Samantha Eslava Martins

Uptake, tissue distribution and depuration of triclosan in the guppy Poecilia vivipara acclimated to freshwater

The agent triclosan has been extensively used in different personal care products as a broad-spectrum antimicrobial and preservative agent. Due to its continuous release into the environment, including discharge via wastewater treatment plants, triclosan has been widely detected in aquatic environments. There is growing interest in improving the knowledge about the environmental fate of triclosan due to its possible bioaccumulation and the toxicity it may pose to organisms, such as fish and other non-target species. To investigate the distribution and bioconcentration of triclosan in fish, Poecilia vivipara was exposed to 0.2mgL(-1). Contents of triclosan in whole fish, brain, gonads, liver, muscle and gills were quantified by LC-MS/MS. When lipid normalised concentration was used, the liver exhibited the highest concentration followed by the gills, gonads, brain and muscle tissues. Bioconcentration was increased with time reaching a steady-state around 7-14days for most all tissues. After 24h depuration, triclosan concentrations declined >80% in all tissues except liver, in which triclosan takes longer to be depurated. These results not only clearly indicate that triclosan accumulated in P. vivipara, with tissue-specific bioconcentration factors (BCF) that ranged from 40.2 to 1025.4, but also show that the elimination of triclosan after transferring the fish to triclosan-free freshwater is rapid in all tissues.

A vortex-assisted MSPD method for triclosan extraction from fish tissues with determination by LC-MS/MS

In this study, a simple, rapid and sensitive analytical method for the detection of TCS from Poecilia vivipara tissues (muscle, gills, brain, liver, gonads and whole fish) was developed. A matrix solid phase dispersion (MSPD) extraction method followed by analysis with a liquid chromatography tandem mass spectrometry (LC-MS/MS) system was developed and the multivariate statistical approach (experimental design) was applied to optimize the extraction conditions. The results showed that the method is accurate, robust and highly reproducible, since high recoveries were achieved. The analytical method showed high extraction yields for the determination of this compound in a complex matrix such as tissue. Moreover, the extraction procedure is very fast and it is possible to perform on a small sample aliquot. Besides, extraction and cleanup are performed in a single step. The LOQ value in fish tissue was 0.083 μg g−1 and the LOD was 0.016 μg g−1. The RSDs for repeatability and intermediate precision studies were in the range of 1.1 to 8.9% and from 0.2% to 8.9%, respectively. Adequate linearity with correlation coefficients (r) higher than 0.99 was obtained for the range of 0.005 to 0.25 mg L−1. Quantitative recoveries (≥80%) and satisfactory precision (average 9%) were obtained. The application of the vortex-assisted MSPD method to the analysis of real samples shows TCS in some fish liver and fish gill samples at trace levels.

Review: ecotoxicity of organic and organo-metallic antifouling co-biocides and implications for environmental hazard and risk assessments in aquatic ecosystems

Abstract Hazard assessments of Irgarol 1051, diuron, 2-(thiocyanomethylthio)benzothiazole (TCMTB), dichloro-octylisothiazolin (DCOIT), chlorothalonil, dichlofluanid, thiram, zinc pyrithione, copper pyrithione, triphenylborane pyridine (TPBP), capsaicin, nonivamide, tralopyril and medetomidine were performed to establish robust environmental quality standards (EQS), based on predicted no effect concentrations (PNECs). Microalgae, zooplankton, fish and amphibians were the most sensitive ecological groups to all the antifoulants evaluated, especially in the early life stages. No differences were identified between freshwater and seawater species. The use of toxicity tests with non-standard species is encouraged because they increase the datasets, allowing EQS to be derived from probabilistic-based PNECs whilst reducing uncertainties. The global ban of tributyltin (TBT) has been heralded as a major environmental success; however, substitute antifoulants may also pose risks to aquatic ecosystems. Environmental risk assessments (ERAs) have driven decision-makings for regulating antifouling products, but in many countries there is still a lack of regulation of antifouling biocides which should be addressed.

Potential ecotoxicity of metals leached from antifouling paint particles under different salinities

Antifouling paint particles (APPs) are residues generated during maintenance of vessels. In boat maintenance areas of South America, waste generation and disposal are not completely regulated. Therefore, APPs can enter into the aquatic environment and act as a source of contamination by metals and other biocides. Thus, the aim of the present study was to evaluate the potential ecotoxicity of the metal mixture present in APPs leached under different salinities. Therefore, the copepod Acartia tonsa was exposed to different concentrations of a leachate solution prepared by the addition of APPs (1.25g/L) in artificial saline water (salinities 5, 15 and 30). Thereafter, complexing agents (EDTA and sodium thiosulfate) were added to the experimental media in order to evaluate metal influence in APPs toxicity. APPs leachate solutions were very toxic to A. tonsa, reaching an estimated LC50 of 1% at salinities 5% and 15%, and 2% at salinity 30. The addition of the chelators in leachate solutions showed that metals are the major responsible compounds for the observed toxicity. Moreover, results from the calculated toxic units suggested a slightly synergic effect between Cu and Zn in the paint formulation. A metal speciation modelling showed that Zn was predominant as a free ion at all salinities, therefore, explaining the high leachate toxicity. Furthermore, the release of Zn was observed more at lower salinities, whereas Cu was observed at higher salinities. APPs are frequently released in estuarine systems, under conditions of salinity gradients. Therefore, navigated estuaries might be under the threat of this neglected residue.

Copper accumulation and toxicity in the yellow clam Mesodesma mactroides DESAHYES 1854 (BIVALVIA, MESODESMATIDAE)

The yellow clam Mesodesma mactroides depends on the intertidal zone of the southernmost Brazilian sandy beaches for recruitment or settlement. Studies aiming to evaluate any kind of alteration of this ecosystem are very important because of the growing industrial and urban development observed around this region over the last decades. Therefore, the main goal of the present study was to evaluate copper accumulation and toxicity in M. mactroides to verify its response to increased environmental levels of this metal. Yellow clams were acutely (96 h) exposed to copper for determination of copper accumulation and toxicity (LC50). Results showed that M. mactroides accumulated copper in its tissues (gills and digestive gland) and was quite tolerant to copper, suggesting this species as a suitable model for future biomonitoring programs of copper contamination in sandy beaches.