IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Biomarkers of exposure and effect in the estuarine polychaete Laeonereis acuta exposed to cadmium
Autor/es:
DOLAGARATZ CARRICAVUR, A.; CHIODI BOUDET, L. N.; ROMERO, M.B.; GERPE, M
Lugar:
Buenos Aires
Reunión:
Congreso; 11th SETAC Latin America Biennial Meeting - The role of science in environmental decision‐making; 2015
Institución organizadora:
SETAC LA
Resumen:
Cadmium (Cd) is a heavy metal with environmental relevance due to its high toxicity, persistence and accumulation in the trophic webs. Laeonereis acuta (Polychaeta, Nereididae) is an abundant estuarine polychaete with a wide geographical distribution. This species is an important component of aquatic trophic webs, integrating the diet of birds and fishes. These organisms could be exposed to metals due to its close association with sediments, constituting both source and sink of these pollutants. The objective was to evaluate the sensitivity of L. acuta to Cd and its biochemical response using biomarkers of exposure (metallothioneins, MTs) and effect (lipid peroxidation, LPO) through bioassays. Worms were captured in the Quequén estuary located in the southeast of the Province of Buenos Aires. Individuals were acclimated in the sediment for 4d, and then in the test vessels without sediment for 6d. During the acclimation and bioassays, water was renewed every 48h, maintaining constant conditions of temperature, pH, salinity and photoperiod. Individuals were fed ad libitum with frozen Artemia spp. For the toxicity test, individuals (n = 10) were exposed to 0.02; 0.08; 0.15; 0.7; 1.2; 2.8; 4.2 ; 9.3; 18.0; 36.0 mgCd/L for 96h. Mortality were registered for each concentration every 24h. Median lethal concentration (LC50) at 96h and its confidence interval (CI) was determined using the trimmed Spearman?Karber method. Based on LC50 value, an assay for 7d was performed with the following concentrations: 0.02; 0.08; 0.15; 0.7; 1.2; 2.8; 4.2; 9.3 mgCd/L. After 7d, the individuals were sacrificed and immediately frozen and stored at -80 ºC until analysis. MTs and LPO levels were determined in whole organisms by UV-Vis spectrometry and Fluorometry, respectively. The LC50 value was 20.78 mg/L, being its 95% CI: 17.08-25.28. This value was between the highest reported for polychaetes, evidencing a certain tolerance to Cd. MTs induction was not observed for any treatment at 7d of exposure. Furthermore, LPO levels showed no differences respect to control, which showed an absence of oxidative damage caused by Cd. These results suggest the presence of another mechanism for detoxification of Cd besides MTs, such as the formation of metal granules.