Metal toxicity and biodiversity in serpentine soils: Application of bioassay tests and microarthropod index

Eco-toxicological or bioassays tests have intensively been discussed as tools for the evaluation of soil quality. Tests with soil organisms, including microarthropods and plants, allow direct estimates of important soil characteristics and functions. In this study we compared the results obtained by two in vitro standard bioassays following ISO or OECD guidelines: i) the short term-chronic phytotoxicity germination and root elongation test using three different plant species Lepidium sativum L. (Brassicaceae), Cucumis sativus L. (Cucurbitaceae) and Medicago sativa L. (Fabaceae) ii) the inhibition of reproduction of Folsomia candida (Collembola) by soil pollutants (ISO 11267:1999) to investigate the toxicity of a serpentine soil present in the Italian Apennines, rich in heavy metals such as Ni, Cr, Co. In addition, microarthropod communities were been characterized to evaluate the effects of metal contents on the soil fauna in natural conditions. Abundances, Acari/Collembola ratio, biodiversity indices and QBS-ar index were calculated. Our results demonstrate that the two in vitro tests discriminate differences correlated with metal and organic matter contents in four sub-sites within the serpentinite. Soil fauna characterization, not previously performed on serpentine soils, revealed differences in peculiar groups of microarthropods among the four sub-sites: microarthropod community was found to be rich and well diversified in the sub-site characterized by the less metal content and the higher organic matter content and vegetation.

JRC.H.5 - Land Resources Management