Ecotoxicity effect factors for plastic additives on the aquatic environment: a new approach for life cycle impact assessment.

All plastic contains additives. Once in the environment, these will start to leach out and will expose and harm aquatic biota, causing potentially lethal and sub-lethal toxic effects. Even though life cycle assessment covers the toxic impacts of several thousands of chemicals, models to assess the toxic impacts of plastic additives are only emerging. We gathered 461 data points from the literature (266 for freshwater and 195 for marine ecosystems) for 75 species belonging to 9 different phyla. The endpoints effective concentration and lethal concentration, no observed effects concentrations and lowest observed effect concentration tested in acute and chronic exposure, were harmonized into chronic values by applying extrapolation factors. The collected data points covered 75 main plastic additives. This allowed us to calculate 25 Effect factors, 19 for single chemicals and four for overarching categories (alkylphenols, benzophenones, brominated flame retardants and phosphates. In addition, we calculated an aggregated effect factor for chemicals that did not fit in any of the previous groups, as well as a Generic effect factor including 404 gathered data points. The estimated potentially affected fraction (PAF) for the single additives varied between 20.69 PAF·m3·kg-1 for diethyl phthalate and 11081.85 PAF·m3·kg-1 for 4-Nonylphenol. The factors can in future be combined with fate and exposure factors to derive a characterization factor for toxicity caused by additives in aquatic species. This is an important advancement for the assessment of the impacts of plastic debris on aquatic species, thus providing information for decision-makers, as well as guiding policies for the use of additives, ultimately aiming to make the plastic value chain more sustainable.

Asparagopsis armata Exudate Cocktail: The Quest for the Mechanisms of Toxic Action of an Invasive Seaweed on Marine Invertebrates.

The seaweed Asparagopsis armata exhibits a strong invasive behavior, producing halogenated compounds with effective biological effects. This study addresses the biochemical responses to sublethal concentrations of A. armata exudate on the marine snail Gibbula umbilicalis whole body and the shrimp Palaemon elegans eyes and hepatopancreas. Antioxidant defenses superoxide dismutase (SOD) and glutathione-S-transferase (GST), oxidative damage endpoints lipid peroxidation (LPO) and DNA damage, the neuronal parameter acetylcholinesterase (AChE), and the fatty acid profile were evaluated. Results revealed different metabolic responses in both species. Despite previous studies indicating that the exudate affected G. umbilicalis' survival and behavior, this does not seem to result from oxidative stress or neurotoxicity. For P. elegans, the inhibition of AChE and the decrease of antioxidant capacity is concomitant with the increase of LPO, suggesting neurotoxicity and oxidative stress as contributor mechanisms of toxicity for this species. Fatty acid profile changes were more pronounced for P. elegans with a general increase in polyunsaturated fatty acids (PUFAs) with the exudate exposure, which commonly means a defense mechanism protecting from membrane disruption. Nonetheless, the omega-3 PUFAs arachidonic acid (ARA) and docosapentaenoic acid (DPA) increased in both invertebrates, indicating a common regulation mechanism of inflammation and immunity responses.

Impacts of the Invasive Seaweed Asparagopsis armata Exudate on Energetic Metabolism of Rock Pool Invertebrates.

The marine red algae Asparagopsis armata is an invasive species gaining competitive advantage by releasing large amounts of toxic compounds to the surrounding invaded area. The main objective of this study was to evaluate the effects of this invasive seaweed on marine invertebrates by exposing the common prawn Palaemon elegans and the marine snail Gibbula umbilicalis to the exudate of this seaweed. The seaweed was collected and placed in a tank for 12 h in the dark in a 1:10 ratio. Afterwards the seawater medium containing the released secondary metabolites was collected for further testing. Lethal and sublethal effects of A. armata were investigated. Biochemical biomarker responses associated with energy metabolism (lactate dehydrogenase, LDH; electron transport system activity, ETS; lipid, protein and carbohydrate content) were analysed. The biomarker responses showed physiological status impairment of invertebrates after exposure to low concentrations of this algal exudate. The highest concentrations of exudate significantly increased lipid content in both organisms. In the shrimp, protein content, ETS, and LDH were also significantly increased. By contrast, these parameters were significantly decreased in G. umbilicalis. A behavioural impairment was also observed in G. umbilicalis exposed to A. armata exudate, reducing feeding consumption. These results represent an important step in the research of natural toxic exudates released to the environment and prospective effects of this seaweed in invaded communities under increasing global change scenarios.

Linking cholinesterase inhibition with behavioural changes in the sea snail Gibbula umbilicalis: Effects of the organophosphate pesticide chlorpyrifos.

Inhibition of acetylcholinesterase (AChE) activity has been widely used to assess the exposure and effects of anticholinergic environmental contaminants in several species. The aim of this study was to investigate if sublethal concentrations of the organophosphorous pesticide chlorpyrifos (CPF), a well-known AChE inhibitor, would also affect cholinesterases (ChE) in Gibbula umbilicalis and if this inhibition would result in an alteration of its behaviour, in an attempt to link the effects observed at the cellular level with effects at higher levels of ecological relevance. The biochemical properties of ChEs in this species were first characterized through the assessment of different enzymatic forms present in the sea snail, using different substrates and selective inhibitors. The results suggest that G. umbilicalis possess ChEs with characteristics of typical AChE, which should be the main form present. Additionally, in vitro and in vivo effects of CPF on AChE activity were investigated, along with effects on snails' behaviour: the ability of the snails to move/turn after exposure to the contaminant (flipping test). As expected, CPF inhibited AChE activity both in vitro and in vivo conditions. Moreover, the link between AChE activity inhibition and adverse effects on behavioural changes was established: AChE inhibition was positively correlated with the flipping test, indicating a mechanistic relationship between the two endpoints determined in in vivo exposures. This study highlights the importance of linking biochemical endpoints such as AChE activity with higher level endpoints like behavioural alterations, increasing the ecological relevance of the effects observed.

Fatty acid profile of the sea snail Gibbula umbilicalis as a biomarker for coastal metal pollution.

Metals are among the most common environmental pollutants with natural or anthropogenic origin that can be easily transferred through the food chain. Marine gastropods are known to accumulate high concentrations of these metals in their tissues. Gibbula umbilicalis ecological importance and abundant soft tissues, which enables extent biochemical assessments, makes this particular organism a potentially suitable species for marine ecotoxicological studies. Fatty acids are carbon-rich compounds that are ubiquitous in all organisms and easy to metabolize. Their biological specificity, relatively well-studied functions and importance, and the fact that they may alter when stress is induced, make fatty acids prospect biomarkers. This work aimed to assess fatty acid profile changes in the gastropod G. umbilicalis exposed to three metal contaminants. After a 168h exposure to cadmium, mercury, and nickel, the following lipid related endpoints were measured: total lipid content; lipid peroxidation; and fatty acid profile (FAP). The analysis of the FAP suggested an alteration in the fatty acid metabolism and indicated a link between metals exposure and homeoviscous adaptation and immune response. In particular, five fatty acids (palmitic, eicosatrienoic, arachidonic, eicosapentaenoic, and docosahexaenoic acids), demonstrated to be especially good indicators of G. umbilicalis responses to the array of metals used, having thus the potential to be used as biomarkers for metal contamination in this species. This work represents a first approach for the use of FAP signature as a sensitive and informative parameter and novel tool in environmental risk assessment (ERA) of coastal environments, using G. umbilicalis as model species.

Enzymatic biomarkers can portray nanoCuO-induced oxidative and neuronal stress in freshwater shredders.

Commercial applications of nanometal oxides have increased concern about their release into natural waters and consequent risks to aquatic biota and the processes they drive. In forest streams, the invertebrate shredder Allogamus ligonifer plays a key role in detritus food webs by transferring carbon and energy from plant litter to higher trophic levels. We assessed the response profiles of oxidative and neuronal stress enzymatic biomarkers in A. ligonifer after 96h exposure to nanoCuO at concentration ranges