seppo hellsten - Academia.edu (original) (raw)
Papers by seppo hellsten
Journal of Soils and Sediments
Purpose Adsorbent amendment to contaminated sediments is one in situ remediation method to decrea... more Purpose Adsorbent amendment to contaminated sediments is one in situ remediation method to decrease the bioaccessibility of pollutants from the sediments. In this work, alkali-activated blast furnace slag (BFS) granules were used in a field experiment at Lake Kivijärvi (Finland). The lake was heavily affected by a mining accident in 2012, which released a significant peak load of metals and sulfate. The purpose of this work was to evaluate the performance of the novel amendment material for in situ remediation in real conditions with a preliminary cost estimation. Methods Alkali-activated BFS granules were prepared and characterized for composition, microstructure, and surface properties. Two mesocosms were placed in the lake: one with granule dosing and another without. Sediment and pore water samples were collected after a two-week period. Similar small-scale experiment was performed in laboratory with a three-month duration. Bioaccessibility of metals from sediments was assessed ...
<p>Browning of surface waters due to increased terrestrial loading of organic carbo... more <p>Browning of surface waters due to increased terrestrial loading of organic carbon is observed in boreal regions. It is explained by large scale changes in ecosystems, including decrease in sulphur deposition that affects soil organic matter solubility, increase in temperature that stimulates export of dissolved organic carbon (DOC) from organic soils, and increase in precipitation and thus runoff. Land use changes and forestry measures are also observed to be one reason for increased transport of DOC. The effects of brownification extend to ecosystem services like water purification, but also freshwater productivity through limiting light penetration and creating more stable thermal stratification. The research question at the Lammi LTER area (Southern Boreal Aquatic and Terrestrial Long-Term Ecological Research Area) was brownification of the lake P&#228;&#228;j&#228;rvi. We studied both past trends of organic carbon loading from catchments and water colour in the lake based on observations since early 1990&#8217;s. We also made simulations of loading for future climate by the physical Persist and INCA models. DOC concentration in the lake was simulated by the physical MyLake model. Simulated DOC concentration was transformed to water colour and light climate of the lake by empirical equations to study the influence on macrophytes (as an indicator of the ecosystem state). In future growing depths might decrease from 2 m to 1.2 m corresponding to observed shift from reference lakes to impacted lakes. Brownification was driven mainly by the change in climate and decay of organic matter in soil, with smaller impact of land use change on organic soil types. Decrease in sulphur deposition had only minor effect on brownification.</p>
SIL Proceedings, 1922-2010
The Senegal River basin is located in West Africa in the Sahel, in a sub-tropical climate zone. T... more The Senegal River basin is located in West Africa in the Sahel, in a sub-tropical climate zone. The river originates in the Fouta Djalon Mountains in Guinea and subsequently flows via Mali, Mauritania and Senegal to the Atlantic Ocean. A long stretch o f the river in the delta forms the border between Mauritania and Senegal. The total drainage area o f the basin is around 290000km2. The hydrology of the Senegal River system has changed markedly since the construction o f two high darns. The Diama Dam (1985) was constructed to prevent intrusion of saline water from the Atlantic Ocean and to create a fresh water reservoir for irrigation purposes. The Manantali Dam in Mali ( 1988) is a hydroelectric dam. The general objectives of the two dams were to expand irrigated farming along the Senegal River and the Delta, to generate electricity for urban and industria! development and to make the river more navigable (e.g. LEMARQUAND 1990, CoGELS et al. 1993). Construction ofthese two dams, as well as erection of dikes, development of hydraulic structures and construction o f irrigation schemes, led to drastic enviromnental changes in the Senegal River Basin (HAMERLYNCK et al. 1999). The wetlands, which originally occurred in the floodplains, disappeared. Large areas o f the former floodplains were transformed into irrigated fields, mainly for the cultivation of rice. The original floodplain ecosystem was only preserved in two national parks, the Djoudj National Park in Senegal and the Diawling National Park in Mauritania, by means of an artificial water flow regulation (HAMERLYNCK et al. 1999, ANON. 1995). A shallow water reservoir just upstream o f the Diama dam (surface area approximately 180km2) became overgrown by aquatic vegetation, mainly consisting of two native aquatic plants: the emergent species Typha australis Schum. & Tonn., and the floating species Pistia stratiotes. This dense vegetation causes considerable problems for the local population. Villages along the river became isolated from open water and fishing was hampered. Moreover, diseases like schistosomiasis and malaria showed a drarnatic increase as the enviromnent became a favourable habitat for snails and mosquitoes. (HELLSTEN et al. 1999, PIETERSE et al. 2002) A subsequent severe ecological catastrophe took place in 1999 when an invasive aquatic weed, the water fem (Salvinia mo/esta Mitchell), was introduced into the area. Shortly afterwards it had formed thick mats over an area o f 70 km along the river. Several measures were taken to fight this pest, but without any success. In the framework of an EUIINCO-project, biological control of Salvinia by a natural enemy, the weevil ( Cyrtobagous salviniae Calder & Sands), proved successful, and the problem has more or less been solved (PIETERSE et al. 2003). Despite of these changes in the Delta region, the enviromnent has remained quite natural in the Middle Valley o f the river. The present flow management by means of artificial floods have kept the original floodplain habitats relatively unchanged without any significant changes in species abundance. The main aims of this study were: (l) To investigate existing habitats of the Senegal River valley, and (2) To estimate the effects of different flow regimes on the future development o f these habitats.
Although a local incident, the leakage of the gypsum pond at the Talvivaara mine in November 2012... more Although a local incident, the leakage of the gypsum pond at the Talvivaara mine in November 2012 was a major environmental accident in Finland. Following the accident, approximately 200,000 cubic metres of waste water ran into the nearby lakes and rivers south of the mine and some 20,000 cubic metres to the north. The amount of hazardous substances released into the environment around the mine area exceeded several times the yearly permitted load. To respond to public concerns and enquiries regarding the leakage, the Finnish Environment Institute (SYKE) explored the potential impact of the incident on the local water systems. This report presents the data used in the assessment, reviews the impacts of the leakage on nearby lakes and looks at the spatial extent of the leakage based on the information available at the end of 2012. In addition, it provides a brief account of the condition of the local lakes and rivers before the waste water leakage, and of the effects of metals, acidi...
Water level regulation for purposes of hydropower production has caused notable changes in the li... more Water level regulation for purposes of hydropower production has caused notable changes in the littoral zones of regulated lakes in northern Finland. Marked geomorphological changes have taken place in the lakes with a raised water level. Lowering of the ice cover during the winter has also caused rapid changes in the littoral. Changes in the environmental conditions and aquatic macrophyte communities were studied largely by comparing the regulated Lake Ontojärvi and the unregulated Lake Lentua in the Kainuu area. The general aims of the study were to analyse environmental effects, to produce information of ecological relationships for remedial measures on the littoral and to apply the restoration methods in the management of regulated lakes. The most obvious effect of regulation was the expanded area of extending ice, which caused an almost complete disappearance of large ice-sensitive isoetids (Isoetes lacustris L., Lobelia dortmanna L.). These species were largely replaced by sma...
Due date of deliverable: Month 24 Actual submission date: Month 26 Project co-funded by the Europ... more Due date of deliverable: Month 24 Actual submission date: Month 26 Project co-funded by the European Commission within the Seventh Framework Programme (2007-2013) Dissemination Level PU Public X PP Restricted to other programme participants (including the Commission Services) RE Restricted to a group specified by the consortium (including the Commission Services) CO Confidential, only for members of the consortium (including the Commission Services)
Although regulated lakes have been studied extensively during the last 20 years in Finland, biolo... more Although regulated lakes have been studied extensively during the last 20 years in Finland, biological data are still scattered. Especially in mildly regulated lakes, data have been insufficient to determine reference conditions and to estimate ecological status as required by the Water Framework Directive. The objective of this study was to increase information about the biological quality elements in order to develop ecological classification system and to define environment objectives for regulated lakes. Both existing and new data were collected from littoral fishes, littoral macroinvertebrates and macrophytes from regulated lakes and unregulated reference lakes. New biological classification metrics were then developed and tested. Moreover, alternative combinations of the biological classification parameters were tested for assessment of ecological status of lakes. Impacts of water-level regulation were found in all three biological quality elements: the littoral fishes, macroi...
SIL Proceedings, 1922-2010
The effects of water-level regulation on lake littoral in northern regions have been extensively ... more The effects of water-level regulation on lake littoral in northern regions have been extensively studied during the past few decades (SUNDBORG 1977, Nu.sSON 1981, NEWBURY & McCuLLOUGH 1984, R0RSLETT 1989, AlASAARELA et al. 1989, WILCOX & MEEKER 1991). Water-level regulation is usually carried out for hydropower production o r flood protection. The increase in water storage capacity is generally achieved by lowering the water level during winter and raising the water level during summer. A lowered water level during the wimer generally causes an extension of the ice cover on the bottom, which brings about a negative effect on littoral communities such as the bemhic fauna and aquatic macrophytes. Moreover, the eggs of autumn-spawning fish are largely destroyed and the use of such a lake for fishing and recreation becomes limited. The increased water-level fluctuation during the winter also inflicts heavy erosion, which in turn affects shore communities, in particular aquatic macrophytes. This increase applies in particular to a drastic decline of isoetids, which are particularly sensitive to these imervemions, as was reported for various regulated lakes ín Norway (e.g. R0RSLETT 1984), Sweden (e.g. QUENNERSTEDT 1958) and Finland (HELLSTEN et al. 1996).
SIL Proceedings, 1922-2010
(2009). Macrophyte responses to water level fluctuation in Fennoscandinavian Lakes — Applying a c... more (2009). Macrophyte responses to water level fluctuation in Fennoscandinavian Lakes — Applying a common index. SIL Proceedings, 1922-2010: Vol. 30, No. 5, pp. 765-769.
Ambio
Nordic water bodies face multiple stressors due to human activities, generating diffuse loading a... more Nordic water bodies face multiple stressors due to human activities, generating diffuse loading and climate change. The ‘green shift’ towards a bio-based economy poses new demands and increased pressure on the environment. Bioeconomy-related pressures consist primarily of more intensive land management to maximise production of biomass. These activities can add considerable nutrient and sediment loads to receiving waters, posing a threat to ecosystem services and good ecological status of surface waters. The potential threats of climate change and the ‘green shift’ highlight the need for improved understanding of catchment-scale water and element fluxes. Here, we assess possible bioeconomy-induced pressures on Nordic catchments and associated impacts on water quality. We suggest measures to protect water quality under the ‘green shift’ and propose ‘road maps’ towards sustainable catchment management. We also identify knowledge gaps and highlight the importance of long-term monitorin...
SIL Proceedings, 1922-2010
The environmenta1 changes of Lake Pãijãnne represent typical examp1es of human induced changes in... more The environmenta1 changes of Lake Pãijãnne represent typical examp1es of human induced changes in the 1ake district of Fin1and. Heavy point source pollution and water Ievel regulation during the I 960s have caused significant changes in the ecological status ofthe 1ake, which is characterised by several subareas with different limnological properties (MERILÃINEN et al. 200 l). Intensive water protection measures during the 1980s have drastically improved water quality, but the overgrowth of aquatic vegetation, especially the expansion of common reed (Phragmites australis Trin ex. Steudl), is still significant (HELLSTEN 2000, KETO et al. 2002). In addition to ecological status, the increase in aquatic vegetation has caused significant changes to the recreational use ofthe lake. Increased demand for restoration measures an d awareness o f environmental issues brought about an interest to study the factors causing this change. The main aim o f this study is to compare the development of aquatic vegetation with aerial photos and species composition from different decades before and after major human impact. The main factors affecting the vegetation are also described by comparing the vegetation of Lake Pãijãnne to reference Lake Keitele and three smaller lakes, Saraavesi, Kuhnamo and Vatia, with higher nutrient status but a relatively natural water level fluctuation regime.
Journal of Soils and Sediments
Purpose Adsorbent amendment to contaminated sediments is one in situ remediation method to decrea... more Purpose Adsorbent amendment to contaminated sediments is one in situ remediation method to decrease the bioaccessibility of pollutants from the sediments. In this work, alkali-activated blast furnace slag (BFS) granules were used in a field experiment at Lake Kivijärvi (Finland). The lake was heavily affected by a mining accident in 2012, which released a significant peak load of metals and sulfate. The purpose of this work was to evaluate the performance of the novel amendment material for in situ remediation in real conditions with a preliminary cost estimation. Methods Alkali-activated BFS granules were prepared and characterized for composition, microstructure, and surface properties. Two mesocosms were placed in the lake: one with granule dosing and another without. Sediment and pore water samples were collected after a two-week period. Similar small-scale experiment was performed in laboratory with a three-month duration. Bioaccessibility of metals from sediments was assessed ...
<p>Browning of surface waters due to increased terrestrial loading of organic carbo... more <p>Browning of surface waters due to increased terrestrial loading of organic carbon is observed in boreal regions. It is explained by large scale changes in ecosystems, including decrease in sulphur deposition that affects soil organic matter solubility, increase in temperature that stimulates export of dissolved organic carbon (DOC) from organic soils, and increase in precipitation and thus runoff. Land use changes and forestry measures are also observed to be one reason for increased transport of DOC. The effects of brownification extend to ecosystem services like water purification, but also freshwater productivity through limiting light penetration and creating more stable thermal stratification. The research question at the Lammi LTER area (Southern Boreal Aquatic and Terrestrial Long-Term Ecological Research Area) was brownification of the lake P&#228;&#228;j&#228;rvi. We studied both past trends of organic carbon loading from catchments and water colour in the lake based on observations since early 1990&#8217;s. We also made simulations of loading for future climate by the physical Persist and INCA models. DOC concentration in the lake was simulated by the physical MyLake model. Simulated DOC concentration was transformed to water colour and light climate of the lake by empirical equations to study the influence on macrophytes (as an indicator of the ecosystem state). In future growing depths might decrease from 2 m to 1.2 m corresponding to observed shift from reference lakes to impacted lakes. Brownification was driven mainly by the change in climate and decay of organic matter in soil, with smaller impact of land use change on organic soil types. Decrease in sulphur deposition had only minor effect on brownification.</p>
SIL Proceedings, 1922-2010
The Senegal River basin is located in West Africa in the Sahel, in a sub-tropical climate zone. T... more The Senegal River basin is located in West Africa in the Sahel, in a sub-tropical climate zone. The river originates in the Fouta Djalon Mountains in Guinea and subsequently flows via Mali, Mauritania and Senegal to the Atlantic Ocean. A long stretch o f the river in the delta forms the border between Mauritania and Senegal. The total drainage area o f the basin is around 290000km2. The hydrology of the Senegal River system has changed markedly since the construction o f two high darns. The Diama Dam (1985) was constructed to prevent intrusion of saline water from the Atlantic Ocean and to create a fresh water reservoir for irrigation purposes. The Manantali Dam in Mali ( 1988) is a hydroelectric dam. The general objectives of the two dams were to expand irrigated farming along the Senegal River and the Delta, to generate electricity for urban and industria! development and to make the river more navigable (e.g. LEMARQUAND 1990, CoGELS et al. 1993). Construction ofthese two dams, as well as erection of dikes, development of hydraulic structures and construction o f irrigation schemes, led to drastic enviromnental changes in the Senegal River Basin (HAMERLYNCK et al. 1999). The wetlands, which originally occurred in the floodplains, disappeared. Large areas o f the former floodplains were transformed into irrigated fields, mainly for the cultivation of rice. The original floodplain ecosystem was only preserved in two national parks, the Djoudj National Park in Senegal and the Diawling National Park in Mauritania, by means of an artificial water flow regulation (HAMERLYNCK et al. 1999, ANON. 1995). A shallow water reservoir just upstream o f the Diama dam (surface area approximately 180km2) became overgrown by aquatic vegetation, mainly consisting of two native aquatic plants: the emergent species Typha australis Schum. & Tonn., and the floating species Pistia stratiotes. This dense vegetation causes considerable problems for the local population. Villages along the river became isolated from open water and fishing was hampered. Moreover, diseases like schistosomiasis and malaria showed a drarnatic increase as the enviromnent became a favourable habitat for snails and mosquitoes. (HELLSTEN et al. 1999, PIETERSE et al. 2002) A subsequent severe ecological catastrophe took place in 1999 when an invasive aquatic weed, the water fem (Salvinia mo/esta Mitchell), was introduced into the area. Shortly afterwards it had formed thick mats over an area o f 70 km along the river. Several measures were taken to fight this pest, but without any success. In the framework of an EUIINCO-project, biological control of Salvinia by a natural enemy, the weevil ( Cyrtobagous salviniae Calder & Sands), proved successful, and the problem has more or less been solved (PIETERSE et al. 2003). Despite of these changes in the Delta region, the enviromnent has remained quite natural in the Middle Valley o f the river. The present flow management by means of artificial floods have kept the original floodplain habitats relatively unchanged without any significant changes in species abundance. The main aims of this study were: (l) To investigate existing habitats of the Senegal River valley, and (2) To estimate the effects of different flow regimes on the future development o f these habitats.
Although a local incident, the leakage of the gypsum pond at the Talvivaara mine in November 2012... more Although a local incident, the leakage of the gypsum pond at the Talvivaara mine in November 2012 was a major environmental accident in Finland. Following the accident, approximately 200,000 cubic metres of waste water ran into the nearby lakes and rivers south of the mine and some 20,000 cubic metres to the north. The amount of hazardous substances released into the environment around the mine area exceeded several times the yearly permitted load. To respond to public concerns and enquiries regarding the leakage, the Finnish Environment Institute (SYKE) explored the potential impact of the incident on the local water systems. This report presents the data used in the assessment, reviews the impacts of the leakage on nearby lakes and looks at the spatial extent of the leakage based on the information available at the end of 2012. In addition, it provides a brief account of the condition of the local lakes and rivers before the waste water leakage, and of the effects of metals, acidi...
Water level regulation for purposes of hydropower production has caused notable changes in the li... more Water level regulation for purposes of hydropower production has caused notable changes in the littoral zones of regulated lakes in northern Finland. Marked geomorphological changes have taken place in the lakes with a raised water level. Lowering of the ice cover during the winter has also caused rapid changes in the littoral. Changes in the environmental conditions and aquatic macrophyte communities were studied largely by comparing the regulated Lake Ontojärvi and the unregulated Lake Lentua in the Kainuu area. The general aims of the study were to analyse environmental effects, to produce information of ecological relationships for remedial measures on the littoral and to apply the restoration methods in the management of regulated lakes. The most obvious effect of regulation was the expanded area of extending ice, which caused an almost complete disappearance of large ice-sensitive isoetids (Isoetes lacustris L., Lobelia dortmanna L.). These species were largely replaced by sma...
Due date of deliverable: Month 24 Actual submission date: Month 26 Project co-funded by the Europ... more Due date of deliverable: Month 24 Actual submission date: Month 26 Project co-funded by the European Commission within the Seventh Framework Programme (2007-2013) Dissemination Level PU Public X PP Restricted to other programme participants (including the Commission Services) RE Restricted to a group specified by the consortium (including the Commission Services) CO Confidential, only for members of the consortium (including the Commission Services)
Although regulated lakes have been studied extensively during the last 20 years in Finland, biolo... more Although regulated lakes have been studied extensively during the last 20 years in Finland, biological data are still scattered. Especially in mildly regulated lakes, data have been insufficient to determine reference conditions and to estimate ecological status as required by the Water Framework Directive. The objective of this study was to increase information about the biological quality elements in order to develop ecological classification system and to define environment objectives for regulated lakes. Both existing and new data were collected from littoral fishes, littoral macroinvertebrates and macrophytes from regulated lakes and unregulated reference lakes. New biological classification metrics were then developed and tested. Moreover, alternative combinations of the biological classification parameters were tested for assessment of ecological status of lakes. Impacts of water-level regulation were found in all three biological quality elements: the littoral fishes, macroi...
SIL Proceedings, 1922-2010
The effects of water-level regulation on lake littoral in northern regions have been extensively ... more The effects of water-level regulation on lake littoral in northern regions have been extensively studied during the past few decades (SUNDBORG 1977, Nu.sSON 1981, NEWBURY & McCuLLOUGH 1984, R0RSLETT 1989, AlASAARELA et al. 1989, WILCOX & MEEKER 1991). Water-level regulation is usually carried out for hydropower production o r flood protection. The increase in water storage capacity is generally achieved by lowering the water level during winter and raising the water level during summer. A lowered water level during the wimer generally causes an extension of the ice cover on the bottom, which brings about a negative effect on littoral communities such as the bemhic fauna and aquatic macrophytes. Moreover, the eggs of autumn-spawning fish are largely destroyed and the use of such a lake for fishing and recreation becomes limited. The increased water-level fluctuation during the winter also inflicts heavy erosion, which in turn affects shore communities, in particular aquatic macrophytes. This increase applies in particular to a drastic decline of isoetids, which are particularly sensitive to these imervemions, as was reported for various regulated lakes ín Norway (e.g. R0RSLETT 1984), Sweden (e.g. QUENNERSTEDT 1958) and Finland (HELLSTEN et al. 1996).
SIL Proceedings, 1922-2010
(2009). Macrophyte responses to water level fluctuation in Fennoscandinavian Lakes — Applying a c... more (2009). Macrophyte responses to water level fluctuation in Fennoscandinavian Lakes — Applying a common index. SIL Proceedings, 1922-2010: Vol. 30, No. 5, pp. 765-769.
Ambio
Nordic water bodies face multiple stressors due to human activities, generating diffuse loading a... more Nordic water bodies face multiple stressors due to human activities, generating diffuse loading and climate change. The ‘green shift’ towards a bio-based economy poses new demands and increased pressure on the environment. Bioeconomy-related pressures consist primarily of more intensive land management to maximise production of biomass. These activities can add considerable nutrient and sediment loads to receiving waters, posing a threat to ecosystem services and good ecological status of surface waters. The potential threats of climate change and the ‘green shift’ highlight the need for improved understanding of catchment-scale water and element fluxes. Here, we assess possible bioeconomy-induced pressures on Nordic catchments and associated impacts on water quality. We suggest measures to protect water quality under the ‘green shift’ and propose ‘road maps’ towards sustainable catchment management. We also identify knowledge gaps and highlight the importance of long-term monitorin...
SIL Proceedings, 1922-2010
The environmenta1 changes of Lake Pãijãnne represent typical examp1es of human induced changes in... more The environmenta1 changes of Lake Pãijãnne represent typical examp1es of human induced changes in the 1ake district of Fin1and. Heavy point source pollution and water Ievel regulation during the I 960s have caused significant changes in the ecological status ofthe 1ake, which is characterised by several subareas with different limnological properties (MERILÃINEN et al. 200 l). Intensive water protection measures during the 1980s have drastically improved water quality, but the overgrowth of aquatic vegetation, especially the expansion of common reed (Phragmites australis Trin ex. Steudl), is still significant (HELLSTEN 2000, KETO et al. 2002). In addition to ecological status, the increase in aquatic vegetation has caused significant changes to the recreational use ofthe lake. Increased demand for restoration measures an d awareness o f environmental issues brought about an interest to study the factors causing this change. The main aim o f this study is to compare the development of aquatic vegetation with aerial photos and species composition from different decades before and after major human impact. The main factors affecting the vegetation are also described by comparing the vegetation of Lake Pãijãnne to reference Lake Keitele and three smaller lakes, Saraavesi, Kuhnamo and Vatia, with higher nutrient status but a relatively natural water level fluctuation regime.