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Duane B Huggett - One of the best experts on this subject based on the ideXlab platform.
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toward improved models for predicting Bioconcentration of well metabolized compounds by rainbow trout using measured rates of in vitro intrinsic clearance
Environmental Toxicology and Chemistry, 2013Co-Authors: Duane B Huggett, Jon A. Arnot, Patrick N. Fitzsimmons, Christina CowanellsberryAbstract:Models were developed to predict the Bioconcentration of well-metabolized chemicals by rainbow trout. The models employ intrinsic clearance data from in vitro studies with liver S9 fractions or isolated hepatocytes to estimate a liver clearance rate, which is extrapolated to a whole-body biotransformation rate constant (kMET). Estimated kMET values are then used as inputs to a mass-balance Bioconcentration prediction model. An updated algorithm based on measured binding values in trout is used to predict unbound chemical fractions in blood, while other model parameters are designed to be representative of small fish typically used in whole-animal Bioconcentration testing efforts. Overall model behavior was shown to be strongly dependent on the relative hydrophobicity of the test compound and assumed rate of in vitro activity. The results of a restricted sensitivity analysis highlight critical research needs and provide guidance on the use of in vitro biotransformation data in a tiered approach to bioaccumulation assessment. Environ Toxicol Chem 2013;32:1611–1622. © 2013 SETAC
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Bioconcentration of ibuprofen in fathead minnow pimephales promelas and channel catfish ictalurus punctatus
Chemosphere, 2011Co-Authors: Gopinath C Nallani, Lisa A Constantine, Barney J. Venables, Peter M Paulos, Duane B HuggettAbstract:Abstract Pharmaceutical products and their metabolites are being widely detected in aquatic environments and there is a growing interest in assessing potential risks of these substances to fish and other non-target species. Ibuprofen is one of the most commonly used analgesic drugs and no peer-reviewed laboratory studies have evaluated the tissue specific Bioconcentration of ibuprofen in fish. In the current study, fathead minnow ( Pimephales promelas) were exposed to 250 μg L −1 ibuprofen for 28 d followed by a 14 d depuration phase. In a minimized Bioconcentration test design, channel catfish ( Ictalurus punctatus ) were exposed to 250 μg L −1 for a week and allowed to depurate for 7 d. Tissues were collected during uptake and depuration phases of each test and the corresponding proportional and kinetic Bioconcentration factors (BCFs) were estimated. The results indicated that the BCF levels were very low (0.08–1.4) implying the lack of Bioconcentration potential for ibuprofen in the two species. The highest accumulation of ibuprofen was observed in the catfish plasma as opposed to individual tissues. The minimized test design yielded similar Bioconcentration results as those of the standard test and has potential for its use in screening approaches for pharmaceuticals and other classes of chemicals.
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the influence of gill and liver metabolism on the predicted Bioconcentration of three pharmaceuticals in fish
Chemosphere, 2010Co-Authors: C F Gomez, Lisa A Constantine, Duane B HuggettAbstract:Abstract The potential for xenobiotic compounds to bioconcentrate is typically expressed through the Bioconcentration factor (BCF), which has gained increased regulatory significance over the past decade. Due to the expense of in vivo Bioconcentration studies and the growing regulatory need to assess Bioconcentration potential, BCF is often calculated via single-compartment models, using KOW as the primary input. Recent efforts to refine BCF models have focused on physiological factors, including the ability of the organism to eliminate the compound through metabolic transformation. This study looks at the ability of in vitro biotransformation assays using S9 fractions to provide an indication of metabolic potential. Given the importance of the fish gill and liver in metabolic transformation, the metabolic loss of ibuprofen, norethindrone and propranolol was measured using rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) gill and liver S9 fractions. Metabolic transformation rates (kM) were calculated and integrated into a refined BCF model. A significant difference was noted between BCF solely based on KOW and BCF including kM. These studies indicate that the inclusion of kM in BCF models can bring predicted Bioconcentration estimates closer to in vivo values.
Michael J Lydy - One of the best experts on this subject based on the ideXlab platform.
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accumulation of trinitrotoluene tnt in aquatic organisms part 2 Bioconcentration in aquatic invertebrates and potential for trophic transfer to channel catfish ictalurus punctatus
Chemosphere, 2005Co-Authors: Jason B Belden, Guilherme R Lotufo, Dennis Randall Ownby, Michael J LydyAbstract:Abstract The potential of TNT to accumulate in aquatic organisms was assessed by determining Bioconcentration factors for TNT and TNT biotransformation products using two benthic invertebrates ( Chironomus tentans and Lumbriculus variegatus ), and by determining the bioaccumulation factor of TNT and TNT biotransformation products due to TNT exposure via feeding for channel catfish ( Ictalurus punctatus ). In all three species, TNT was rapidly biotransformed resulting in minimal accumulation. The Bioconcentration factors for parent TNT ranged from 3 to 4 ml g −1 for the invertebrates studied, while the TNT bioaccumulation factor for catfish via oral exposure of food pellets was 2.4 × 10 −5 g g −1 based on the concentration of TNT in the food pellet. As indicated by this small bioaccumulation factor, TNT accumulation in channel catfish through trophic transfer would be negligible compared to aqueous exposure (previously reported BCF of 0.79 ml g −1 ). TNT extractable biotransformation products accumulated to a greater degree than parent TNT for all three species. In addition, a large fraction of the radioactivity within all three species resisted solvent extraction. The highest Bioconcentration factors occurred in L. variegatus with extractable radioactivity measuring 76 ml g −1 and total radioactivity measuring 216 ml g −1 . Because the bioaccumulation of TNT is very low compared to the bioaccumulation of its biotransformation products, further research including identifying and determining the relative toxicities of these biotransformation products is necessary to fully evaluate the environmental risk posed by exposure to TNT.
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accumulation of trinitrotoluene tnt in aquatic organisms part 1 Bioconcentration and distribution in channel catfish ictalurus punctatus
Chemosphere, 2005Co-Authors: Dennis Randall Ownby, Guilherme R Lotufo, Jason B Belden, Michael J LydyAbstract:Abstract Little is currently known regarding the toxicokinetics of TNT in fish. In the present study, the Bioconcentration and distribution of trinitrotoluene (TNT) and TNT biotransformation products was investigated in juvenile channel catfish by exposing catfish to 14 C-labeled TNT in water. Uptake experiments showed relatively fast rates ( k u = 10.1 ml g −1 h −1 ) for TNT from the water; however, Bioconcentration factors for TNT were low (0.79 ml g −1 ) due to rapid biotransformation and potential elimination of TNT. Accumulation of extractable radioactivity (TNT and all extractable biotransformation products) was much greater (BCF = 10.5 ml g −1 ) than that for parent compound. TNT (parent compound) bioconcentrated to the greatest extent in the gills of the fish, while total radioactivity bioconcentrated to the greatest extent in the viscera. Residual portions of the fish that contained muscle and skin had lower concentrations of TNT than the whole fish, indicating that ingestion of fish filets would result in decreased exposure to human consumers. Although the Bioconcentration potential of TNT is very low, future research needs to be conducted to identify the biotransformation products that make up most of the radioactivity in exposed fish and evaluate their potential to promote toxicity.
Christian Schlechtriem - One of the best experts on this subject based on the ideXlab platform.
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Testing the bioaccumulation potential of manufactured nanomaterials in the freshwater amphipod Hyalella azteca.
Chemosphere, 2020Co-Authors: Sebastian Kuehr, R. Kaegi, Dirk Maletzki, Christian SchlechtriemAbstract:Abstract Standardized experimental approaches for the quantification of the bioaccumulation potential of nanomaterials in general and in (benthic) invertebrates in particular are currently lacking. We examined the suitability of the benthic freshwater amphipod Hyalella azteca for the examination of the bioaccumulation potential of nanomaterials. A flow-through test system that allows the generation of Bioconcentration and biomagnification factors was applied. The feasibility of the system was confirmed in a 2-lab comparison study. By carrying out Bioconcentration and biomagnification studies with gold, titanium dioxide and silver nanoparticles as well as dissolved silver (AgNO3) we were able to assess the bioaccumulation potential of different types of nanomaterials and their exposure pathways. For this, the animals were examined for their total metal body burden using inductively coupled mass spectroscopy (ICP-MS) and for the presence of nanoparticulate burdens using single-particle ICP-MS. The role of released ions was highlighted as being very important for the bioavailability and bioaccumulation of metals from nanoparticles for both examined uptake paths examined (Bioconcentration and biomagnification). In 2018 a tiered testing strategy for engineered nanomaterials was proposed by Handy et al. that may allow a waiver of bioaccumulation fish studies using inter alia invertebrates. Data gained in studies carried out with invertebrates like the developed Hyalella azteca test may be included in this proposed tiered testing strategy.
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Bioconcentration studies with the freshwater amphipod Hyalella azteca: are the results predictive of Bioconcentration in fish?
Environmental science and pollution research international, 2018Co-Authors: Christian Schlechtriem, Sebastian Kampe, Hans-jörg Bruckert, Ina Bischof, Ina Ebersbach, Verena Kosfeld, Matthias Kotthoff, Christoph Schäfers, Jacques L’haridonAbstract:Bioconcentration factors (BCF) for regulatory purposes are usually determined by fish flow-through tests according to technical guidance document OECD 305. Fish Bioconcentration studies are time consuming, expensive, and use many laboratory animals. The aim of this study was to investigate whether the freshwater amphipod Hyalella azteca can be used as an alternative test organism for Bioconcentration studies. Fourteen substances of different hydrophobicity (log Kow 2.4–7.6) were tested under flow-through conditions to determine steady state and kinetic Bioconcentration factors (BCFss and BCFk). The results were compared with fish BCF estimates for the same substances described in the literature to show the relationship between both values. Bioconcentration studies with the freshwater amphipod H. azteca resulted in BCF estimates which show a strong correlation with fish BCF values (r2 = 0.69). Hyalella BCF values can be assessed in accordance with the regulatory B criterion (BCF > 2000, i.e., REACH) and thereby enable the prediction of B or non-B classification in the standard fish test. Therefore, H. azteca has a high potential to be used as alternative test organism to fish for Bioconcentration studies.
Harald J. Geyer - One of the best experts on this subject based on the ideXlab platform.
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two compartment thermodynamic model for Bioconcentration of hydrophobic organic chemicals by alga quantitative relationshiop between Bioconcentration factor and surface area of marine algae or octanol water partition coefficient
Chemosphere, 1997Co-Authors: Xiulin Wang, Weijun Yu, Harald J. GeyerAbstract:Abstract A two-compartment thermodynamic model for Bioconcentration of hydrophobic organic chemicals (HOCs) by algae was proposed. In the model, it was assumed that 1) the Bioconcentration is comparable to physicochemical liquid-liquid partitioning, and is predominantly the result of interfacial processes of alga cells as well as HOC; 2) the surface excess quantity of HOC with respect to water phase can be expressed by Gibbs equation, and increases with increasing HOC concentration in alga cells; 3) the hydrophobic nature of alga cells, wherein only dispersion interaction contributes to their surface tension, remain almost unchanged after adsorption of HOC. From the model it was concluded that Bioconcentration factor (log BCF) has linear relation with specific surface area (log S) of alga cells, n-octanol/water partition coefficient (log Kow) of HOC, and HOC concentration in the water (log Cw) respectively. The model was tested by the Bioconcentration of monochlorobenzene, 1,2-dichlorobenzene, 1,2,3,4-tetrachlorobenzene, and pentachlorobenzene by marine algae including Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis, and Phaeodactylum tricornutum. BCF values were obtained not only with the Bioconcentration model, but also with the combined Bioconcentration and probability model. It was found that the Bioconcentration factors of a chemical was increaseing with the specific surface area (S) of different marine algae.
Jason B Belden - One of the best experts on this subject based on the ideXlab platform.
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accumulation of trinitrotoluene tnt in aquatic organisms part 2 Bioconcentration in aquatic invertebrates and potential for trophic transfer to channel catfish ictalurus punctatus
Chemosphere, 2005Co-Authors: Jason B Belden, Guilherme R Lotufo, Dennis Randall Ownby, Michael J LydyAbstract:Abstract The potential of TNT to accumulate in aquatic organisms was assessed by determining Bioconcentration factors for TNT and TNT biotransformation products using two benthic invertebrates ( Chironomus tentans and Lumbriculus variegatus ), and by determining the bioaccumulation factor of TNT and TNT biotransformation products due to TNT exposure via feeding for channel catfish ( Ictalurus punctatus ). In all three species, TNT was rapidly biotransformed resulting in minimal accumulation. The Bioconcentration factors for parent TNT ranged from 3 to 4 ml g −1 for the invertebrates studied, while the TNT bioaccumulation factor for catfish via oral exposure of food pellets was 2.4 × 10 −5 g g −1 based on the concentration of TNT in the food pellet. As indicated by this small bioaccumulation factor, TNT accumulation in channel catfish through trophic transfer would be negligible compared to aqueous exposure (previously reported BCF of 0.79 ml g −1 ). TNT extractable biotransformation products accumulated to a greater degree than parent TNT for all three species. In addition, a large fraction of the radioactivity within all three species resisted solvent extraction. The highest Bioconcentration factors occurred in L. variegatus with extractable radioactivity measuring 76 ml g −1 and total radioactivity measuring 216 ml g −1 . Because the bioaccumulation of TNT is very low compared to the bioaccumulation of its biotransformation products, further research including identifying and determining the relative toxicities of these biotransformation products is necessary to fully evaluate the environmental risk posed by exposure to TNT.
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accumulation of trinitrotoluene tnt in aquatic organisms part 1 Bioconcentration and distribution in channel catfish ictalurus punctatus
Chemosphere, 2005Co-Authors: Dennis Randall Ownby, Guilherme R Lotufo, Jason B Belden, Michael J LydyAbstract:Abstract Little is currently known regarding the toxicokinetics of TNT in fish. In the present study, the Bioconcentration and distribution of trinitrotoluene (TNT) and TNT biotransformation products was investigated in juvenile channel catfish by exposing catfish to 14 C-labeled TNT in water. Uptake experiments showed relatively fast rates ( k u = 10.1 ml g −1 h −1 ) for TNT from the water; however, Bioconcentration factors for TNT were low (0.79 ml g −1 ) due to rapid biotransformation and potential elimination of TNT. Accumulation of extractable radioactivity (TNT and all extractable biotransformation products) was much greater (BCF = 10.5 ml g −1 ) than that for parent compound. TNT (parent compound) bioconcentrated to the greatest extent in the gills of the fish, while total radioactivity bioconcentrated to the greatest extent in the viscera. Residual portions of the fish that contained muscle and skin had lower concentrations of TNT than the whole fish, indicating that ingestion of fish filets would result in decreased exposure to human consumers. Although the Bioconcentration potential of TNT is very low, future research needs to be conducted to identify the biotransformation products that make up most of the radioactivity in exposed fish and evaluate their potential to promote toxicity.