Evaluating the suitability of plant and crustacean microbiotests for assessing soil toxicity caused by ethylbenzene contamination

Plant and crustacean microbiotests were assessed for their suitability in evaluating soil and groundwater contamination with ethylbenzene (EB) following a railway accident. Bioassays using Lepidium sativum, Sinapis alba, Sorghum saccharatum, Heterocypris incongruens, and Thamnocephalus platyurus were conducted to measure acute toxicity in both naturally and artificially contaminated podzolic soils. Results of direct contact tests showed significant correlations between toxicity endpoints and EB concentrations. In naturally contaminated soils (EB: 67–2865 mg.kg-1), seed germination decreased by 17–52%, and root growth by 55–70%. L. sativum and H. incongruens exhibited the highest sensitivity. T. platyurus also responded to EB in soil pore water and groundwater, although only temporary narcotic effects were observed at lower concentrations (≤76 mg.dm-3). In contrast, artificially spiked soils did not affect seed germination but inhibited root elongation and crustacean growth. These findings highlight the influence of environmental factors, such as contamination duration and soil moisture, on EB toxicity and support the application of microbiotests in evaluating contaminated soils.