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Tres Cantos, Spain

Cuello S.,Complutense University of Madrid | Sanz-Landaluze J.,Complutense University of Madrid | Madrid Y.,Complutense University of Madrid | Guinea J.,Zf BioLabs | Camara C.,Complutense University of Madrid
Talanta | Year: 2012

Bioaccumulation and possible transformation of methylmercury and selenite has been checked on a 72 h-cycle of bioaccumulation and depuration using larvae from zebrafish. The larvae were exposed to methylmercury and selenite at concentrations of 1% and 0.1% of their LC 50 values. Quantitative extraction of methylmercury and selenite from exposed larvae was achieved by using ultrasonic probe-assisted extraction (USP), thus reducing extraction time and solvent consumption. Extracted species collected at different exposure times were characterized and quantified by liquid chromatography coupled to ICP-MS. Bioconcentration factors (BCFs) were estimated by two procedures: (i) as the ratio of the contaminant concentration in larvae and exposure media (BCF 48 h) and (ii) fitting contaminant concentration in larvae to bioaccumulation models that describe uptake and depuration processes (BCF k). The BCFs obtained for methylmercury were 5000 and 2333 for larvae exposed to 1 μg L -1 and 10 μg L -1, respectively; while for selenite the BCF was 74 for larvae exposed to 10 μg L -1. The good correlation between the BCFs found and those previously reported in the literature shows the proposed method as a good and promising alternative to the OECD Bioconcentration Test 305. Actually, the use of zebrafish larvae reduces the bioaccumulation test time from forty two (OECD Bioconcentration Test 305) to three days. In addition, potential biotransformation of both methylmercury and selenite was evaluated by LC-ICP-MS. For this purpose, a method for species extraction in small size samples by using ultrasonic probe sonication was developed. © 2011 Elsevier B.V. All rights reserved. Source

A simple and fast approach for a novel bioaccumulation test by exposing zebrafish eleutheroembryos to fluorene and anthracene (PAHs) at two concentration levels below 1% of their LC50 is presented. This alternative protocol sets an uptake period of 48 h at 26 °C for bioconcentration of the compounds tested and an additional 24 h for depuration. Two different methods to estimate bioconcentration factors (BCFs) of PAHs were used. The first consists in the ratio between concentrations of the tested compounds in the zebrafish eleutheroembryos and the exposure media when a steady state during exposure is reached (BCFss). The second employs the concentration-time profile with the use of a least-square fit to a non-linear model (BCFk). A steady state (ss) was reached after 12 h and 22 h for fluorene and anthracene exposure, respectively. Uptake and depuration rate constants obtained were similar for the two exposure levels tested, hence toxicokinetic rate constants appeared to be independent of the exposure level. Bioconcentration factors of 1164 and 817 for fluorene exposure at 0.99 ng mL-1 and 7.9 ng mL-1 and of 2089 and 2344 for anthracene at 0.63 ng mL-1 and 6.1 ng mL-1 were assessed. The good agreement of the obtained results with those reported in the literature proves the feasibility of the proposed method for estimation of both toxicokinetic parameters and bioconcentration factors. Furthermore, this protocol, has potential to be an alternative to the Organisation for Economic Cooperation and Development (OECD) 305 method, considerably reducing time and associated costs of the test suggested by European legislation. © 2012 Elsevier B.V. Source

Gonzalo-Lumbreras R.,Complutense University of Madrid | Sanz-Landaluze J.,Complutense University of Madrid | Guinea J.,Zf BioLabs | Camara C.,Complutense University of Madrid
Analytical and Bioanalytical Chemistry | Year: 2012

Triclosan, an antibacterial and antifungal agent, is widely used in household and personal care products, processed foods and food packaging, etc., and thus also released into the environment. Triclosan is acutely and chronically toxic to aquatic organisms and bioaccumulates in fish tissue. Here, we propose a new miniaturized triclosan extraction method for aqueous and fish roe samples, based on the use of a vortex mixer and an ultrasonic probe, respectively, and useful for triclosan determination by gas chromatography coupled to a micro electron capture detector. Different solvents for extraction and sorbents for cleanup purposes were tested. Multivariate optimization of the variables affecting ultrasonic extraction (ultrasound radiation amplitude, sonication time, sample temperature, and the ratio of sample amount and extracting volume) was carried out. Solvent extraction using ethyl acetate and further cleanup with mixed bed cartridges with two layers of Florisil ® and Florisil ® impregnated with 10% sulfuric acid only for fish roe samples was finally selected. Extraction efficiencies of up to 95% and 90%, and detection limits of 0.165 ng ml -1 and 2.7 ng g-1 for aqueous and fish roe samples were obtained, respectively. The optimized method was used in bioconcentration studies with zebrafish larvae (Danio rerio), as an alternative method to the Organization for Economic Cooperation and Development technical guideline 305. Bioconcentration values, BCF02,630 and 2,018 at exposure concentrations of 30 and 3 μg L -1, respectively, were assessed. These results are in agreement with those reported in the literature, showing the feasibility of the method for estimation of toxicokinetic parameters and bioconcentration factors using zebrafish larvae instead of adult fishes, reducing considerable animal testing, as suggested by the European legislation. © Springer-Verlag 2012. Source

Guinea M.,University of Alcala | Franco V.,University of Alcala | Araujo-Bazan L.,Zf BioLabs | Rodriguez-Martin I.,Zf BioLabs | And 2 more authors.
Food and Chemical Toxicology | Year: 2012

The photoprotective potential against UVB radiation of extracts obtained from 21 commercial macroalgae from the Phyla Ochrophyta and Rhodophyta, was evaluated in vivo, using the zebrafish embryo as a whole model organism. Our results showed that the phenolic extracts from Macrocystis pyrifera and Porphyra columbina exhibited the highest photoprotective activity, close to complete photoprotection (100%), similar to that obtained for the carrageenophytes Sarcothalia radula and Gigartina skottsbergii. Under the assayed conditions, the extracts were safe and non-toxic to the embryos at a concentration of 0.04. mg/ml PGE. © 2012 Elsevier Ltd. Source

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