91. There is a significant decrease in the activity concentration of Cs-137 in the fuel which was especially pronounced between the first two seasons after the Chernobyl accident. In spite of the varying deposition of Cs-137 over the country it has been possible to find a relation between the activity concentration in the peat and wood chips, and the deposition. The total number of Swedish heating plants of which 35–40 are burning peat and 70–75 wood chips have been divided in three groups according to the activity concentration in the ash products. The mean Cs-137 concentration in ash and the total activity ‘produced’ per year in Sweden have been calculated. The maximum ground concentration and corresponding effective dose rate of inhaled Cs-137 as a function of the emission rates of flue gases from stacks with varying heights and during different Pasquill atmospheric stability conditions have been calculated.

Ergonomic development work: Co-education as a support for user participation at a car assembly plant. A case study

This study deals with the design, trials and evaluation of a co-education programme at the Volvo Uddevalla plant in Sweden. Involving operators, manufacturing engineers and managers, the programme served as a support for the creation of a participatory ergonomics process, intended for continuous use at the plant. It consisted of a basic ergonomics knowledge package, and a dialogue model defining the roles and relations of actors involved. As a practical part of the programme, trial development projects were also carried out by the participants. The main and long term objective of the project was to start the participants cooperating in a continuous change and development process on the shop-floor. The outcome of the co-education programme was evaluated immediately after the first two regular courses, and, as a longterm follow-up, after seven subsequent courses shortly after the closing of the Uddevalla plant. The co-education programme was shown to be successful. Later on, the expertize of both operators and manufacturing engineers became obvious to everyone at the plant, and the cooperation between operators and manufacturing engineers increased steadily. The main conclusion drawn was that the co-education programme is a good starting point for a process of participation and industrial change work. However, in order to get a permanent impact, the whole organization must nurse and nourish the further development, and implementation of the process.

Cancer incidence, mortality and exposure-response among Swedish man-made vitreous fiber production workers.

The objective of this study was to provide an extended follow-up of workers in three Swedish plants producing man-made vitreous fibers (MMVF). Mortality and cancer incidence was investigated among 3539 male and female workers, employed for at least one year before 1978. Mortality was followed from 1952 to 1990 and cancer incidence from 1958 to 1989. National and regional mortality and cancer incidence rates were used to calculate the expected numbers. Twenty-seven lung cancer deaths were observed compared with 23 expected (standardized mortality ratio 117, 95% confidence interval 81-176), based on regional mortality. With a latency time of 30 years, the lung cancer risk was significantly elevated, but not trend was found for the standardized mortality ratio with increasing duration of exposure to MMVF. The lung cancer and stomach cancer mortality was higher in the rock wool industry than in the fiber glass industry. Fiber exposure from 1938 to 1990 was estimated in the two rock wool plants by applying a model for historical fiber exposure estimation, specific for different job titles in the rock wool production industry. No relationship was found between individually cumulated rock wool fiber exposure and lung cancer or stomach cancer risk. The numbers of lung cancers and stomach cancer cases were low and did not therefore allow more general conclusions regarding the cancer hazard for exposed workers. A large European study in progress will probably allow more precise conclusions.

Robots carry the load at Scania

Outlines how Scania is planning to automate its truck axle production lines at its Falun plant in Sweden. The automation package includes 40 PCs, 26 robots and 15 AGVs. The PCs are linked up to an Ethernet LAN which connects to the factory management system. IBM’s Plantworks software co‐ordinates the entire operation. Describes how the robots were chosen and how they will operate on the production line. The new plant will begin operating in August 1996 and will be required to function with a utilization rate of 90–94 per cent.

Characterization of current exposure to man-made vitreous fibres (MMVF) in the prefabricated house industry in Sweden

The exposure to man-made vitreous fibres (MMVF) was investigated at 11 Swedish plants manufacturing prefabricated wooden houses. Current fibre levels were studied by monitoring personal exposure using the membrane filter technique. All samples were analysed by phase contrast optical microscopy (PCOM) according to Swedish standard rules; they were also analysed using a set of modified criteria for fibre counting, developed for this study, which in addition also required straight, parallel and/or convergent edges of the fibres. The objective of this alternating counting method, the modified fibre method, was to exclude fibres with appearance other than MMVF, that might be present in the wood industries. The method was validated by scanning electron microscopy (SEM). In all, 120 samples were taken and 273 analyses were performed. The mean exposure (GM), analysed by the standard method, was for insulators 0.10 f ml−1 (range 0.03–0.30 f ml−1) and for woodcutters 0.09 f ml−1 (range 0.05–0.19 f ml−1). Analysed by the modified fibre method the insuslators were exposed to 0.029 f ml−1 (range 0.013–0.077 f ml−1) and the cutters to 0.021 f ml−1 (range 0.014–0.033 f ml−1). A significant difference was observed between the exposure for near-field workers/job titles and far-field workers/job titles. Analysis of fibre levels by the modified fibre method indicated that only a minor proportion, around 25%, of the total airborne fibres were MMVFs. The reliability of the alternative modified counting method was high, and a high correlation (r = 0.94) with the SEM results was also achieved.

Factors influencing the changes in Cs levels with time in boreal-forest plants in Sweden

The distribution and turnover of radiocesium from the reactor accident at Chernobyl in 1986 has been monitored in boreal forest vegetation in Sweden since 1986. The purpose has been to characterise the distribution of 137Cs in plants and biotopes over time. The study was mainly performed in an experimental forest where the fall-out in 1986 was 23 000 (S.D. 11 000) Bq/m2137Cs. In addition, we included 36 sites in a radius of ∼ 200 km from the experimental forest representing a range of ground deposition levels from 8000 to 80 000 Bq/m2 of 137Cs. Significant differences in 137Cs activity were found between plant species. The highest concentration in 1986 was 48 000 Bq per kg 137Cs dry mass in Nymphaéa cándida, and the lowest was 31 Bq per kg 137Cs dry mass (Epilobium angustifolium). We found a weak, but significant, correlation between ground deposition and cesium concentration in Betula pubescens and Vaccinum myrtillus. A significant decline in 137Cs levels occurred between 1986 and 1990. The cesium level in bilberry declined faster in young mixed forests (5- to 10-year-old clear cuttings) than in mature coniferous forests.

Reaction norm variation in a rare plant, Senecio integrifolius (Asteraceae)

This study examines the pattern of reaction norm variation and the extent to which genetic constraints could prevent the evolution of broader ecological tolerance in Senecio integrifolius, a rare and declining plant in Sweden. Following the establishment of biparental progenies, we planted seedlings from each full-sib family in two greenhouse environments: full daylight and 50 per cent shade. A 2-year demographic study indicated that full-sib genotypes representing a large population at a site with a fine-scale mosaic habitat (meadow with clumps of shrubs) had a significantly greater overall performance across the environments and a lower sensitivity to a drastic reduction in light intensity than genotypes representing a small and patchily distributed population at a site without spatial variation (meadow exposed to full sun), confirming the supposition of more broadly adapted genotypes in a large population subject to selection across a wider range of micro-habitats. There was a significant average effect of genotype for all traits but we failed to detect within-population variation in phenotypic response (G × E) for direct components of fitness and conclude that there is little potential for specialization to particular light regimes. Across-environment correlations using full-sib means were small and positive and there was no change in the ranking of population means across the two environments, implying a lack of strong trade-offs within the reaction norm. However, the changes in ecological amplitude may not be of sufficient magnitude to permit long-term survival of remaining populations, as implied by the rapid decline of S. integrifolius in Sweden.

Radioactive elements in the forest industry

Ash from 16 different biofuel powered plants in Sweden collected in 2-week intervals over half a year were analyzed for the activity concentration of radiocesium, potassium and radiostrontium. The flux of radionuclides at different steps in a pulp mill process were also studied. The gamma emitting radionuclides such as 137Cs and 134Cs are of prime interest when considering current dose rates on a biofuel waste deposit. Measurements of the absorbed dose to superficial tissue using TL-dosimeters showed a clearly increasing trend for the dose rate (+5 nGy/year) as a function of time when measure 1 m above different locations on the dump corresponding to deposits made from 1987 to 1990. The present investigation shows that besides the potential increase in absorbed doses to a rather limited population, waste products must be considered from a radiological point of view due to the involved concentration processes. The radionuclides might play an important role in the understanding of the effects of using waste products as fertilizers.

Assessment of Worker Exposure in the Processing of Ultraviolet Radiation-Cured Acrylate Lacquer-Coated Wood Products

Abstract Manufacturing of wood products coated with ultraviolet (UV) radiation-curable acrylate coatings has increased in recent years and, to our knowledge, an assessment of worker exposure has not been conducted. To assess worker exposure we identified manufacturing plants in Sweden using this technology and evaluated work force and production by questionnaire. From this database we selected eight plants that we believed were representative of the industry. At each plant, an industrial hygiene survey was conducted. Worker exposure to acrylate vapors and aerosols, dust, solvents, ozone, UV radiation (including operational performance of UV lamps), and work practices were investigated. We found that ∼350 of the 8500 production workers are potentially directly exposed to acrylates and UV radiation. Although dust levels were low (∼0.4 mg/m3, 8-hour time-weighted average), ∼30 percent of dust particles were respirable (< 5 μm diameter). Exposure to potential sensitizing agents (acrylates and photoinitiators)...

Factors influencing the changes in 137Cs levels with time in boreal-forest plants in Sweden

The distribution and turnover of radiocesium from the reactor accident at Chernobyl in 1986 has been monitored in boreal forest vegetation in Sweden since 1986. The purpose has been to characterise the distribution of 137Cs in plants and biotopes over time. The study was mainly performed in an experimental forest where the fall-out in 1986 was 23 000 (S.D. 11 000) Bq/m 2 137Cs. In addition, we included 36 sites in a radius of ∼ 200 km from the experimental forest representing a range of ground deposition levels from 8000 to 80 000 Bq/m 2 of 137Cs. Significant differences in 137Cs activity were found between plant species. The highest concentration in 1986 was 48 000 Bq per kg 137Cs dry mass in Nymphaéa cándida, and the lowest was 31 Bq per kg 137Cs dry mass ( Epilobium angustifolium). We found a weak, but significant, correlation between ground deposition and cesium concentration in Betula pubescens and Vaccinum myrtillus. A significant decline in 137Cs levels occurred between 1986 and 1990. The cesium level in bilberry declined faster in young mixed forests (5- to 10-year-old clear cuttings) than in mature coniferous forests.

Process options for nitrogen and phosphorus removal in domestic wastewater

The introduction of biological nitrogen removal at many sewage treatment plants in Sweden, particularly those located at coastal regions up to Stockholm archipelagio in the east, is now proceeding primarily by plant trial operation and construction works to be finalised in 1995/96 at the latest. The most characteristic problems with biological nitrogen removal in Sweden are the cold winter climate and the deficit of an easily biodegradable carbon source for anoxic denitrification.This report includes some R&D works from the sewage treatment plant in Halmstad on the west coast, including the concluding results of 2-years' trial operation on nitrogen removal. The main problems have been to evaluate two different process alternatives during different climate conditions as well as different external carbon sources and compare such a carbon source with an internal carbon source generated by anaerobic enzymatic hydrolysis of primary or mixed raw sludge.Methanol has been evaluated to be the best external carbon source with the lowest biological sludge production and little detrimental influence on the sludge characteristics. The results of experimental works and cost calculations on the acid phase of anaerobic sludge digestion under formation of volatile organic acids (acetic acid etc.) showed that the costs for this carbon source with a modified sludge treatment scheme is competitive with methanol from both a technical and economical point of view. Dosage of primary sludge as carbon source for anoxic predenitrification has also given satisfactory results during the warmer period of the year (June - November). This method is not applicable in Sweden during the colder period of the year, because the nitrification will be depressed due to a decrease of the sludge age.The two different process alternatives for biological nitrogen removal were conventional pre-denitrification and a combined pre- and post- denitrification respectively. The last-mentioned system is probably the best process alternative with better operation flexibility and possibilities to a more far-reaching nitrogen removal. Both alternatives are recommended for practical operation in order to make it possible to switch over from one alternative to the other with respect to e.g. the water temperature.Problems in connection with an expected, more stringent phosphorus limit of 0.3 mg P/l in the effluent are also discussed. A polishing step in addition to chemical pre-precipitation is required.

Immigrants and occupational accidents: A comparative study of the frequency and types of accidents encountered by foreign and Swedish citizens at an engineering plant in Sweden

The study concerns the relationship between citizenship and accidents, broken down by workshop, occupational group, age and experience, at a Swedish automobile and truck factory. It covers 537 accidents among personnel employed under collective agreement over the years 1986–1987. Comparisons between average annual frequency rates for Swedish and foreign citizens are made. The study offers no support for the view that immigrants are at greater risk than nationals for occupational accidents. In fact, most of the comparisons showed a higher accident frequency among workers of Swedish nationality, although statistically significant differences between groups were obtained in only a few cases. There was, however, a higher accident frequency for young and less experienced foreign citizens than for young Swedish nationals. In an analysis of the 178 accidents that occurred at the company's engine workshops, attention was also paid to the relationships between type of accident situation on the one hand and citizenship and country of birth on the other. These shops had a high proportion of immigrants and a relatively high accident frequency. A multivariate method of analysis was employed, involving the application of cross-tabulations and Chi-square tests to previously factored/clustered data. No significant difference between foreign and Swedish citizens emerged with respect to type of accident situation. This study does not indicate that there is a need for immigrants as a group to be specifically targeted in work designed to prevent occupational accidents.

Linnaeus as an Economic Botanist

Summary The interest of Carl Linnaeus (1707–1778) in the uses of plants as manifested in his travel books and dissertations was much influenced by the urge of his country, war-impoverished Sweden, for national recovery and self-sufficiency. His official Swedish journeys of 1741–1749 were primarily economic surveys, giving much attention to locally used dye-plants. The dissertation Pan Suecicus (1749) details experimental feeding of cattle, pigs, sheep and goats with native Swedish plants: it also represents an important stage in the development of the Linnaean binomial method for naming species.

Cancer incidence and mortality in the Swedish polyurethane foam manufacturing industry.

Toluene diisocyanate (TDI) and methylene diphenyldiisocyanate (MDI) are used in large quantities in the polyurethane foam manufacturing industry. Both substances are mutagenic and at least TDI is carcinogenic to animals, but the occupational hazard with respect to cancer is not known. Cancer incidence and mortality patterns were therefore investigated in a cohort of 4154 workers from nine Swedish plants manufacturing polyurethane foam, employed for at least one year. Each workplace and job task in the nine plants was categorically assessed for each calendar year by an experienced occupational hygienist, for "no exposure", "low or intermittent exposure", or "apparent exposure" to TDI and MDI. The observed deficit for all cause mortality (standardised mortality ratio (SMR) 0.78, (95% confidence interval (95% CI) 0.66-0.93) became smaller (SMR 0.92) excluding the first 10 years since the start of exposure and was ascribed to a healthy worker effect. No increased risk for death from bronchial obstructive diseases was found. An almost statistically significant deficit occurred for all malignant neoplasms (standardised incidence ratio (SIR) 0.81, 95% CI 0.63-1.02); slight (not significant) increased risks were found for rectal cancer (SIR 1.66) and non-Hodgkin's lymphoma (SIR 1.53). The SIR for non-Hodgkin's lymphoma increased to 2.80 (95% CI 0.76-7.16) when the first 10 years since first exposure were excluded from the observation period. The corresponding figure for rectal cancer was 1.92 (95% CI 0.52-4.92). Further restricting the analysis to those who had experienced an apparent exposure to TDI or MDI increased the SIR for both rectal cancer (3.19, 95% CI 0.66-9.33), and non-Hodgkin's lymphoma (3.03, 95% CI 0.37-10.9). These estimates were based, however, on few incident cases. As the cohort is still young and little time has elapsed since the start of exposure, future follow ups will enable a more conclusive evaluation.

Quantitative genetics of life-history and morphology in a rare plant, Senecio integrifolius

A paternal half-sib analysis was performed to estimate the narrow-sense heritability for 35 morphological and life-history characters in two populations of Senecio integrifolius, a rare and threatened plant in Sweden. The two populations differed greatly in size, the small one consisting of separate patches and the large one having a more or less continuous distribution. In addition to significant population differences in the mean of 26 characters, we found slightly higher heritabilities in the small and patchy population (average 0.49) than in the large and continuous population (average 0.43). Overall, the small population displayed significant additive genetic variation for a larger number of characters than the large population (19 vs. 14). Paternal (genetic) effects were consistent in two different environments; the ranking of sire means was similar despite a drastic reduction in light intensity, and few characters had a significant sire × environment interaction. Genetic correlations were also found between different characters measured in the same environment, although most of these were in the 'favourable' direction. Population differences in genetic parameters may reflect contrasting selection regimens at the two sites, although genetic drift may also be important. That more genetic variability was detected in the small population where plants occur in small and isolated patches indicates that the spatial structure has great effects on the retention of heritable variation, and that demographic and environmental factors are more important in the long-term survival of S. integrifolius. This is the first study that relates quantitative genetic variation to population size in a rare and threatened plant.

The End of the Middle Road: What Happened to the Swedish Model?

If there is one single industrial product that has symbolized the Swedish "middle road," it must be the Volvo car: high quality, middle to upper class, safety first, and manufactured in a humane way, without a traditional assembly line. Now this symbol has run up against serious problems. In November 1992, Volvo announced that it would close down two of its assembly plants in Sweden, precisely the two plants in Kalmar and Uddevalla where the new assembly concept was developed. Furthermore, future expansion would only take place at Volvo plants outside Sweden. Saab, which had already been sold to General Motors in an earlier crisis, also announced reductions in production and employment levels. These cutbacks are not just a simple reflection of the global economic crisis. They announce more profound changes in the Swedish model which have taken place over a longer period of time. They also indicate that the middle way has become a dead end.This article can also be found at the Monthly Review website, where most recent articles are published in full.Click here to purchase a PDF version of this article at the Monthly Review website.

Extension of the Sewage Treatment Plants in Stockholm: Some Technical and Economical Aspects

The requirements for the sewage treatment plants in Sweden will be more stringent in the future. The three plants in Stockholm, Henriksdal, Bromma and Loudden have to be extended to meet requirements for nitrogen removal and increased phosphorus removal. Since 1989 the plants have the same recipient for the treated sewage and to save money during the future extension the city would like to regard the three effluents as one common. The authorities have not yet decided to admit this but there is a good chance for it. The paper describes the strategy for extension and how the plants have been designed.

Biological control of pests in Swedish pot plant production

Biological control of glasshouse pests is nowadays an important factor in the production of pot plants in Sweden. During 1990, more than 100 growers applied one or more methods of biocontrol, some only in propagation units but many during the entire production of several crops. Poinsettia is the major crop in this context. Eighty growers were interviewed about their experiences of various biocontrol methods. The use of Neoaplectana carpocapsae against sciarids and Otiorhynchus sulcurus was the most popular and reliable method. Next comes Encarsia formosa against whiteflies. Other methods include Verticillium lecanii against whiteflies and thrips, Aphidius matricariae against aphids, and predatory mites against thrips and spider mites.

Model and Sensor Based Optimization of Nitrogen Removal at Klagshamn Wastewater Treatment Plant

Optimization of wastewater treatment plants with extensive phosphorus and nitrogen removal is complicated. The Klagshamn wastewater treatment plant in Sweden is operated with pre-precipitation of phosphorus with ferric chloride and denitrification with methanol as carbon source. An activated sludge process, operated with pre-precipitation and denitrification with external carbon source in a compartmentalized plant, requires only small tank volumes but increases the need for proper operation and optimization. On-line nitrogen, ammonia, and TOC sensors are used for a day-to-day control and optimization while mathematical modelling is used for long term strategic planning. The on-line measurements are further used as the basis for the modelling. TOC and ammonia sensors at the influent clearly identify typical and extreme loading variations and nitrate measurements in the activated sludge tanks and the effluent shows the dynamics of the processes. These measurements provide a basis for model calibration. In combination low residuals of nitrogen, phosphorus and organic matter can be achieved.

Industnal Relations and ProductMty: Evidence from Sweden and Australia

Two case studies, which are reported in this paper, are part of a wider study comparing matched Swedish and Australian plants in the automotive components industry. The study examined productivity levels in each of the cases and sought to determine which variables were significant in explaining differences between the performance of the two plants. The Swedish plant achieved higher levels of both productivity and quality than its Australian counterpart. This appeared to be related not only to higher levels of investment in technology, but also to a greater emphasis on skills development and work organization which emphasized teamwork and consultation. Not surprisingly, there was a high level of cooperation between the workforce, unions and management in the Swedish case. By contrast, the Australian plant was caught in a vicious cycle of low productivity and quality, poor industrial relations and a declining market share. As a consequence, it will be hard pressed to survive the current recession without radical changes in its operations.