Metal/metalloid accumulation/remobilization during aquatic litter decomposition in freshwater

Transcription

1 Fakultät Forst-, Geo-, Hydrowissenschaften, Institut of General Ecology and Environmental Protection Metal/metalloid accumulation/remobilization during aquatic litter decomposition in freshwater Jörg Schaller Orlando, 4. June 2012

2 Key-processes during litter decay Schaller et al. 2011, Sci. Total Environ., 409: TU Dresden, Intecol 2012 Folie 2 von 20

3 Aquatic ecosystems affected by former mining ph 7.5 eh 400 mv discharge 5-10 L s -1 Leaf litter input Population of invertebrate shredder (key-species of litter decomposition) TU Dresden, Intecol 2012 Folie 3 von 20

4 Background: metal/ metalloid content in water of polluted streams Content in water µg*l -1 Content in sediments mg*kg -1 *DM -1 (organic rich) Mn Co Cu Zn As Cd Pb U TU Dresden, Intecol 2012 Folie 4 von 20

5 Background: Main processes of litter decay in aquatic systems FPOM = fine particulate organic matter CPOM = coarse particulate organic matter DOC = dissolved organic carbon Gammarus pulex is a main litter processing invertebrate in Europe Schaller et al. 2011, Sci. Total Environ., 409: TU Dresden, Intecol 2012 Folie 5 von 20

6 Resulting questions: Which influences do invertebrate shredders have on metal/ metalloid fixation? Which influence do invertebrate shredders have on DOC release and consequently on metal remobilization? TU Dresden, Intecol 2012 Folie 6 von 20

7 Batch experiment TU Dresden, Intecol 2012 Folie 7 von 20

8 What are the effects of invertebrate shredder on litter proporties? litter processing formation of smaller particles increasing of the surface area G+ with invertebrates G- without invertebrates higher surface area more biofilm biofilm has very good sorption proporties Schaller et al. 2010, Environmental Pollution 158: TU Dresden, Intecol 2012 Folie 8 von 20

9 In which fraction of the sediments the highest metal and metalloid content is found? below 2000 µm data in mg kg -1 DW -1 Schaller et al. 2010, Chemosphere 79: TU Dresden, Intecol 2012 Folie 9 von 20

10 In which fraction of the sediments the highest metal and metalloid content is found? below 2000 µm data in mg kg -1 DM -1 U+ with uranium U- without uranium G+ with invertebrates G- without invertebrates ore level Schaller et al. 2008, Environmental Science & Technology 42: TU Dresden, Intecol 2012 Folie 10 von 20

11 Field experiment TU Dresden, Intecol 2012 Folie 11 von 20

12 Confirmation of laboratory data in the field data in mg kg -1 DM -1 L6+G = leaf litter after 6 weeks of with invertebrate fedding POM+G = particulate organic matter after 2 weeks of intebrate feeding ph = 7.5 eh = 400 mv Schaller et al. 2010, Chemosphere 79: exception uranium TU Dresden, Intecol 2012 Folie 12 von 20

13 In which fraction of the sediments the highest metal and metalloid content is found? Schaller et al. 2010, Chemosphere 79: in the biofilm data in mg kg -1 DM -1 ILL = inital leaf litter (unpolluted) L6-G = leaf litter after 6 weeks of without invertebrate fedding BL6-G = removed bioflim from the 6 weeks exposed leaf litter ph = 7.5 eh = 400 mv TU Dresden, Intecol 2012 Folie 13 von 20

14 Which influence do invertebrate shredders have on DOC release? U+ with uranium U- without uranium G+ with invertebrates G- without invertebrates Schaller et al. 2008, Environmental Science & Technology 42: TU Dresden, Intecol 2012 Folie 14 von 20

15 Which influence does increase of DOC have on the metal/ metalloid remobilization? very low influence! U+ with uranium U- without uranium G+ with invertebrates G- without invertebrates Schaller et al. 2008, Environmental Science & Technology 42: TU Dresden, Intecol 2012 Folie 15 von 20

16 Cu / Zn Which influence does increase of DOC have on the metal/ metalloid remobilization? very low influence! Schaller et al. 2010, Environmental Pollution 158: TU Dresden, Intecol 2012 Folie 16 von 20

17 Which influence does increase of DOC have on the metal/ metalloid remobilization? Any exceptions? molybdenum Correlation between dissolved molybdenum and dissolved organic carbon (DOC). R , p < Schaller et al. 2010, Environmental Pollution 158: TU Dresden, Intecol 2012 Folie 17 von 20

18 Conclusion Invertebrate shredder affect significantly the accumulation of metals and metalloids into organic sediments Concentrations of ore level can be reached These effects also take place at a low metal / metalloid concentrations in the water Increased DOC levels do not weaken this effect (exception: molybdenum) TU Dresden, Intecol 2012 Folie 18 von 20

19 Outlook: Schaller et al. 2011, Sci. Total Environ., 409: TU Dresden, Intecol 2012 Folie 19 von 20

20 Thank you for your attention! Schaller, J., A. Weiske, M. Mkandawire, and E. G. Dudel Enrichment of Uranium in Particulate Matter during Litter Decomposition Affected by Gammarus pulex L. Environmental Science & Technology 42: Schaller, J., A. Weiske, M. Mkandawire, and E. G. Dudel Invertebrates control metals and arsenic sequestration as ecosystem engineers. Chemosphere 79: Schaller, J., M. Mkandawire, and E. G. Dudel Heavy metals and arsenic fixation into freshwater organic matter under Gammarus pulex L. influence. Environmental Pollution 158: Schaller, J., C. Brackhage, M. Mkandawire and E.G. Dudel, Metal/metalloid accumulation/remobilization during aquatic litter decomposition in freshwater: A review. Sci. Total Environ., 409: TU Dresden, Intecol 2012 Folie 20 von 20