Soil contact bioassay for rapid determination of acute toxicity with Eisenia foetida

Abstract

A rapid bioassay is presented for determining acute toxicity directly in soil. Modifying the Organisation for Economic Cooperation and Development (OECD) protocol 207, it uses a thin layer of moistened soil laid directly in the bottom of the bioassay jar into which the earthworms are placed and incubated. Examples are presented in comparisons between the soil contact bioassay vs. the filter paper bioassay run on Toxicity Characteristic Leaching Procedure (TCLP) extracts of pesticide contaminated soil and petroleum drilling cuttings. In 2,4-dichlorophenoxyacetic acid (2,4-D) contaminated soil (300mg/Kg), no mortality was found in soil extracts, but 100% mortality was found when exposed directly to soil. Treatment with the Daremend® product in five anaerobic/aerobic cycles slowly reduced the 24 h mortality (0%) but still showed 100% mortality at 48 h. However, severe sub-lethal effects (expulsion of celomic/bloody fluids) were reduced from 50% to 37%, and further treatment may reduce the toxicity to acceptable levels. The petroleum drilling cuttings treated by chemical oxidation (1.3% H 2 O 2 , w/w) and bioremediation (simulation of biopiles), showed a similar response, where 0% mortality in soil extracts was found, but 100% mortality with soil contact. Post-treatment with chemical oxidation resulted in a reduction in the soil contact bioassay to 3% and 13% mortality, within the accepted range (10%) of the OECD protocol. Observations are presented with respect to moisture control to prevent earthworm desiccation and recommendation for confirmation using the sub-chronic test in the OECD protocol but by testing the contaminated/treated soil itself rather than artificial soil.

Pollution indices and biotests as useful tools for the evaluation of the degree of soil contamination by trace elements

“…Biotests can be a useful research tool for assessing the ecological effects of contaminations in soil ecosystems (Baran et al 2014;Adams et al 2015;Sforzini et al 2016;El-Alam et al 2018;Cuske et al 2017;Domínguez-Rodríguez et al 2020;Szopka et al 2021). Biotests use a living organism as an indicator and rely on its exposure to toxic substances present in the sample as well as the qualitative and quantitative assessments of the effects of this exposure (Wierzbicka et al 2015;Lyubenova and Boteva 2016;Wieczerzak et al 2016;Heise et al 2020).…”

Application of an Ecotoxicological Battery Test to the Paddy Field Soils of the Albufera Natural Park

“…Nevertheless, earthworms have the capacity to regulate and excrete them. This effect is stressed with Zn, Pb and Cu (presence of these elements was greater in the analyses) that, along with low bioavailability, limits absorption or intake of this species, which could avoid harm to this species [ 58 , 59 ].…”

Evaluation of Acute Toxicity and Antioxidant Response of Earthworm Exposed to a Lignin-Modified Crosslinked Hydrogel

“…Upon exposure of Eisenia fetida to the hydrogel in the contact test, the stress suffered by the organisms was manifested by inflammation, bleeding, and death at the highest amounts tested (0.9242 and 1.848 mg hydrogel/cm 2 ), with mortality rates of 48.3% and 100%, respectively. Effects on exposed earthworms [ 65 ] can be assessed with respect to growth inhibition, reproduction [ 61 ], or egg formation [ 50 , 66 ]. In the case of growth inhibition (%), significant physical effects were caused by contact through the skin of the earthworms exposed to the amounts of 0.9242 and 1.848 mg hydrogel/cm 2 ; moreover, as exposure time elapsed, the earthworms presented elongation of the posterior part of the clitellum, a sign accompanied by segmented cuts and excessive movement at the slightest contact.…”