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Mollusc rearing is a relevant global socioeconomic activity. However, this activity has faced severe problems in the last years in southeast Brazil. The mariculture scallop production dropped from 51,2 tons in 2016 to 10,2 tons in 2022 in the Baia da Ilha Grande (BIG; Rio de Janeiro). However, the possible causes of this collapse are unknown. This study aimed to analyze decadal trends of water quality in Nodipecten nodosus spat and adult production in BIG. We also performed physical-chemical and biological water quality analyses of three scallop farms and two nearby locations at BIG in 2022 to evaluate possible environmental stressors and risks. Scallop spat production dropped drastically in the last five years (2018-2022: mean ± stdev: 0.47 ± 0.45 million). Spat production was higher in colder waters and during peaks of Chlorophyll a in the last 13 years. Reduction of Chlorophyll a coincided with decreasing spat production in the last five years. Warmer periods (>27 °C) of the year may hamper scallop development. Counts of potentially pathogenic bacteria (Vibrios) and Escherichia coli were significantly higher in warmer periods which may further reduce scallop productivity. Shotgun metagenomics of seawater samples from the five studied corroborated these culture-based counts. Vibrios and fecal indicator bacteria metagenomic sequences were abundant across the entire study area throughout 2022. The results of this study suggest the collapse of scallop mariculture is the result of a synergistic negative effect of global warming and poor seawater quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

At present, the European Union legislation facilitates the use of similar pesticides among European Member States, thereby assuming that biodiversity and ecosystems have equal sensitivities to contaminants throughout the whole of Europe. However, with this assumption, fundamental environmental and biological differences between climatic zones are being ignored in Environmental Risk Assessment. Such differences may strongly influence the behaviour of contaminants, their effects on biodiversity and on the natural functioning of ecosystems. Furthermore, toxicity testing in European ecoregions other than cold-temperate has largely depended on standardized tests using cold-temperate species and conditions, which may lead to a false estimation of risks to organisms from other ecoregions. The present study aim was to determine the response of freshwater macroinvertebrate communities to the fungicide pyrimethanil by conducting aquatic mesocosm experiments in two different ecoregions with different climates: cold-temperate (Frankfurt, Germany) and warm-temperate (Coimbra, Portugal). The results indicate that the community in the cold-temperate climate was more sensitive to the fungicide in comparison to the warm-temperate community. This difference was most likely related to a different rate of fungicide disappearance, which was slower in the colder climate. Based upon our results we discuss important implications for improving Environmental Risk Assessment across climate zones and under present-day global climate change scenarios., (Copyright © 2019. Published by Elsevier B.V.)

Recently, a bioremediation tool consisting of freshly grown cells of the Arthrobacter aurescens strain TC1 proved successful in the cleanup of terbuthylazine (TBA) contaminated soil, with potential to prevent TBA dispersal via the soil-water pathway. The present work aimed at examining the feasibility of preparing and formulating bioaugmentation bacterial cells in advance which retain adequate viability and herbicide-degrading activity during storage and transport to contaminated sites. Three different types of formulation of A. aurescens TC1 cells were performed, namely cell paste, lyophilized, and adsorbed onto the mineral carrier vermiculite. Vermiculite-based cell material and cell paste offered survival rates significantly higher (≥78% of cells recovered viable, when compared to the initial numbers) than lyophilized cells (≥65%) after storage at 4 °C for up to a maximum period of 30 days. Inocula prepared from the three types of formulated and stored cells supported adequate levels of herbicide-biodegradation activity, ultimately allowing an almost complete removal of TBA from either liquid buffer or soil. In soil microcosms, the efficacy of bioremediation of TBA-contaminated soil in terms of decontamination (%) based on the ecotoxicity assessment of soil eluates towards a freshwater microalga was found to differ within formulations in the order: lyophilized cells (~100% efficacy at the end of one or two weeks of bioremediation treatment with an initial inoculum of ~2.5 × 10 7  viable cells/g of soil; similar to fresh cells) > vermiculite-adsorbed cells (81% with ~2.4 × 10 8  cells/g) > cell paste (68% with ~2.4 × 10 8  cells/g). The limitations and advantages of each type of bacterial formulation, together with the prediction of their applicability in the field are discussed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Even though empirical data supporting sound ecoregion-specific ecotoxicological evaluations are still scarce, the differences of environmental (including climatic) conditions in specific ecoregions are already currently being regulated for environmental risk assessment of pesticides in Europe. To shed new light on the ecotoxicological effects of pesticides on aquatic communities across ecoregions, the model pollutant pyrimethanil (fungicide) was tested in an outdoor mesocosm study with macrophyte-dominated communities in the European "South" (Portugal) and "Centre" (Germany) regulatory zones. Phytoplankton indicators monitored over 12 months indicated a low risk of the fungicide (0.73 or 0.77 mg pyrimethanil L -1 , single application) to phytoplankton functioning; as expected since exposure simulated worst-case scenarios. However, the growth of key structural macroalgae and macrophytes was affected by the fungicide and negative effects occurred, especially in the Central zone experiment. Such effects were not detected earlier than approximately nine months post single pyrimethanil application. The presence or absence of such extremely long-lasting/delayed pyrimethanil effects depended on species, competitive situation, and ecoregion-specific physico-chemical environment. The present findings suggest that a better understanding of both direct and indirect effects of fungicide pollution on aquatic flora in two European ecoregions helps to consolidate the environmental risk assessment of pesticides in specific regulatory zones., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Lines of evidence used in ecological risk assessment (ERA) are essentially three: chemistry, biology and ecotoxicology. Until now, the fundamental assumption made when measuring ecological risks is that organisms are forcedly exposed to stressors. However, when organisms can avoid disturbed habitats by escaping to less stressful areas, the assumption that exposure is mandatory to pose risk may not match field disturbance scenarios. A non-forced exposure approach using a linear free-choice multi-compartmented system has been proposed previously as a complementary tool to assess the effects on organisms' spatial avoidance/preference responses. Yet, the linearity of the latter system limits avoidance measurements to one spatial dimension. A novel, heterogeneous multi-habitat assay system (HeMHAS) consisting of 18 connected circular compartments (3 compartments on a vertical axis in each one of 6 zones on a longitudinal axis; a 2D system) is put forward here to be used in heterogeneous-habitat selection studies, as it makes it possible to assess the ability of organisms to detect contamination and other stressors and select more favorable habitats. In the present study, the avoidance to copper by zebrafish (Danio rerio) was tested after exposing organisms to a copper gradient in the HeMHAS and compared with that in the linear system. Avoidance occurred for all copper concentrations: 43% in the lowest (21 μg·L -1 ) to 72% in the highest (221 μg·L -1 ). Results obtained within the HeMHAS (AC 50 : 60 μg·L -1 ) were statistically (p = 0.72) similar to avoidance of copper by D. rerio in the linear non-forced system (AC 50 : 89 μg·L -1 ). In summary, the simulation of a copper gradient in the HeMHAS (2D system) allowed to assess the potential repellency of copper to zebrafish and to corroborate the ability of organisms to detect and avoid potentially toxic concentrations., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Although essential to conservation, little is known about how stress intensity can provoke emigration from disturbed habitats and allow recolonisation of those same environments. To demonstrate the applicability of laboratory experiments, we tested two hypotheses empirically using zebrafish response to artificially polluted environments that exhibited a linear gradient of stressor (acid mine drainage) levels. We hypothesized that emigration is distance-independent but time-correlated (spacelessness hypothesis). Additionally, we hypothesized that stressor-driven emigration could predict the extent of population growth in recovering habitats (avoidance-recolonisation hypothesis). For example, if half the organisms emigrate at a given stressor level, then the remainder should be able to recolonise a habitat experiencing the same stressor intensity. Comparisons of the small-scale experiment with a larger-scale simulation suggested that controlled laboratory results can be extrapolated to field populations (although time to perceive the contamination gradient may pose differential individual effects) because AC 50 (median avoidance concentration) values of an acid mine drainage sample (AMD) were not statistically different when fish were exposed to the same gradient in 3-m long [0.50% (0.43-0.57)] or 30-m long [0.73% (0.30-2.2)] systems. Regarding the avoidance-recolonisation hypothesis, the number of recolonisers was inversely proportional to the number of avoiders (AC x  = RC 100-x ). In particular, the similar distribution of fish along the 0-3% AMD gradient in both avoidance and recolonisation experiments resulted in identical AC 50 and RC 50 values: 0.55% (0.34-0.87) and 0.55% (0.45-0.67) AMD, respectively. The inclusion of avoidance and recolonisation responses in the environmental risk assessments provides a novel perspective of risk based on the emigration of organisms and contributes to the understanding and prediction of biological invasions and ecosystem recovery after restoration., (Copyright © 2018 Elsevier B.V. All rights reserved.)

An increasing number of studies have shown the ability of organisms to escape from toxic effects due to contamination, by moving spatially towards less contaminated habitats. However, this issue has been investigated in monospecific scenarios, without considering possible interactions between species during the contamination avoidance process. It is widely known that the spatial distribution of one species can be affected by another one, in different ways. Therefore, the main question addressed in the present study was as follows: Might interspecific interaction between the freshwater fish Danio rerio (zebrafish) and Poecilia reticulata (guppy) change their behavior patterns in terms of avoidance in the presence of a copper gradient? Zebrafish and guppies exposed to a copper gradient were tested for avoidance responses in a free-choice, non-forced, static, multi-compartmented exposure system, using two distinct approaches: (1) monospecific tests, in which only one species was exposed to the copper gradient, at two different population densities; and (2) multispecific tests, in which both species were tested simultaneously. In the control (with no copper) monospecific tests, both species were randomly distributed; however, in the control multispecific test, P. reticulata tended to aggregate. In the monospecific tests with a copper gradient, both species avoided copper in a similar way, with AC 50 (concentration triggering avoidance in 50% of the exposed population) values between 15 and 18 μg·L -1 , irrespective of the population density. However, in the multispecific tests, P. reticulata displaced D. rerio to previously avoided copper levels, consequently increasing the AC 50 of D. rerio to 75 μg·L -1 . This study shows the importance of understanding the interactions among species in contaminated areas, and the way that one species can prevent the avoidance behavior of another., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aquatic ecotoxicity assays used to assess ecological risk assume that organisms living in a contaminated habitat are forcedly exposed to the contamination. This assumption neglects the ability of organisms to detect and avoid contamination by moving towards less disturbed habitats, as long as connectivity exists. In fluvial systems, many environmental parameters vary spatially and thus condition organisms' habitat selection. We assessed the preference of zebra fish (Danio rerio) when exposed to water samples from two western Ecuadorian rivers with apparently distinct disturbance levels: Pescadillo River (highly disturbed) and Oro River (moderately disturbed). Using a non-forced exposure system in which water samples from each river were arranged according to their spatial sequence in the field and connected to allow individuals to move freely among samples, we assayed habitat selection by D. rerio to assess environmental disturbance in the two rivers. Fish exposed to Pescadillo River samples preferred downstream samples near the confluence zone with the Oro River. Fish exposed to Oro River samples preferred upstream waters. When exposed to samples from both rivers simultaneously, fish exhibited the same pattern of habitat selection by preferring the Oro River samples. Given that the rivers are connected, preference for the Oro River enabled us to predict a depression in fish populations in the Pescadillo River. Although these findings indicate higher disturbance levels in the Pescadillo River, none of the physical-chemical variables measured was significantly correlated with the preference pattern towards the Oro River. Non-linear spatial patterns of habitat preference suggest that other environmental parameters like urban or agricultural contaminants play an important role in the model organism's habitat selection in these rivers. The non-forced exposure system represents a habitat selection-based approach that can serve as a valuable tool to unravel the factors that dictate organisms' spatial distribution in connected ecosystems., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Sea level rise, as a consequence of climate changes, is already causing seawater intrusion in some freshwater coastal ecosystems worldwide. The increase in salinity at these freshwater coastal ecosystems may occur gradually (through groundwater) or abruptly (through extreme weather events). Moreover, many of them are also being altered and threatened by anthropogenic activities. Accordingly, the present study aimed at assessing the multigenerational lethal and sublethal effects caused by increased salinity in six clonal lineages of the freshwater cladoceran Daphnia longispina differing in their sensitivity to lethal levels of copper. Three specific objectives were delineated: i) to compare the lethal and sublethal toxicity of sodium chloride (NaCl) and natural seawater (SW); ii) to evaluate possible multigenerational effects after exposure to low levels of salinity, and iii) to evaluate if an association exists between tolerance to lethal and sublethal levels of salinity and tolerance to metals. Overall, NaCl was found to elicit sublethal effects at lower or similar concentrations than SW, suggesting its use as a protective surrogate of SW in early phases of ecological risk assessment schemes. Multigenerational exposure to conductivities of 0.73±0.015mScm -1 led to dissimilar responses by the six clonal lineages. Significant associations were found neither between lethal and sublethal endpoints nor between salinity and metals, possibly indicating the absence of common mechanisms responsible to confer metal tolerance and salt stress. However, some clonal lineages presented an inverse sensitivity to lethal levels of NaCl and of copper. These results suggest that natural populations of D. longispina, by exhibiting clonal lineages with differential tolerance to increased salinity, may cope with long-term exposure to small increases of this stressor. However, over time those populations may face the occurrence of genetic erosion due to the loss of the most sensitive genotypes before or after a multigenerational exposure., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Potential synergetic interaction between chemicals, climate change and the emergence of opportunistic diseases is of utmost concern within the amphibian decline scenario. Understand the structure and dynamic of this microbiome and how environmental stressors act on this community is a priority. The present study aimed to: i) characterize the skin microbiome of Pelophylax perezi frog by looking for variations between populations in reference and under stress conditions (one metal contaminated and another with salinity fluctuations) and ii) evaluate the tolerance of skin-isolated bacteria to chemical contamination. Skin swabs were collected from frog populations inhabiting three reference sites (LB, VA and AM), one metal-rich contaminated (TP) and one brackish lentic aquatic system (SL). The frogs' skin microbiome was characterized by culture independent method (DGGE) and by cultivation methods. DGGE showed a characteristic profile in frogs from TP population. Results of recovered communities revealed low morphotype diversity and density (Colony Forming Units per frog) on individuals from TP population, comparatively to the other sampled populations. Isolated bacteria identified based on 16S rRNA gene sequence belong mainly to the classes Actinobacteria and Alphaproteobacteria. Ecotoxicological assays with acid-metal contaminated effluent (ETP) showed that the percentage of tolerant strains was higher in frogs from TP population than in SL and LB populations. In conclusion, results suggest that: a) environmental specific characteristics, as the presence of chemical contaminants, influence the composition of amphibian microbiome, comparing with sites without such contaminants; b) there are differences in microbiome composition between populations; and c) bacteria historically exposed to effluent may evolve tolerance to this kind of contamination., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The present study is aimed at evaluating whether a gene expression assay with the microbial eukaryotic model Saccharomyces cerevisiae could be used as a suitable warning tool for the rapid preliminary screening of potential toxic effects on organisms due to scenarios of soil and water contamination with pyrimethanil. The assay consisted of measuring changes in the expression of the selected pyrimethanil-responsive genes ARG3 and ARG5,6 in a standardized yeast population. Evaluation was held by assessing the toxicity of surface runoff, a major route of pesticide exposure in aquatic systems due to non-point-source pollution, which was simulated with a pyrimethanil formulation at a semifield scale mimicking worst-case scenarios of soil contamination (e.g. accident or improper disposal). Yeast cells 2-h exposure to the runoff samples led to a significant 2-fold increase in the expression of both indicator genes. These results were compared with those from assays with organisms relevant for the aquatic and soil compartments, namely the nematode Caenorhabditis elegans (reproduction), the freshwater cladoceran Daphnia magna (survival and reproduction), the benthic midge Chironomus riparius (growth), and the soil invertebrates Folsomia candida and Enchytraeus crypticus (survival and reproduction). Under the experimental conditions used to simulate accidental discharges into soil, runoff waters were highly toxic to the standard test organisms, except for C. elegans. Overall, results point out the usefulness of the yeast assay to provide a rapid preview of the toxicity level in preliminary screenings of environmental samples in situations of inadvertent high pesticide contamination. Advantages and limitations of this novel method are discussed., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This work presents the results of an interlaboratory proficiency exercise for whole-sediment toxicity assays with the benthic marine diatom Cylindrotheca closterium. An assay protocol was established and followed by all participating laboratories. Cell growth after 72 h exposure was the endpoint used. Four sediment samples of unknown toxicity were assayed. The main problem encountered during this exercise was the differences in the cell growth of algae exposed to reference sediment. Those differences may be associated with changes in the physiological status of the initial culture due to temperature changes during transport to the other laboratories. In general, the method proposed presented good replicability (precision between replicates) and reproducibility (interlaboratory precision). Around 80% (17 out of 21) of results obtained were classified as satisfactory (Z-scores <2). The whole-sediment assay with C. closterium presented here can be considered sufficiently successful for possible use as a standard toxicity test. The assay is simple to perform, the proposed species is ecologically relevant as an integral component of microphytobenthos, and is widely distributed around the world. These positive factors suggest that the whole-sediment assay with the benthic marine diatom C. closterium can be used as a reliable tool in marine sediment quality assessment., (Copyright 2009 Elsevier B.V. All rights reserved.)

Hair samples from the scalp were used in a preliminary assessment of heavy metals exposure (As, Cd, Cr, Cu, Mn and Zn) of the human population living near an abandoned cupric pyrite mine (Mina de S. Domingos, Southeast Alentejo, Portugal). In parallel with the collection of hair samples, individuals from two different communities at the South and North of the mine area answered a questionnaire designed to obtain information about potential exposure pathways to these elements. The questionnaire allowed data collection about the most frequently consumed foodstuffs, drinking water sources, smoking habits, alcohol consumption and health condition. Higher concentrations, and subsequently higher ranges, of Cd, Cu and As were recorded in individuals living near the mine (MSD group), in opposition to individuals living several kilometers apart. Additionally, the concentrations recorded in the hair of some individuals from the MSD group were above the reference values for non-exposed individuals, suggesting their enhanced exposure. However, no significant differences were found for the average concentration of these elements between villages. Individuals from the CP and SC groups presented significantly higher concentrations of Zn and Mn in scalp hair. These results were in agreement with the concentrations of these elements recorded in soil samples. The water supplies of the area do not seem to be potential sources of trace elements for human beings. In opposition, individuals that frequently consume milk and cheese obtained from cattle that usually breeds in the area presented significantly higher concentrations of As and Mn in their scalp hair. Our results suggest that the population of S. Domingos mine area and neighbour localities may be exposed to some of the elements analysed namely Mn and Zn. The most likely exposure pathways seemed to be animal foodstuffs, however, a more detailed analysis of these products, as well as garden vegetables and fruits, should be performed.