Orthonychiurus pseudostachianus (collembola) as a toxicity test organism and selection of an ecotoxicological test battery to assess soil quality

This study aimed at developing a test using an autochthonous collembolan species (Orthonychiurus pseudostachianus, Gisin 1956) to assess soil toxicity. To evaluate the feasibility of this species in soil ecotoxicity assessment, it was considered whether the biological characteristics of the proposed species met the criteria reported in OECD guideline 232 for toxicity testing using Folsomia candida. Next, the sensitivity to soil metal contamination was evaluated performing the test on an artificial soil spiked with Zn concentrations ranging from 4.79 to 479 μg g−1 d.w. To verify its suitability for soil ecotoxicity assessment, the proposed test was performed on soils collected at six sites in the urban area of Naples together with other ecotoxicological tests. The other aim of the study was to identify the lowest number of tests needed to obtain an optimized test battery for soil ecotoxicity assessment. At the tested Zn concentrations, no mortality of O. pseudostachianus was observed whereas reproduction was halved at 37.4 μg Zn g−1 d.w. (95% confidence limits 29.3–44.8). In the field-collected soils, reproduction of O. pseudostachianus proved a useful tool to assess soil quality. A test battery composed only by Sinapis alba (germination index), O. pseudostachianus (reproduction), Eisenia veneta (body growth), and Heterocypris incongruens (body growth) tests were shown to be sufficiently informative to assess soil toxicity.

► The indigenous collembolan Orthonychiurus pseudostachianus is sensitive to soil metal contamination.
► O. pseudostachianus reproduction is a useful tool in assessing soil quality.
► An ecotoxicity test battery is proposed to optimize soil quality assessment.
► The test battery should include plants, earthworms, collembolan and ostracods.