Polluted sediments in Bjørvika the submerged tunnel project Aud Helland Dr.scient Marine geology aud.helland@ramboll.no 2 Contents Pollution history The submerged tunnel project Pollution in the tunnel alignment The Norwegian EPA permit concerning the construction work Monitoring and challenges Conclusions and lessons learned 3
PCB in sediments insignificantly polluted moderately polluted markedly polluted severely polluted extremely polluted 4 Vertical profile of pollutants in Bjørvika sediments prior to dredging PAH 16 PCB 7 TBT 1 2 3 2 4 6 1 2 3 4 2 4 6 Depth (cm) 8 1 12 14 16 Oen, 26 5 6
Copyright: Norwegian Public Road Administration 8 Sub bottom profile Copyright: Norwegian Public Road Administration Ramboll Norway AS 28-11-19 9
Tunnel elements 1 11 Thickness of polluted sediments Vertical profiles through Paulsen utstikkeren m BU-B-1 BU-B-2 BU-B-3 BU-B-4 BU-B-5 BU-B-6 Alun Tergl BU-B-7 BU-B-8 BU-B-9 BU-B-1 BU-B-11 BU-B-12 BU-B-13 BU-B-14 1m Fillings, remnants from city development (6-7 m) 2m 3m 4m 5m Log houses filled with rock and deris (2 m) o 6m ooo o ooo ooo ooo ooo Terverk Sandig Bløtere 7m Saw dust (8 m) Sandig Slagg 8m Stopp Slagg TD=7 m 9m Marine clay 1 m Stopp TD=1 m 11 m 12 m 13 m 14 m 15 m TD=14 m TD=14 m TD=14 m TD=14 m 12
13 14 Silt curtains 15
Dreding and filtration of water 16 Monitoring stations Different colours - different operations AK-FV1 HL-FV9 AK-FV3 AK-FV4 BJ-FV1 BI-BV1 BU-FV2 BJ-FV7 AK-FV5 BI-BV9 BJ-MV3 BJ-FV5 BI-BV2 AK-FV6 BJ-MV1 BI-BV3 BJ-MV4 AK-FV7 BJ-MV2 PK-FV2 BI-BV4 AK-FV8 PK-FV1 Bi-MV1 SØ-FV6 PK-FV3 Bi-MV2 BI-BV5 PK-FV4 Bi-MV3 BJ-MV7 BJ-MV5 PK-FV5 Bi-MV4 BI-BV7 BJ-MV8 AK-FV2 BJ-MV6 BI-BV8 SØ-FV3 LO-FV8 VT-FV1 LO-FV4 Bi-BV6 = PK-FV3 Røde punkt ble opprinnelig opprettet som en overvåkning av vannkvaliteten i tilknytning til hele anlegget og ble prøvetatt med jevne mellomrom. (Vippetangen-VT, Havnelageret-HL, Lohavn-LO, Sørenga-SØ, Bjørvikautstikkeren- 17 BU, Bjørvika-BJ, Akerselva-AK) Blå punkt er opprinnelig opprettet i forbindelse med mudringsovervåkning (Bispevika-Bi og Bjørvika-Bj) Mørk grønne punkt er opprettet i forbindelse med tildekking og mudring i Bispevika Turbiditity monitoring Bispevika 17.4.8 Kl.: 11:24 NTU Profil: BI-FV4NI.5 NTU 2 4 6 8 1 12 2.5 Inside silt curtain 4.5 6.5 8.5 Bispevika 17.4.8 Kl.: 1:41 NTU Profil: BI-FV2 1.5.5 NTU 5 1 15 2 25 3 35 4 45 2.5 12.5 4.5 6.5 8.5 Outside silt curtain 1.5 12.5 14.5 16.5 18.5 2.5 18
Monitoring of water quality Pb (µg/l) 14 12 1 8 SØ-FV1N 6 4 SØ-FV2S SØ-FV3S SØ-FV4NI Hg (µg/l) 2 1.4.28 1.4.28 17.4.28 23.4.28 6.5.28 1,8 1,6 1,4 1,2 1,8,6,4 SØ-FV1N SØ-FV2S SØ-FV3S SØ-FV4NI,2 1.4.28 1.4.28 17.4.28 23.4.28 6.5.28 19 Correlation between Cu & Pb (total sample) p=. Cor.coef=.89 15 12 Cu (µg/l) 9 6 3 3 6 9 12 15 Pb (µg/l) 2 Unfiltered / Filtered Station Pb Cr Hg Zn SØ-FV1N 1 2,48 1,1 1,5 SØ-FV1N 7 2,4 1,1 1,4 SØ-FV1N 21 4,4 1,5 2,5 SØ-FV2S 26 6 1,3 1,9 SØ-FV3S 4,4 1 1,1 1,6 SØ-FV4NI 21 4,8 1,1 1,8 SØ-FV4NI 86 23,2 1,6 4,8 SØ-FV4NI 25 6,8 1,1 2,3 SØ-FV4NI 2 13,2 1, 4,8 21
Conclusions and lessons learned Improved sediment quality Particle spreading within the permit Turidity monitoring fixed positions one depth vs. profiling measurements Turbidity a measure of particle spreading, but not always a measure of micro pollutant spreading The importance of linking preinvestigations to operational plans 22