1. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Field effects of LAS enriched sludge on soil fauna Paul Henning Krogh John Jensen Martin Holmstrup National Environmental Research Institute Kristian K. Brandt Veterinary and Agricultural University Georgio Cassani CONDEA Augusta Italy Kaj Henriksen Aalborg University

2. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Aims Is LAS toxic under field condition? How does the laboratory results agree with field results? How can we explain the field results?

3. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Mixing LAS into sludge

4. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Laying down string of sludge in soil groove

5. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 LAS in sludge stimulates plant growth

6. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Experimental design 19 m 12 m Blok 2Blok 3Blok 4Blok 5Blok 1 Aerobic sludge + LAS g kg -1 4 cm cm 2 4 0 50“0”10

7. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Plant roots grow in whole bundles through the sludge

8. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001

9. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 LAS disappearance from sludge 0 20 40 60 80 100 MAYJUNJUL LAS % remaining of initial

10. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Digging up a soil block for determination of earthworm abundance

11. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 A. caliginosa

12. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Enchytraeids in sludge

13. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Enchytraeids in soil

14. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 F. fimetaria Individuals 10 3 m -2

15. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Willemia sp. Individuals 10 3 m -2

16. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 M. macrochaeta Individuals 10 3 m -2

17. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Prostigmatid mites Individuals 10 3 m -2

18. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Gamasid mites (predators) Individuals 10 3 m -2

19. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Astigmatid mites Individuals 10 3 m -2

20. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Summary of results Short term: Colonisation of all soil invertebrates studied is inhibited by LAS (except two groups of mites) Long term: Collembolans and earthworms have recovered from LAS Enchytraeids did not recover from LAS after 5 months Mites and M. macrochaeta are stimulated by LAS

21. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Lab toxicity of LAS in soil EC 50 reproduction, mg kg -1 0 100 200 300 400 500 H. assimilis F. fimetaria H. aculeifer A. caliginosa A. longa E. albidus

22. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 How does laboratory results agree with field results? Inhibitory effects both in lab and field to all soil invertebrates except gamasid mites Enchytraeids were the most sensitive species in both lab and field Earthworm and enchytraeid populations were not more sensitive to LAS compared with microarthropods Recovery of earthworms and collembolans

23. National Environmental Research Institute Department of Terrestrial Ecology SETAC Madrid 2001 Conclusion LAS in sludge has a short term toxic effect to soil invertebrates in sludge, but recovery has been attained for allmost all soil invertebrates, except enchytraeids that had just started to recover