PARENT SESSION
WP2 Assessing and predicting toxicant effects in an ecologically complex world
3:00 PM to 6:30 PM, Wednesday, 09 May 2001
Session Chair: P. Calow, V. Forbes
Room 2

(371) Field effects of LAS enriched sludge on soil fauna .

Krogh, Paul Henning¹, Jensen, John ¹, Holmstrup, Martin¹, Brandt, Kristian², Cassani, Georgio³, Henriksen, Kaj⁴, ^{1 2 3 4}

ABSTRACT- Field effects of linear alkylbenzene sulfonates (LAS) on the soil ecosystem was studied to validate a laboratory toxicity data set. Four cm thick "strings" of sludge spiked with 0, 10 or 50 g kg^-1 of LAS were put into soil grooves. Effects (EC₅₀ approx. 5 g kg-1) of LAS treatments on enchytraeids and some microarthropods were found in the sludge during the first months of the entire 5-month field trial. These populations had recovered after 4 months. Stimulations lasting the whole period were found for Mesaphorura collembolans and the mites. In the soil surrounding the sludge strings mites were reduced by 10% while Collembola were unaffected. The field results are compared with laboratory results and an ecological interpretation is offered.

Key words: LAS, Sludge, Soil ecological changes