Person:
Contardo-Jara, Valeska

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Contardo-Jara

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Valeska

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Deutschland, Umweltbundesamt, Fachgebiet IV.2.5 - Spurenanalytik , Fließ- und Stillgewässersimulation

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2018 - 201912020 - 20211

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  • Vorschaubild nicht verfügbar
    Veröffentlichung
    Fate, bioaccumulation and toxic effects of triclosan on a freshwater community - a mesocosm study
    (2021) Berghahn, Rüdiger; Contardo-Jara, Valeska; Feibicke, Michael; Meinecke, Stefan; Mohr, Silvia; Schmidt, Ralf
    The antibacterial agent triclosan (TCS) is added to many daily-used consumer products and can therefore reach the aquatic environment via treated wastewater and potentially harm aquatic ecosystems. A 120 days pond mesocosm study was conducted in order to investigate the fate of TCS in water and sediment, its bioaccumulative potential in different biota as well as the effects of TCS and its main transformation product methyl-triclosan (M-TCS) on plankton, periphyton, macrophytes, and benthos communities. TCS was dosed once each in six pond mesocosms (nominal concentrations: 0.12, 0.6, 3.5, 21, 130 and 778 (micro)g/L TCS, respectively) while two ponds served as controls. A concentration-dependent increase in the DT50 values from 5.0 to 15.0 and 7.5 to 16.3 days was observed for TCS in water and the whole pond system (water, sediment, biota), respectively. Consequently, the substance should be categorized as non-persistent. For TCS, the bioaccumulation factors (non steady-state conditions, BAFnssc) in Lymnaea stagnalis, Myriophyllum spicatum and periphyton were below the critical limit of 2000, above which a substance is classified as bioaccumulative. In contrast, a BAFnssc value of >10,000 was found for M-TCS in L. stagnalis, denoting that M-TCS definitely falls under this classification. Although strong effects on freshwater communities could only be observed in the highest TCS treatments, some periphyton species, such as Oedogonium spp., reacted very sensitive to TCS with an EC50 (time weighted average, 28 d) of 0.3 (micro)g/L TCS. Considering the high bioaccumulative potential of M-TCS in combination with the observed effects of TCS at low doses suggests that the use of TCS, and therefore its release into the environment, should cease. © 2021 The Authors
  • Vorschaubild nicht verfügbar
    Veröffentlichung
    Protein association of ß-N-methylamino-L-alanine in Triticum aestivum via irrigation
    (2018) Contardo-Jara, Valeska; Esterhuizen-Londt, Maranda; Schwanemann, Torsten
    Bioaccumulation of several cyanotoxins has been observed in numerous food webs. More recently, the neurotoxic, non-proteinogenic amino acid Î2-N-methylamino-L-alanine (BMAA) was shown to biomagnify in marine food webs. It was thus necessary to assess whether a human exposure risk via a terrestrial food source could exist. As shown for other cyanotoxins, spray irrigation of crop plants with cyanobacterial bloom-contaminated surface water poses the risk of toxin transfer into edible plant parts. Therefore, in the present study, we evaluated a possible transfer of BMAA via spray irrigation into the seeds of one of the worldâ€Ìs most widely cultivated crop plants, Triticum aestivum. Wheat plants were irrigated with water containing 10 Ìg Lâ Ì1 BMAA until they reached maturity and seed-bearing stage (205 days). Several morphological characteristics, such as germination rate, number of roots per seedling, length of primary root and cotyledon, and diameter of the stems were evaluated to assess the effects of chronic exposure. After 205 days, BMAA bioaccumulation was quantified in roots, shoots, and mature seeds of T. aestivum. No adverse morphology effects were observed and no free intracellular BMAA was detected in any of the exposed plants. However, in mature seeds, protein-associated BMAA was detected at 217 Ì 150 ng g FWâ Ì1; significantly more than in roots and shoots. This result demonstrates the unexpected bioaccumulation of a hydrophilic compound and highlights the demand to specify in addition to limit values for drinking water, tolerable daily intake rates for the cyanobacterial-neurotoxin BMAA. Quelle: https://www.tandfonline.com