Chemical Monitoring in the Context of Sediment Management in Estuaries

Transcription

1 Chemical Monitoring in the Context of Sediment Management in Estuaries Dr. B. Schubert, Dr. C. Pies, C. Heil Department G1: General Water Quality Issues Bundesanstalt für Gewässerkunde, Koblenz 6th International SedNet Conference, Hamburg, 7-8 October 29

2 Objectives of monitoring contaminants in sediments and suspended particulate matter Assessment of sediment quality Trend assessment, i.a. for the no-deterioration objective of the Water Framework Directive and the EQS-Directive 28/15/EC Derivation of criteria for the assessment of dredged material quality Selection of disposal sites Contribution of contaminants as tracers to a better understanding of the transport of estuarine cohesive fine-grained solids 6th International SedNet Conference, Hamburg, 7-8 October 29

3 Contaminants as tracers for transport of fine-grained sediments in estuaries Estimation of the ratio marine/fluvial cohesive solids Evaluation of the impact of natural or anthropogenic changes on contaminant concentrations Medium to long-term destination of relocated dredged material Identification of areas of sediment accumulation, i.e. in wadden areas Retention of (contaminated) cohesive particulate matter potential secondary source for contaminants (remobilisation) Contribution to the estimation of input of particle-associated contaminants into the German Bight support for optimising dredged material and sediment management 6th International SedNet Conference, Hamburg, 7-8 October 29

4 Monitoring programme in German North Sea estuaries Investigations on and assessment of contaminants in sediments and suspended particulate matter Surface samples and sediment cores Ems Weser Elbe Spatial and temporal monitoring Analyses of grain size distribution, trace metals, organic contaminants, organotin compounds Assessment of contaminant concentrations in the fine-grained fraction <2 µm 6th International SedNet Conference, Hamburg, 7-8 October 29

5 Investigations Grain-size analysis, TOC, N, P, S Trace metals: cadmium, chromium, copper, mercury, nickel, lead, zinc, and arsenic organic contaminants: chloroenezenes, PCBs, hexachlorcyclohexanes, DDT and metabolites, PAHs, oil hydrocarbons, organo-tin compunds contaminant concentrations are measured in or normalised on the fine-grained fraction <2 µm 6th International SedNet Conference, Hamburg, 7-8 October 29

6 Long-term monitoring sites in estuaries: surface sediments, SPM Bunthaus, Seemannshöft : ARGE Elbe Other stations: BfG High frequency of 4 12 samples /a Sediments from sampling sites with high sedimentation rates Sampling of SPM 2 4 weeks 6th International SedNet Conference, Hamburg, 7-8 October 29

7 a) Long-term monitoring in the river: Contaminants in SPM and in recently deposited surface samples - High frequency of 4 12 samples/a - Sampling of SPM 2 4 weeks - Sediments from sampling sites with high sedimentation rates 6th International SedNet Conference, Hamburg, 7-8 October 29

8 Survey in sedimentation areas: sediment cores Neufelder Watt Außendeich Nordkehdingen (8-12 km²) Brunsbüttel Hadelner/Belumer Außendeich (2-3 km²) Elbe estuary Allwördener Außendeich ( ca. 2 km²) Schwarztonnensand Störmündung (ca. 2 km²) Glückstadt Haseldorfer Binnenelbe (2-3 km²) Fährmannsander Watt (ca. 4 km²) Depth profiles, surface layers one-off studies or low frequency of sampling (several years) Weser estuary Hamburg 6th International SedNet Conference, Hamburg, 7-8 October 29 Mühlenberger Loch (ca. 5 km²)

9 Results and assessment: Long-term monitoring in estuaries Surface sediments 6th International SedNet Conference, Hamburg, 7-8 October 29 Suspended particulate matter

10 Contaminant concentrations in estuaries Elbe estuary Tidal weir Weser estuary Tidal weir concentration in mg/kg or µg/kg ,3 657,5 642 km 628,8 69 Zn*,1 p,p'-ddd Cd*1 7 PCB As 6 PAH TBT* 585,9 Ems estuary concentration in mg/kg or µg/kg ,5 56,6 26, 7, 361-5,77 km 6 PAH Zn*,1 Cd*1 7 PCB As TBT*,2 p,p'-ddd concentration in mg/kg or µg/kg Tidal weir 5, 24,5 212,8-13,5,6-2,2 km 6th International SedNet Conference, Hamburg, 7-8 October 29 7 PCB Zn*,1 6 PAH*1 As Cd*1 TBT*,2 p,p'-ddd

11 Temporal trend of Cd concentrations Annual averages in spm in the Elbe estuary Mittelwert Mittelwert±Stdabw. Mittelwert±1,96*Stdabw Cd * Cd Mittelwert Mittelwert±Stdabw. Mittelwert±1,96*Stdabw. * * * * *** Jahr Jahr Geesthacht (km 584) Wedel (km 642) Scheffe-Test: * statistically significant lower concentrations than in the reference year ( ) 6th International SedNet Conference, Hamburg, 7-8 October 29

12 Temporal trend of Cd concentrations Annual averages in spm in the Elbe estuary Mittelwert Mittelwert±Stdabw. Mittelwert±1,96*Stdabw. Geesthacht Elbe-km 584 Cd * th International SedNet Conference, Hamburg, 7-8 October 29 Jahr

13 Temporal trend of Cd concentrations Annual averages in spm in the Elbe estuary 18 Cd Mittelwert Mittelwert±Stdabw. Mittelwert±1,96*Stdabw. * * * * * * Wedel Elbe-km Jahr 6th International SedNet Conference, Hamburg, 7-8 October 29

14 Spatial and temporal variations of contaminant concentrations (<2 µm) in the Elbe estuary Geesthachtkm 584 Bunthaus km 61 Cd Cd-Konzentration in mg / kg th International SedNet Conference, Hamburg, 7-8 October 29

15 Spatial and temporal variations of contaminant concentrations (<2 µm) in the Elbe estuary Cd-Konzentration in mg / kg North Sea level high discharge: 15 3 % marine Low discharge: 6 8 % marine Geesthacht km 584 Bunthaus km 61 Seemannshöft km 629 Wedel km 642 high discharge: 6 7 % marine Cd Low discharge: 85 % marine Discharge Neu Darchau in m³ / s th International SedNet Conference, Hamburg, 7-8 October 29

16 Räumliche und zeitliche Änderung der Schadstoffgehalte im Elbeästuar 18 Geesthacht km 584 Brunsbüttel km Bunthaus km 61 Seemannshöft km 629 Wedel km 642 Cuxhaven km 628 Cd 9 8 Cd-Konzentration in mg / kg Bützfleth km 657, Discharge Neu Darchau in m³ / s th International SedNet Conference, Hamburg, 7-8 October 29

17 Variationen der Zinkgehalte in Schwebstoffen und Sedimenten (<2 µm) in der Tideems 12 1 Herbrum OW Zn Bollingerfähr Zn-Konzentrationen in mg/kg Nordsee-Niveau: nq/hq: 7-9 % marin nq/hq: % marin 1 8 Herbrum UW 6 Terborg 4 Knock Abfluss Versen in m³/s th International SedNet Conference, Hamburg, 7-8 October 29

18 Percentage of marine particulate matter in German North Sea estuaries Anteil mariner Feststoffe in % from tidal limit Ems Elbe ab 2 Till tidal limit till Elbe-km 68 from Elbekm 6 till Weserkm 2- Elbe vor before 2 2 Weser from Weserkm 5 : low niedriger discharge Abfluss : hoher Abfluss high discharge >8 % marine <2 % marine % der Länge des Ästuars Length of estuaries in % 6th International SedNet Conference, Hamburg, 7-8 October 29

19 Transport times of fine-grained solids in the Elbe estuary 1 Transport time of freshwater solids after Qmax: till Wedel: 3 7 weeks till Brunsb.: 7 12 weeks Flood August 22 Wedel 1 Zn-concentration in mg / kg Maximal percentage of fines: Wedel: 6 16 weeks after Qmin Brunsb.: 2 24 weeks after Qmin 13 W 2 W 12 W 15 W 24 W 3 W 1 W 8 W 2 W 7 W 8 W 1 W 3 W 16 W 24 W 6 W 7 W 8 6 Brunsbüttel 4 2 discharge Discharge Neu Darchau in m3 / s th International SedNet Conference, Hamburg, 7-8 October 29

20 Transport times of particulate matter in estuaries Transport of freshwater solids towards the North Sea after Qmax: Elbe: till Wedel: 3-7 weeks till Brunsbüttel 8-12 weeks Weser: till Farge: 2-4 weeks partially input to the German Bight Return of solids of marine origin at low river discharge (Q) Elbe: Wedel: till the next increase of Q (till 8 16 weeks after Qmin) Brunsbüttel: still during next increase of Q (till 2 24 Wochen after Qmin Weser: Farge: till 2-7 weeks after Qmin 6th International SedNet Conference, Hamburg, 7-8 October 29

21 b) Investigations in flat zones (wadden areas, branches) Sediment cores: - Depth profiles, surface layers - one-off studies or low frequency of sampling (several years) 6th International SedNet Conference, Hamburg, 7-8 October 29

22 Results and assessment: Investigations in flat zones box corer vibrocorer 6th International SedNet Conference, Hamburg, 7-8 October 29

23 Elbe: Cd (mg/kg) ) K4 K2 K K7 K6 K1 K K K a 1a 5 1 8a a th International SedNet Conference, Hamburg, 7-8 October K3b 9a

24 2, 15, 1, 5,, Elbe: Cd (mg/kg) (28) K2/28 K2_2/28 2, 15, 1, 5,,,9,6 1, 1,3 1,1 1,6 1,7 1,9 2, , 15, 1, 5,, ,8 1,6 1,7 2,6 2,4 4,5 2,5 3,2 1, K17/28 K16/ K21/28 K22/28 2, 15, 1, 5,, 2, 15, 1, 5,, a 1,1 2,1 1,9,6,3 1,2,8,4,6,,1, ,7 1,51,7 2,7 8,49,2 1,6 1,82,2 1,62,22,2,53,1 3, 4,5 6, K23/28 K14/28 Kern 1/28 Kern 4/28 K7/28 6th International SedNet Conference, Hamburg, 7-8 October 29

25 Contaminant loads in sedimentation areas of the Elbe estuary ( ) Zn (t) HCB*1 (kg) TBT*1 (kg) Zn (t) Cd (kg) Schnackenburg (load/a) sum for sed. areas Mühlenberger Loch Fährmannsander Watt Haseldorfer Binnenelbe Allwördener Außend... Nordkehdinger Watt HCB*1 (kg) Schnackenburg: average annual load (24 26), ARGE Elbe 6th International SedNet Conference, Hamburg, 7-8 October 29

26 Temporal development of Cd concentrations in spm at Wedel, Elbe-km , Cd in suspended particulate matter (<2µm) Station Wedel, Elbe-km , /7 1996/97 26/7 1, 8, 6, 4, 2,, Jan 8 Jan 81 Jan 82 Jan 83 Jan 84 Jan 85 Jan 86 Jan 87 Jan 88 Jan 89 Jan 9 Jan 91 Jan 92 Jan 93 Jan 94 Jan 95 Jan 96 Jan 97 Jan 98 Jan 99 Jan Jan 1 Jan 2 Jan 3 Jan 4 Jan 5 Jan 6 Jan 7 Jan 8 mg/kg Jan 9 3,4 mg/kg 2,1 mg/kg 6th International SedNet Conference, Hamburg, 7-8 October 29

27 Cd (mg/kg) in sediment cores 1997 and 28 - Fährmannsander Watt (Elbe) a core 9a / core 9 / core 5a / core 7 / a 5a core 5 / core 6 / core 8a / core 8 / 28 8a th International SedNet Conference, Hamburg, 7-8 October 29 15

28 Cd (mg/kg) in sediment cores 1997 and core 1a / core 7 / a core 9a / a core 9 / 28 5a core 5a / core 5 / core 6 / core 4 / core 1 / 28 8a core 8a / core 8 / 28 6th International SedNet Conference, Hamburg, 7-8 October

29 Cd (mg/kg) in sediment cores 1998 and core 2 / core 2_2 / core 1 / core 1 / core 4 / core 4 / th International SedNet Conference, Hamburg, 7-8 October 29

30 Kern Weser estuary: Cd concentrations in sediment cores (1999) 6th International SedNet Conference, Hamburg, 7-8 October 29 Bremen Kern 1 Kern Kern 8

31 Kern Kern Kern1 6th International SedNet Conference, Hamburg, 7-8 October Kern Kern Weser estuary: Zn concentrations in sediment cores (1999) Bremen

32 Summary Results of long-term contaminant analyses confirm the upstream transport of fine-grained solids as predicted by model calculations, Indicate a larger extent of upstream transport in the river Elbe after the year 2 how a different extent of upstream transport for the estuaries of Elbe, Weser and Ems give an indication on transport time of fine-grained solids Results from depth profiles in wadden areas Contaminated layers in tidal flats and branches of Elbe and Weser have a thickness of up to 3 m. Contaminant quantities accumulated in sediments of tidal flats of the Elbe estuary amount to ca the 2-fold of loads entering the estuary annually. Re-investigation of contaminants in tidal flats may give an indication of deposition rates. 6th International SedNet Conference, Hamburg, 7-8 October 29

33 Conclusions and perspective Results of chemical monitoring should be considered In the planning of construction works, capital dredging, and sediment management meassures for navigation, In the planning of measures for improving waterbodies in the implementation of the EC-Water Framwork Directive In the estimation of particle-bound contaminant input to the North Sea Future planning Use of trace metal data for veryfying numerical models for transport of fine-grained sediments Re-investigation of wadden areas and branches Investigations in further flat zones and floodplains 6th International SedNet Conference, Hamburg, 7-8 October 29

34 Thanks go to the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) which provided essential funding the Waterways and Shipping Agencies, facilitating the sampling programme the colleagues in the laboratory of the BfG Dr. Fridbert Ackermann, who initiated these investigations 6th International SedNet Conference, Hamburg, 7-8 October 29

35 6th International SedNet Conference, Hamburg, 7-8 October 29 Thank you for your attention