SURVIVAL, BODY MASS CHANGE AND METAL BIOACCUMULATION IN Eisenia fetida (OLIGOCHAETA: LUMBRICIDAE) INCUBATED IN SOIL AMENDED WITH ORGANIC WASTES

The application of organic wastes to agricultural soils may have adverse effects on soil quality. Different end-points are proposed to be analysed and included in organic waste management programmes. The aim of this laboratory study was to determine how the application of increasing concentrations of broiler chicken litter, dairy sludge and cattle slurry can affect survival, body mass change and metal accumulation in Eisenia fetida (Savigny, 1826). Generally, no mortality occurred for the different organic wastes concentrations at the end of the study. In addition, significant increases of body mass were observed on earthworms exposed to the highest concentrations of the organic wastes. Organic wastes increased concentration of some metals in soil (mainly, Cu and Zn in broiler litter and dairy sludge mixtures) and in E. fetida tissue (mainly, Cu in earthworms from broiler litter containers), although metal contents in soil-waste mixtures were always below legal limits. The negligible toxic effect of organic wastes on earthworms was due to the low heavy metal levels of those organic wastes and due to some nutritional or habitat advantages promoted by them. Results obtained demonstrated that body mass change was the most sensitive end-point and, therefore, should be integrated on a battery of ecotoxicological assays to evaluate the ecotoxicity of this type of organic wastes.