Effect of PAC (PAH & Polar-PAC) availability on aquatic organisms’ ecotoxicity - Université de Lorraine Access content directly
Poster Communications Year : 2023

Effect of PAC (PAH & Polar-PAC) availability on aquatic organisms’ ecotoxicity

Abstract

Historically contaminated sites have gained attention in recent decades. Some of them, e.g., former coking plants, are contaminated by polycyclic aromatic compounds (PACs), including 16 US-EPA PAHs and polar-PACs (O/N/S-PACs) which can induce potential risk for aquatic organisms[1]. Several studies reported that PAC (bio)availability can be limited in such sites, due to aging phenomenon [2,3], explaining the low impact on soil biota of some heavily contaminated soils . Consequently, bioavailability is a major factor to consider in the risk evaluation associated to PAC-contaminated soil and PAC transfer to the aqueous phase [2, 3] but is scarcely taken into account The objective of this work is to evaluate the influence of the PAC availability on PAC transfer from soil to the aqueous phase and its consequences on toxicity towards model aquatic organisms. Two soils (HOM and THI) were sampled on former coking plants. Aliquote of both soils were heated at 100 °C under inert atmosphere for one week in order to increase PAC availability by 10-30% for HOM and THI respectively [4]. Batch leaching tests were carried out according to the ISO 18772 (2008) procedure, PACs were quantified in the leachates by GC-MS after solid phase extraction. Simultaneously, ecotoxicity tests were performed through limit assays using standard acute bioassays. Rotifers and daphnie mobility and reproduction rate, respectively, as well as the growth inhibition of algae were evaluated. Results showed that leachates from raw soils have identical physico-chemical properties , except ionic strength that was ten times higher in THI than in HOM leachate. The PAC content was higher in HOM than in THI leachate, with polar PAC concentrations of 37300 and 6150 ng/L and PAH concentrations of 95 510 and16 030 ng/L for HOM and THI, respectively.Both leachates exhibited a similar PAH distribution. The results show a preferencial release of low-molecular-weight PAHs and polar PACs, especially O-PAC, mainly by dissolution, while higher-molecular-weight PAHs are released in association with colloids. An Important toxic effect of growth inhibition (85%) was observed on algae for both leachates. No toxic effects were observed in daphnie mobility and only THI leachate induced a slight decrease on rotifer reproduction (25%). The pre-heating treatment increased PAC content in leachates by 35% and 74% for HOM and THI, turning them into 105678 and 48094 ng/L for 16 PAHs and into 98100 and 39300 ng/L for polar PAC, respectively. As a result ,the leachates from preheated soils were more toxic than those from raw soils. Algae growth inhibition was observed to be 8% higher for both soils' pre-heated leachates. As for raw soil leachate, THI presented no toxic effects on daphnia mobility, and it exhibited a similar degree of toxicity on rotifer reproduction. On daphnia, however, HOM demonstrated 95% mobility inhibition and presented a toxic effect on rotifer reproduction (37%). This study showed that soils with similar chemical composition but contrasting levels of PAC availability release higher amounts of PACs into the aqueous phase, contributing to important ecotoxic responses in aquatic organisms.These results pointed out the importance of considering the contamination availability parameter in risk assessment and not only the total contaminant concentration. References: [1] Eom et al. (2007), Ecotoxicology and Environmental Safety, 67(2),190-205 [2] Fernández et al. (2005), Ecotoxicology and Environmental Safety, 62(2), 174-184 [3] Boulangé et al. (2019) Chemosphere 224: 437‑44. [4] Biache, C. et al. (2021) Talanta 228: 122235.
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Dates and versions

hal-04271358 , version 1 (06-11-2023)

Identifiers

  • HAL Id : hal-04271358 , version 1

Cite

Imane Aabbar, Coralie Biache, C. Cossu-Leguille, Céline Simon, Catherine Lorgeoux, et al.. Effect of PAC (PAH & Polar-PAC) availability on aquatic organisms’ ecotoxicity. AquaConSoil 2023, Sep 2023, Prague, Czech Republic. ⟨hal-04271358⟩
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