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Simple Summary: Applications of nanoparticles as well as their use have increased over the past decades without sufficient research on their environmental impact. Focusing on Daphnia magna, a widely adopted aquatic organism employed to evaluate the adverse effects of pollutants, we investigated several aspects of the experimental design used in D. magna toxicity testing which could impact the observed effect of exposure to nanoparticles. Furthermore, we evaluated the feasibility of a miniaturized version of D. magna toxicity test as a potential candidate for nanoparticle toxicity assays. Results showed that the exposure vessel and its characteristics can affect the impact of nanoparticles and, therefore, skew the observed effects. Additionally, the miniaturized exposure showed that for physiology markers such as toxicity and feeding rate it can be a good alternative to the traditional setups, as it vastly reduces the amount of media and number of nanoparticles required as well as generated waste. The rapid progress of the modern world has resulted in new materials and products created at an accelerating pace. As such, nanoparticles have widespread applications and often find their way into the aquatic ecosystem. In the case of freshwater ecosystems, one of the commonly used bioindicators species used for pollution assessment is Daphnid magna. The Organization for Economic Co-operation and Development (OECD), and other organizations such as the European Chemicals Agency (ECHA) and Environmental Protection Agency (EPA), have set guidelines for acute toxicity testing in daphnids that are severely lacking in terms of information on the characteristics of the exposure vessel when studying the adverse effects of nanoparticles (NPs). Understanding the toxicity mechanisms of nanomaterials is imperative given the scarcity of information on their adverse effects. Furthermore, miniaturization of nanotoxicity assays can reduce the number of daphnids used, as well as the cost and nanomaterial waste, and provide results even at the individual animal level with enhanced reproducibility of testing. In this study, the impact of the exposure vessel on the observed physiological changes of daphnids was investigated for a silver nano ink. Exposures in eleven commercially available vessels; nine made of plastic and two made of glass were compared for 24 h. The effect of surface to volume ratio of the exposure vessel and the animal number or "crowding" during exposure was investigated in the context of miniaturizing biomarker assays as alternatives to traditional experimental setups in Daphnid magna. Toxicity curves showed differences depending on the vessel used, while a novel feeding rate assay and the activity of key enzymes were assessed as physiology endpoints. [ABSTRACT FROM AUTHOR]

The biodegradable biopolymer polylactic acid (PLA) has been used in the recent past in single-use packaging as a suitable replacement for non-biodegradable fossil fuel-based plastics, such as polyethylene terephthalate (PET). Under FDA and EU regulations, lactic acid (LA), the building block of PLA, is considered safe to use as a food contact material. The mechanical, thermal, and barrier properties of PLA are, however, major challenges for this material. PLA is a brittle material with a Young's modulus of 2996–3750 MPa and an elongation at break of 1.3–7%. PLA has a glass transition temperature (Tg) of 60 °C, exhibiting structural distortion at this temperature. The water permeability of PLA can lead to hydrolytic degradation of the material. These properties can be improved with biopolymer blending and composites. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), for instance, increases the thermal stability of PLA while decreasing the water permeability by up to 59%. Polypropylene (PP) is one of the most common plastics in reusable food containers. This study will compare PLA-based blends and composites to the currently used PP as a sustainable alternative to fossil fuel-based plastics. The end-of-life options for PLA-based food containers are considered, as is the commercial cost of replacing PP with PLA. [ABSTRACT FROM AUTHOR]

Sport-related concussion (SRC) management may be poor in community sports such as Ladies Gaelic Football (LGF). This study examined factors associated with SRC management behavior in adult LGF players. Participants (n = 657) answered an online survey on demographic factors, concussion knowledge, attitudes, and education, and SRC management behavior. Data from participants who reported sustaining an LGF-related SRC during the previous year (n = 115) were further analyzed. Being diagnosed with SRC was the main factor influencing subacute management behavior. Players with diagnosed SRCs had increased odds of following a graded return-to-play (RTP) programme (OR = 4.89), following a medically supervised graded RTP programme (OR = 10.16), and being medically cleared before full RTP (OR = 13.45) compared with those with suspected SRCs. Concussion history was associated with increased odds of informing a coach of a possible SRC (OR = 2.86). Demographic factors, previous use of Ladies Gaelic Football Association concussion education resources, and concussion knowledge and attitudes had minimal or no influence on management behaviors. Greater access to medical personnel at LGF training and matches is recommended. Due to limited medical resources in community sport, a clear referral pathway for players with SRC and comprehensive SRC education should be introduced to ensure players receive adequate medical care. [ABSTRACT FROM AUTHOR]

The Organization for Economic Co-operation and Development (OECD) has set widely used guidelines that are used as a standardized approach for assessing toxicity in a number of species. Given that various studies use different experimental setups, it is difficult to compare findings across them as a result of the lack of a universally used setup in nano-ecotoxicology. For freshwater species, Daphnia magna, a commonly used filter feeding crustacean, can generate significant molecular information in response to pollutant exposure. One factor that has an effect in toxicity induced from nanomaterials in daphnids is the surface-to-volume ratio of the exposure vessels; however, there is limited information available about its impact on the observed effect of exposure. In this study, daphnids were exposed to silver nanoparticle ink in falcon tubes and Petri dishes for 24 h. Toxicity curves revealed differences in the observed mortality of daphnids, with animals exposed in Petri dishes displaying significantly higher mortality. Differences in the activities of a number of key enzymes involved in the catabolism of macromolecules and phosphate were also observed across the exposure setups, indicating possible differences in the toxicity mechanism of silver nano-ink. Understanding the impact of factors relevant to experimental setups in ecotoxicology can increase the reproducibility of testing, and also reduce experimental costs, time, generated waste, and daphnids used in research. [ABSTRACT FROM AUTHOR]

The great increase in nanotechnology in the last 20 years has led to the alarming presence of nanomaterials in the environment as a new category of pollutants. Given the fact that legislation on nanomaterials is not concrete, the monitoring of their toxicity responses remains central. Focusing on tests in aquatic environments, daphnids are commonly employed as a bioindicator species for experiments with nanomaterials. However, until now, there has not been a unified and agreed approach to nanotoxicity testing, while research among different laboratories has been performed with significantly different setups, which may affect the reproducibility of the results. In this study, daphnids were exposed to silver nanoinks and the impact of surface to volume was assessed by comparing shallow vessels such as Petri dishes with deeper exposure vessels. Furthermore, in an attempt to assess whether the tests can be performed in smaller volumes, and thus in miniaturized versions, experiments compared larger and smaller volume setups. Finally, another parameter explored was the crowding of animals in exposure, and therefore their absolute number. Mortality was affected by both surface to volume and miniaturization, and significantly with crowding, supporting the implication of the number of animals in the tests. Further investigation with molecular and phenotypic endpoints confirmed these changes. [ABSTRACT FROM AUTHOR]