Developing behavioural ecotoxicology assessment methods in the tropical marine amphipod, Parhyale hawaiensis: A study with benzo[a]pyrene (BaP).

Toxicant-induced behavioural changes provide important insights into environmental toxicity, particularly in vulnerable tropical marine habitats. However, ecotoxicological knowledge of organisms in these environments is insufficient. We aimed to develop innovative and cost-effective ecotoxicology methods using Parhyale hawaiensis as a tropical model organism.

Environmental significance of PAH photoproduct formation: TiO nanoparticle influence, altered bioavailability, and potential photochemical mechanisms.

Interactions between polycyclic aromatic hydrocarbons (PAHs) and titanium dioxide (TiO) nanoparticles (NPs) can produce unforeseen photoproducts in the aqueous phase. Both PAHs and TiO-NPs are well-studied and highly persistent environmental pollutants, but the consequences of PAH-TiO-NP interactions are rarely explored. We investigated PAH photoproduct formation over time for benzo[a]pyrene (BaP), fluoranthene (FLT), and pyrene (PYR) in the presence of ultraviolet A (UVA) using a combination of analytical and computational methods including, identification of PAH photoproducts, assessment of expression profiles for gene indicators of PAH metabolism, and computational evaluation of the reaction mechanisms through which certain photoproducts might be formed.

Identification of the bacterial community that degrades phenanthrene sorbed to polystyrene nanoplastics using DNA-based stable isotope probing.

In the Anthropocene, plastic pollution has become a new environmental biotope, the so-called plastisphere. In the oceans, nano- and micro-sized plastics are omnipresent and found in huge quantities throughout the water column and sediment, and their large surface area-to-volume ratio offers an excellent surface to which hydrophobic chemical pollutants (e.g.

Fate and toxicity of 2,4-D and fipronil in mesocosm systems.

2,4-D and fipronil are among Brazil's most used pesticides. The presence of these substances in surface waters is a concern for the aquatic ecosystem health. Thus, understanding the behavior of these substances under environmentally relevant conditions is essential for an effective risk assessment.

Evaluation of bioaccumulation of nanoplastics, carbon nanotubes, fullerenes, and graphene family materials.

Bioaccumulation is a key factor in understanding the potential ecotoxicity of substances. While there are well-developed models and methods to evaluate bioaccumulation of dissolved organic and inorganic substances, it is substantially more challenging to assess bioaccumulation of particulate contaminants such as engineered carbon nanomaterials (CNMs; carbon nanotubes (CNTs), graphene family nanomaterials (GFNs), and fullerenes) and nanoplastics. In this study, the methods used to evaluate bioaccumulation of different CNMs and nanoplastics are critically reviewed.

Potential Artifacts and Control Experiments in Toxicity Tests of Nanoplastic and Microplastic Particles.

To fully understand the potential ecological and human health risks from nanoplastics and microplastics (NMPs) in the environment, it is critical to make accurate measurements. Similar to past research on the toxicology of engineered nanomaterials, a broad range of measurement artifacts and biases are possible when testing their potential toxicity. For example, antimicrobials and surfactants may be present in commercially available NMP dispersions, and these compounds may account for toxicity observed instead of being caused by exposure to the NMP particles.

Interspecific differences in oxidative DNA damage after hydrogen peroxide exposure of sea urchin coelomocytes.

Interspecific comparison of DNA damage can provide information on the relative vulnerability of marine organisms to toxicants that induce oxidative genotoxicity. Hydrogen peroxide (H2O2) is an oxidative toxicant that causes DNA strand breaks and nucleotide oxidation and is used in multiple industries including Atlantic salmon aquaculture to treat infestations of ectoparasitic sea lice. H2O2 (up to 100 mM) can be released into the water after sea lice treatment, with potential consequences of exposure in nontarget marine organisms.

The amphipod Parhyale hawaiensis as a promising model in ecotoxicology.

Near-shore marine/estuarine environments play an important role in the functioning of the marine ecosystem and are extremely vulnerable to the presence of chemical pollution. The ability to investigate the effects of pollution is limited by a lack of model organisms for which sufficient ecotoxicological information is available, and this is particularly true for tropical regions. The circumtropical marine amphipod Parhyale hawaiensis has become an important model organism in various disciplines, and here we summarize the scientific literature regarding the emergence of this model within ecotoxicology.

Marine Sponges in a Snowstorm - Extreme Sensitivity of a Sponge Holobiont to Marine Oil Snow and Chemically Dispersed Oil Pollution.

Holobionts formed by a host organism and associated symbionts are key biological units in marine ecosystems where they are responsible for fundamental ecosystem services. Therefore, understanding anthropogenic impacts on holobionts is essential. Sponges (Phylum Porifera) are ideal holobiont models.

Transgenic zebrafish larvae as a non-rodent alternative model to assess pro-inflammatory (neutrophil) responses to nanomaterials.

Hazard studies for nanomaterials (NMs) commonly assess whether they activate an inflammatory response. Such assessments often rely on rodents, but alternative models are needed to support the implementation of the 3Rs principles. Zebrafish () offer a viable alternative for screening NM toxicity by investigating inflammatory responses.

Time-Related Alteration of Aqueous-Phase Anthracene and Phenanthrene Photoproducts in the Presence of TiO Nanoparticles.

Polycyclic aromatic hydrocarbons (PAHs) and titanium dioxide (TiO) nanoparticles (NPs) are photoactive environmental pollutants that can contaminate aquatic environments. Aqueous-phase interactions between PAHs and TiO-NPs are of interest due to their emerging environmental relevance, particularly with the deliberate application of TiO-NPs to remediate pollution events (e.g.

Neutrophil activation by nanomaterials : comparing strengths and limitations of primary human cells with those of an immortalized (HL-60) cell line.

Assessment of nanomaterial (NM) induced inflammatory responses has largely relied on rodent testing via measurement of leukocyte accumulation in target organs. Despite observations that NMs activate neutrophil driven inflammatory responses , a limited number of studies have investigated neutrophil responses to NMs . We compared responses between the human neutrophil-like HL-60 cell line and human primary neutrophils following exposure to silver (Ag), zinc oxide (ZnO), copper oxide (CuO) and titanium dioxide (TiO) NMs.

Antibacterial Activities of Ga(III) against Are Substantially Impacted by Fe(III) Uptake Systems and Multidrug Resistance in Combination with Oxygen Levels.

The continued emergence and spread of antimicrobial resistance (AMR), particularly multidrug resistant (MDR) bacteria, are increasing threats driving the search for additional and alternative antimicrobial agents. The World Health Organization (WHO) has categorized bacterial risk levels and includes among the highest priority, making this both a convenient model bacterium and a clinically highly relevant species on which to base investigations of antimicrobials. Among many compounds examined for use as antimicrobials, Ga(III) complexes have shown promise.

Polyvinyl chloride (PVC) plastic fragments release Pb additives that are bioavailable in zebrafish.

Plastic polymers such as polyvinyl chloride (PVC) may contain chemical additives, such as lead (Pb), that are leachable in aqueous solution. The fragmentation into microplastics (MPs) of plastics such as PVC may facilitate desorption of chemical additives and increase exposure of aquatic animals. In this study, the role of chemical additives in the aqueous toxicity of PVC, high-density polyethylene (HDPE) and polyethylene terephthalate (PET) MPs were investigated in early-life stage zebrafish (Danio rerio) by assessment of changes in expression of biomarkers.

Transcriptome analysis in Parhyale hawaiensis reveal sex-specific responses to AgNP and AgCl exposure.

Analysis of the transcriptome of organisms exposed to toxicants offers new insights for ecotoxicology, but further research is needed to enhance interpretation of results and effectively incorporate them into useful environmental risk assessments. Factors that must be clarified to improve use of transcriptomics include assessment of the effect of organism sex within the context of toxicant exposure. Amphipods are well recognized as model organisms for toxicity evaluation because of their sensitivity and amenability to laboratory conditions.

Toxicity of Cyanopeptides from Two Strains on Larval Development of .

Absorption and accumulation of bioavailable cyanobacterial metabolites (including cyanotoxins) are likely in fish after senescence and the rupturing of cells during bloom episodes. We determined the toxicity of cyanopeptides identified from two strains of ( MIRS-04 and NPDC-01) in a freshwater tropical fish, (yellowtail tetra, lambari). Aqueous extracts of both strains were prepared in order to simulate realistic fish exposure to these substances in a freshwater environment.

Use of fluorescent-labelled nanoplastics (NPs) to demonstrate NP absorption is inconclusive without adequate controls.

Whether nanoplastics (NPs) are able to be absorbed across epithelial membranes and accumulate within internal tissues of organisms is an important determinant of their potential toxicity. Evidence of absorption and accumulation requires detection of NPs within internal tissues, and investigations with fluorescently labelled NPs have attempted to provide this information. We hypothesize that studies that do not control for the fluorescent dye leachate and/or cellular autofluorescence are inconclusive and can be misinterpreted.

Differences in Engineered Nanoparticle Surface Physicochemistry Revealed by Investigation of Changes in Copper Bioavailability During Sorption to Nanoparticles in the Aqueous Phase.

Sorption of chemical substances to nanoparticles (NPs) in the aqueous phase strongly influences NP physicochemisty, and investigations of these complex interactions can provide important insights into the environmental fate of NPs. The objective of the present study was to use differences in copper (Cu) bioavailability to investigate aqueous-phase sorption with NPs that had different physicochemical characteristics (silicon [Si], perovskite, and titanium dioxide NPs [TiO NPs]). Sorption of Cu with NPs was assessed by the presence of adsorbent in water and onto the NP surface after ultracentrifugation, and by changes in Cu bioavailability under static conditions during exposure of larval zebrafish, as well as under conditions of continuous agitation during exposure of the alga Chlorella vulgaris.

Microplastic contamination in surface waters in Guanabara Bay, Rio de Janeiro, Brazil.

Microplastics (MPs) are contaminants of environmental concern that represent a threat to marine systems. Here we report data on the abundance and characteristics of MPs collected from surface waters of the urban Guanabara Bay. Samples were collected, by horizontal trawling of a plankton net on two occasions (summer of 2016).

Conservation and restoration of a keystone species: Understanding the settlement preferences of the European oyster (Ostrea edulis).

The European oyster Ostrea edulis is a keystone species that is internationally recognised as 'threatened and declining' in the NE Atlantic by OSPAR and several nations have consequently adopted strategies for its conservation and restoration. Understanding the settlement behaviour of O. edulis larvae is crucial to inform these strategies.

Higher silver bioavailability after nanoparticle dietary exposure in marine amphipods.

On release into surface waters, engineered silver nanoparticles (AgNPs) tend to settle to sediments and, consequently, epibenthic fauna will be exposed to them through diet. We established Ag uptake and accumulation profiles over time in the hemolymph of a marine amphipod fed with a formulated feed containing AgNPs or AgCl. Silver bioavailability was higher in organisms exposed to AgNPs, indicating that the nanoparticles pose a higher risk of toxicity compared to similar concentrations of AgCl.

Uptake, Whole-Body Distribution, and Depuration of Nanoplastics by the Scallop Pecten maximus at Environmentally Realistic Concentrations.

Previous studies of uptake and effects of nanoplastics by marine organisms have been conducted at what may be unrealistically high concentrations. This is a consequence of the analytical challenges in tracking plastic particles in organisms at environmentally relevant concentrations and highlights the need for new approaches. Here, we present pulse exposures of C-radiolabeled nanopolystyrene to a commercially important mollusk, Pecten maximus, at what have been predicted to be environmentally relevant concentrations (<15 μg L).

Potential Impacts of Offshore Oil and Gas Activities on Deep-Sea Sponges and the Habitats They Form.

Sponges form an important component of benthic ecosystems from shallow littoral to hadal depths. In the deep ocean, beyond the continental shelf, sponges can form high-density fields, constituting important habitats supporting rich benthic communities. Yet these habitats remain relatively unexplored.

Agglomeration of nano- and microplastic particles in seawater by autochthonous and de novo-produced sources of exopolymeric substances.

Microplastics (<5 mm) have often been studied under in-vitro conditions where plastics have been investigated in isolation. However, in the natural environment microplastics readily form agglomerates conferring the particles with properties different to their pristine counterparts. Here, we examined the interaction of exopolymers with polystyrene nanoplastics and microplastics.