Exploring the terrestrial ecosystem hazards of perfluorooctanoic acid: a comparative acute and chronic study of Eisenia fetida responses in different soil types

Human activities predominantly release perfluorooctanoic acid (PFOA) and other fluorinated chemicals, which are highly persistent, leading to long-term accumulation in organisms and posing significant health risks. Therefore, it is essential to study the long-term impacts of PFOA on terrestrial ecosystems using sentinel organisms such as earthworms. This research investigated the toxicity of PFOA on earthworms (Eisenia fetida) across three different soil types. An acute toxicity assay was conducted to assess the effects of PFOA on survival, growth, cellulase activity, lysosomal membrane stability, and avoidance behaviour. Concurrently, a chronic toxicity assay examined the impact on reproduction, specifically focusing on cocoon production and juvenile emergence. For the 14-day acute toxicity study, LC₅₀ values were found to be 823.9 mg/kg, 894.9 mg/kg, and 672.2 mg/kg in alkaline, neutral, and OECD soils, respectively. Although PFOA showed lower toxicity in neutral soils, it still caused significant sublethal effects in all soil types. Chronic exposure to a concentration of 100 mg/kg significantly affected reproduction in all soils tested. Overall, the findings suggested that earthworms were effective sentinel organisms for evaluating the toxic potential of PFOA, with reproductive effects serving as particularly sensitive indicators of PFOA contamination.