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Polychlorinated biphenyls (PCB) in a river ecosystem

Bremle, Gudrun LU (1997)
Abstract (Swedish)
Popular Abstract in Swedish

Atmosfäriskt nedfall är den största källan till miljögiftet PCB i sötvatten. I flertalet vattendrag, exempelvis Emån, fungererar också sediment som en källa. Ett pappersbruk i anslutning till Emån hade använt returpapper som innehöll PCB som råvara. PCB följde med utsläppen till ån och lagrades in i sedimenten. Miljögiftet läckte sedan ut långsamt till vattnet. Största mängden PCB låg i Järnsjöns sediment, vilket innehöll 400 kg. Halten av PCB i vatten och fisk ökade i Emån nedströms Järnsjön. Eftersom PCB är ett beständigt ämne vilket lagras i organismer och dessutom är toxiskt (bl.a. påverkar reproduktionen och immunförsvaret) var det speciallt olämpligt att det fanns i höga halter just i en... (More)
Popular Abstract in Swedish

Atmosfäriskt nedfall är den största källan till miljögiftet PCB i sötvatten. I flertalet vattendrag, exempelvis Emån, fungererar också sediment som en källa. Ett pappersbruk i anslutning till Emån hade använt returpapper som innehöll PCB som råvara. PCB följde med utsläppen till ån och lagrades in i sedimenten. Miljögiftet läckte sedan ut långsamt till vattnet. Största mängden PCB låg i Järnsjöns sediment, vilket innehöll 400 kg. Halten av PCB i vatten och fisk ökade i Emån nedströms Järnsjön. Eftersom PCB är ett beständigt ämne vilket lagras i organismer och dessutom är toxiskt (bl.a. påverkar reproduktionen och immunförsvaret) var det speciallt olämpligt att det fanns i höga halter just i en värdefull å som Emån. Emån hyser stammar av bl.a. mal och utter, vilka båda är utrotningshotade arter, och storväxt havsöring vandrar upp i ån.



Järnsjön sanerades 1993 och 1994 genom att sugmuddra 150 000 m3 sediment och efter avvattning placerades sedimentet i en deponi på land i närheten av sjön. Det beräknas att 97% av mängden PCB i sedimenten blev deponeradt på land. Halten PCB nedströms i ån var inte högre under sanering än före, vilket antyder att den teknik som användes för att minska uppgrumling och spridning verkar ha fungerat. PCB-halterna i luft kring deponin ökade jämfört med bakgrundshalter i omgivningen, men bara kring deponins närhet och under anläggningsfasen. När deponin var täckt minskade PCB halten i luften till bakgrundsvärden igen. Ingen förhöjning av PCB-halten i grundvatten kring deponiområdet till följd av saneringen kunde spåras.



Efter avslutad sanering minskade PCB-halten i vattnet i sjöns utlopp. Halten varierade säsongsvis beroende på vattenflöde och temperatur. Vid lågt flöde och hög temperatur var PCB-halterna högst. Variationerna liknade de vi fann i en lokal uppströms Järnsjön där nederbörden visade sig vara den dominerande PCB-källan under högflöde, emedan sedimentet dominerade under lågflöde. Sommaren 1996, nästan två år efter saneringen, upprepades en undersökning med avseende på halter av PCB i vatten och fisk i Emån som tidigare gjorts 1991, d.v.s. före sanering. Halten i Järnsjöns vatten hade då minskat två tredjedelar och halten i ett årig abborre var halverad. Även fisk från sjöar uppströms Järnsjön hade lägre halter 1996 jämfört med 1991. Minskningen av PCB i uppströmslokaler speglar troligtvis en reducering av bakgrundskällor, som t.ex. minskat atmosfäriskt nedfall av PCB. (Less)
Abstract
Atmospheric deposition is one source of persistent pollutants such as polychlorinated biphenyls (PCB) in aquatic environments. Other point sources can also contribute to the PCB loadings in the water. In the Emån River, in southeast Sweden, contaminated sediment was a source of PCB, the largest deposits of it being found in a small lake connected with the river, Lake Järnsjön, the sediment of it contained about 400 kg of PCB. The concentration of PCB in the water and in the fish was more elevated downstream from the lake than at upstream sites. Lake Järnsjön was cleaned up by the dredging of it during 1993 and 1994. The dredged sediment, estimated to contain over 95% of the PCB in the lake, was deposited in a landfill. During the cleanup... (More)
Atmospheric deposition is one source of persistent pollutants such as polychlorinated biphenyls (PCB) in aquatic environments. Other point sources can also contribute to the PCB loadings in the water. In the Emån River, in southeast Sweden, contaminated sediment was a source of PCB, the largest deposits of it being found in a small lake connected with the river, Lake Järnsjön, the sediment of it contained about 400 kg of PCB. The concentration of PCB in the water and in the fish was more elevated downstream from the lake than at upstream sites. Lake Järnsjön was cleaned up by the dredging of it during 1993 and 1994. The dredged sediment, estimated to contain over 95% of the PCB in the lake, was deposited in a landfill. During the cleanup action, the concentration of PCB downstream from the lake did not become higher than before. The PCB concentration in the air around the landfill increased in the vicinity and during construction of the landfill. After closure of the landfill by a layer placed on top of it, the PCB concentration in the air fell to background levels. No increase in the PCB concentration in the ground water around the landfill as a result of the remedial action could be detected.



Monitoring carried on for two-years following completion of the remediation showed there to be a decrease in the PCB concentration in the water of the lake. The PCB was found to vary seasonally with water discharge and with temperature. The PCB concentration was highest at low water discharge and high temperature. Both the levels of PCB and the variations in them approached those found at the upstream location. There, precipitation was found to be the main source of PCB during high water discharge, desorption from the sediment prevailing under conditions of low water discharge. In the summer of 1996, nearly two years after remediation had been completed, an investigation of the PCB concentration in the fish of the river system was conducted. This investigation was a repetition of one made in 1991, prior to remediation. It showed that after remediation the concentration of PCB in one-year old fish in Lake Järnsjön was halved. The concentration of PCB in fish upstream was also lower, probably because of the decrease in overall background contamination. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Dr Jones, Kevin, Lancaster University, U.K.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Hydrobiology, dredging, landfill, cleanup, remedial action, air, fish, sediment, Persistent organic pollutants, freshwater, marine biology, aquatic ecology, limnology, Marinbiologi, limnologi, akvatisk ekologi
pages
144 pages
publisher
Chemical Ecology and Ecotoxicology, Department of Biology, Lund University
defense location
Blåhallen, Ekologihuset, Lund
defense date
1997-04-25 10:15
external identifiers
  • Other:ISRN: SE-LUNBDS/NBKE-97/1011+144p
ISBN
91-7105-085-X
language
English
LU publication?
yes
id
3d4cb054-d508-4d6d-85f8-357500635c7a (old id 29097)
date added to LUP
2007-06-12 14:34:57
date last changed
2016-09-19 08:45:06
@misc{3d4cb054-d508-4d6d-85f8-357500635c7a,
  abstract     = {Atmospheric deposition is one source of persistent pollutants such as polychlorinated biphenyls (PCB) in aquatic environments. Other point sources can also contribute to the PCB loadings in the water. In the Emån River, in southeast Sweden, contaminated sediment was a source of PCB, the largest deposits of it being found in a small lake connected with the river, Lake Järnsjön, the sediment of it contained about 400 kg of PCB. The concentration of PCB in the water and in the fish was more elevated downstream from the lake than at upstream sites. Lake Järnsjön was cleaned up by the dredging of it during 1993 and 1994. The dredged sediment, estimated to contain over 95% of the PCB in the lake, was deposited in a landfill. During the cleanup action, the concentration of PCB downstream from the lake did not become higher than before. The PCB concentration in the air around the landfill increased in the vicinity and during construction of the landfill. After closure of the landfill by a layer placed on top of it, the PCB concentration in the air fell to background levels. No increase in the PCB concentration in the ground water around the landfill as a result of the remedial action could be detected.<br/><br>
<br/><br>
Monitoring carried on for two-years following completion of the remediation showed there to be a decrease in the PCB concentration in the water of the lake. The PCB was found to vary seasonally with water discharge and with temperature. The PCB concentration was highest at low water discharge and high temperature. Both the levels of PCB and the variations in them approached those found at the upstream location. There, precipitation was found to be the main source of PCB during high water discharge, desorption from the sediment prevailing under conditions of low water discharge. In the summer of 1996, nearly two years after remediation had been completed, an investigation of the PCB concentration in the fish of the river system was conducted. This investigation was a repetition of one made in 1991, prior to remediation. It showed that after remediation the concentration of PCB in one-year old fish in Lake Järnsjön was halved. The concentration of PCB in fish upstream was also lower, probably because of the decrease in overall background contamination.},
  author       = {Bremle, Gudrun},
  isbn         = {91-7105-085-X},
  keyword      = {Hydrobiology,dredging,landfill,cleanup,remedial action,air,fish,sediment,Persistent organic pollutants,freshwater,marine biology,aquatic ecology,limnology,Marinbiologi,limnologi,akvatisk ekologi},
  language     = {eng},
  pages        = {144},
  publisher    = {ARRAY(0x90266c8)},
  title        = {Polychlorinated biphenyls (PCB) in a river ecosystem},
  year         = {1997},
}