MicroRNAs (miRNAs) are a class of small non-coding RNA that control multiple biological processes through negative post-transcriptional regulation of gene expression. Recently a role of miRNAs in the response of aquatic organisms to environmental toxicants emerged. Toxicant-induced changes in miRNA expression might then represent novel biomarkers to evaluate the health status of these organisms. In this study, we aimed to identify the miRNA repertoire in the liver of the European eel Anguilla anguilla and to compare their differential expression between a polluted site located in the Gironde Estuary and a pristine site in Arcachon Bay (France).A total of 299 mature miRNAs were identified. In polluted water, 19 miRNAs were up-regulated and 22 were down-regulated. We predicted that these differentially expressed miRNAs could target 490 genes that were involved in ribosome biogenesis, response to hormones, response to chemical and chromatin modification. Moreover, we observed only few examples (29) of negative correlation between the expression levels of miRNAs and their targets suggesting that, in the system studied, miRNAs might not only regulate gene expression directly by degrading mRNA but also by inhibiting protein translation or by regulating other epigenetic processes.This study is the first example of in situ investigation of the role of miRNAs in the response of a fish species to water quality. Our findings provide new insights into the involvement of epigenetic mechanisms in the response of animals chronically exposed to pollution and pave the way for the utilization of miRNAs in aquatic ecotoxicology.

MicroRNAs (miRNAs) are a class of small non-coding RNA that control multiple biological processes through negative post-transcriptional regulation of gene expression. Recently a role of miRNAs in the response of aquatic organisms to environmental toxicants emerged. Toxicant-induced changes in miRNA expression might then represent novel biomarkers to evaluate the health status of these organisms. In this study, we aimed to identify the miRNA repertoire in the liver of the European eel Anguilla anguilla and to compare their differential expression between a polluted site located in the Gironde Estuary and a pristine site in Arcachon Bay (France). A total of 299 mature miRNAs were identified. In polluted water, 19 miRNAs were up-regulated and 22 were down-regulated. We predicted that these differentially expressed miRNAs could target 490 genes that were involved in ribosome biogenesis, response to hormones, response to chemical and chromatin modification. Moreover, we observed only few examples (29) of negative correlation between the expression levels of miRNAs and their targets suggesting that, in the system studied, miRNAs might not only regulate gene expression directly by degrading mRNA but also by inhibiting protein translation or by regulating other epigenetic processes. This study is the first example of in situ investigation of the role of miRNAs in the response of a fish species to water quality. Our findings provide new insights into the involvement of epigenetic mechanisms in the response of animals chronically exposed to pollution and pave the way for the utilization of miRNAs in aquatic ecotoxicology.

While humans are exposed to mixtures of persistent organic pollutants (POPs), their risk assessment is usually based on a chemical-by-chemical approach. To assess the health effects associated with mixed exposures, knowledge on mixture toxicity is required. Several POPs are potential ligands of the Aryl hydrocarbon receptor (AhR), which involves in xenobiotic metabolism and controls many biological pathways. This study assesses AhR agonistic and antagonistic activities of 29 POPs individually and in mixtures by using Chemical-Activated LUciferase gene eXpression bioassays with 3 transgenic cell lines (rat hepatoma DR-H4IIE, human hepatoma DR-Hep G2 and human mammary gland carcinoma DR-T47-D). Among the 29 POPs, which were selected based on their abundance in Scandinavian human blood, only 4 exerted AhR agonistic activities, while 16 were AhR antagonists in DR-H4IIE, 5 in DR-Hep G2 and 7 in DR-T47-D when tested individually. The total POP mixture revealed to be AhR antagonistic. It antagonized EC₅₀ TCDD inducing AhR transactivation at a concentration of 125 and 250 and 500 fold blood levels in DR-H4IIE, DR-T47-D and DR-Hep G2, respectively, although each compound was present at these concentrations lower than their LOEC values. Such values could occur in real-life in food contamination incidents or in exposed populations. In DR-H4IIE, the antagonism of the total POP mixture was due to chlorinated compounds and, in particular, to PCB-118 and PCB-138 which caused 90% of the antagonistic activity in the POP mixture. The 16 active AhR antagonists acted additively. Their mixed effect was predicted successfully by concentration addition or generalized concentration addition models, rather than independent action, with only two-fold IC₅₀ underestimation. We also attained good predictions for the full dose-response curve of the antagonistic activity of the total POP mixture.

peer reviewed

The spatial and temporal distribution of selected endocrine disrupting compounds (4-tert-octylphenol, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol, and bisphenol A) in two coastal areas of the Iberian Peninsula (Ria de Vigo and Mar Menor lagoon) were evaluated for the first time. Seawater and sediment samples collected during spring and autumn of 2015 were analysed using greener extraction techniques and liquid chromatography-tandem mass spectrometry. The presence of branched isomers (4-tert-octylphenol and nonylphenol) and bisphenol A in almost all seawater and sediment samples demonstrated their importance as pollutants in the frame of water policy, while no concentrations of linear isomers (4-n-octylphenol and 4-n-nonylphenol) were found. Higher seawater levels were observed in Mar Menor lagoon, especially in spring, associated with wastewater treatment plant effluents and nautical, agricultural and industrial activities. Similar sediment concentrations were measured in both studied areas, being nonylphenol levels five times higher than those measured for the other EDCs. Experimental sediment–water partition coefficients showed a moderate sorption of target compounds to sediments. Risk quotients for water compartment evidenced a moderate risk posed by nonylphenol, considering the worst-case scenario. For sediments, moderate risk related to 4-tert-octylphenol and high risk to nonylphenol were estimated.

The spatial and temporal distribution of selected endocrine disrupting compounds (4-tert-octylphenol, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol, and bisphenol A) in two coastal areas of the Iberian Peninsula (Ria de Vigo and Mar Menor lagoon) were evaluated for the first time. Seawater and sediment samples collected during spring and autumn of 2015 were analysed using greener extraction techniques and liquid chromatography-tandem mass spectrometry. The presence of branched isomers (4-tert-octylphenol and nonylphenol) and bisphenol A in almost all seawater and sediment samples demonstrated their importance as pollutants in the frame of water policy, while no concentrations of linear isomers (4-n-octylphenol and 4-n-nonylphenol) were found. Higher seawater levels were observed in Mar Menor lagoon, especially in spring, associated with wastewater treatment plant effluents and nautical, agricultural and industrial activities. Similar sediment concentrations were measured in both studied areas, being nonylphenol levels five times higher than those measured for the other EDCs. Experimental sediment–water partition coefficients showed a moderate sorption of target compounds to sediments. Risk quotients for water compartment evidenced a moderate risk posed by nonylphenol, considering the worst-case scenario. For sediments, moderate risk related to 4-tert-octylphenol and high risk to nonylphenol were estimated. | Sí

The contamination of marine ecosystems by contaminants of emerging concern such as personal care products or per- and polyfluoroalkyl substances is of increasing concern. This work assessed the concentrations of selected contaminants of emerging concern in water and sediment of European aquaculture areas, to evaluate their co-variation with legacy contaminants (polycyclic aromatic hydrocarbons) and faecal biomarkers, and estimate the risks associated with their occurrence. The 9 study sites were selected in 7 European countries to be representative of the aquaculture activities of their region: 4 sites in the Atlantic Ocean and 5 in the Mediterranean Sea. Musks, UV filters, preservatives, per- and polyfluoroalkyl substances and polycyclic aromatic hydrocarbons were detected in at least one of the sites with regional differences. While personal care products appear to be the main component of the water contamination, polycyclic aromatic hydrocarbons were mostly found in sediments. As expected, generally higher levels of personal care products were found in sewage impacted sites, urbanised coasts and estuaries. The risk assessment for water and sediment revealed a potential risk for the local aquatic environment from contaminants of both legacy and emerging concern, with a significant contribution of the UV filter octocrylene. Despite marginal contributions of per- and polyfluoroalkyl substances to the total concentrations, PFOS (perfluorooctane sulfonate) aqueous concentrations combined to its low ecotoxicity thresholds produced significant hazard quotients indicating a potential risk to the ecosystems.

The contamination of marine ecosystems by contaminants of emerging concern such as personal care products or per- and polyfluoroalkyl substances is of increasing concern. This work assessed the concentrations of selected contaminants of emerging concern in water and sediment of European aquaculture areas, to evaluate their co-variation with legacy contaminants (polycyclic aromatic hydrocarbons) and faecal biomarkers, and estimate the risks associated with their occurrence. The 9 study sites were selected in 7 European countries to be representative of the aquaculture activities of their region: 4 sites in the Atlantic Ocean and 5 in the Mediterranean Sea. Musks, UV filters, preservatives, per- and polyfluoroalkyl substances and polycyclic aromatic hydrocarbons were detected in at least one of the sites with regional differences. While personal care products appear to be the main component of the water contamination, polycyclic aromatic hydrocarbons were mostly found in sediments. As expected, generally higher levels of personal care products were found in sewage impacted sites, urbanised coasts and estuaries. The risk assessment for water and sediment revealed a potential risk for the local aquatic environment from contaminants of both legacy and emerging concern, with a significant contribution of the UV filter octocrylene. Despite marginal contributions of per- and polyfluoroalkyl substances to the total concentrations, PFOS (perfluorooctane sulfonate) aqueous concentrations combined to its low ecotoxicity thresholds produced significant hazard quotients indicating a potential risk to the ecosystems.

The contamination of marine ecosystems by contaminants of emerging concern such as personal care products or per- and polyfluoroalkyl substances is of increasing concern. This work assessed the concentrations of selected contaminants of emerging concern in water and sediment of European aquaculture areas, to evaluate their co-variation with legacy contaminants (polycyclic aromatic hydrocarbons) and faecal biomarkers, and estimate the risks associated with their occurrence. The 9 study sites were selected in 7 European countries to be representative of the aquaculture activities of their region: 4 sites in the Atlantic Ocean and 5 in the Mediterranean Sea. Musks, UV filters, preservatives, per- and polyfluoroalkyl substances and polycyclic aromatic hydrocarbons were detected in at least one of the sites with regional differences. While personal care products appear to be the main component of the water contamination, polycyclic aromatic hydrocarbons were mostly found in sediments. As expected, generally higher levels of personal care products were found in sewage impacted sites, urbanised coasts and estuaries. The risk assessment for water and sediment revealed a potential risk for the local aquatic environment from contaminants of both legacy and emerging concern, with a significant contribution of the UV filter octocrylene. Despite marginal contributions of per- and polyfluoroalkyl substances to the total concentrations, PFOS (perfluorooctane sulfonate) aqueous concentrations combined to its low ecotoxicity thresholds produced significant hazard quotients indicating a potential risk to the ecosystems. | This study was financially supported by the SEA-on-a-CHIP project, funded from European Union Seventh Framework Programme (FP7-OCEAN-2013) under grant agreement No. 614168. Antonio Marques is supported through the FCT Investigator program (IF). | Peer reviewed

The interpretation of biomarkers in natura should be based on a referential of expected values in uncontaminated conditions. Nevertheless, to build a reference data set of biomarker responses in estuarine areas, which receive chronic pollution loads due to their transition position between continent and sea, is impossible. In this context, the aim of the present work was to propose the use of laboratory recovery period to define a baseline for the measurement of sperm DNA damage by Comet assay in the estuarine prawn Palaemon longirostris. For that, sperm DNA integrity was observed after both a passive (i.e. 20 days in a clean environment) and an active (i.e. forced renewal of spermatophores) recovery of wild P. longirostris specimens from the Seine estuary, in laboratory conditions. Then, the levels of sperm DNA damage recorded within the P. longirostris population of the Seine estuary, during six campaigns of sampling from April 2015 to October 2017, have been interpreted according to the defined threshold values. The results showed a persistence in the level of DNA damage after 20-day in clean environment with the passive recovery. This strategy was inconclusive to reach a baseline level but it revealed the lack of DNA repair mechanisms. For the active recovery, a decrease of 54% of the level of DNA damage has been observed after the first renewal of spermatophores and this level stabilized after the second renewal. On the basis of this second strategy, we defined a mean basal value of sperm DNA damage of 54.9 A.U. and a maximum threshold of 69.7 A.U. (i.e. 95 %CI). The analysis of the results using the reference value highlighted significant abnormal sperm DNA damage within the native population of P. longirostris from the Seine estuary on all stations during the six-sampling campaigns.

[Departement_IRSTEA]Eaux [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiples | International audience | The interpretation of biomarkers in natura should be based on a referential of expected values in uncontaminated conditions. Nevertheless, to build a reference data set of biomarker responses in estuarine areas, which receive chronic pollution loads due to their transition position between continent and sea, is impossible. In this context, the aim of the present work was to propose the use of laboratory recovery period to define a baseline for the measurement of sperm DNA damage by Comet assay in the estuarine prawn Palaemon longirostris. For that, sperm DNA integrity was observed after both a passive (i.e. 20 days in a clean environment) and an active (i.e. forced renewal of spermatophores) recovery of wild P. longirostris specimens from the Seine estuary, in laboratory conditions. Then, the levels of sperm DNA damage recorded within the P. longirostris population of the Seine estuary, during six campaigns of sampling from April 2015 to October 2017, have been interpreted according to the defined threshold values. The results showed a persistence in the level of DNA damage after 20-day in clean environment with the passive recovery. This strategy was inconclusive to reach a baseline level but it revealed the lack of DNA repair mechanisms. For the active recovery, a decrease of 54% of the level of DNA damage has been observed after the first renewal of spermatophores and this level stabilized after the second renewal. On the basis of this second strategy, we defined a mean basal value of sperm DNA damage of 54.9 A.U. and a maximum threshold of 69.7 A.U. (i.e. 95 %CI). The analysis of the results using the reference value highlighted significant abnormal sperm DNA damage within the native population of P. longirostris from the Seine estuary on all stations during the six-sampling campaigns.

The accumulation of 17 human pharmaceuticals (HPs) was investigated in the muscle of three fish species characteristic of the “Rio de la Plata Basin” with different feeding habits and of relevance for human consumption: Megaleporinus obtusidens, Salminus brasiliensis, and Prochilodus lineatus. Fish were sampled in fall and spring from 8 localities distributed along 500 Km of the Uruguay River. Atenolol and carbamazepine were the most frequently detected HPs (>50%), but at concentrations always below 1 μg/kg wet weight (w/w). Hydrochlorothiazide, metoprolol, venlafaxine, propranolol, codeine, and the carbamazepine metabolite, 2-hydroxycarbamazepine, were accumulated at higher levels showing maximum concentrations between 1 and 10 μg/kg (w/w), but infrequently (<50%). The other HPs were always below 1 μg/kg (w/w) and at frequencies lower than 50%. Distinctive accumulation patterns were observed among species at different trophic levels. However, biomagnification trends were not identified for any compound. The highest number and concentration of HPs were found in M. obtusidens (omnivorous), followed by P. lineatus (detritivorous), and lastly S. brasiliensis (piscivorous). The most recurrent HPs (i.e. carbamazepine and atenolol) were present in all species, but others exclusively in one. Geographical variations were only found for carbamazepine and atenolol in M. obtusidens and P. lineatus, showing higher concentrations in localities closer to the Rio de la Plata estuary. Differences in the HPs concentrations among seasons were not identified. Acceptable daily intake and predicted no effect concentrations would indicate that measured muscle concentrations in fish from the Uruguay River do not pose a serious risk for human consumption nowadays. Further studies will be necessary for assessing the potential adverse effects on studied fish species.

The accumulation of 17 human pharmaceuticals (HPs) was investigated in the muscle of three fish species characteristic of the “Rio de la Plata Basin” with different feeding habits and of relevance for human consumption: Megaleporinus obtusidens, Salminus brasiliensis, and Prochilodus lineatus. Fish were sampled in fall and spring from 8 localities distributed along 500 Km of the Uruguay River. Atenolol and carbamazepine were the most frequently detected HPs (>50%), but at concentrations always below 1 μg/kg wet weight (w/w). Hydrochlorothiazide, metoprolol, venlafaxine, propranolol, codeine, and the carbamazepine metabolite, 2-hydroxycarbamazepine, were accumulated at higher levels showing maximum concentrations between 1 and 10 μg/kg (w/w), but infrequently (<50%). The other HPs were always below 1 μg/kg (w/w) and at frequencies lower than 50%. Distinctive accumulation patterns were observed among species at different trophic levels. However, biomagnification trends were not identified for any compound. The highest number and concentration of HPs were found in M. obtusidens (omnivorous), followed by P. lineatus (detritivorous), and lastly S. brasiliensis (piscivorous). The most recurrent HPs (i.e. carbamazepine and atenolol) were present in all species, but others exclusively in one. Geographical variations were only found for carbamazepine and atenolol in M. obtusidens and P. lineatus, showing higher concentrations in localities closer to the Rio de la Plata estuary. Differences in the HPs concentrations among seasons were not identified. Acceptable daily intake and predicted no effect concentrations would indicate that measured muscle concentrations in fish from the Uruguay River do not pose a serious risk for human consumption nowadays. Further studies will be necessary for assessing the potential adverse effects on studied fish species. Human pharmaceuticals in native fish from the Uruguay River, Rio de la Plata Basin, South America. © 2019 Elsevier Ltd | Macarena Rojo, the sampling and partially the sample analysis were granted by the Fish and Fisheries Program of the Administrative Commission of the Uruguay River (CARU). The study was also granted by CONICET (PIP2012-2014-0090) and ANPCyT (PICT2014-1690). The scientific facilities of ICRA have been co-financed by the Spanish Ministry of Economy and Competitiveness (MINECO) and by the European Regional Development Fund (ERDF) in the frame of the Catalonia ERDF Operative programme 2007–2013. This work was partly supported by the Generalitat de Catalunya (Consolidated Research Group: Catalan Institute for Water Research 2014 SGR 291). S. Rodriguez-Mozaz also acknowledges the Ramon y Cajal program (RYC-2014-16707) and. Diana Álvarez-Muñoz the support of the project XENOMETABOLOMIC (CTM2015-73179-JIN) (AEI/FEDER/UE). | Peer reviewed

The accumulation of 17 human pharmaceuticals (HPs) was investigated in the muscle of three fish species characteristic of the “Rio de la Plata Basin” with different feeding habits and of relevance for human consumption: Megaleporinus obtusidens, Salminus brasiliensis, and Prochilodus lineatus. Fish were sampled in fall and spring from 8 localities distributed along 500 Km of the Uruguay River. Atenolol and carbamazepine were the most frequently detected HPs (>50%), but at concentrations always below 1 μg/kg wet weight (w/w). Hydrochlorothiazide, metoprolol, venlafaxine, propranolol, codeine, and the carbamazepine metabolite, 2-hydroxycarbamazepine, were accumulated at higher levels showing maximum concentrations between 1 and 10 μg/kg (w/w), but infrequently (<50%). The other HPs were always below 1 μg/kg (w/w) and at frequencies lower than 50%. Distinctive accumulation patterns were observed among species at different trophic levels. However, biomagnification trends were not identified for any compound. The highest number and concentration of HPs were found in M. obtusidens (omnivorous), followed by P. lineatus (detritivorous), and lastly S. brasiliensis (piscivorous). The most recurrent HPs (i.e. carbamazepine and atenolol) were present in all species, but others exclusively in one. Geographical variations were only found for carbamazepine and atenolol in M. obtusidens and P. lineatus, showing higher concentrations in localities closer to the Rio de la Plata estuary. Differences in the HPs concentrations among seasons were not identified. Acceptable daily intake and predicted no effect concentrations would indicate that measured muscle concentrations in fish from the Uruguay River do not pose a serious risk for human consumption nowadays. Further studies will be necessary for assessing the potential adverse effects on studied fish species. Human pharmaceuticals in native fish from the Uruguay River, Rio de la Plata Basin, South America. | Fil: Rojo, Macarena Gisele. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina | Fil: Álvarez Muñoz, Diana. Instituto Catalán de Investigaciones en Agua; España. Comision Administradora del Rio Uruguay; Argentina | Fil: Domanico, Alejandro. Comision Administradora del Rio Uruguay; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires; Argentina | Fil: Foti, Antonio Roberto. Comision Administradora del Rio Uruguay; Argentina. Ministerio de Agricultura, Ganadería y Pesca del Uruguay; Uruguay | Fil: Rodríguez Mozaz, Sara. Instituto Catalán de Investigaciones en Agua; España. Consejo Superior de Investigaciones Científicas; España | Fil: Barceló, Damián. Instituto Catalán de Investigaciones en Agua; España. Consejo Superior de Investigaciones Científicas; España | Fil: Carriquiriborde, Pedro. Comision Administradora del Rio Uruguay; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

We monitor pollutant accumulation and investigate associated changes at the physiological level within the population of an obligate avian scavenger, the Egyptian Vulture (Neophron percnopterus), from Catalonia (NE Spain). This population is expanding its range, presumably because of the use of human waste disposal sites as food resource. We hypothesized that habitat urbanization, presumably associated with feeding from human wastes, could influence the accumulation of persistent organic pollutants and metals. The aim of this study was to explore the relationship between accumulated pollutants and biochemical parameters in nestling blood. We used the proportion of urban surface within an 8 km radius of each nest as a proxy to study the relationship between anthropic influence and pollutant accumulation. Observed blood levels of metals, organochlorine pesticides, polychlorinated biphenyls (PCBs), per- and polyfluoroalkylated substances (PFAS) and polybrominated diphenyl ethers (PBDEs) were relatively low, as expected for nestling individuals due to short-term exposures. CB-180 and PBDEs were associated with variations in blood biochemistry parameters; hexa-BDEs appeared positively associated with activities of the enzymes aspartate aminotransferase and lactate dehydrogenase, whereas CB-180 accumulation was associated with an increased activity of creatine phosphokinase and elevated glutathione levels. Increased CB-180 levels were also related to decreased blood concentrations of calcium, cholesterol, α-tocopherol and lutein. A proportion of urban surfaces as low as 6.56% within a radius of 8 km around the nest appears related to the accumulation of CB-180, the majority of analysed PFAS and of PBDE congeners 99 and 209, and increased urbanization was also associated with decreased plasma levels of α-tocopherol and carotenoids. These associations suggest that changes in blood profiles of vitamins, carotenoids or other analytes, despite related to increased plasma levels of CB-180, would be consequence of exploitation of artificial food sources rather than of a direct effect of the pollutants.

We monitor pollutant accumulation and investigate associated changes at the physiological level within the population of an obligate avian scavenger, the Egyptian Vulture (Neophron percnopterus), from Catalonia (NE Spain). This population is expanding its range, presumably because of the use of human waste disposal sites as food resource. We hypothesized that habitat urbanization, presumably associated with feeding from human wastes, could influence the accumulation of persistent organic pollutants and metals. The aim of this study was to explore the relationship between accumulated pollutants and biochemical parameters in nestling blood. We used the proportion of urban surface within an 8 km radius of each nest as a proxy to study the relationship between anthropic influence and pollutant accumulation. Observed blood levels of metals, organochlorine pesticides, polychlorinated biphenyls (PCBs), per- and polyfluoroalkylated substances (PFAS) and polybrominated diphenyl ethers (PBDEs) were relatively low, as expected for nestling individuals due to short-term exposures. CB-180 and PBDEs were associated with variations in blood biochemistry parameters; hexa-BDEs appeared positively associated with activities of the enzymes aspartate aminotransferase and lactate dehydrogenase, whereas CB-180 accumulation was associated with an increased activity of creatine phosphokinase and elevated glutathione levels. Increased CB-180 levels were also related to decreased blood concentrations of calcium, cholesterol, α-tocopherol and lutein. A proportion of urban surfaces as low as 6.56% within a radius of 8 km around the nest appears related to the accumulation of CB-180, the majority of analysed PFAS and of PBDE congeners 99 and 209, and increased urbanization was also associated with decreased plasma levels of α-tocopherol and carotenoids. These associations suggest that changes in blood profiles of vitamins, carotenoids or other analytes, despite related to increased plasma levels of CB-180, would be consequence of exploitation of artificial food sources rather than of a direct effect of the pollutants. | All experimental procedures described in the present study were authorized by the Service of Biodiversity and Animal Protection, Department of Territory and Sustainability, Generalitat de Catalunya (permit references SF/419-426, SF/492-500, SF/492-497, SF/174-181 and SF/091-098 for years 2012, 2013, 2014, 2015 and 2016, respectively). This study was financed by the Spanish Ministry of Science and Innovation through the research supporting funds from the Ramón y Cajal Program (ref. RYC-2015-17504 to MEOS), the University of Barcelona (JR, AHM and HTA), and Red Electrica de España-SA. HTA was supported by a predoctoral grant from the IRBIO-University of Barcelona (APIF 2014). | Peer reviewed

While numerous studies have examined the effect of N deposition on ecosystem N retention, few have analyzed the involvement of plant species and climate warming in this process. We experimentally investigated the effects of increasing N deposition (Nexo) and climate warming on the fate of Nexo in a subalpine meadow and established the involvement of plant species. Using 15N tracer, we tracked Nexo sprayed on the vegetation in belowground and aboveground plant biomasses (AGB) and in bulk soil over three growing seasons. We assessed the Nexo absorption capacity of plant species and the contribution of Nexo to their AGB N pool. The meadow retained a large proportion of Nexo (≈65%, mostly in AGB) for depositions up to four times the background N rate. Nexo present in the meadow compartments in year 2 was still present in year 3, suggesting that the ecosystem was unsaturated after three years of high N input. Nexo retention resulted more from an increase in N concentration in plant tissues than from the increase in AGB. The species-specific Nexo absorption capacity was inversely related to their AGB N concentration. Nexo accounted for up to 40% of total AGB N depending on the species and the N treatments. The contribution of species to ecosystem Nexo retention more contingent on their AGB than on their relative cover in the community, ranked as follows: C. vulgaris (14.0%) > N. stricta (7.0%) > other Poaceae = C. caryophyllea (2.5%) > other Eudicotyledons (1.5%) > non-vascular species = P. erecta > Fabaceae (0.8–0.2%). Climate warming increased AGB and decreased tissue N concentration. No warming-Nexo interaction was observed. Thus, Pyrenean subalpine meadows that have not undergone a decline in plant species richness in recent decades paradoxically display a high potential to sequester atmospheric N deposition.

International audience | While numerous studies have examined the effect of N deposition on ecosystem N retention, few have analyzed the involvement of plant species and climate warming in this process. We experimentally investigated the effects of increasing N deposition (Nexo) and climate warming on the fate of Nexo in a subalpine meadow and established the involvement of plant species. Using 15N tracer, we tracked Nexo sprayed on the vegetation in belowground and aboveground plant biomasses (AGB) and in bulk soil over three growing seasons. We assessed the Nexo absorption capacity of plant species and the contribution of Nexo to their AGB N pool. The meadow retained a large proportion of Nexo (≈65%, mostly in AGB) for depositions up to four times the background N rate. Nexo present in the meadow compartments in year 2 was still present in year 3, suggesting that the ecosystem was unsaturated after three years of high N input. Nexo retention resulted more from an increase in N concentration in plant tissues than from the increase in AGB. The species-specific Nexo absorption capacity was inversely related to their AGB N concentration. Nexo accounted for up to 40% of total AGB N depending on the species and the N treatments. The contribution of species to ecosystem Nexo retention more contingent on their AGB than on their relative cover in the community, ranked as follows: C. vulgaris (14.0%) &gt; N. stricta (7.0%) &gt; other Poaceae = C. caryophyllea (2.5%) &gt; other Eudicotyledons (1.5%) &gt; non-vascular species = P. erecta &gt; Fabaceae (0.8–0.2%). Climate warming increased AGB and decreased tissue N concentration. No warming-Nexo interaction was observed. Thus, Pyrenean subalpine meadows that have not undergone a decline in plant species richness in recent decades paradoxically display a high potential to sequester atmospheric N deposition.

Average nitrogen (N) deposition across Europe has declined since the 1990s. This resulted in decreased N inputs to forest ecosystems especially in Central and Western Europe where deposition levels are highest. While the impact of atmospheric N deposition on forests has been receiving much attention for decades, ecosystem responses to the decline in N inputs received less attention. Here, we review observational studies reporting on trends in a number of indicators: soil acidification and eutrophication, understory vegetation, tree nutrition (foliar element concentrations) as well as tree vitality and growth in response to decreasing N deposition across Europe. Ecosystem responses varied with limited decrease in soil solution nitrate concentrations and potentially also foliar N concentrations. There was no large-scale response in understory vegetation, tree growth, or vitality. Experimental studies support the observation of a more distinct reaction of soil solution and foliar element concentrations to changes in N supply compared to the three other parameters. According to the most likely scenarios, further decrease of N deposition will be limited. We hypothesize that this expected decline will not cause major responses of the parameters analysed in this study. Instead, future changes might be more strongly controlled by the development of N pools accumulated within forest soils, affected by climate change and forest management.

Average nitrogen (N) deposition across Europe has declined since the 1990s. This resulted in decreased N inputs to forest ecosystems especially in Central and Western Europe where deposition levels are highest. While the impact of atmospheric N deposition on forests has been receiving much attention for decades, ecosystem responses to the decline in N inputs received less attention. Here, we review observational studies reporting on trends in a number of indicators: soil acidification and eutrophication, understory vegetation, tree nutrition (foliar element concentrations) as well as tree vitality and growth in response to decreasing N deposition across Europe. Ecosystem responses varied with limited decrease in soil solution nitrate concentrations and potentially also foliar N concentrations. There was no large-scale response in understory vegetation, tree growth, or vitality. Experimental studies support the observation of a more distinct reaction of soil solution and foliar element concentrations to changes in N supply compared to the three other parameters. According to the most likely scenarios, further decrease of N deposition will be limited. We hypothesize that this expected decline will not cause major responses of the parameters analysed in this study. Instead, future changes might be more strongly controlled by the development of N pools accumulated within forest soils, affected by climate change and forest management.

Antidepressant drugs such as Venlafaxine (VFX) and O-desmethylvenlafaxine (ODMVFX) are emerging contaminants that are commonly detected in aquatic environments, since conventional wastewater treatment plants are unable to completely remove them. They can be precursors of hazardous by-products, such as the carcinogenic N-nitrosodimethylamine (NDMA), generated upon water chlorination, as they contain the dimethylamino moiety, necessary for the formation of NDMA. In this study, the capability of three white rot fungi (Trametes versicolor, Ganoderma lucidum and Pleurotus ostreatus) to remove both antidepressants from water and to decrease NDMA formation potential was investigated. Furthermore, transformation by-products (TPs) generated along the treatment process were elucidated and also correlated with their NDMA formation potential.Very promising results were obtained for T. versicolor and G. lucidum, both being able to remove up to 100% of ODMVFX. In the case of VFX, which is very recalcitrant to conventional wastewater treatment, a 70% of removal was achieved by T. versicolor, along with a reduction in NDMA formation potential, thus decreasing the associated problems for human health and the environment. However, the NDMA formation potential remained practically constant during treatment with G. lucidum despite of the equally high VFX removal (70%). This difference was attributed to the generation of different TPs during both fungal treatments. For example, G. lucidum generated more ODMVFX, which actually has a higher NDMA formation potential than the parent compound itself.

Antidepressant drugs such as Venlafaxine (VFX) and O-desmethylvenlafaxine (ODMVFX) are emerging contaminants that are commonly detected in aquatic environments, since conventional wastewater treatment plants are unable to completely remove them. They can be precursors of hazardous by-products, such as the carcinogenic N-nitrosodimethylamine (NDMA), generated upon water chlorination, as they contain the dimethylamino moiety, necessary for the formation of NDMA. In this study, the capability of three white rot fungi (Trametes versicolor, Ganoderma lucidum and Pleurotus ostreatus) to remove both antidepressants from water and to decrease NDMA formation potential was investigated. Furthermore, transformation by-products (TPs) generated along the treatment process were elucidated and also correlated with their NDMA formation potential. Very promising results were obtained for T. versicolor and G. lucidum, both being able to remove up to 100% of ODMVFX. In the case of VFX, which is very recalcitrant to conventional wastewater treatment, a 70% of removal was achieved by T. versicolor, along with a reduction in NDMA formation potential, thus decreasing the associated problems for human health and the environment. However, the NDMA formation potential remained practically constant during treatment with G. lucidum despite of the equally high VFX removal (70%). This difference was attributed to the generation of different TPs during both fungal treatments. For example, G. lucidum generated more ODMVFX, which actually has a higher NDMA formation potential than the parent compound itself. © 2018 Elsevier Ltd | This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness (project CTQ2010-21776-C02 and CTM2013-48545-C2), co-financed by the European Union through the European Regional Development Fund (ERDF) and supported by the Generalitat de Catalunya (Consolidated Research Groups: Catalan Institute for water Research 2014 SGR 291 and 2014 SGR 476). The Department of Chemical, Biological and Environmental Engineering of the Autonomous University of Barcelona (UAB) is member of the Xarxa de Referència en Biotecnologia de la Generalitat de Catalunya. Castellet-Rovira, F. acknowledges a predoctoral grant from UAB. Dr. SRM acknowledges her Ramón y Cajal fellowship (RyC-2014-16707) and Dr. MJF acknowledges her Ramón y Cajal fellowship (RyC-2015-17108) from the Spanish Ministry of Economy, Industry and Competitiveness. Dr. MJF acknowledges the European Commission for funding project 623711 under the FP7-PEOPLE-2013-IIF - Marie Curie Action: “International Incoming Fellowships”. Adrián Jaén-Gil acknowledge their PhD scholarship from AGAUR (2017FI_B 00778). Pleurotus ostreatus (NCBI KJ020935) cultures were kindly provided by Laura Palli. | Peer reviewed