Bioaccumulation potential of chemicals is frequently assessed from bioconcentration, conventionally measured according to OECD 305 (Bioaccumulation: Flow-through Fish Test) (OECD,1996) and expressed as Bioconcentration Factor (BCF). These studies deliberately reduce the manifold uptake and elimination mechanisms in aquatic organisms to respiratory absorption via gills and diffusion through the skin (e.g. Arnot and Gobas, 2003; Sijm et al. 2007). Despite the simplifications, testing costs are high and a minimum of 108 fish are consumed in each OECD 305 bioconcentration guideline study (ILSI HESI, 2006). Veröffentlicht in Texte | 15/2011.
A test concept for bioconcentration tests with the freshwater amphipod Hyalella azteca (HYBIT) was recently described. It was shown that the Hyalella bioconcentration factors (BCFs) derived for compounds with different hydrophobic characteristics (log Kow 2.4 – 7.8) show a strong correlation to those from fish tests. This project was carried out to elucidate the suitability of the HYBIT test for testing an extended range of substance classes including difficult to test compounds and, if required, to further enhance the test concept. The bioaccumulation potential of highly lipophilic UV stabilisers and ionic organic PFAS as well as silver, titanium dioxide and gold nanomaterials were tested. The two possible set-ups to conduct bioconcentration studies with H. azteca using a semi-static test set-up or a flow-through approach were applied. The solvent-facilitated and solvent-free application of the hydrophobic test compounds were compared. Due to the difficulties regarding the aqueous exposure of nanomaterials, biomagnification studies were also carried out as part of this project. We could show that the HYBIT approach permits the application of difficult to test compounds and enables to derive bioaccumulation endpoints for regulatory assessment. Due to the shorter exposure periods required, and the smaller experimental units used, the HYBIT approach provides several advantages in comparison to the flow-through fish test. As a non-vertebrate test, the Hyalella bioconcentration (or biomagnification) test may help to further reduce the amount of fish required for the regulatory testing of chemicals. Veröffentlicht in Texte | 134/2022.
Rüdel, Heinz; Böhmer, Walter; Müller, Martin; Fliedner, Annette; Ricking, Mathias; Teubner, Diana; Schröter-Kermani, Christa Chemosphere 91 (2013), 11, 1517-1524 A retrospective monitoring of triclosan (TCS; period 1994-2003 and 2008) and its potential transformation product methyl-triclosan (MTCS; period 1994-2008) was performed using archived fish samples from German rivers (16 sites, including Elbe and Rhine). At four of these sites suspended particulate matter (SPM) was also investigated covering the period 2005-2007. Samples were analyzed by GC/MS, either directly (MTCS) or after derivatization (TCS). TCS burdens of fish muscle tissue ranged from <0.2-3.4 ng g -1 ww (wet weight; corresponding to <2-69 ng g -1 lw, lipid weight) without apparent concentration trends over time. MTCS was detected at considerably higher concentrations in fish ranging from 1.0-33 ng g -1 ww (47-1010 ng g -1 lw) and increased until about 2003-2005. Thereafter, concentrations generally were lower, although at some sites single higher values were observed in recent years. In SPM, decreasing MTCS concentrations in the range 1-4 ng g -1 dry weight were detected while TCS was always below the limit of quantification. Assuming that MTCS concentrations are correlated to TCS consumption, the observed decrease in MTCS levels may be partly a result of the voluntary renunciation of TCS use in detergents for, e.g., laundry or dishwashing declared by a manufacturers’ association in 2001. Because of a lack of ecotoxicity studies for MTCS, a QSAR-derived predicted no effect concentration (PNEC) was compared to averaged ambient water concentrations of fish which were calculated from maximum tissue residues by applying an appropriate bioconcentration factor from literature. Since these calculated water concentrations were below the PNEC it is assumed that MTCS alone poses no immediate risk to aquatic organism. The conversion to a PNEC for SPM organisms and comparison with detected SPM levels of MTCS also revealed no risk. doi:10.1016/j.chemosphere.2012.12.030
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
A main source of perfluoroalkyl and polyfluoroalkyl substances (PFASs) residues in agricultural plants is their uptake from contaminated soil. Bioaccumulation factors (BAFs) can be an important tool to derive recommendations for cultivation or handling of crops prior consumption. This review compiles >4500 soil-to-plant BAFs for 45 PFASs from 24 studies involving 27 genera of agricultural crops. Grasses (Poaceae) provided most BAFs with the highest number of values for perfluorooctanoic acid and perfluorooctane sulfonic acid. Influencing factors on PFAS transfer like compound-specific properties (hydrophobicity, chain length, functional group, etc.), plant species, compartments, and other boundary conditions are critically discussed. Throughout the literature, BAFs were higher for vegetative plant compartments than for reproductive and storage organs. Decreasing BAFs per additional perfluorinated carbon were clearly apparent for aboveground parts (up to 1.16 in grains) but not always for roots (partly down to zero). Combining all BAFs per single perfluoroalkyl carboxylic acid (C4-C14) and sulfonic acid (C4-C10), median log BAFs decreased by -0.25(+/-0.029) and -0.24(+/-0.013) per fluorinated carbon, respectively. For the first time, the plant uptake of ultra-short-chain (</= C3) perfluoroalkyl acids (PFAAs) was reviewed and showed a ubiquitous occurrence of trifluoroacetic acid in plants independent from the presence of other PFAAs. Based on identified knowledge gaps, it is suggested to focus on the uptake of precursors to PFAAs, PFAAs </= C3, and additional emerging PFASs such as GenX or fluorinated ethers in future research. Studies regarding the uptake of PFASs by sugar cane, which accounts for about one fifth of the global crop production, are completely lacking and are also recommended. Furthermore, aqueous soil leachates should be tested as an alternative to the solvent extraction of soils as a base for BAF calculations. © 2020 Elsevier B.V.
Fish bioconcentration factors (BCFs) are commonly used in chemical hazard and risk assessment. For neutral organic chemicals BCFs are positively correlated with the octanol-water partition ratio (KOW), but KOW is not a reliable parameter for surfactants. Membrane lipid-water distribution ratios (DMLW) can be accurately measured for all kinds of surfactants, using phospholipid-based sorbents. This study first demonstrates that DMLW values for ionic surfactants are more than 100â€č000 times higher than the partition ratio to fish-oil, representing neutral storage lipid. A non-ionic alcohol ethoxylate surfactant showed almost equal affinity for both lipid types. Accordingly, a baseline screening BCF value for surfactants (BCFbaseline) can be approximated for ionic surfactants by multiplying DMLW by the phospholipid fraction in tissue, and for non-ionic surfactants by multiplying DMLW by the total lipid fraction. We measured DMLW values for surfactant structures, including linear and branched alkylbenzenesulfonates, an alkylsulfoacetate and an alkylethersulfate, bis(2-ethylhexyl)-surfactants (e.g., docusate), zwitterionic alkylbetaines and alkylamine-oxides, and a polyprotic diamine. Together with sixty previously published DMLW values for surfactants, structure-activity relationships were derived to elucidate the influence of surfactant specific molecular features on DMLW. For 23 surfactant types, we established the alkyl chain length at which BCFbaseline would exceed the EU REACH bioaccumulation (B) threshold of 2000 L kg-1, and would therefore require higher tier assessments to further refine the BCF estimate. Finally, the derived BCFbaseline are compared with measured literature in vivo BCF data where available, suggesting that refinements, most notably reliable estimates of biotransformation rates, are needed for most surfactant types. © Royal Society of Chemistry 2021
he assessment of the bioaccumulation potential of chemicals is an essential and mandatory part of their regulatory environmental risk and hazard assessment. So far, in vitro data on fish metabolism is rarely available for biocidal active substances such as anticoagulant rodenticides. In this case study we present in vitro biotransformation rates of eight biocidal and one pharmaceutical anticoagulants in rainbow trout (Oncorhynchus mykiss) liver subcellular S9 fraction (RT-S9) determined following the Organisation for Economic Co-operation and Development test guideline 319B method at two different incubation temperatures (i.e., 12 +/- 1 ËÌC and 23 +/- 2 ËÌC). Furthermore, we address challenges associated with the usability and interpretation of in vitro data to support the decision making within the regulatory bioaccumulation assessment in bridging the gap between in silico methods and in vivo studies. According to our results, four of the tested substances (i.e., chlorophacinone, coumatetralyl, bromadiolone, and difenacoum) exhibited significant intrinsic clearance (p < .001) in the RT-S9 assay. Overall, the observed metabolism was (very) slow and clearance rates were temperature-dependent. Whether the determined in vitro biotransformation rate had a substantial influence on the predicted bioconcentration factor during extrapolation was subject to the lipophilicity of the test substance. Further improvements of existing concepts are needed to overcome uncertainties in the prediction of bioconcentration factors for chemicals such as anticoagulants. © 2022 Elsevier Ltd.
A retrospective monitoring of triclosan (TCS; period 1994-2003 and 2008) and its potential transformation product methyl-triclosan (MTCS; period 1994-2008) was performed using archived fish samples from German rivers (16 sites,including Elbe and Rhine). At four of these sites suspended particulate matter (SPM) was also investigated covering the period 2005-2007. Samples were analyzed by GC/MS, either directly (MTCS) or after derivatization (TCS). TCS burdens of fish muscle tissue ranged from <0.2-3.4 ng g-1 ww (wet weight; corresponding to <2-69 ng g-1 lw, lipid weight) without apparent concentration trends over time. MTCS was detected at considerably higher concentrations in fish ranging from 1.0-33 ng g-1 ww (47-1010 ng g-1 lw) and increased until about 2003-2005. Thereafter, concentrations generally were lower, although at some sites single higher values were observed in recent years. In SPM, decreasing MTCS concentrations in the range 1-4 ng g-1dry weight were detected while TCS was always below the limit of quantification. Assuming that MTCS concentrations are correlated to TCS consumption, the observed decrease in MTCS levels may be partly a result of the voluntary renunciation of TCS use in detergents for, e.g., laundry ordishwashing declared by a manufacturersĄf association in 2001. Because of a lack of ecotoxicity studies for MTCS, a QSAR-derived predicted no effect concentration (PNEC) was compared to averaged ambient water concentrations of fish which were calculated from maximum tissue residues by applying an appropriate bioconcentration factor from literature. Since these calculated water concentrations were below the PNEC it is assumed that MTCS alone poses no immediate risk to aquatic organism. The conversion to a PNEC for SPM organisms and comparison with detected SPM levels of MTCS also revealed no risk.Quelle: http://www.sciencedirect.com
Bioaccumulation plays a vital role in understanding the fate of a substance in the environment and is key to the regulation of chemicals in several jurisdictions. The current assessment approaches commonly use the octanol-water partition coefficient (log K OW) as an indicator for bioaccumulation and the bioconcentration factor (BCF) as a standard criterion to identify bioaccumulative substances show limitations. The log K OW does not take into account active transport phenomena or special structural properties (e.g., amphiphilic substances or dissociating substances) and therefore additional screening criteria are required. Regulatory BCF studies are so far restricted to fish and uptake through the gills. Studies on (terrestrial) air-breathing organisms are missing. Though there are alternative tests such as the dietary exposure bioaccumulation fish test described in the recently revised OECD test guideline 305, it still remains unclear how to deal with results of alternative tests in regulatory decision-making processes. A substantial number of bioaccumulation fish tests are required in regulation. The development of improved test systems following the 3R principles, namely to replace, reduce and refine animal testing, is thus required. All these aspects stress the importance to further develop the assessment of bioaccumulation. The Dessau Workshop on Bioaccumulation which was held from June 26th to 27th 2014, in Dessau, Germany, provided a comprehensive overview of the state of the art of bioaccumulation assessment, provided insights into the problems and challenges addressed by the regulatory authorities and described new research concepts and their regulatory implications. The event was organised by UBA (Dessau, Germany) and Fraunhofer IME (Schmallenberg, Germany). About 50 participants from industry, regulatory bodies and academia listened to 14 lectures on selected topics and joined the plenary discussions.Quelle: http://enveurope.springeropen.com
Niedersächsischer Landesbetrieb für Wasserwirtschaft, Küsten- und Naturschutz Dezember 2016 Schwermetalle und organische Schadstoffe in Fischen der Elbe, Weser, Aller, Ems und Vechte - Niedersächsische Untersuchungsergebnisse aus den Jahren 2014 und 2015 Schwermetalle und organische Schadstoffe in Fischen der Elbe, Weser, Aller, Ems und Vechte Niedersächsische Untersuchungsergebnisse aus den Jahren 2014 und 2015 1. ta-Untersuchungen durchgeführt, die auf die Vorgaben der Europäischen Wasser- rahmenrichtlinie (WRRL) abgestimmt wa- ren, speziell der Oberflächengewässerver- ordnung 2016 1, und dem LAWA- Arbeitspapier IV.3 2. Die Ergebnisse dieser Untersuchungen wurden bereits unter dem Titel „Biota Schadstoffuntersuchungen in niedersächsischen Gewässern entspre- chend der Europäischen Wasserrahmen- richtlinie, Ausgabe 1/2016“ veröffentlicht und können im Internet des NLWKN unter dem folgenden Link als PDF-Datei herun- ter geladen werden, so dass an dieser Stelle nicht näher darauf eingegangen wird: http://www.nlwkn.niedersachsen.de/servic e/veroeffentlichungen_webshop/schriften_ zum_downloaden/downloads_gewaesserg uete/veroeffentlichungen-zum-thema- gewaesserguete-107788.html Allgemeines Bei Schadstoffen, die über ein entspre- chendes Potenzial zur Bioakkumulation verfügen, sind Biota-Untersuchungen ne- ben der etablierten Untersuchung von Wasser und Sedimenten bzw. Schweb- stoffen ein zusätzliches Instrument der Gewässerüberwachung. Ein wichtiges Kriterium ist der sogenannte Biokonzentra- tionsfaktor (BCF), der als dimensionsloser Quotient von in Biota gemessenen Schad- stoffgehalten im Vergleich zu denen in der Wasserphase enthaltenen Schadstoffge- halten definiert ist. Für Schadstoffe mit einem Biokonzentrationsfaktor > 500 - die Biotamatrix ist also um mindestens das 500fache gegenüber der Wasserphase angereichert - sind Biota-Untersuchungen besonders gut geeignet. Während bei- spielsweise Hexachlorbenzol (BCF 2.000 - 230.000) für ein Biota-Monitoring beson- ders gut geeignet ist, sind sie dagegen z.B. bei Diuron (BCF 2) nicht zu empfeh- len, da die Biota-Ergebnisse ggf. zu einer Fehlinterpretation (Minderbewertung) der Gewässerbelastung führen könnten. Die beschriebenen Biota-Untersuchungen nach WRRL sind jedoch innerhalb des im Folgenden beschriebenen Projekts noch deutlich erweitert worden. Neben den 11 prioritären Stoffen und Untersuchung der Muskulatur nach den Vorgaben der WRRL wurden etwa 200 weitere Schadstoffe und die zusätzliche Untersuchung von Leber- gewebe in das Projekt einbezogen. Dabei berücksichtigt wurden insbesondere nach- folgende Stoffgruppen: Alkylphenole, Al- kylphenolethoxylate, Bisphenole, bromier- te Flammschutzmittel, Chorbenzole, Chlorparaffine, Dioxine und Furane, dio- xinähnliche polychlorierte Biphenyle (dl- PCB), Indikator-PCB, Schwermetalle (die teilweise auch als Elemente bezeichnet werden), Moschusverbindungen, Orga- nochlorpestizide, perfluorierte Tenside, Phthalate, polycyclische aromatische Koh- lenwasserstoffe (PAK) sowie zinnorgani- sche Verbindungen. In Niedersachsen werden Biota- Untersuchungen seit 1996 praktiziert, an- gefangen mit Betrachtungen von zinnor- ganischen Verbindungen. Zwischenzeitlich wurde der Umfang der untersuchten Schadstoffe bzw. Schadstoffgruppen er- heblich erweitert. Die Untersuchungen erfolgten nach dem Modus des sogenann- ten „passiven Biota-Monitorings“, indem in bestimmten Gewässerabschnitten Fische gefangen und auf Schadstoffe untersucht werden. Ein sogenanntes „aktives Monito- ring“, indem z.B. bestimmte Fische oder Muscheln über einen bestimmten Zeitraum im Gewässer exponiert und die Differenz der Schadstoffgehalte betrachtet werden, wurde dagegen bisher nicht betrieben. Vom Niedersächsischen Landesbetrieb für Wasserwirtschaft, Küsten- und Natur- schutz (NLWKN) wurden in enger Zusam- menarbeit mit dem Niedersächsischen Landesamt für Verbraucherschutz und Lebensmittelsicherheit (LAVES), Dezernat Binnenfischerei und Fischereikundlicher Dienst, sowie dem Institut GALAB Labora- tories in den Jahren 2014 und 2015 im Rahmen der Gewässerüberwachung Bio- 1 Verordnung zum Schutz von Oberflächengewäs- sern vom 20. Juni 2016, Bundesgesetzblatt Jahr- gang 2016 Teil I Nr. 28, ausgegeben zu Bonn am 23. Juni 2016, 1373-1443. 2 Bund/Länder-Arbeitsgemeinschaft Wasser (LA- WA), Arbeitspapier IV.3 , Konzeption für Biota- Untersuchungen zur Überwachung von Umweltqua- litätsnormen gemäß RL 2013/39/EU (Stand: Okto- ber 2015). 2 Schwermetalle und organische Schadstoffe in Fischen der Elbe, Weser, Aller, Ems und Vechte Niedersächsische Untersuchungsergebnisse aus den Jahren 2014 und 2015 2. Im Folgenden werden die Untersuchungs- ergebnisse dargestellt. Dabei wird weniger auf die Eigenschaften, das Vorkommen und die Verwendung der einzelnen Stoffe bzw. Stoffgruppen eingegangen, da dies den Rahmen des vorliegenden Berichts sprengen würde und diese Informationen bei Bedarf im Internet problemlos zu erhal- ten sind. Die im Folgenden präsentierten Ergebnisse sollen vielmehr einen Über blick bezüglich der Relevanz von bestimm- en Schadstoffen in Biota geben: Welche Schadstoffe sind in niedersächsischen Oberflächengewässern auffällig und soll- ten bei künftigen Biota-Untersuchungen bevorzugt berücksichtigt werden? Monitoringkonzept Die vorliegenden Untersuchungen wurden nach dem folgenden Monitoringkonzept durchgeführt. Messstellen und Untersuchungsfrequenz Die untersuchten Überblicksmessstellen mit den dazugehörigen Koordinaten kön- nen sowohl Abbildung 1 als auch Tabelle 1 entnommen werden. Abbildung 1: Lage der Biota-Messstellen. 3
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