The Experts below are selected from a list of 23814 Experts worldwide ranked by ideXlab platform
Thomas Braunbeck - One of the best experts on this subject based on the ideXlab platform.
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The tox is in the detail: technical fundamentals for designing, performing, and interpreting experiments on toxicity of microplastics and associated substances
Environmental Science and Pollution Research, 2020Co-Authors: Patrick Heinrich, Lisa Hanslik, Nadine Kämmer, Thomas BraunbeckAbstract:Over the last 10 years, there has been a plethora of experimental studies estimating the potential of microplastic particles (MPs) to exert toxic effects in the environment, many specifically focusing on their postulated capacity to enhance the transfer of environmental pollutants into organisms after ingestion. Obviously, there is little to no consensus on appropriate experimental design, which is mainly owing to the novelty, the interdisciplinarity of the subject, and the complexity of parameters involved. This results in fundamental discrepancies regarding the materials applied, the approach for spiking MPs with pollutants, and the exact Exposure Scenario. Aiming for a non-chemist audience and providing illustrative, representative, and comparative examples, this review first outlines the theoretical essentials of processes involved in sorption. Also, it discusses the implications for designing experimental approaches using MPs and interpreting the results obtained under consideration of their relevance for environmental conditions. It may help to improve the interpretation of studies on MP toxicity already published, while also calling experimenters’ attention to various aspects important to consider when designing and performing environmentally relevant experiments with MPs.
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prochloraz causes irreversible masculinization of zebrafish danio rerio
Environmental Science and Pollution Research, 2015Co-Authors: Lisa Baumann, Susanne Knorr, Susanne Keiter, Tina Nagel, Helmut Segner, Thomas BraunbeckAbstract:The aim of the present study was to investigate the persistence of endocrine effects by prochloraz, a fungicide known to have multiple effects on the endocrine system of vertebrates. Since discontinuous Exposure is particularly relevant in aquatic ecosystems, an Exposure Scenario with an Exposure phase and a subsequent recovery period was chosen to assess the potential for reversibility of effects by prochloraz on the sexual development of zebrafish (Danio rerio). Zebrafish were exposed to different concentrations of prochloraz (10–300 μg/L) until 60 days post hatch (dph), which includes the period of sexual differentiation. For the subsequent 40 days, fish were either held in clean water for depuration or under further continuous Exposure. Histological investigations of the gonads revealed persistent effects on sexual differentiation. The sex ratio was skewed towards males and significantly more intersex individuals were found after Exposure to prochloraz at 60 dph. No intersex fish, but masculinized sex ratios were still present after the depuration period, documenting that prochloraz irreversibly affects the sexual development of zebrafish.
Treye A Thomas - One of the best experts on this subject based on the ideXlab platform.
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nanoparticles containing spray can aerosol characterization Exposure assessment and generator design
Inhalation Toxicology, 2010Co-Authors: Bean T Chen, Aliakbar Afshari, Samuel Stone, Mark Jackson, Diane Schweglerberry, David G Frazer, Vincent Castranova, Treye A ThomasAbstract:This is the first report demonstrating that a commercially available household consumer product produces nanoparticles in a respirable range. This report describes a method developed to characterize nanoparticles that were produced under typical Exposure conditions when using a consumer spray product. A well-controlled indoor environment was simulated for conducting spray applications approximating a human Exposure Scenario. Results indicated that, while aerosol droplets were large with a count median diameter of 22 µm during spraying, the final aerosol contained primarily solid TiO2 particles with a diameter of 75 nm. This size reduction was due to the surface deposition of the droplets and the rapid evaporation of the aerosol propellant. In the breathing zone, the aerosol, containing primarily individual particles (>90%), had a mass concentration of 3.4 mg/m3, or 1.6 × 105 particles/cm3, with a nanoparticle fraction limited to 170 µg/m3, or 1.2 × 105 particles/cm3. The results were used to estimate the ...
Lisa Baumann - One of the best experts on this subject based on the ideXlab platform.
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prochloraz causes irreversible masculinization of zebrafish danio rerio
Environmental Science and Pollution Research, 2015Co-Authors: Lisa Baumann, Susanne Knorr, Susanne Keiter, Tina Nagel, Helmut Segner, Thomas BraunbeckAbstract:The aim of the present study was to investigate the persistence of endocrine effects by prochloraz, a fungicide known to have multiple effects on the endocrine system of vertebrates. Since discontinuous Exposure is particularly relevant in aquatic ecosystems, an Exposure Scenario with an Exposure phase and a subsequent recovery period was chosen to assess the potential for reversibility of effects by prochloraz on the sexual development of zebrafish (Danio rerio). Zebrafish were exposed to different concentrations of prochloraz (10–300 μg/L) until 60 days post hatch (dph), which includes the period of sexual differentiation. For the subsequent 40 days, fish were either held in clean water for depuration or under further continuous Exposure. Histological investigations of the gonads revealed persistent effects on sexual differentiation. The sex ratio was skewed towards males and significantly more intersex individuals were found after Exposure to prochloraz at 60 dph. No intersex fish, but masculinized sex ratios were still present after the depuration period, documenting that prochloraz irreversibly affects the sexual development of zebrafish.
Dale J Hoff - One of the best experts on this subject based on the ideXlab platform.
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species sensitivity and dependence on Exposure conditions impacting the phototoxicity of tio2 nanoparticles to benthic organisms
Environmental Toxicology and Chemistry, 2014Co-Authors: Shibin Li, Lindsay K Wallis, Stephen A Diamond, Dale J HoffAbstract:Toxicityoftitaniumdioxidenanoparticles(nano-TiO2)toaquaticorganismscanbegreatlyincreasedafterExposuretoultraviolet (UV) radiation. This phenomenon has received some attention for water column species; however, investigations of nano-TiO2 phototoxicity for benthic organisms are still limited. In the present study, bioassays of 3 representative benthic organisms (Hyalella azteca, Lumbriculusvariegatus,andChironomusdilutus)wereconductedtoevaluatenano-TiO2phototoxicity.Whenexposedto20mg/Lofnano- TiO2andvariouslightintensities(0-30W/m 2 ),H.aztecawasthemostsensitive,withamedianlethaldoseof40.7(95%confidenceinterval, 36.3-44.7) Wh/m 2 , and hence is a potential model organism in future toxicological guidelines for photoactive nanomaterials to freshwater benthos. Without the presence of nano-TiO2, no mortality was observed in L. variegatus and C. dilutus exposed to UV intensity ranging from 0W/m 2 to 41W/m 2 . However, a sharp drop of H. azteca survival was observed when UV intensity was higher than 9.4W/m 2 , demonstrating the importance of UV-only effects on the ultimate phototoxicity of nanomaterials. Furthermore, both bioavailability and surface attachment of nano-TiO2 onto organisms were affected by the Exposure Scenario, supported by the Exposure Scenario-dependent phototoxicity seen in H. azteca and C. dilutus. Overall, the present study demonstrates the importance of species sensitivity and Exposure Scenarios in future test guidelines of nano-phototoxicity. Environ Toxicol Chem 2014;33:1563-1569. # 2014 SETAC
Matthias Liess - One of the best experts on this subject based on the ideXlab platform.
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aquatic passive sampling of a short term thiacloprid pulse with the chemcatcher impact of biofouling and use of a diffusion limiting membrane on the sampling rate
Journal of Chromatography A, 2008Co-Authors: Ralf B Schafer, Albrecht Paschke, Matthias LiessAbstract:We examined the performance of the Chemcatcher (University Portsmouth, UK) in two different configurations when used for the aquatic passive sampling of a 1-day pulse contamination with thiacloprid under field-relevant conditions. The configuration without diffusion-limiting membrane led to biofouling of the Empore disk receiving phase resulting in a fourfold reduction in analyte uptake compared to unfouled passive samplers. The sampling rate for the configuration with diffusion-limiting polyethersulfone membrane was also much lower than in a long-term Exposure Scenario, although no biofouling occurred. Both configurations of the Chemcatcher exhibited high variation in analyte uptake with up to 100% RSD. Short-term contamination events may be underestimated in passive sampling when the receiving phase is biofouled or a diffusion-limiting membrane is employed.
