Papers by Henriette Selck
Frontiers in Marine Science, Jan 4, 2023
Microplastics (MPs) are ubiquitous in the marine environment. Here, most MPs are expected to sink... more Microplastics (MPs) are ubiquitous in the marine environment. Here, most MPs are expected to sink, either due to polymer density or environmental processes, such as biofouling, leading to sediment being proposed to act as a final sink for marine MPs. There is a discrepancy between the anticipated accumulation of MPs in the sediment compartment and the MP experiments conducted, since most MP effect studies have been conducted with pelagic species using water-only exposures. Here we address fundamental questions in relation to MP pollution to close the knowledge gap related hereto. A systematic literature search was performed to address these questions. We found that benthic invertebrates ingest MPs and that, even though these organisms evolutionary are adapted to handle particles, adverse effects may be observed upon ingestion of MPs. The analysis further revealed that there is a major knowledge gap on the impacts of sediment-associated MPs in marine, benthic invertebrates. To facilitate further and structured research within this topic, we recommend more studies with emphasis on the sediment as an important exposure pathway, and to focus on sediment-associated MP effects on benthic invertebrates. We recommend studies with ecological relevant exposure concentrations and ecological relevant exposure durations with emphasis on impacts on population-and community-level to reduce the knowledge gap within this central area of MP pollution research.
Environmental Toxicology and Chemistry, Mar 28, 2017
Environmental Toxicology and Chemistry, Jun 19, 2016
The US-EU Community of Research (CoR) was established in 2012 to provide a platform for scientist... more The US-EU Community of Research (CoR) was established in 2012 to provide a platform for scientists to develop a 'shared repertoire of protocols and methods to overcome nanotechnology environmental health and safety (nanoEHS) research gaps and barriers' (www.us-eu.org/). Based on work within the Ecotoxicology CoR (2012-2015) we provide here an overview of the state-of-theart of nanomaterials (NMs) in the aquatic environment by addressing different research questions with a focus on ecotoxicological test systems and the challenges faced when assessing nanomaterial (NM) hazards (e.g., uptake routes, bioaccumulation, toxicity, test protocols and model organisms). Our recommendation is to place particular importance on studying the ecological effects of aged/weathered NMs, as-manufactured NMs, as well as NMs released from consumer products in addressing the following overarching research topics: i) NM characterization and quantification in environmental and biological matrices, ii) NM transformation in the environment and consequences for bioavailability and toxicity, iii) alternative methods to assess exposure, iv) influence of exposure scenarios on bioavailability and toxicity, v) development of more environmentally realistic bioassays and vi) uptake, internal distribution, and depuration of NMs. Research addressing these key topics will reduce uncertainty in ecological risk assessment and support the sustainable development of nanotechnology.
Environmental Pollution, Nov 1, 2020
Sediments serve as both source and sink of contaminants (e.g., Cu) and biologically important mat... more Sediments serve as both source and sink of contaminants (e.g., Cu) and biologically important materials (e.g., metals, nutrients). Bioturbation by benthic organisms is ecologically relevant as bioturbation affects the physio-chemical characteristics of sediments, thus altering nutrient and contaminant distribution and bioavailability. We examined the effects of sediment-associated Cu on T. tubifex with conventional toxicity endpoints, such as mortality and growth, and less commonly used non-destructive endpoints, such as bioturbation and feeding. An experimental approach was developed to examine the applicability of simple methods to detect effects on bioturbation and feeding. Two experiments were conducted with 7-day exposures to uncontaminated or Cu-spiked natural sediment at six Cu concentrations to examine Cu bioaccumulation and effects. Endpoints included worm mortality, feeding rate and growth (experiment A) and worm bioturbation (particle diffusion and maximum penetration depth, experiment B). A microparticle tracer was placed on the sediment surface and vertical particle transport was followed over time. Adverse effects were detected for all endpoints (bioturbation, feeding rate, growth and survival): a slight positive effect at the lowest Cu concentrations followed by adverse effects at higher concentrations indicating hormesis. These simple, non-destructive endpoints, provided valuable information and demonstrated that sediment-associated contaminants, such as Cu, can influence bioturbation activity, which in turn may affect the distribution of sediment-bound or particulate pollutants, such as the plastic microparticles studied here. Thus, we suggest to use simple endpoints, such as bioturbation and feeding rate, in ecotoxicity testing since these endpoint account for the influence of interactions between pollutants and benthos and, thus, increase ecological relevance.
Aquatic Toxicology, Jul 1, 2015
Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic envi... more Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic environment. Both aqueous (i.e., dissolved Cu) and particulate Cu can be taken up by organisms. However, how exposure routes influence the bioavailability and subsequent toxicity of Cu remains largely unknown. Here, we assess the importance of exposure routes (water and sediment) and Cu forms (aqueous and nanoparticulate) on Cu bioavailability and toxicity to the freshwater oligochaete, Lumbriculus variegatus, a head-down deposit-feeder. We characterize the bioaccumulation dynamics of Cu in L. variegatus across a range of exposure concentrations, covering both realistic and worst-case levels of Cu contamination in the environment. Both aqueous Cu (Cu-Aq; administered as Cu(NO 3) 2) and nanoparticulate Cu (CuO NPs), whether dispersed in artificial moderately hard freshwater or mixed into sediment, were weakly accumulated by L. variegatus. Once incorporated into tissues, Cu elimination was negligible, i.e., elimination rate constants were in general not different from zero for either exposure route or either Cu form. Toxicity was only observed after waterborne exposure to Cu-Aq at very high concentration (305 g L −1), where all worms died. There was no relationship between exposure route, Cu form or Cu exposure concentration on either worm survival or growth. Slow feeding rates and low Cu assimilation efficiency (approximately 30%) characterized the uptake of Cu from the sediment for both Cu forms. In nature, L. variegatus is potentially exposed to Cu via both water and sediment. However, sediment progressively becomes the predominant exposure route for Cu in L. variegatus as Cu partitioning to sediment increases.
Toxicology in Vitro, Dec 1, 2017
The use of engineered metal nanoparticles (NPs) is continuously increasing and so is the need for... more The use of engineered metal nanoparticles (NPs) is continuously increasing and so is the need for information regarding their toxicity. This study compares the toxicity of CuO NPs with ionic Cu in three zebrafish model systems; zebrafish hepatoma cell line (ZFL), fish embryo toxicity test (FET) and fry locomotion. In the ZFL tests, no significant cytotoxicity (cell death, decreased metabolic or cell membrane integrity) was detected for either treatment, though both significantly affected reactive oxygen species (ROS) production. Embryo mortality was affected by both Cu ions and CuO NPs with similar concentration-response relationships, whereas only Cu ions affected fry mortality (24 h LC 50 ≈30 µM, ≈2 mg Cu L-1 for Cu ions and no significant mortality observed at up to 200 µM, 12.7 mg Cu L-1 for CuO NP). Both Cu forms increased fry swimming activity during light cycles and decreased activity during dark cycles: Cu ions had significant impact at lower concentrations than CuO NPs. The implications are that Cu ions generally are more toxic than CuO NPs to embryos and fry but there is a marked difference in toxicity among the different zebrafish model systems. Metal NPs release into the environment may have adverse effects on fish and other aquatic organisms.
Environmental science. Nano, 2019
One of the key components for environmental risk assessment of engineered nanomaterials (ENMs) is... more One of the key components for environmental risk assessment of engineered nanomaterials (ENMs) is data on bioaccumulation potential. Accurately measuring bioaccumulation can be critical for regulatory decision making regarding material hazard and risk, and for understanding the mechanism of toxicity. This perspective provides expert guidance for performing ENM *
Toxicology in Vitro, Aug 1, 2013
Nanoparticles (NPs) have unique chemical and physical properties caused by their small size (1-10... more Nanoparticles (NPs) have unique chemical and physical properties caused by their small size (1-100 nm) and high surface to volume ratio. This means that the NPs are potentially more toxic than their bulk counterparts. In the present study a cultured epithelial cell line from Xenopus laevis (A6) was used to investigate toxicity of copper (Cu) in 3 different forms; Cu ions (Cu 2+), CuO NPs (6 nm) and poly-dispersed CuO NPs (100 nm, poly-CuO). Continuous exposures at concentrations of 143-200 lM demonstrated that cytotoxicity differed among the 3 Cu forms tested and that the effects depend on cell state (dividing or differentiated). Dividing cells treated with poly-CuO, CuO NPs (6 nm) or Cu 2+ showed cell cycle arrest and caused significant increase in cell death via apoptosis after 48 h, 6 and 7 days of treatment, respectively. Treatment with either CuO NPs (6 nm) or Cu 2+ caused significant decrease in cell proliferation. Treatments of differentiated cells, revealed the same patterns of toxicity for Cu forms tested, but after shorter exposure periods.
Nanotoxicology, Mar 16, 2017
A major challenge in nanoecotoxicology is finding suitable methods to determine the uptake and lo... more A major challenge in nanoecotoxicology is finding suitable methods to determine the uptake and localisation of nanoparticles on a whole-organism level. Some uptake methods have been associated with artefacts induced by sample preparation, including staining for electron microscopy. This study used light sheet microscopy (LSM) to define the uptake and localisation of fluorescently labelled nanoparticles in living organisms with minimal sample preparation. Zebrafish (Danio rerio) were exposed to fluorescent gold nanoparticles (Au NPs) and fluorescent polystyrene NPs via aqueous or dietary exposure. The in vivo uptake and localisation of NPs was investigated using LSM at different time points (1, 3 and 7 days). A time-dependent increase in fluorescence was observed in the gut after dietary exposure to both Au NPs and polystyrene NPs. No fluorescence was observed within gut epithelia regardless of the NP exposure route indicating no or limited uptake via intestinal villi. Fish exposed to polystyrene NPs through the aqueous phase emitted fluorescence signals from the gills and intestine. Fluorescence was also detected in the head region of the fish after aqueous exposure to polystyrene NPs. This was not observed for Au NPs. Aqueous exposure to Au NPs resulted in increased relative swimming distance, while no effect was observed for other exposures. This study supports that the route of exposure is essential for the uptake and subsequent localisation of nanoparticles in zebrafish. Furthermore, it demonstrates that the localisation of NPs in whole living organisms can be visualised in real-time, using LSM.
Table of contents artwork Strategies, discussion, and case studies are provided for making robust... more Table of contents artwork Strategies, discussion, and case studies are provided for making robust and accurate measurements of engineered nanomaterial bioaccumulation by single-cell organisms, multicellular organisms, and plants.
Aquatic Toxicology, Nov 1, 2016
Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic envi... more Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic environment. Both aqueous (i.e., dissolved Cu) and particulate Cu can be taken up by organisms. However, how exposure routes influence the bioavailability and subsequent toxicity of Cu remains largely unknown. Here, we assess the importance of exposure routes (water and sediment) and Cu forms (aqueous and nanoparticulate) on Cu bioavailability and toxicity to the freshwater oligochaete, Lumbriculus variegatus, a head-down deposit-feeder. We characterize the bioaccumulation dynamics of Cu in L. variegatus across a range of exposure concentrations, covering both realistic and worst-case levels of Cu contamination in the environment. Both aqueous Cu (Cu-Aq; administered as Cu(NO 3) 2) and nanoparticulate Cu (CuO NPs), whether dispersed in artificial moderately hard freshwater or mixed into sediment, were weakly accumulated by L. variegatus. Once incorporated into tissues, Cu elimination was negligible, i.e., elimination rate constants were in general not different from zero for either exposure route or either Cu form. Toxicity was only observed after waterborne exposure to Cu-Aq at very high concentration (305 g L −1), where all worms died. There was no relationship between exposure route, Cu form or Cu exposure concentration on either worm survival or growth. Slow feeding rates and low Cu assimilation efficiency (approximately 30%) characterized the uptake of Cu from the sediment for both Cu forms. In nature, L. variegatus is potentially exposed to Cu via both water and sediment. However, sediment progressively becomes the predominant exposure route for Cu in L. variegatus as Cu partitioning to sediment increases.
Environmental Science & Technology, Jul 16, 2018
Personal care products are widely used in our daily life in considerable quantities and discharge... more Personal care products are widely used in our daily life in considerable quantities and discharged through the down-the-drain route to the aquatic environments, resulting in potential risks to aquatic organisms. We investigated bioaccumulation and biotransformation of two widely used personal care products, triclosan (TCS) and galaxolide (HHCB) spiked to sediment, in the oligochaete worm Limnodrilus hoffmeisteri in water/sediment microcosms. After 7 days of sediment exposure to 3.1 μg TCS or HHCB /g dry weight (dw) sediment, the accumulation of TCS and HHCB in L. hoffmeisteri reached equilibrium, at which point the biota-sediment accumulation factors (BSAFs) were 2.07 and 2.50 for TCS and HHCB, respectively. The presence of L. hoffmeisteri significantly accelerated the dissipation of TCS and HHCB in the microcosms, with approximately 9.03% and 2.90% of TCS and HHCB eliminated from the water-sediment systems after 14 d exposure in presence of worms, respectively. Two biotransformation products, methyl triclosan and triclosan-O-sulfate, were identified for TCS in the worm tissue, whereas only methyl triclosan was identified in the sediment. Unlike TCS, no evidence of biotransformation products was found for HHCB in either worm tissue or sediment. These experiments demonstrate that L. hoffmeisteri biotransformed TCS through methylation and sulfation, whereas HHCB biotransformation was undetectable.
Marine Environmental Research, Sep 1, 2007
Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of p... more Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of pyrene in two macrofaunal species and their surrounding sediment
Ecotoxicology and Environmental Safety, Mar 1, 2019
Galaxolide (HHCB) is used as a fragrance ingredient in household and personal care products, and ... more Galaxolide (HHCB) is used as a fragrance ingredient in household and personal care products, and has been ubiquitously detected in the environment. Here we investigated the fate of HHCB in subtropical freshwater microcosms, and evaluated effects of sediment-associated HHCB on a biological community consisting of algae, Daphnia, benthic macroinvertebrates and bacteria. The concentrations of sediment-associated HHCB did not change significantly during a 28 days exposure period, but HHCB accumulated in worms with biota-sediment accumulation-factor (BSAF) values in the range of 0.29-0.66 for Branchiura sowerbyi and 0.94-2.11 for Limnodrilus hoffmeisteri. There was no significant effects of HHCB (30 μg/g dry weight (dw) sediment) on chlorophyll-a content, sediment bacterial community composition, and survival and growth of benthic macroinvertebrates. However, the presence of benthic macroinvertebrates altered the sediment bacterial community structure relative to microcosms without introduced organisms. The findings of this study suggest that a single high-dose of HHCB, over 28 days, at environmentally relevant concentrations would not impose direct toxicological risks to aquatic organisms such as benthic macroinvertebrates.
Science of The Total Environment, Mar 1, 2020
Benthic invertebrate and microbial biodiversity in subtropical urban rivers Correlations with env... more Benthic invertebrate and microbial biodiversity in subtropical urban rivers Correlations with environmental variables and emerging chemicals
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Papers by Henriette Selck