Stabilization of tar contaminated sediments in the area of Kolkajen-Ropsten

Sedimenten i området Kolkajen-Ropsten, Stockholm, innehåller höga halter av tjäroljor till följd avtidigare produktion i gasverket på området. Stockholms stad planerar att utföra byggnation i detnuvarande vattenområdet, vilket ökar risken för spridning av föroreningar. För att skydda arbetandeunder planerad byggnation och framtida boende måste föroreningssituationen åtgärdas. Tjäroljornainnehåller höga halter av polyaromatiska kolväten (PAH) och det är föroreningen av PAH-16 som styråtgärdsbehovet för området. En metod som använts med god framgång i flera projekt i Norden ochandra delar av världen är stabilisering och solidifiering, s/s, av sediment. Metoden går ut på att blandain utvalda bindemedel i sedimenten som då härdar. Därigenom minskar föroreningens mobilitet och degeotekniska egenskaperna förbättras. Om kravet på skjuvhållfasthet (>140 KPa), låg permeabilitet (10-8-10-9 m/s) samt minskad utlakning uppfylls kan de stabiliserade massorna utgöra grunden för planeradbyggnation.För att utvärdera möjligheterna av denna åtgärdsmetod analyserades en sats av prover från området föratt tillhandahålla information om platsspecifika parametrar. Analysen visade att sedimenten hade högvattenkvot och organiskt innehåll, dominerades av fina fraktioner samt en föroreningsgrad av PAH-16på 13000 mg/kg TS. Utifrån dessa parametrar och med stöd från en litteraturstudie valdes fyra receptpå bindemedel ut, med olika mängd bindemedel. De bindemedel som använts är: Bascement frånSkövde som är ett portland-flygaskecement, Monofill som består av 20 % cement och 80 % granuleratmasugnsslagg samt aktivt kol. De olika recepten blandades med sediment från området och lämnadesatt härda under 28 dygn. Efter härdningen utvärderades de stabiliserade massorna med avseende påminskad utlakning av PAH jämfört med obehandlat sediment, skjuvhållfasthet och permeabilitet.Analyser av de fyra blandningarna visade att kravet på skjuvhållfasthet och permeabilitet uppfylldesför samtliga tillsatser av bindemedel och överlag innebar större mängder tillsatt bindemedel högreskjuvhållfasthet och lägre permeabilitet. Resultaten från laktester indikerade att en större tillsats avaktivt kol minskade utlakningen av PAH.Tillsatsen av bindemedel som bedöms vara bäst lämpad för stabilisering av sedimenten från områdetvar en total mängd av cement och Monofill på 250 kg/m3 (30 % cement och 70 % Monofill) samt entillsats av aktivt kol på 5 % av TS.Inblandning i sedimenten enligt receptet ovan resulterade i en skjuvhållfasthet på 413 KPa samt enönskat låg permeabilitet. Utlakningen av PAH-16 reducerades med ~45 % jämfört med obehandlatsediment.The sediments in the area Kolkajen-Ropsten, Stockholm, have shown high levels of tar oils due to thegasworks in the area. The city of Stockholm is planning construction in the area which increases therisk of contaminants spreading to the surrounding area. In order to protect workers during the plannedconstruction and future inhabitants, remediation has to be carried out. The tar oils have highconcentrations of polyaromatic hydrocarbons (PAH) and it is pollution of PAH-16 that dictates theneed for remediation.A remediation method that has been used in similar projects, with good results, is stabilization andsolidification (s/s) of the sediments. This is done by mixing binder materials with the sediments whichharden and it results in lowered mobility of the contaminants and improved geotechnical properties ofthe soil. If the shear strength is high enough (>140 KPa), the permeability is low enough (10-8-10-9m/s) and the leaching is reduced sufficiently, the stabilized sediments can be used as a foundation.To evaluate the possibility of this remediation method, a batch of sediment samples from the area wasanalyzed to obtain information about site specific parameters. The analysis showed that the sedimentshad high water content and were rich in organic matter. They were dominated by small particlefractions and had a PAH-16 concentration of 13000 mg/kg DM. With regard to these site specificparameters and a literature study, four different recipes with different amounts of binders wereselected and tested in a laboratory study. The used binders were: cement from Skövde which is aportland-fly ash cement, Monofill composed of 20 % cement and 80 % granulated furnace slag, andaddition of activated carbon.The sediments were mixed with binders according to the recipes and left to harden for 28 days.Following the 28 days of hardening, the stabilized mixtures were evaluated with regard to: thereduction of leaching of PAH in comparison to the untreated sediments, shear strength, andpermeability.Analyses of the four mixtures showed that the desirable values of both shear strength and permeabilitywere achieved for all mixtures, and that a higher concentration of binders resulted in a higher shearstrength and lower permeability. The results from the leaching tests indicated that a higherconcentration of activated carbon resulted in a lowered leaching of PAH.The mixture of binders that was deemed to be most suitable for stabilizing the sediments from the areawas a total amount of cement and Monofill at 250 kg/m3 (30 % cement and 70 % Monofill) with anaddition of activated carbon at 5 % of DM (dry matter).Addition of this binder mixture to the sediments resulted in a shear strength of 413 KPa and a desiredlow permeability. The reduced leaching of PAH-16 was ~45 % compared to untreated sediments

Stabilization of tar contaminated sediments in the area of Kolkajen-Ropsten

Sedimenten i området Kolkajen-Ropsten, Stockholm, innehåller höga halter av tjäroljor till följd avtidigare produktion i gasverket på området. Stockholms stad planerar att utföra byggnation i detnuvarande vattenområdet, vilket ökar risken för spridning av föroreningar. För att skydda arbetandeunder planerad byggnation och framtida boende måste föroreningssituationen åtgärdas. Tjäroljornainnehåller höga halter av polyaromatiska kolväten (PAH) och det är föroreningen av PAH-16 som styråtgärdsbehovet för området. En metod som använts med god framgång i flera projekt i Norden ochandra delar av världen är stabilisering och solidifiering, s/s, av sediment. Metoden går ut på att blandain utvalda bindemedel i sedimenten som då härdar. Därigenom minskar föroreningens mobilitet och degeotekniska egenskaperna förbättras. Om kravet på skjuvhållfasthet (>140 KPa), låg permeabilitet (10-8-10-9 m/s) samt minskad utlakning uppfylls kan de stabiliserade massorna utgöra grunden för planeradbyggnation.För att utvärdera möjligheterna av denna åtgärdsmetod analyserades en sats av prover från området föratt tillhandahålla information om platsspecifika parametrar. Analysen visade att sedimenten hade högvattenkvot och organiskt innehåll, dominerades av fina fraktioner samt en föroreningsgrad av PAH-16på 13000 mg/kg TS. Utifrån dessa parametrar och med stöd från en litteraturstudie valdes fyra receptpå bindemedel ut, med olika mängd bindemedel. De bindemedel som använts är: Bascement frånSkövde som är ett portland-flygaskecement, Monofill som består av 20 % cement och 80 % granuleratmasugnsslagg samt aktivt kol. De olika recepten blandades med sediment från området och lämnadesatt härda under 28 dygn. Efter härdningen utvärderades de stabiliserade massorna med avseende påminskad utlakning av PAH jämfört med obehandlat sediment, skjuvhållfasthet och permeabilitet.Analyser av de fyra blandningarna visade att kravet på skjuvhållfasthet och permeabilitet uppfylldesför samtliga tillsatser av bindemedel och överlag innebar större mängder tillsatt bindemedel högreskjuvhållfasthet och lägre permeabilitet. Resultaten från laktester indikerade att en större tillsats avaktivt kol minskade utlakningen av PAH.Tillsatsen av bindemedel som bedöms vara bäst lämpad för stabilisering av sedimenten från områdetvar en total mängd av cement och Monofill på 250 kg/m3 (30 % cement och 70 % Monofill) samt entillsats av aktivt kol på 5 % av TS.Inblandning i sedimenten enligt receptet ovan resulterade i en skjuvhållfasthet på 413 KPa samt enönskat låg permeabilitet. Utlakningen av PAH-16 reducerades med ~45 % jämfört med obehandlatsediment.The sediments in the area Kolkajen-Ropsten, Stockholm, have shown high levels of tar oils due to thegasworks in the area. The city of Stockholm is planning construction in the area which increases therisk of contaminants spreading to the surrounding area. In order to protect workers during the plannedconstruction and future inhabitants, remediation has to be carried out. The tar oils have highconcentrations of polyaromatic hydrocarbons (PAH) and it is pollution of PAH-16 that dictates theneed for remediation.A remediation method that has been used in similar projects, with good results, is stabilization andsolidification (s/s) of the sediments. This is done by mixing binder materials with the sediments whichharden and it results in lowered mobility of the contaminants and improved geotechnical properties ofthe soil. If the shear strength is high enough (>140 KPa), the permeability is low enough (10-8-10-9m/s) and the leaching is reduced sufficiently, the stabilized sediments can be used as a foundation.To evaluate the possibility of this remediation method, a batch of sediment samples from the area wasanalyzed to obtain information about site specific parameters. The analysis showed that the sedimentshad high water content and were rich in organic matter. They were dominated by small particlefractions and had a PAH-16 concentration of 13000 mg/kg DM. With regard to these site specificparameters and a literature study, four different recipes with different amounts of binders wereselected and tested in a laboratory study. The used binders were: cement from Skövde which is aportland-fly ash cement, Monofill composed of 20 % cement and 80 % granulated furnace slag, andaddition of activated carbon.The sediments were mixed with binders according to the recipes and left to harden for 28 days.Following the 28 days of hardening, the stabilized mixtures were evaluated with regard to: thereduction of leaching of PAH in comparison to the untreated sediments, shear strength, andpermeability.Analyses of the four mixtures showed that the desirable values of both shear strength and permeabilitywere achieved for all mixtures, and that a higher concentration of binders resulted in a higher shearstrength and lower permeability. The results from the leaching tests indicated that a higherconcentration of activated carbon resulted in a lowered leaching of PAH.The mixture of binders that was deemed to be most suitable for stabilizing the sediments from the areawas a total amount of cement and Monofill at 250 kg/m3 (30 % cement and 70 % Monofill) with anaddition of activated carbon at 5 % of DM (dry matter).Addition of this binder mixture to the sediments resulted in a shear strength of 413 KPa and a desiredlow permeability. The reduced leaching of PAH-16 was ~45 % compared to untreated sediments

Stabilization of tar contaminated sediments in the area of Kolkajen-Ropsten

Sedimenten i området Kolkajen-Ropsten, Stockholm, innehåller höga halter av tjäroljor till följd avtidigare produktion i gasverket på området. Stockholms stad planerar att utföra byggnation i detnuvarande vattenområdet, vilket ökar risken för spridning av föroreningar. För att skydda arbetandeunder planerad byggnation och framtida boende måste föroreningssituationen åtgärdas. Tjäroljornainnehåller höga halter av polyaromatiska kolväten (PAH) och det är föroreningen av PAH-16 som styråtgärdsbehovet för området. En metod som använts med god framgång i flera projekt i Norden ochandra delar av världen är stabilisering och solidifiering, s/s, av sediment. Metoden går ut på att blandain utvalda bindemedel i sedimenten som då härdar. Därigenom minskar föroreningens mobilitet och degeotekniska egenskaperna förbättras. Om kravet på skjuvhållfasthet (>140 KPa), låg permeabilitet (10-8-10-9 m/s) samt minskad utlakning uppfylls kan de stabiliserade massorna utgöra grunden för planeradbyggnation.För att utvärdera möjligheterna av denna åtgärdsmetod analyserades en sats av prover från området föratt tillhandahålla information om platsspecifika parametrar. Analysen visade att sedimenten hade högvattenkvot och organiskt innehåll, dominerades av fina fraktioner samt en föroreningsgrad av PAH-16på 13000 mg/kg TS. Utifrån dessa parametrar och med stöd från en litteraturstudie valdes fyra receptpå bindemedel ut, med olika mängd bindemedel. De bindemedel som använts är: Bascement frånSkövde som är ett portland-flygaskecement, Monofill som består av 20 % cement och 80 % granuleratmasugnsslagg samt aktivt kol. De olika recepten blandades med sediment från området och lämnadesatt härda under 28 dygn. Efter härdningen utvärderades de stabiliserade massorna med avseende påminskad utlakning av PAH jämfört med obehandlat sediment, skjuvhållfasthet och permeabilitet.Analyser av de fyra blandningarna visade att kravet på skjuvhållfasthet och permeabilitet uppfylldesför samtliga tillsatser av bindemedel och överlag innebar större mängder tillsatt bindemedel högreskjuvhållfasthet och lägre permeabilitet. Resultaten från laktester indikerade att en större tillsats avaktivt kol minskade utlakningen av PAH.Tillsatsen av bindemedel som bedöms vara bäst lämpad för stabilisering av sedimenten från områdetvar en total mängd av cement och Monofill på 250 kg/m3 (30 % cement och 70 % Monofill) samt entillsats av aktivt kol på 5 % av TS.Inblandning i sedimenten enligt receptet ovan resulterade i en skjuvhållfasthet på 413 KPa samt enönskat låg permeabilitet. Utlakningen av PAH-16 reducerades med ~45 % jämfört med obehandlatsediment.The sediments in the area Kolkajen-Ropsten, Stockholm, have shown high levels of tar oils due to thegasworks in the area. The city of Stockholm is planning construction in the area which increases therisk of contaminants spreading to the surrounding area. In order to protect workers during the plannedconstruction and future inhabitants, remediation has to be carried out. The tar oils have highconcentrations of polyaromatic hydrocarbons (PAH) and it is pollution of PAH-16 that dictates theneed for remediation.A remediation method that has been used in similar projects, with good results, is stabilization andsolidification (s/s) of the sediments. This is done by mixing binder materials with the sediments whichharden and it results in lowered mobility of the contaminants and improved geotechnical properties ofthe soil. If the shear strength is high enough (>140 KPa), the permeability is low enough (10-8-10-9m/s) and the leaching is reduced sufficiently, the stabilized sediments can be used as a foundation.To evaluate the possibility of this remediation method, a batch of sediment samples from the area wasanalyzed to obtain information about site specific parameters. The analysis showed that the sedimentshad high water content and were rich in organic matter. They were dominated by small particlefractions and had a PAH-16 concentration of 13000 mg/kg DM. With regard to these site specificparameters and a literature study, four different recipes with different amounts of binders wereselected and tested in a laboratory study. The used binders were: cement from Skövde which is aportland-fly ash cement, Monofill composed of 20 % cement and 80 % granulated furnace slag, andaddition of activated carbon.The sediments were mixed with binders according to the recipes and left to harden for 28 days.Following the 28 days of hardening, the stabilized mixtures were evaluated with regard to: thereduction of leaching of PAH in comparison to the untreated sediments, shear strength, andpermeability.Analyses of the four mixtures showed that the desirable values of both shear strength and permeabilitywere achieved for all mixtures, and that a higher concentration of binders resulted in a higher shearstrength and lower permeability. The results from the leaching tests indicated that a higherconcentration of activated carbon resulted in a lowered leaching of PAH.The mixture of binders that was deemed to be most suitable for stabilizing the sediments from the areawas a total amount of cement and Monofill at 250 kg/m3 (30 % cement and 70 % Monofill) with anaddition of activated carbon at 5 % of DM (dry matter).Addition of this binder mixture to the sediments resulted in a shear strength of 413 KPa and a desiredlow permeability. The reduced leaching of PAH-16 was ~45 % compared to untreated sediments

Parasite faunas of farmed cod and adjacent wild cod populations in Norway: a comparison

Atlantic cod Gadus morhua L. is host to more than 120 parasite species. Background abundance of these parasite species on adjacent wild hosts determines the infection pressure on cod farmed in open pens. In 2006, 2007 and 2008, 343 cod were collected from 4 locations along the coast of Norway: Øksfjord, Kvarøy, Brønnøysund and Ålesund. Freshly killed wild local cod, wild migratory cod, hatchery-reared farmed cod and wild-caught farmed cod were given a complete autopsy according to a standardized protocol. A total of 343 cod were examined, from which 48 parasite taxa, including 37 named species, were recorded. Wild local cod had the most diverse parasite fauna. Wild-caught farmed cod had a more diverse parasite fauna than the wild migratory cod, and the latter had 2 more parasite taxa than the hatchery-reared cod. The most common parasites in hatchery-reared cod were the digenean Cryptocotyle lingua, the monogenean Gyrodactylus marinus and the protozoans Spironucleus torosa and Trichodina spp. Other parasites occurring frequently in hatchery-reared cod were the parasitic copepod Cresseyus confusus, the myxosporean Zschokkella hildae and the nematode Hysterothylacium aduncum. The nematode and digenean fauna of the hatchery-reared fish was sparse compared to wild cod and the wild-caught farmed cod. Caligid copepods were very rare on the hatchery-reared cod. These results support the hypothesis that food-borne parasites, such as nematodes and mature stages of digeneans, are most unlikely to become a health problem for farmed cod, and that parasites with simple life cycles and pelagic transmission stages, such as monogeneans and trichodinids, may dominate the parasite fauna of farmed cod in the future

Parasite faunas of farmed cod and adjacent wild cod populations in Norway: a comparison

Atlantic cod Gadus morhua L. is host to more than 120 parasite species. Background abundance of these parasite species on adjacent wild hosts determines the infection pressure on cod farmed in open pens. In 2006, 2007 and 2008, 343 cod were collected from 4 locations along the coast of Norway: Øksfjord, Kvarøy, Brønnøysund and Ålesund. Freshly killed wild local cod, wild migratory cod, hatchery-reared farmed cod and wild-caught farmed cod were given a complete autopsy according to a standardized protocol. A total of 343 cod were examined, from which 48 parasite taxa, including 37 named species, were recorded. Wild local cod had the most diverse parasite fauna. Wild-caught farmed cod had a more diverse parasite fauna than the wild migratory cod, and the latter had 2 more parasite taxa than the hatchery-reared cod. The most common parasites in hatchery-reared cod were the digenean Cryptocotyle lingua, the monogenean Gyrodactylus marinus and the protozoans Spironucleus torosa and Trichodina spp. Other parasites occurring frequently in hatchery-reared cod were the parasitic copepod Cresseyus confusus, the myxosporean Zschokkella hildae and the nematode Hysterothylacium aduncum. The nematode and digenean fauna of the hatchery-reared fish was sparse compared to wild cod and the wild-caught farmed cod. Caligid copepods were very rare on the hatchery-reared cod. These results support the hypothesis that food-borne parasites, such as nematodes and mature stages of digeneans, are most unlikely to become a health problem for farmed cod, and that parasites with simple life cycles and pelagic transmission stages, such as monogeneans and trichodinids, may dominate the parasite fauna of farmed cod in the future

Life-history traits and potential invasiveness of introduced pumpkinseed Lepomis gibbonus populations in northwestern Europe

Contains fulltext : 76077.pdf (publisher's version ) (Open Access)Special Issue10 p

Impacts of climate warming on the long-term dynamics of key fish species in 24 European lakes

Fish play a key role in the trophic dynamics of lakes. With climate warming, complex changes in fish assemblage structure may be expected owing to direct effects of temperature and indirect effects operating through eutrophication, water level changes, stratification and salinisation. We reviewed published and new long-term (10–100 years) fish data series from 24 European lakes (area: 0.04–5,648 km2; mean depth: 1–177 m; a north–south gradient from Sweden to Spain). Along with an annual temperature increase of about 0.15–0.3°C per decade profound changes have occurred in either fish assemblage composition, body size and/or age structure during recent decades and a shift towards higher dominance of eurythermal species. These shifts have occurred despite a reduction in nutrient loading in many of the lakes that should have benefited the larger-sized individuals and the fish species typically inhabiting cold-water, low-nutrient lakes. The cold-stenothermic Arctic charr has been particularly affected and its abundance has decreased in the majority of the lakes where its presence was recorded. The harvest of cool-stenothermal brown trout has decreased substantially in two southern lakes. Vendace, whitefish and smelt show a different response depending on lake depth and latitude. Perch has apparently been stimulated in the north, with stronger year classes in warm years, but its abundance has declined in the southern Lake Maggiore, Italy. Where introduced, roach seems to take advantage of the higher temperature after years of low population densities. Eurythermal species such as common bream, pike–perch and/or shad are apparently on the increase in several of the lakes. The response of fish to the warming has been surprisingly strong and fast in recent decades, making them ideal sentinels for detecting and documenting climate-induced modifications of freshwater ecosystems