B. Cornelis 2, A. De Vocht 2, S. Van Slycken 1, K. Adriaensen 3, F. Tack 1, J. Vangronsveld 3

Transcriptie

1 RISK BASED SOIL REMEDIATION OF HEAVY METAL POLLUTED SOILS IN THE CAMPINE REGION (FLANDERS - BELGIUM) Erik Meers 1 B. Cornelis 2, A. De Vocht 2, S. Van Slycken 1, K. Adriaensen 3, F. Tack 1, J. Vangronsveld 3 1 Laboratory of Analytical Chemistry and Applied Ecochemistry, Ghent University 2 PHL University College, Department Bio 3 Laboratory of Environmental Biology, University of Hasselt

2 Localisation

3 Soil pollution Flemish & Dutch Kempen region 700 km 2 historically contaminated with heavy metals History: End 19th century 1970 pyrometallurgic processing of Zn and Pb ore in the Kempen

4 Soil pollution Emissions: - Zn, Pb, Cd (relatively volatile) - Diffusion elevated concentrations Residues: 700 km 2 affected 350 km 2 Cd > 1 mg/kg (Netherlands and Flanders) - Ashes, slags km roads have been constructed with Zn rich slags Discharge on surface water: - Contaminated sediments - Contaminated riparian zones and flooding areas - Contaminated disposal sites Soil characteristics Sandy soils, low ph (ph KCl ~ 5,5)

5 Contaminated soils Conventional Remediation Excavation Treatment or dumping + Ex situ treatment + Small areas + High contamination level + Short sanitation period - Not for diffuse contamination - Loss of soil texture - High cost Risk based alternatives Phytoremediation Phytoextraction Phyto-attenuation Phytostabilisation Chemical stabilization + In situ treatment + Extended areas + Low/moderate contamination level + Low cost + Negative impact of metals reduced - Not for heavily polluted soils - Standardized assessment - Metals remain or gradual removal - In case of phyto-extr./att. - time

6 Particular interest for Cd Attention for cadmium: - Human toxic at relatively low concentrations - Kidney damage - Bone decalcification - (Lung) cancer Observations: - Elevated Cd concentrations in urin and blood - Elevated Cd concentrations in crops - Elevated Cd concentrations in cattle (kidney, liver)

7 Particular interest for Cd

8 Particular interest for Cd % Cd SR1 SR2 SR3 SR4 BA1 FA ph

9 Particular interest for agriculture Cd: mg/kg, (background Flanders: 0.8 mg/kg) Carrots, black salsify > EU standards

10 Risk based approach to Cd remediation A B Sol Exch Res Voor Na Voor Na Risk-reduction by influencing soil metal fractionation (e.g. chemical stabilization) Risk reduction by selective removal of soluble/bioavailable Metals (e.g. phyto-extraction)

11 Strategy 1 The use of non-food crops for phyto-attenuation of Cd / Zn

12 Stimulated attenuation of soil contamination Sustainable, renewable energy production Metal introduction in human food chain Metal sequestration during biomass processing Alternative farmer income FAVV EU Currently in use for food and feed production Phytoremediation crops Non-food crops Energy crops Agricultural land containing (elevated) levels of heavy metals Alternative land use?

13 Extensive field-experiments

14 Case study Energiemaïs Energiemaïs = non-food teelt die met behulp van vergisting wordt omgezet in groene stroom en groene warmte

15 Wat is vergisting? Biomassa Biogas Vergisting = anaeroob microbiologisch proces waarbij organisch materiaal uit mest, organisch-biologisch afval en energieteelten wordt omgezet in een hernieuwbare, methaanrijke energiedrager (biogas)

16 Overzicht evaluatie energiemaïs Agrarisch potentieel Biomassa productie (6 cultivars) Bemestingsproeven (4 regimes) Fytoremediatie potentieel Totale extractie van zware metalen Remediatie duur Energie-recuperatie potentieel Concentratie metalen in diverse componenten Impact op vergisting Kwaliteit digestaat - Concentratie metalen in digestaat - Digestaatbehandeling

17 Resultaten: biomassa productie 20 ± 3 ton DS (36 ± 6 %DS-inhoud) ~ t/ha VS Geen significante verschillen tussen de 6 geteste cultivars Geen verschillen t.o.v. maïs op niet verontreinigde grond

18 Resultaten: biomassa productie Bemestingsproeven: 0, 85, 170, 250 kg N/ha Biomassa opbrengst : 30 tot > 80 t/ha FM Nitraatuitloging via opvolging Bodemkundige Dienst = onder norm voor alle behandelingen

19 Resultaten: fytoremediatie potentieel Totale extractie: 18 ± 3 g Cd ha -1 (opm. Zn ~ g/ha.j) Geen significante verschillen tussen de cultivars Lange remediatie periode => NIET eerste doelstelling!!! 2 naar 1.2 mg Cd kg -1 ~ ± 200 jaren 5 naar 2 mg Cd kg -1 ~± 500 jaren

20 Resultaten: biomassa gebruik (normen) Gebruik als Voederteelt Norm : 1.1 mg Cd/kg DM Metaal concentratie > voedernorm voor ons terrein Opm. korrelmaïs wel < norm Non-food anaerobe vergisting Norm : 6 mg Cd/kg DM

21 Resultaten: energie conversie Energie conversie Batch testen Geen verschillen in biogas-opbrengst gecontamineerd vs. niet gecontamineerd Biogaspotentieel voornamelijk in de kolf (2/3)! Continue testen (ongoing) Biogas potentieel over langere periode impact M op biogas? Resultaten komen goed overeen met batch testen ( Nm3/t, uitgemiddeld 195 m3/t VS)

22 Resultaten: energie opbrengst Energie (GJ/ha) Teelt energie-maïs -8.3 Transport (maïs naar lokale vergister) -2.4 Transport digestaat (export) -1.8 Totaal fossiele energie input Energie inhoud biogas 224 Electriciteit 79 Warmte 30 Totaal energie productie 109 Netto energie winst 96

23 Resultaten: kwaliteit digestaat % DS Cd mg kg -1 Zn mg kg -1 N g kg -1 P g kg -1 K g kg -1 Ca g kg -1 Maïs ref 31±2 < DL 33±2 12±1 2.1±0.2 13±1 2.3±0.2 Maïs Lommel 24±5 1.0± ±34 8.3± ± ±1 2.5±0.2 Digestaat ref 9.5± ± ±15 28±2 21±1 42±2 19±1 Digestaat Lommel 12±1 3.2± ±27 26±1 9.5±0.1 39±1 72±1 Opm. Vlarea-norm Cd: 6 mg/kg Vlarea-norm Zn: 900 mg/kg

24 Resultaten: kwaliteit digestaat Selectieve metaal extractie bij digestaatverwerking = technisch haalbaar? = praktisch zinvol? niet voor micronutriënten (Zn, Ni, Cu, Co, ) voor microcontaminanten, afhankelijk van context in geval gebruik v/e excluder zoals mais niet

25 Conclusie Energie maïs voor fytoremediatie van metaal aangerijkte gronden & productie van energie???

26 Conclusie: mogelijkheden van energie maïs Lange remediatie periode Goede productiviteit Economisch valoriseerbaar Energie conversie toont veelbelovende resultaten

27 Algemene conclusie Een perfect alternatief op metaal aangerijkte gronden Houdt de landbouwer in business Gecontroleerd & veilig gebruik van biomassa Ecologisch & duurzaam Phyto-assisted attenuation

28 References on phytoremediation research Meers, E., Hopgood, M., Lesage, E., Vervaeke, P., Tack, F.M.G. & Verloo, M. (2004). Enhanced Phytoextraction : In Search for EDTA Alternatives. International Journal of Phytoremediation, 6, 2, Meers, E., Lamsal, S., Vervaeke, P., Hopgood, M., Lust, N., Tack, F.M.G. & Verloo, M.G. (2005). Availability of heavy metals for uptake by Salix viminalis on a moderately contaminated dredged sediment disposal site. Journal of Environmental Pollution, 137, Meers, E., Ruttens, A., Samson, D., Hopgood, M. & Tack, F.M.G. (2005). Comparison of EDTA and EDDS as Potential Soil Amendments for Enhanced Phytoextraction of Heavy Metals. Chemosphere, 58, Meers, E., Ruttens, A., Hopgood, M., Lesage, E. & Tack, F.M.G. (2005). Potential of Brassica rapa, Cannabis sativa, Helianthus annuus and Zea mays for phytoextraction of heavy metals from calcareous dredged sediment derived soils. Chemosphere, 61, Meers, E., Lesage, E., Lamsal, S., Hopgood, M., Vervaeke, P., Tack, F.M.G. & Verloo, M.G. (2005). Enhanced Phytoextraction : I. Effect of EDTA & citric acid on heavy metal mobility in a calcareous soil. International Journal of Phytoremediation, 7, Meers, E., Vandecasteele, B., Ruttens, A., Vangronsveld, J. & Tack, F.M.G. (2007). Potential of five willow species (Salix spp.) for phytoextraction of heavy metals. Journal of Experimental Environmental Botany, 120, Meers, E., Tack, F.M.G., Van Slycken, S., Ruttens, A., Du Laing, G., Vangronsveld, J. & Verloo, M.G. (2008). Chemically-assisted phytoextraction: a review of potential soil amendments for increasing plant uptake of heavy metals. International Journal of Phytoremediation, 10, Meers, E., Van Slycken, S., Adriaensen, K., Vangronsveld, J., Du Laing, G., Witters, N., Thewys, T. & Tack, F.M.G. The use of bioenergy crops (Zea mays) for phytoattenuation of heavy metals on moderately contaminated soils : a field experiment. Chemosphere, in press. Lesage E., Meers E., Vervaeke P., Lamsal S., Hopgood M., Tack F.M.G. & Verloo M.G. (2005). Enhanced Phytoextraction : II. Effect of EDTA & citric acid on heavy metal uptake by Helianthus annuus from a calcareous soil. International Journal of Phytoremediation, 7, Van Ginneken, L., Meers, E., Guisson, R., Ruttens, A., Tack, F.M.G., Vangronsveld, J., Diels, L. & Dejonghe, W. (2007). Phytoremediation for heavy metal contaminated soils and combined bio-energy production. Journal of Environmental Engineering and Landscape Management, 4, Saifullah, S., Meers, E., Qadir, M., de Caritat, P., Tack, F.M.G., Du Laing, G. and M. H. Zia (2009). A review on EDTA-assisted Pb phytoextraction. Chemosphere, 74, Vervaeke, P., Luyssaert, S., Mertens, J., Meers, E., Tack, F.M.G. & Lust N. (2003). Phytoremediation prospects of willow stands on contaminated sediment: a field trial. Environmental Pollution, 126, Mertens, J., Vervaeke, P., Meers, E. & Tack F.M.G. (2006). Seasonal changes of metals in willow (Salix sp.) stands for phytormediation on dredged sediment. Environmental Science and Technology, 40, Vangronsveld, J., Herzig, R., Weyens, N., Boulet, J., Adriaensen, K., Ruttens, A., Thewys, T., Vassilev, A., Meers, E., Nehnevajova, E., van der Lelie, D., Mench, M. (2009) Phytoremediation of contaminated soils and groundwater: lessons from the field. Environmental Science and Pollution Research, in press.

29 Strategy 2 The use of soil amendments to reduce the solubility / mobility / bioavailability of heavy metals

30 The use of soil amendments to reduce metal solubility

31 Chemistry Toxicology Biology

32 Assessment standardization : Multi-disciplinary phased cascade approach to screening Amendment characterisation ph dependent metal-mobility Long term sustainability of stabilisation Ecological availability & ecotoxicity Human exposure assays

33 Assessment standardization : Multi-disciplinary phased cascade approach to screening Amendment characterisation ph dependent metal-mobility Soil treatment, incubation: (i) rhizon extraction, (ii) ph batch L:S 10:1

34 Assessment standardization : Multi-disciplinary phased cascade approach to screening Amendment characterisation ph dependent metal-mobility Long term sustainability of stabilisation (i) Accelerated rainfall & percolation from treated soils (ii) Forced ageing of soils treated In previous step

35 Assessment standardization : Multi-disciplinary phased cascade approach to screening (i) CaCl 2 (ii) TCLP (toxicity characteristic leaching procedure) (iii) Plant Tox (Phaseolus vulgaris) (iv) Earthworms (growth, weight, reproduction, bait lamina) (v) Reproduction (Eisenia fetida ; Folsomia candida) (vi) ROTAS (Vibrio fischeri) (Rapid On-site Toxicity Audit System) Ecological availability & ecotoxicity Human exposure assays

36 Assessment standardization : Multi-disciplinary phased cascade approach to screening (i) PBET (Physiologically Based Extraction Test ) (ii) Accumulation in vegetables Human exposure assays