Environmental Pollution, in press | International audience | Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental complexity. We provide new insights into the understanding of the impact of molecular and cellular responses on individual and population dynamics and assess the potential related effects on communities and ecosystem functioning.

Global warming is drastically altering the climate conditions of our planet. Soils will be among the most affected components of terrestrial ecosystems, especially in contaminated areas. In this study we investigated if changes in climate conditions (air temperature and soil moisture) affect the toxicity of historically metal(loid)-contaminated soils to the invertebrate Folsomia candida, followed by an assessment of its recovery capacity. Ecotoxicity tests (assessing survival, reproduction) were performed in field soils affected by metal(loid)s under different climate scenarios, simulated by individually changing air temperature or soil moisture conditions. The scenarios tested were: standard conditions (20°C + 50% soil water holding capacity-WHC); increased air temperature (daily fluctuation of 20–30°C + 50% WHC); soil drought (20°C + 25% WHC); soil flood (20°C + 75% WHC). Recovery potential was assessed under standard conditions in clean soil. Increased temperature was the major climate condition negatively affecting collembolans performance (decreased survival and reproduction), regardless of metal(loid) contamination. Drought and flood conditions presented less pronounced effects. When it was possible to move to the recovery phase (enough juveniles in exposure phase), F. candida was apparently able to recover from the exposure to metal(loid) contamination and/or climate alterations. The present study showed that forecasted climate alterations in areas already affected by contamination should be considered to improve environmental risk assessment.

To determine whether natural recovery was occurring in a depositional area of the St. Marys River (Ontario, Canada) known as East Bellevue Marine Park (EBMP), sediment was collected from two depth ranges, 0–5 cm and 0–10 cm, and subjected to a series of laboratory toxicity tests and chemical analysis. Toxicological responses (survival, growth, reproduction, development) of four benthic invertebrates and the fathead minnow were compared at test vs. reference sites using univariate and multivariate (ordination) techniques. Temporal trends in sediment chemistry and invertebrate toxicity were examined with time series data from 2008 through to 2018. Polycyclic aromatic hydrocarbons (PAHs; ≤ 37 mg/kg) and petroleum hydrocarbons (PHCs; ≤ 6266 mg/kg) were elevated in EBMP compared to reference sites (PAHs, ≤ 1.6 mg/kg; PHCs ≤ 180 mg/kg). Comparatively, the 0–5 cm sediment layer had lower concentrations of all contaminants than the 0–10 cm layer at three of four test sites. Over time, contaminant concentrations have mostly remained stable or have decreased. There were no significant differences in survival, growth, or development of the larval fish in EBMP compared to the upstream reference sites, and no differences between sampling depths. However, most EBMP sediments were toxic to invertebrates, driven by reduced reproduction by the worm Tubifex and reduced survival by the amphipod Hyalella. Among habitat variables, a combination of different classes of compounds based on ordination scores (PHCs, oil and grease, metals) was most strongly correlated to toxicological response. There was little to no difference in toxicity between sampling depths based on integrated endpoint response; however, individual endpoints showed mostly greater toxicity from exposure to the 0–10 cm layer. Over time, toxicity has mostly remained stable or showed improvement. These results provided some positive indications that gradual natural recovery is occurring in EBMP.

Despite the importance of bioavailability for organic chemical bioaccumulation by terrestrial and benthic invertebrates, the principles of bioavailability for organic chemical bioaccumulation remain poorly understood. Here we use large-scale databases with contrasting geographic, compound and organism coverage (from 925 sites, 446 compounds and 184 invertebrate species), and report that bioavailability for organic chemical bioaccumulation follows the power law. It represents that the internal concentration of organic chemicals is the composite power function of the lipid fraction of invertebrates, bulk site concentration of compounds, and organic carbon content of soils/sediments. This law directly links environmental exposures and body burdens of organic chemicals in contaminated sites, and provides a method for enabling case-specific risk assessments of a vast number of organic chemicals and contaminated sites. Our findings may pave the way for translating bioavailability knowledge into risk-oriented regulation of organic chemicals and contaminated sites.

Evidence about the adverse effects of methamphetamine (METH) on invertebrates is scarce. Hence, C. elegans, a representative invertebrate model, was exposed to METH at environmental levels to estimate chronic and transgenerational toxicity. The results of chronic exposure were integrated into an underlying toxicity framework of METH in invertebrates (e.g., benthos) at environmentally relevant concentrations. The induction of cellular oxidative damage-induced apoptosis and fluctuation of ecologically important traits (i.e., feeding and locomotion) might be attributed by the activation of the longevity regulating pathway regulated by DAF-16/FOXO, and detoxification by CYP family enzymes. The adverse effects to the organism level included impaired viability and decreased fecundity. The results from transgenerational exposure elucidated the cumulative METH-induced damage in invertebrates. Finally, a new risk assessment method named toxicity indicator sensitivity distribution (TISD) analysis was proposed by combining multiple toxicity indicator test data (ECₓ) to derive the hazardous concentration for 10% indicators (C₁₀) of one species. The risk quotient (RQ) values calculated by measured environmental concentrations and C₁₀ in southern China, southeastern Australia, and the western US crossed the alarm line (RQ = 5), suggesting a need for long-term monitoring.

Thiacloprid is a neonicotinoid insecticide widely exploited in agriculture and easily mobilized towards aquatic environments by atmospheric agents. However, little information about its toxicological effects on aquatic invertebrate bioindicators is available. In this study, specimens of the mussel Mytilus galloprovincialis were exposed to thiacloprid at environmental (4.5 μg L⁻¹) and 100 times higher than environmental (450 μg L⁻¹) concentrations for 20 days. Thiacloprid affected haemolymph biochemical parameters, cell viability in the digestive gland, antioxidant biomarkers and lipid peroxidation in the digestive gland and gills at environmentally relevant concentrations (4.5 μg L⁻¹). In addition, thiacloprid exposure caused histological damage to the digestive gland and gills. Interestingly, the pesticide was detected at levels equal to 0.14 ng g⁻¹ in the soft tissues of sentinels exposed for 20 days to 450 μg L⁻¹ thiacloprid in seawaterμ. Due to its harmful potential and cumulative effects after long-term exposure of M. galloprovincialis, thiacloprid may pose a potential risk to nontarget aquatic organisms, as well as to human health. This aspect requires further in-depth investigation.

Knowledge about how the COVID-19 pandemic can affect aquatic wildlife is still extremely limited, and no effect of SARS-CoV-2 or its structural constituents on invertebrate models has been reported so far. Thus, we investigated the presence of the 2019-new coronavirus in different urban wastewater samples and, later, evaluated the behavioral and biochemical effects of the exposure of Culex quinquefasciatus larvae to two SARS-CoV-2 spike protein peptides (PSPD-2002 and PSPD-2003) synthesized in our laboratory. Initially, our results show the contamination of wastewater by the new coronavirus, via RT-qPCR on the viral N1 gene. On the other hand, our study shows that short-term exposure (48 h) to a low concentration (40 μg/L) of the synthesized peptides induced changes in the locomotor and the olfactory-driven behavior of the C. quinquefascitus larvae, which were associated with increased production of ROS and AChE activity (cholinesterase effect). To our knowledge, this is the first study that reports the indirect effects of the COVID-19 pandemic on the larval phase of a freshwater invertebrate species. The results raise concerns at the ecological level where the observed biological effects may lead to drastic consequences.

Environmental emissions of perfluoroalkyl acids (PFAAs) often contaminate aquatic ecosystems and accumulate in the species therein. This can represent an exposure pathway for human populations where seafood is consumed. Concentrations of PFAAs in water breathing animals may be a function of many different factors, however, little is known about how these different factors impact contaminant accumulation in estuarine and marine species. This study explores the relationships between PFAA accumulation and two key variables, animal size and sediment concentrations, for a number of important seafood species. Sixty Dusky Flathead (Platycephalus fuscus), 58 Mulloway (Argyrosomus japonicus) and 53 Giant Mud Crab (Scylla serrata) were tested for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) in edible tissues, and the concentrations compared with animal size and sediment concentrations at the location of capture. PFAAs showed a high degree of variation among species, and PFOA and PFHxS were only common in Giant Mud Crab. Log-transformed PFOS concentrations in all three species showed negative correlations with animal size (weight). There was limited evidence for relationships between PFOS muscle tissue concentration and sediment PFOS concentration. The patterns observed are potentially explained by changes in trophic position, relative growth rate, consumption rate and metabolic rate, throughout the species life history. The results contrast with observations for other persistent organic pollutants, whereby larger individuals tend to carry greater contaminant loads. Future work is required to establish whether these patterns are evident for PFAAs in other species and contaminant sources.