Effect of fluidized bed combustion ashes used in metal polluted soil remediation on life history traits of the oligochaeta Eisenia andrei

The aim of the present work was to investigate the effects of two fluidized bed combustion (FBC) ashes (silico-alumineous and sulfo-calcical) used as immobilizing agents for metals in contaminated soils, on the earthworm Eisenia andrei life history traits in OECD artificial soil. A significant mortality of either juveniles or mature worms was observed following silico-alumineous (>60% mortality) or sulfo-calcical (100% mortality) ashes addition. This effect was due to a transient pH rise of soil. No mortality occurred when worms were introduced eight weeks after soils were amended with FBC ashes. However, growth rates were significantly reduced for both treatments and both ashes exhibited sub-lethal effects likely to affect population dynamics. Thus, cocoon productions were reduced for both amendments and no hatching was recorded with sulfo-calcical ashes. Most of the harmful effects observed on worms growth and reproduction could be attributed to an increase of pH and/or an osmotic disturbance caused by FBC ashes, especially sulfo-calcical ones.