Evaluation of the toxicity of the water-soluble oil fraction in the freshwater crustacean Hyalella curvispina

DEL BRÍO J; MONTAGNA M; VENTURINO A

Buenos Aires

Congreso; 11th Biennial Meeting Society of Environmental Toxicology and Chemistry (SETAC) Latin America; 2015

SETAC LA

Oil and gasextraction is one of the main economic activities in NeuquénProvince-Argentina. Although all the productive steps are environmentallyregulated, spill events occasionally occur affecting water courses. The aim ofthis work was to evaluate the chronic toxicity of water-soluble oil fraction(WSF) in the autochthonous amphipod H.curvispina. Adults (3-4 mm) were exposed to five progressive dilutions ofWSF, and the exposure media were renewed at 7-14 d registering mortality up to21 d. At the end of the exposure, individuals were collected to determineglutathione-S-transferase (GST) activity. The chemical composition of WSF wasalso analyzed by gas chromatography. Aryl hydrocarbons (AH) were the maincomponent (C8-C18 0.059 mg/L; C18-C25 0.012 mg/L; C25-C33 0.010 mg/L), whiletrace quantities of PAH were detected. The LC50 was assessed by non-linear fittingof logistic mortality model to data. At 14d, the LC50 corresponded to 1:197dilution of WSF, equivalent to 0.41±0.17 µg total AH; the toxicity increased at21d, with a LC50 equal to 1:345 WSF dilution, about 0.23±0.14 µg total AH. Themortality slope was very smooth (lower than 1: 0.54 and 0.68 at 14d and 21drespectively), indicating a high influence of individual sensitivity to the WSFcomponents. Dilution of WSF to 1:50 caused a highly significant induction ofGST activity (45%) compared to controls, suggesting the utility of thisparameter as a biomarker. The induction of this enzyme resulting from exposureto WSF components from oil is an expected detoxifying response accompanyingPhase I detoxification.