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- Adamsson, Marie, 1966, et al.
(author)
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Toxicity Identification Evaluation of ammonia, nitrite and heavy metals at the Stensund Wastewater Aquaculture plant, Sweden.
- 1998
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In: Water Science and Technology. - 0273-1223. ; 38:3, s. 151-157
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Journal article (peer-reviewed)abstract
- The Stensund Wastewater Aquaculture plant was built in 1989. The plant is contained in a greenhouse because of its northern location with a temperate climate; The plant receives wastewater from 40 persons and has a residence time of 30 days. The purification concept is to use a constructed aquatic food chain (algae, zooplankton and fish) combined with hydroponic culture of higher plants to further deplete the nutrients in the wastewater. However, the production of algae and zooplankton has not been working as expected from pilot studies. The purpose of this investigation was to study if toxic chemicals were limiting the production of zooplankton (Daphnia magna) in the aquaculture treatment system. Grab samples were taken at six sites and tested for acute toxicity to Daphnia magna and analyzed for BOD, COD, ammonium-, nitrite-, nitrate- and total nitrogen, total phosphorus and heavy metals (Cd, Ci, Cu, Ni, Pb, Zn). Toxicity to D. magna was also determined after addition of EDTA, sodium thiosulphate and pH adjustment of the,water to 6, 7 and 8, in order to assess if heavy metals and/or pH-dependent toxicants were present Potential toxicants, with concentrations high enough to intoxicate Daphnia magna, were Cu, ammonia and nitrite. Subsequent improvement of nitrification reduced the ammonia and nitrite concentrations as well as the toxicity. Furthermore, the improved production of algae and Daphnia at the Stensund Wastewater Aquaculture plant verified that the primary cause of toxicity was ammonia. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
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- Adamsson, Marie, 1966, et al.
(author)
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Toxicity of human urine and its main nitrogen excretory and degradation products to Daphnia magna
- 1996
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In: Environmental Research Forum. - 1421-0274. ; 5-6, s. 137-144
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Journal article (peer-reviewed)abstract
- The discovery of nitrogen as a major cause of eutrophication, especially in the marine environment, has intensified the research on nitrogen removal from sewage water. About eighty percent of the nitrogen in domestic sewage water originates from human urine. One alternative for nitrogen reduction technology in sewage treatment, is to separate the urine from fecal matter, and use the urine as a fertilizer, either in agriculture or in aquaculture. In temperate regions urine has to be stored during the winter season. The objectives of this study were to determine the toxicity to Daphnia magna of human urine, its major nitrogen excretory products (urea, uric acid, ammonia and creatinine) and their degradation products (nitrite and nitrate) and to determine how storage affects the chemical composition of these nitrogen compounds in urine and the resulting effect on urine toxicity to D.magna. The 48-h EC50 for D.magna of fresh morning urine from ten persons ranged from 2.8 to 12.5 percent by volume (mean +/- SD: 5.4 +/- 2.9). The 48h EC50s (expressed as mM of nitrogen) for the nitrogen compounds were 679 for urea, 78 for nitrate, 49 for creatinine, 2.4 for uric acid, 1.5 for ammonia and 0.6 for nitrite, at pH between 8.2-8.5. The toxicity of urine increased approximately five rimes during storage in 32 days at 20 degrees C. The major cause of this increase was conversion of urea to ammonia, which was accompanied by an increase in pH from 5.7 to 9.7, making the ammonia even more toxic. Therefore, the use of human urine as a fertilizer in aquaculture and probably also in agriculture must consider the potential toxicity of ammonia.
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- Filipsson, Karl, et al.
(author)
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Encystment of parasitic freshwater pearl mussel (Margaritifera margaritifera) larvae coincides with increased metabolic rate and haematocrit in juvenile brown trout (Salmo trutta)
- 2017
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In: Parasitology Research. - : Springer Science and Business Media LLC. - 0932-0113 .- 1432-1955. ; 116, s. 1353-1360
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Journal article (peer-reviewed)abstract
- © 2017 The Author(s)Gill parasites on fish are likely to negatively influence their host by inhibiting respiration, oxygen transport capacity and overall fitness. The glochidia larvae of the endangered freshwater pearl mussel (FPM, Margaritifera margaritifera (Linnaeus, 1758)) are obligate parasites on the gills of juvenile salmonid fish. We investigated the effects of FPM glochidia encystment on the metabolism and haematology of brown trout (Salmo trutta Linnaeus, 1758). Specifically, we measured whole-animal oxygen uptake rates at rest and following an exhaustive exercise protocol using intermittent flow-through respirometry, as well as haematocrit, in infested and uninfested trout. Glochidia encystment significantly affected whole-animal metabolic rate, as infested trout exhibited higher standard and maximum metabolic rates. Furthermore, glochidia-infested trout also had elevated levels of haematocrit. The combination of an increased metabolism and haematocrit in infested fish indicates that glochidia encystment has a physiological effect on the trout, perhaps as a compensatory response to the potential respiratory stress caused by the glochidia. When relating glochidia load to metabolism and haematocrit, fish with low numbers of encysted glochidia were the ones with particularly elevated metabolism and haematocrit. Standard metabolic rate decreased with substantial glochidia loads towards levels similar to those of uninfested fish. This suggests that initial effects visible at low levels of encystment may be countered by additional physiological effects at high loads, e.g. potential changes in energy utilization, and also that high numbers of glochidia may restrict oxygen uptake by the gills.
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- Johansson, Jonas, et al.
(author)
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Solar disinfection at low costs: an experimental approach towards up-scaled continuous flow systems
- 2022
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In: H2open Journal. - : IWA Publishing. - 2616-6518. ; 5:1, s. 153-165
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Journal article (peer-reviewed)abstract
- SOlar DISinfection (SODIS) systems have been studied with the aim of maintaining pathogen removal efficiencies and low costs. Such systems are useful for quickly improving the situation of more than 700 million people worldwide that lack access to an improved water source. Currently, SODIS is mainly used with PET-bottles that are exposed to UV-A radiation for 6 h in the sun. Up-scaled continuous flow SODIS systems could instead provide a continuous source of drinking water, whereas the use of plastic tubes, easily available on local markets, ensures a low construction cost of the systems. Such tubes (PVC) were tested and the best option showed a UV-A transparency ratio of similar to 50%, to be compared with similar to 60% for PET-bottles. By using static batches in samples of this tube, the residence time was investigated and the results show that E. coli concentrations of 0 CFU/ml are reached within less than 4 h of exposure to solar radiation, starting from an initial concentration of 10(6) CFU/ml. It can be concluded that cheap, easily available plastic tubes can be used for treating contaminated water with the SODIS technique, which is promising for future investigations towards constructing continuous flow SODIS systems at low costs.
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- Pettersson, Annelie, et al.
(author)
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Toxicity and detoxification of Swedish detergents and softener products
- 2000
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In: Chemosphere. - 0045-6535. ; 41:10, s. 1611-1620
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Journal article (peer-reviewed)abstract
- Detergents and softeners are used in large quantities and some of their ingredients are highly toxic to aquatic organisms. In the present study the acute toxicity to Daphnia magna was determined for 26 detergents and five softener Swedish products. Only one of the detergents had a 48-h EC50 > 100 mg/l. The 48-h EC50 for the other 25 detergents ranged from 4 to 85 mg/l. The 48-h EC50 for the five softeners ranged from 15 to 166 mg/l. Detoxification tests, with and without inoculum of sewage organisms, showed that all tested products were detoxified to some extent after 16 days and that the rate of detoxification was considerably higher with addition of sewage organisms. Toxicity to D. magna of the detergents and softeners, and the biotic detoxification rate was correlated with the concentration of surfactants used in formulating the products (more surfactants increased toxicity and a slower rate of detoxification). These results emphasize the importance of biological purification of domestic wastewater containing detergents and a suggested development of less toxic and more easily degradable surfactants. (C) 2000 Elsevier Science Ltd. All rights reserved.
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