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(M/EH109) Acute toxicity of homologues of linear alkylbenzene sulphonates (LAS C10 to C14) and commercial LAS on survival of seabream (Sparus aurata) larvae. Hampel, M.1, Moreno-Garrido, I.1, Blasco, J.1, 1 ABSTRACT- Among aquatic organisms, fish as well as their eggs and larvae have attracted considerable interest in toxicity testing. The developing fish embryo or larvae is generally considered the most sensitive stage in the life cycle of a teleost, being particularly sensitive to all kinds of low-level environmental changes to which it might be exposed. The yolk-sac or alevin stage is known to be the most sensitive in the teleost life cycle. Linear alkylbenzene sulphonates (LAS) are the main ingredients of domestic cleaning and personal care products discharged in important amounts into rivers and estuaries. Commercial LAS is composed of different proportions of homologues which contain between 10 and 14 acrbon atoms in their alkyl chain. The urgent need for the determination of legally applicable measures of pollutants and their effects on the aquatic biota in different environmental compartments has increased the use of several parameters such as LC50/EC50/NOEC of xenobiotic compounds, which, in combination with safety factors are employed to establish legal threshold concentrations of pollutants. In order to assess acute toxicity of LAS homologues and commercial LAS on the aquatic biota, larvae of seabream, a representative species with high economic importance in the region of southern Spain, were selected. The larvae were exposed to increasing concentrations between 0.01 and 10.0 mg×L-1 of the different homologues and the commercial LAS mixture during 72 hours. Several parameters were reported every 24 hours and survival, as well as mortality percentages were calculated and represented versus time in days. The LC50(24h) was calculated and compared to previously obtained toxicity data with seabream eggs. Including different safety factors proposed by the EU and the EPA, those homologues which present environmental risk at concentrations found in the marine environment, were determined. Key words: surfactants, LAS, homologues, seabream |
