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Abstract This study provides a description of the water quality status in the tributaries of the upper Tagus River and a preliminary risk assessment for freshwater organisms. A wide range of physico-chemical parameters, nutrients, metals and organic contaminants (20 pesticides, and 32 point source chemicals, mainly pharmaceuticals) were monitored during spring, summer and autumn of 2016. Monitoring of organic contaminants was performed using conventional grab sampling and passive samples (POCIS). The variation of the different groups of parameters as regards to land use and sampling season was investigated. The prioritization of organic and inorganic contaminants was based on the toxic unit (TU) approach, using toxicity data for algae, invertebrates and fish. Finally, the compliance with the Environmental Quality Standards (EQS) set as part of the Water Framework Directive (WFD) was evaluated for the listed substances. This study shows that the land use characteristics had a large influence on the spatial distribution of the contaminants and other water quality parameters, while temporal trends were only significant for physico-chemical parameters, and marginally significant for insecticides. Acute toxicity is likely to occur for some metals (copper and zinc) in the most impacted sites (TU values close to or above 1). Low acute toxicity was determined for organic contaminants (individual compounds and mixtures) on the basis of grab samples. However, the assessment performed with POCIS samples identified diuron, chlorpyrifos and imidacloprid as potentially hazardous compounds. Several contaminant mixtures that may cause chronic toxicity and that should be considered in future regional chemical monitoring plans were identified. Our study also shows that some metals and pesticides exceeded the WFD regulatory thresholds and that only 30% of the sampled sites had a good chemical status. Further research is needed to identify chemical emission sources and to design proper abatement options in the Tagus river basin. Graphical abstract Unlabelled Image Highlights • Chemical status evaluated in 16 sites of the Tagus river basin over three seasons. • Land use had a stronger influence than season on contamination patterns. • Copper and zinc may exert acute toxicity to primary producers and invertebrates. • Diuron, chlorpyrifos and imidacloprid identified as priority hazardous compounds. • Only 30% of the sampled sites showed good chemical status as per the WFD. [ABSTRACT FROM AUTHOR]

Abstract Pesticides and point source contaminants (primarily pharmaceuticals) were monitored in 16 sampling sites of the upper Tagus river basin during spring, summer and autumn of 2016. A qualitative screening analysis was performed using a library of 430 compounds. Next, a novel method was implemented for the selection and quantification of contaminants with LC-MS/MS. The method is based on the frequency of detection in the screening, ecotoxicity data and the potential use in the watershed. Moreover, the efficacy of grab samples and passive samples (POCIS) in detecting compound-specific exposure patterns was compared during the summer sampling campaign. The screening method detected the presence of 268 compounds in the study area, out of which 52 were selected for the quantitative analysis (20 pesticides and 32 point source chemicals). Although very helpful in the prioritization exercise, the qualitative screening demonstrated some biases and the need for improvement by using more effective instruments for confirming positive results. Grab samples proved not to be fully suitable for contaminants with discontinuous exposure such as pesticides, which may be underestimated, but offer a sufficient basis for the characterization of contaminants coming from urban wastewaters. All selected chemicals showed a very high concentration variability due to differences among sampling sites, which are related to agricultural intensity and demographic pressure. Some insecticides (chlorpyrifos, dimethoate, imidacloprid), herbicides (diuron, metribuzine, simazine, terbuthylazine), and fungicides (carbendazim) were measured at concentrations exceeding 100 ng/L; while paracetamol, ibuprofen, some antibiotics (azithromycin, sulfamethoxazole, trimethoprim) and life-style compounds (caffeine, paraxanthine, nicotine) were found at very high concentrations (up to several μg/L). The results of this work represent the basis for the development of an ecological risk assessment for the aquatic ecosystem in the upper Tagus river basin and for the identification of basin-specific contaminant mixtures of environmental concern. Graphical abstract Unlabelled Image Highlights • Pesticides and point-source chemicals (PSCs) monitored in the Tagus river basin. • A method for improving the selection of basin-specific contaminants is proposed. • Matching between screening and quantitative analysis shows higher accuracy for PSCs. • POCIS is a superior sampling technique as compared to grab samples for pesticides. • Some pesticides measured above 0.1 μg/L, and some PSCs up to several μg/L. [ABSTRACT FROM AUTHOR]

Abstract Skeleton growth variables of hermatypic corals, such as extension rate, density and calcification rate, are widely used to study coral response to environmental stressors, establish chronological age models and reconstruct the evolution of key climate variables. In this work, we addressed methodological aspects of the measurement of coral growth variables and the implications of their variability. A core of Orbicella faveolata was collected from the Puerto Morelos coral reef, in the Mexican Caribbean, and we measured and analysed 10 parallel transects of a core slab, covering 30 years. Density calibration was performed by measuring a high-quality and well-characterised wedge of Tridacna maxima , and the interval of interest was adjusted to the measured coral optical densities. The measurement uncertainties of extension rate, density and calcification rate were 0.011%, 1.1% and 1.6%, respectively. However, for density and calcification rate, overall variability was 29% and 33%, respectively, of which about half was attributed to intra-band growth variability. The intra-band variability of extension rate was only 0.68%, indicating the suitability of extension rate as a precise environmental proxy. These results likely differ by coral species, environments and experimental conditions, such as the exact location of the core within the colony and the method used to determine density. Uncertainties of coral growth variables should be carefully considered when reconstructing past environmental conditions. Graphical abstract Unlabelled Image Highlights • Hermatypic corals are widely used to reconstruct past environmental conditions. • Uncertainties of all measurements were considered to calculate growth variables. • The measurement uncertainty was small (<2%). • Band variability was half of the overall variability (~30%). • Coral growth variability must be considered for environmental reconstructions. [ABSTRACT FROM AUTHOR]

Water scarcity is an expanding climate and human related condition, which drives and interacts with other stressors in freshwater ecosystems such as chemical pollution. In this study we provide an overview of the existing knowledge regarding the chemical fate, biological dynamics and the ecological risks of chemicals under water scarcity conditions. We evaluated a total of 15 studies dealing with the combined effects of chemicals and water scarcity under laboratory conditions and in the field. The results of these studies have been elaborated in order to evaluate additive, synergistic or antagonistic responses of the studied endpoints. As a general rule, it can be concluded that, in situations of water scarcity, the impacts of extreme water fluctuations are much more relevant than those of an additional chemical stressor. Nevertheless, the presence of chemical pollution may result in exacerbated ecological risks in some particular cases. We conclude that further investigations on this topic would take advantage on the focus on some specific issues. Experimental (laboratory and model ecosystem) studies should be performed on different biota groups and life stages (diapausing eggs, immature stages), with particular attention to those including traits relevant for the adaptation to water scarcity. More knowledge on species adaptations and recovery capacity is essential to predict community responses to multiple stressors and to assess the community vulnerability. Field studies should be performed at different scales, particularly in lotic systems, in order to integrate different functional dynamics of the river ecosystem. Combining field monitoring and experimental studies would be the best option to reach more conclusive, causal relationships on the effects of co-occurring stressors. Contribution of these studies to develop ecological models and scenarios is also suggested as an improvement for the prospective aquatic risk assessment of chemicals in (semi-)arid areas. [ABSTRACT FROM AUTHOR]

A key challenge for the ecological risk assessment of chemicals has been to evaluate the relative contribution of chemical pollution to the variability observed in biological communities, as well as to identify multiple stressor groups. In this study we evaluated the toxic pressure exerted by > 200 contaminants to benthic macroinvertebrates in the Danube River using the Toxic Unit approach. Furthermore, we evaluated correlations between several stressors (chemical and non-chemical) and biological indices commonly used for the ecological status assessment of aquatic ecosystems. We also performed several variation partitioning analyses to evaluate the relative contribution of contaminants and other abiotic parameters (i.e. habitat characteristics, hydromorphological alterations, water quality parameters) to the structural and biological trait variation of the invertebrate community. The results of this study show that most biological indices significantly correlate to parameters related to habitat and physico-chemical conditions, but showed limited correlation with the calculated toxic pressure. The calculated toxic pressure, however, showed little variation between sampling sites, which complicates the identification of pollution-induced effects. The results of this study show that the variation in the structure and trait composition of the invertebrate community are mainly explained by habitat and water quality parameters, whereas hydromorphological alterations play a less important role. Among the water quality parameters, physico-chemical parameters such as suspended solids, nutrients or dissolved oxygen explained a larger part of the variation in the invertebrate community as compared to metals or organic contaminants. Significant correlations exist between some physico-chemical measurements (e.g. nutrients) and some chemical classes (i.e. pharmaceuticals, chemicals related to human presence) which constitute important multiple stressor groups. This study demonstrates that, in large rivers like the Danube, the variation in the invertebrate community seems to be more related to varying habitat and physico-chemical conditions than to chemical pollution. [ABSTRACT FROM AUTHOR]

The objectives of the current study were to determine the occupational health hazards posed by the application of pesticides in rice-prawn concurrent systems of south-west Bangladesh and to assess their potential risks for the aquatic ecosystems that support the culture of freshwater prawns ( Macrobrachium rosenbergii ). Information on pesticide use in rice-prawn farming was collected through structured interviews with 38 farm owners held between January and May of 2012. The risks of the pesticide use to human health were assessed through structured interviews. The TOXSWA model was used to calculate pesticide exposure (peak and time-weighted average concentrations) in surface waters of rice-prawn systems for different spray drift scenarios and a simple first tier risk assessment based on threshold concentrations derived from single species toxicity tests were used to assess the ecological risk in the form of risk quotients. The PERPEST model was used to refine the ecological risks when the first tier assessment indicated a possible risk. Eleven synthetic insecticides and one fungicide (sulphur) were recorded as part of this investigation. The most commonly reported pesticide was sulphur (used by 29% of the interviewed farmers), followed by thiamethoxam, chlorantraniliprole, and phenthoate (21%). A large portion of the interviewed farmers described negative health symptoms after pesticide applications, including vomiting (51%), headache (18%) and eye irritation (12%). The results of the first tier risk assessment indicated that chlorpyrifos, cypermethrin, alpha-cypermethrin, and malathion may pose a high to moderate acute and chronic risks for invertebrates and fish in all evaluated spray drift scenarios. The higher tier assessment using the PERPEST model confirmed the high risk of cypermethrin, alpha-cypermethrin, and chlorpyrifos for insects and macro- and micro-crustaceans thus indicating that these pesticides may have severe adverse consequences for the prawn production yields. [ABSTRACT FROM AUTHOR]

Novel nanomaterials based on doped TiO 2 nanoparticles with different morphological, textural and band-gap properties have been synthesized using scalable methods. The influence of synthetic parameters such as titanium source (titanium(IV) isopropoxide and titanium(IV) butoxide), doping quantity (0%, 2% or 5% Zn), acidic solution for the hydrolysis reaction (ascorbic acid, nitric acid) and calcination temperatures (500 °C and 600 °C) was simultaneously investigated. The obtained nanomaterials were characterized by different methods and photocatalytic tests of methylene blue (MB) degradation under UV-light were conducted to determine their activity. The results revealed that the synthesized nanomaterials are porous aggregates with very high crystallinity and are mainly composed of the anatase phase; although their physical properties vary depending on the different synthetic parameters employed. These changes are able to modify the apparent rate constant of the degradation of MB up to one order of magnitude, indicating, substantial changes in their photoactivity. Hybrid materials TiO 2 –Pd nanoparticles have also been prepared, characterized and tested for hydrogen production using photocatalytic methanol reforming where supported palladium nanoparticles acted as co-catalyst. Furthermore, the hybrid materials TiO 2 –Pd nanoparticles were studied in photocatalytic tests of methylene blue degradation under visible LED-light. The results obtained in the production of hydrogen from the photocatalytic reforming of methanol by hybrid materials suggest that the reported hybrid systems could be suitable photocatalysts for future sustainable hydrogen production upon tuning of the morphological, textural and band gap energy properties to allow processes to be carried out under visible light. [ABSTRACT FROM AUTHOR]

Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato ( Solanum lycopersicum L.) plants were cultivated for 210 days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO 2 , CA + nCeO 2 ) bulk cerium oxide (bCeO 2 ), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500 mg/kg, both the uncoated and CA + nCeO 2 increased shoot length by ~ 9 and ~ 13%, respectively, while bCeO 2 and CeAc decreased shoot length by ~ 48 and ~ 26%, respectively, compared with MPW ( p ≤ 0.05). Total chlorophyll, chlo- a , and chlo- b were significantly increased by CA + nCeO 2 at 250 mg/kg, but reduced by bCeO 2 at 62.5 mg/kg, compared with MPW. At 250 and 500 mg/kg, nCeO 2 increased Ce in roots by 10 and 7 times, compared to CA + nCeO 2 , but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO 2 nor CA + nCeO 2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125 mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500 mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO 2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO 2 at 62.5 mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO 2 on tomato plants. [ABSTRACT FROM AUTHOR]

The carbon (C) balance of agricultural soils may be largely affected by climate change. Increasing temperatures are discussed to cause a loss of soil organic carbon (SOC) due to enhanced decomposition of soil organic matter, which has a high intrinsic temperature sensitivity. On the other hand, several modeling studies assumed that potential SOC losses would be compensated or even outperformed by an increased C input by crop residues into agricultural soils. This assumption was based on a predicted general increase of net primary productivity (NPP) as a result of the CO 2 fertilization effect and prolonged growing seasons. However, it is questionable if the crop C input into agricultural soils can be derived from NPP predictions of vegetation models. The C input in European croplands is largely controlled by the agricultural management and was strongly related to the development of crop yields in the last decades. Thus, a glance at past yield development will probably be more instructive for future estimations of the C input than previous modeling approaches based on NPP predictions. An analysis of European yield statistics indicated that yields of wheat, barley and maize are stagnating in Central and Northern Europe since the 1990s. The stagnation of crop yields can probably be related to a fundamental change of the agricultural management and to climate change effects. It is assumed that the soil C input is concurrently stagnating which would necessarily lead to a decrease of agricultural SOC stocks in the long-term given a constant temperature increase. Remarkably, for almost all European countries that are faced with yield stagnation indications for agricultural SOC decreases were already found. Potentially adverse effects of yield stagnation on the C balance of croplands call for an interdisciplinary investigation of its causes and a comprehensive monitoring of SOC stocks in agricultural soils of Europe. [ABSTRACT FROM AUTHOR]

Abstract: Aquaculture production constitutes one of the main sources of pollution with veterinary medicines into the environment. About 90% of the global aquaculture production is produced in Asia and the potential environmental risks associated with the use of veterinary medicines in Asian aquaculture have not yet been properly evaluated. In this study we performed a probabilistic risk assessment for eight different aquaculture production scenarios in Asia by combining up-to-date information on the use of veterinary medicines and aquaculture production characteristics. The ERA-AQUA model was used to perform mass balances of veterinary medicinal treatments applied to aquaculture ponds and to characterize risks for primary producers, invertebrates, and fish potentially exposed to chemical residues through aquaculture effluents. The mass balance calculations showed that, on average, about 25% of the applied drug mass to aquaculture ponds is released into the environment, although this percentage varies with the chemical's properties, the mode of application, the cultured species density, and the water exchange rates in the aquaculture pond scenario. In general, the highest potential environmental risks were calculated for parasitic treatments, followed by disinfection and antibiotic treatments. Pangasius catfish production in Vietnam, followed by shrimp production in China, constitute possible hot-spots for environmental pollution due to the intensity of the aquaculture production and considerable discharge of toxic chemical residues into surrounding aquatic ecosystems. A risk-based ranking of compounds is provided for each of the evaluated scenarios, which offers crucial information for conducting further chemical and biological field and laboratory monitoring research. In addition, we discuss general knowledge gaps and research priorities for performing refined risk assessments of aquaculture medicines in the near future. [Copyright &y& Elsevier]

Chemical residues released from aquaculture farms may persist in the environment and may pose adverse ecological effects. The aim of this study was to assess the pollution status of marine sediments underneath or close to aquaculture farms in the Eastern Mediterranean Sea, the factors that affect the elemental distribution, and the exceedance of environmental quality standards and factors. To this end, surface sediment samples were collected (underneath fish cages, at 25 m distance and from a reference station) from 48 fish farms in Greece with variable environmental and geochemical characteristics. The content of 29 metals and major and trace elements, and three antibiotics (oxytetracycline, florfenicol, and flumequine), was determined in the sediment samples. Most of the elements found in the sediments originated from geological sources and their concentrations were close to Earth's Crust content. Below and close to fish farm cages, the sediment was enriched with P, Cu, Zn, Mo, and Cd mainly due to the aquaculture biosolid deposition, and changes in environmental conditions (increased organic matter, low redox potential). Cr and As were found to exceed twice the upper threshold limit of the available sediment quality guidelines in 13.5% and 7.3% of sampling stations, respectively. The potential ecological risk of V, Cr, Mn, Co, Ni, Cu, Zn, As and Pb was found to be low in the sediment close to fish cages except for Cd, which may pose a moderate to considerable risk in 12.5% of sampled fish farms. However, the estimated risks for this metal may be influenced by the high background levels found in the investigated areas. This study also shows that the occurrence of antibiotics in sediments below fish farms in the Eastern Mediterranean Sea is very sparse (i.e., only flumequine was found in two farms) and concentration levels are relatively low. Unlabelled Image • Pollutants in the surficial sediment from 48 fish farms in Greece were explored. • The sediment was enriched with P, Cu, Zn, Mo, and Cd originating from aquaculture. • Cr and As exceeded twice the sediment quality guidelines in some sampling stations. • The ecological risk of metals in the sediment from fish farm was low except for Cd. • Sparse presence of antibiotics in sediments below fish farms in Greece was found. [ABSTRACT FROM AUTHOR]

This study investigated changes in metabolite compositions over three generation exposure of wheat (Triticum aestivum) to cerium oxide nanoparticles (CeO 2 -NPs) in low or high nitrogen soil. The goal was to determine if CeO 2 -NPs affects grains/seeds quality across generational exposure. Seeds from plants exposed for two generations to 0 or 500 mg CeO 2 -NPs per kg soil treatment were cultivated for third year in low or high nitrogen soil amended with 0 or 500 mg CeO 2 -NPs per kg soil. Metabolomics identified 180 metabolites. Multivariate analysis showed that continuous generational exposure to CeO 2 -NPs altered 18 and 11 metabolites in low N and high N grains, respectively. Interestingly, DNA/RNA metabolites such as thymidine, uracil, guanosine, deoxyguanosine, adenosine monophosphate were affected; a finding that has not been observed on DNA/RNA metabolites of plants exposed to nanoparticles. Nicotianamine, a metabolite playing crucial role in Fe storage in grains, decreased by 33% in grains continuously exposed for three generations to CeO 2 -NPs at high N soil. Notably, these grains also exhibited a concomitant decrease of 13–16% in Fe concentration. Together these changes suggest alterations in grain quality or implications in ecosystem processes (i.e., productivity, nutrient cycling, ecosystem stability) of progeny plants generationally-exposed to CeO 2 -NPs. Unlabelled Image • Generational exposure to CeO 2 -NPs decreased nicotianamine in wheat grains. • Decreased nicotianamine abundance was accompanied by decreased Fe concentration. • More metabolites were affected when wheat was exposed to CeO 2 -NPs at low N soil. [ABSTRACT FROM AUTHOR]

Nature's contributions to people (NCP) are all the contributions of living nature, both beneficial and detrimental, to the societies' life's quality. Ungulates play this dual role of providers of beneficial and detrimental NCP, as they are responsible of the supply of benefits (e.g. extractive experiences, habitat maintenance) and detriments (e.g. crops damage, traffic collisions). Our aim was to analyze the NCP provided by wild ungulates through examining the scientific priorities and the shepherds' perceptions in peninsular Spain. We reviewed scientific articles of NCP provided by ungulates in Spain and conducted questionnaires regarding NCP to shepherds in farming systems where domestic and wild ungulates cohabit. Then, we compared whether the scientific priorities match with those perceived by shepherds. Both stakeholders highlight more detrimental than beneficial NCP, although there are some mismatches between scientific priorities and shepherds' perceptions. Regarding detrimental NCP, soil alteration, silvicultural damage, human safety or traffic collision were included in scientific literature but not mentioned by shepherds. Contrarywise, shepherds mainly considered grazing competence and damage to animals (i.e. game species and livestock) as important detrimental NCP. Concerning beneficial NCP, whilst hunting was prominent in the publications, shepherds did not conceived it as an important beneficial contribution and considered the regulation of organisms (i.e. scavenging alternative prey) important benefits. These results can have twofold implications. The emphasis on detrimental NCP (studied and perceived) can reinforce the idea that ungulates can threaten humans rather than contribute to societies' wellbeing. The fact that research does not address the interests of shepherds can affect the social tolerance towards ungulates as the damages experienced or perceived by shepherds are not studied. Our results show the relevance of considering local knowledge held by shepherds and their perceptions, something highlighted by the NCP approach. Unlabelled Image • Ungulates play a dual role as beneficial and detrimental contributions to people. • Researchers and shepherds highlight detrimental aspects related with wild ungulates. • However, both stakeholders stood out different ungulates' contributions to people. • These results could affect the social tolerance towards ungulates. [ABSTRACT FROM AUTHOR]

Abstract This study has been carried out on the Nalón estuary, a mining impacted estuarine contaminated by metals(oid), to evaluate how the metals(oids) concentrations in the sediments contributes to the toxicity and, therefore, supposes a potential risk for the biota. For this purpose, a total of 14 surface sediment samples were collected and analysed by different techniques. Estuary sediments showed a maximum high concentration of As (68.10 μg g−1), Hg (1.33 μg g−1) and Pb (189.60 μg g−1), exceeding the NOAA Effects Range Low. Likewise, these three elements were one of the most bioavailable in the sediments according to the toxicity characteristic leaching procedure performed, reaching average values of 14.28% for As, 12.81% for Hg and 9.23% for Pb. The bioavailable concentrations of As and Hg significantly correlated with toxicity (R > 0.92), suggesting that both were the main contributors to the toxicity of the sediments. Toxicity values detected (avg. 499 TU g−1) were similar to those showed by other sites considered contaminated in the Cantabrian coastline, confirming its status as a contaminated area. The location of the highest toxicity values in the estuary was restricted to the port areas where the fine sediments that act of sink of metals(oids) are mainly deposited. This result is very important if re-mobilization of sediments take place in these areas related to dredging or other human activities. Graphical abstract Unlabelled Image Highlights • Estuary sediments showed high levels of As, Hg and Pb as a consequence of mining. • Bioassay toxicity test by means of Vibrio fischeri was accomplished on sediments. • Bioavailable concentrations of metal(oids) are the main cause of toxicity. • Sediments present important toxicity, reaching 1470 TU g−1. • Hg and As appear to be the main toxic elements in the sediments. [ABSTRACT FROM AUTHOR]

Rivers extend in space and time under the influence of their catchment area. Our perception largely relies on discrete spatial and temporal observations carried out at certain sites located throughout the catchment (monitoring networks, MN). However, MNs are constrained by (a) the distribution of sampling sites, (b) the dynamics of the variable considered and (c) the river hydrological conditions. In this study, all three aspects were captured and quantified by applying a spatial autocorrelation modeling approach. We exemplarily studied its application to 235 emerging contaminants (pesticides, pharmaceuticals, and personal care products [PPCP], industrial and miscellaneous) measured at 55 sampling sites in the Danube River. 22 out of the 235 compounds monitored were present at all sites and 125 were found in at least 50%.We first calculated the Moran Index (MI) to characterize the spatial autocorrelation of the compound set. 59 compounds showed MI ≤ 0, which can be interpreted as ‘no spatial correlation’. Next, spatial autocorrelation models were set for each compound. From the autocorrelation parameter ρ , catchment average correlation lengths were derived for each compound. MN optimality was examined and compounds were classified into three groups: (a) those with ρ ≤ 0 [25%]; (b) those with ρ > 0 and correl. length < average distance between consecutive sites [ 2%] and (c) those with ρ > 0 and correl. length > average distance between consecutive sites [73%]. The MN was considered optimal only for the latter class. Networks with the larger average distance between consecutive sites resulted in a decreasing number of optimally monitored compounds. Furthermore, neighbors vs . local relative contributions were quantified based on the spatial autocorrelation model for all the measured compounds. The results of this study show how autocorrelation models can aid water managers to improve the design of river MNs, which are a key aspect of the Water Framework Directive. [ABSTRACT FROM AUTHOR]

Composting of sewage sludge is a common practice for sludge disposal. Some previous studies found high levels of polychorodibenzo- p -dioxins and polychorodibenzofurans (PCDD/Fs) after composting, especially octachlorodibenzo- p -dioxin (OCDD) but also 1234678-heptachlorodibenzo- p -dioxin (1234678-HpCDD) to a lesser extent. In this work, the concentrations of OCDD, 1234678-HpCDD and the rest of the 17 toxic congeners of PCDD/Fs were determined in compost obtained under different conditions. Although the toxicity of the two compounds mentioned above is small, their generation may reach undesirable levels. The PCDD/F content was analyzed in a composting plant and in a laboratory test. In both cases, the composted material was a mixture of sewage sludge, straw and sawdust. The composting plant was a tunnel with air turbine aeration and with a turner to homogenize and move the mixture upwards. The laboratory tests were carried out with Dewar vessels (with air dispersion at the bottom and controlled temperature) and with small vessels inside a controlled oven with non-forced aeration. The laboratory runs were also carried out with the addition of pentachlorophenol in some runs, as a dioxin precursor. The highest OCDD levels were found in three samples of the composting plant (30000–90000 pg/g dry matter or dm), with toxicity values surpassing the limit level for soil amendment (17 pg I-TEQ/g dm). Their formation was analyzed considering their concentration vs. that of octachorodibenzofuran (OCDF), which is not formed during composting. In the laboratory, in experiments carried out in a vessel with non-forced aeration conditions and with the addition of pentachlorophenol, the formation of OCDD was significant (e.g. from 80 to 1500 pg/g dm). That means that these two factors, non-forced aeration and the presence of pentachlorophenol, can cause the OCDD formation. [ABSTRACT FROM AUTHOR]

Since the last decade, the metal composite nanostructures have evolved as promising candidates in regard to their wide applications in the fields of science and engineering. Recently, several investigators identified the titanium based nanomaterials as excellent agents for multifunctional environmental and biomedical applications. In this perspective, we have developed a series of zinc-doped (2 and 5%) titanium oxide-based nanomaterials using various reaction conditions and calcination temperatures ( TZ1 – TZ3: calcined at 500 °C, TZ4 – TZ6: calcined at 600 °C and TZ7 – TZ9: calcined at 700 °C). The calcined materials ( TZ1 to TZ9 ) were thoroughly analyzed by several physico-chemical characterization methods. The increase of the calcination temperature results in significant changes of the textural properties of the nanostructured materials. In addition, the increase of the calcination temperature leads to the formation of anatase/rutile mixtures with higher quantity of rutile. Furthermore, incorporation of zinc changes the morphology of the obtained nanoparticles. The materials were studied in the photodegradation of methylene blue observing that materials calcined at lower temperatures ( TZ1 – TZ3 ) have higher photocatalytic activity than those of the materials calcined at 600 °C ( TZ4 – TZ6 ), rutile-based systems TZ7 – TZ9 are not active. Based on the background literature of titanium and zinc based nanostructures in therapeutic angiogenesis, we have explored the pro-angiogenic properties of these materials using various in vitro and in vivo assays. The zinc-doped titanium dioxide nanostructures ( TZ5 and TZ6 ) exhibited increased cell viability, proliferation, enhanced S-phase cell population, increased pro-angiogenic messengers (ROS: reactive oxygen species and NO: nitric oxide) production and promoted in vivo blood vessel formation in a plausible mechanistic p38/STAT3 dependent signaling cascade. Altogether, the results of the present study showcase these zinc doped-titanium oxide nanoparticles as promising candidates for environmental (water-remediation) and therapeutic angiogenic applications. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrate communities are used as indicators for anthropogenic stress in freshwater ecosystems. To better understand the relationship between anthropogenic stress and changes in macroinvertebrate community composition, it is important to understand how different stressors and species traits are associated, and how these associations influence variation in species occurrence and abundances. Here, we show the capacity of the multivariate technique of double constrained correspondence analysis (dc-CA) to analyse trait-environment relationships, and we compare it with the redundancy analysis method on community weighted mean values of traits (CWM-RDA), which is frequently used for this type of analysis. The analyses were based on available biomonitoring data for macroinvertebrate communities from the Danube River. Results from forward selection of traits and environmental variables using dc-CA analyses showed that aquatic stages, reproduction techniques, dispersal tactics, locomotion and substrate relations, altitude, longitudinal and transversal distribution, and substrate preferendum were significantly related to habitat characteristics, hydromorphological alterations and water quality measurements such as physico-chemical parameters, heavy metals, pesticides and pharmaceuticals. Environmental variables significantly associated with traits using the CWM-RDA method were generally consistent with those found in dc-CA analysis. However, the CWM-RDA does neither test nor explicitly select traits, while dc-CA tests and selects both traits and environmental variables. Moreover, the dc-CA analysis revealed that the set of environmental variables was much better in explaining the community data than the available trait set, a kind of information that can neither be obtained from CWM-RDA nor from RLQ (Environment, Link and Trait data), which is a close cousin of dc-CA but not regression-based. Our results suggest that trait-based analysis based on dc-CA may be useful to assess mechanistic links between multiple anthropogenic stressors and ecosystem health, but more data sets should be analysed in the same manner. Unlabelled Image • CWM-RDA and RLQ have drawbacks to examine trait-environment relationships. • We compare dc-CA with CWM-RDA and RLQ for analysis of trait-environment relationships. • We illustrate the application and benefits of dc-CA to biological data analysis. • Human impact on macroinvertebrates is of similar magnitude to the natural impact. • dc-CA may be useful to assess mechanistic links between multiple stressors and ecosystem health. [ABSTRACT FROM AUTHOR]

Wastewater-based epidemiology (WBE) has become a very useful tool to monitor a population's drug consumption or exposure to environmental and food contaminants. In this work, WBE has been applied to estimate tobacco consumption in seven Spanish regions. To this end, 24 h composite wastewater samples were taken daily for one week in 17 wastewater treatment plants, covering altogether a population of ca. 6 million inhabitants. The samples were treated by enzymatic deconjugation and the wastewater content of two human-specific nicotine metabolites (namely, cotinine and trans-3′-hydroxycotinine) was measured to estimate the daily consumption of nicotine. The population-weighted average nicotine consumption in the seven analyzed regions was 2.2 g/(day∙1000 inh.), without any daily pattern. This average estimated nicotine consumption value agreed with the value derived from official tobacco sales data. Differences in consumption among the seven studied regions were found, being Galicia, the region with the lowest rate, and the Basque Country and Catalonia those with the highest rates. However, no conclusive correlation was found between those values and the prevalence data taken from two different national surveys, nor sociodemographic and health data. This study demonstrates that this tool can complement other indicators in order to accurately assess tobacco consumption rates at regional and national levels and provides the most extensive application of the approach in the Spanish territory. Unlabelled Image • Nicotine metabolites measured in 17 wastewater treatment plants (WWTPs) • The nicotine consumed was estimated through wastewater-based epidemiology (WBE). • The mean per capita nicotine consumed daily was 2.2 mg (ca. 2.8 cigarettes). • Largest Spanish study on nicotine by WBE • The consumption estimates through WBE are consistent with official sales data. [ABSTRACT FROM AUTHOR]

Abstract Understanding the oral bioaccessibility of lead (Pb) present in soils in urbanized areas is important for the human exposure risk assessment. In particular, the role of the soil-mineralogy in the oral bioaccessibility has not been extensively studied. To investigate bioaccessibility, five types of periurban soils were collected, samples were spiked with the same amount of lead-chromates from traffic paint, and subjected to the in vitro Physiological Based Extraction Test (PBET). Ten samples of urban topsoils were collected at elementary schools playgrounds, Pb-bioaccessibility was measured, and a prediction equation for bioaccessibility was constructed. Mineralogy, and metal content were identified with a combination of X-ray powder diffraction, scanning electron microscopy, and portable X-ray fluorescence techniques. Traffic paint sample is made of 15% quartz (SiO 2), 13% crocoite (PbCrO 4), 55% calcite (CaCO 3), and 17% kaolinite (Al 2 Si 2 O 5 (OH) 4) and it contains high metal content (Pb, Cr, Zn, and Ca). Studied soils are characterized by variable amounts of acid-neutralizing minerals (carbonates) and low metal content. Spiked soils contained almost equal concentration of Pb, Cr, and Zn, because the contribution of these metals is from the added paint. However, obtained Pb-bioaccessibility at gastric and intestinal conditions are variable (40 to 51% gastric, 24 to 70.5% intestinal). Carbonate content shows significant correlation (p < 0.05) with Cr, Ca, calcite, crocoite, and Pb-bioaccessible at gastric conditions. Correlation of Pb-bioaccessible at intestinal conditions is significant (p < 0.05) with kaolinite. Variability of Pb-bioaccesibility in urban environments is commonly associated to differences in Pb-sources, however, our results show that the bioaccessibility of the same pollutant behaves different for each soil type. This suggests that soil mineralogy may play a role in Pb-releasing at gastrointestinal conditions. Soil information about mineralogical characteristics from this study may help to reduce exposure to lead from urban sources if data are incorporated into urban planning. Graphical abstract Unlabelled Image Highlights • Bioaccessibility of lead was analyzed using PBET. • Natural soils were spiked with lead-based paint. • Soils mineralogy affect lead bioaccessibility. • Soil type influences health-risk assessment. [ABSTRACT FROM AUTHOR]

Abstract Antibiotics used in marine aquaculture have been reported to accumulate in sediments and non-target aquatic organisms, modifying the biodiversity and the environmental conditions in areas close to the fish farms. Improved analytical methods are required to assess the spread and the impacts of aquaculture antibiotics in the marine environment, as well as to estimate resistance development risks. In this study, we have optimized a method for simultaneous quantitative determination of oxytetracycline, florfenicol and flumequine in marine samples using liquid chromatography coupled to time-of-flight high resolution mass spectrometry (LC-TOF/MS). The method optimization was carried out for seawater, sediment and biological samples (biofilm and two benthic invertebrate species: Gammarus aequicauda and Monodonta articulata ). Special attention was paid to the optimization of the extraction and purification steps, testing: liquid-liquid and solid-liquid extractions, the use of silica and other commercial sorbents' clean-up, and single and tandem solid phase extraction procedures. The limits of quantification (MQLs) achieved with the developed method are 0.1–0.5 μg L-1 in seawater; 1–5 μg kg−1 in marine sediments; 5–25 μg kg−1 in biofilm; and 100–500 μg kg−1 in invertebrates, with good accuracy and precision. Method recoveries in spiked samples are 65–120% in seawater and sediment samples, and 63–110% in the biological samples. The method has been successfully implemented for the determination of antibiotic concentrations in sediment and invertebrate samples collected from a Mediterranean bay in south-east Spain. These represent significant advances in the analysis of antibiotics in environmental samples, especially for wild marine taxa, and attend for a proper assessment of the environmental fate and side effects of aquaculture antibiotics in the marine environment. Graphical abstract Unlabelled Image Highlights • LC-TOF MS determination of antibiotics in several marine samples • Antibiotic extraction from environmental samples is based on SPE tandem purification. • The methods show a high sensitivity and reproducibility. • MQLs of 0.1–0.5 μg L−1 in seawater; 0.3–50 μg/kg in sediments and biota samples • Measurable concentrations of oxytetracycline and flumequine were found. [ABSTRACT FROM AUTHOR]

In this study, the removal of parabens from waters, using a combined treatment of magnetic ion exchange resins and subsequent filtration through nanofiltration membranes, was investigated. The selected parabens were methylparaben, ethylparaben, propylparaben and butylparaben. Two different magnetic anionic exchanger resins, MIEX® DOC and MIEX® GOLD, and two nanofiltration membranes (NF), NF-90 and DESAL-HL, were tested. The study was carried out using mono and multicomponent systems, using deionized water and natural waters sampled from two different rivers. In this way, competitive and matrix effects could be evaluated. The results showed, that with the combined treatments, higher elimination rates were obtained. The best removal efficiencies were obtained when the DOC resin was combined with both NF-90 and DESAL-HL membranes. Thus, butylparaben and propylparaben reached removal yields around 100% with both membranes, whereas the corresponding values for methylparaben were 91%, when the NF-90 membrane was employed, or 92% when DESAL-HL membrane was utilized. The elimination rates of ethylparaben with the same treatments were 96% with the NF-90 and 97% when the DESAL-HL membrane was combined with the DOC resin. The elimination percentages were higher as the paraben alkyl chain length increased. In addition, no competitiveness or matrix effects were detected. When the MIEX® GOLD resin was used for pre-treatment, membrane fouling worsened which indicated that resin selection needs to be carefully considered to achieve the best results. [ABSTRACT FROM AUTHOR]

There is lack of information about the effects of foliar applied nanoparticles on fruit quality. In this study, three week-old soil grown cucumber seedlings were foliar-exposed to n CeO 2 , n CuO, and corresponding bulk counterparts at 50, 100, and 200 mg/L. Respective suspensions/solutions were sprayed to experimental units in a volume of 250 ml. Net photosynthesis rate ( Pn ), stomatal conductance ( Gs ), and transpiration rate ( E ) were measured 15 days after treatment application and in 74 day-old plants. Yield, fruit characteristics (size, weight, and firmness), Ce, Cu, and nutritional elements were also measured. Results showed a nano-specific decrement on Pn (22% and 30%) and E (11% and 17%) in seedling leaves exposed to n CeO 2 and n CuO at 200 mg/L, respectively, compared with control. n CeO 2 at 50 mg/L, b CeO 2 at 200 mg/L, and all Cu treatments, except n CuO at 100 mg/L, significantly reduced fruit firmness ( p ≤ 0.05), compared with control. However, n CuO at 200 mg/L and b CuO at 50 mg/L significantly increased fruit fresh weight ( p ≤ 0.05). At 200 mg/L, n CeO 2 and b CeO 2 reduced fruit Zn by 25%, while n CuO and b CuO reduced fruit Mo by 51% and 44%, respectively, compared with control. This study has shown that when the route of exposure is the foliage, differences in particle size are less significant, compared to root-based exposure. To the authors' knowledge, this is the first report on the effect of foliar application of n CeO 2 and n CuO upon yield and nutritional quality of cucumber. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles (NPs) are reported as potentially phytotoxic in hydroponic and soil media. However, studies on ZnO NPs toxicity in a plant inoculated with bacterium in soil are limited. In this study, ZnO NPs, bulk ZnO, and ZnCl 2 were exposed to the symbiotic alfalfa ( Medicago sativa L.)– Sinorhizobium meliloti association at concentrations ranging from 0 to 750 mg/kg soil. Plant growth, Zn bioaccumulation, dry biomass, leaf area, total protein, and catalase (CAT) activity were measured in 30 day-old plants. Results showed 50% germination reduction by bulk ZnO at 500 and 750 mg/kg and all ZnCl 2 concentrations. ZnO NPs and ionic Zn reduced root and shoot biomass by 80% and 25%, respectively. Conversely, bulk ZnO at 750 mg/kg increased shoot and root biomass by 225% and 10%, respectively, compared to control. At 500 and 750 mg/kg, ZnCl 2 reduced CAT activity in stems and leaves. Total leaf protein significantly decreased as external ZnCl 2 concentration increased. STEM-EDX imaging revealed the presence of ZnO particles in the root, stem, leaf, and nodule tissues. ZnO NPs showed less toxicity compared to ZnCl 2 and bulk ZnO found to be growth enhancing on measured traits. These findings are significant to reveal the toxicity effects of different Zn species (NPs, bulk, and ionic Zn) into environmentally important plant-bacterial system in soil. [ABSTRACT FROM AUTHOR]

In this study, the deterioration effects of lichens and other lithobionts in a temperate mesothermal climate were explored. We examined samples of dolostone and limestone rocks with visible signs of biodeterioration taken from the exterior wall surfaces of four Romanesque churches in Segovia (Spain): San Lorenzo, San Martín, San Millán and La Vera Cruz. Biofilms developing on the lithic substrate were analyzed by scanning electron microscopy. The most common lichen species found in the samples were recorded. Fungal cultures were then obtained from these carbonate rocks and characterized by sequencing Internal Transcribed Spacers (ITS). Through scanning electron microscopy in back-scattered electron mode, fungi (lichenized and non-lichenized) were observed as the most frequent microorganisms occurring at sites showing signs of biodeterioration. The colonization process was especially conditioned by the porosity characteristics of the stone used in these buildings. While in dolostones, microorganisms mainly occupied spaces comprising the rock''s intercrystalline porosity, in bioclastic dolomitized limestones, fungal colonization seemed to be more associated with moldic porosity. Microbial biofilms make close contact with the substrate, and thus probably cause significant deterioration of the underlying materials. We describe the different processes of stone alteration induced by fungal colonization and discuss the implications of these processes for the design of treatments to prevent biodeterioration. [Copyright &y& Elsevier]

Seasonal hydrological variation and chemical pollution represent two main drivers of freshwater biodiversity change in Mediterranean rivers. We investigated to what extent low flow conditions can modify the effects of chemical pollution on macroinvertebrate communities. To that purpose, we selected twelve sampling sites in the upper Tagus river basin (central Spain) having different sources of chemical pollution and levels of seasonal hydrological variation. The sites were classified as natural (high flow variation, low chemical impact), agricultural (high flow variation, high agricultural chemical inputs) and urban (limited flow variation, high urban chemical inputs). In these sites, we measured daily water discharge, nutrients, and contaminant concentrations, and we sampled benthic macroinvertebrates, in spring, summer and autumn. Significant differences related to toxic pressure and nutrient concentrations were observed between the three groups of sites. Seasonal patterns were found for some water quality parameters (e.g. nitrites, ammonia, suspended solids, metal toxicity), particularly in agricultural sites. Taxonomic and functional richness were slightly lower in the polluted sites (agricultural and urban), particularly during low flow periods (summer and early autumn). Functional diversity was significantly lower in sites with seasonal flow variation (agricultural sites) as compared to the more constant ones (urban sites). The frequency of traits such as large size, asexual reproduction, aquatic passive dispersion and the production of cocoons increased in response to pollution during low flow periods. This study shows that the impacts of anthropogenic chemical pollution on taxonomic and functional characteristics of macroinvertebrate communities seem to be larger during low flow periods. Therefore, further studies and monitoring campaigns assessing the effects of chemical pollution within these periods are recommended. Unlabelled Image • We assessed the effect of varying flow conditions and pollution on invertebrates. • Stronger functional diversity response to pollution during low flow periods. • Traits representative of pollution and low-flow conditions have been identified. • Late summer monitoring is recommended to tackle maximum ecological disturbance. [ABSTRACT FROM AUTHOR]

In this study, the reduction of the emerging organic contaminant atrazine in water, was investigated by adsorption, oxidation and a combination of both technologies. Adsorption tests were performed using method ASTM D3860-98 with two types of activated carbon: powdered activated carbon and granular activated carbon. For the oxidation tests, advanced ozone oxidation technology was used. Finally, in the combined tests, firstly adsorption treatment was applied followed by oxidation and then the order was reversed. We studied the contaminant removal percentage using different treatments at various reaction times. Results for the different treatments under study showed that, for an initial atrazine concentration of 0.7 mg L−1 and a dose of 16 mg L−1 of powdered activated carbon, with contact times of 60 min, 24 h and 48 h, percentage reductions of the contaminant of 81%, 92% and 94% respectively were obtained. For the same concentration of contaminant, but instead using granular activated carbon, the percentage reduction of atrazine at 60 min was 2%, this percentage rising to 34% and 35% after 24 and 48 h of contact time, respectively. For the same initial contaminant concentration, when ozone was applied at a dose of 19.7 mg L−1, and with a reaction time of 18 min, a reduction of atrazine of 93% was obtained, but oxidation by-products were also produced. For the combined treatments, with the same initial concentration of contaminant and the same doses of carbon and ozone as previously indicated, better contaminant reductions were obtained when the treatment started with activated carbon followed by ozone, achieving a 90% reduction of atrazine observing a 17 minute contact time with powdered activated carbon and a 3 day contact time using the granulated carbon. When the order was reversed by starting with ozone, the contact time was 52 min and 4 days, respectively. Unlabelled Image • Powdered activated carbon obtained greater reductions than granular activated carbon. • The treatment with ozone, reaches higher reductions compared to the treatment with any activated carbon. • Oxidation is very effective for removing atrazine, but generates by-products. • Both treatments (adsorption and oxidation) significantly reduced the pesticide. • The combined treatments (AC/O 3 and O 3 /AC), obtained reductions of more than 90%. [ABSTRACT FROM AUTHOR]

Inhalation of playground dust-derived fine particles in schoolyards poses a risk from exposure to metal(oids) and minerals. In this work, we obtained the total concentration and bioaccessibility of metal(oids) with Gamble Solution (GS) and Artificial Lysosomal Fluid (ALF) synthetic solutions, simulating the extracellular neutral pH environment of the lung and the intracellular conditions of the macrophage, respectively. Scanning Electron Microscope (SEM), and Dynamic Light Scattering analysis (DLS) techniques were used to characterize particles with a size smaller than 2.5 μm, which can be assimilated by macrophages in the deep part of the lung. Arsenic (As), lead (Pb), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) showed concentrations of 39.9, 147.9, 286, 1369, 2313, 112,457 mg·kg−1, respectively. The results indicated that all studied elements were enriched when compared to (i) local geochemical background and (ii) findings reported in other cities around the world. Bioaccessibility of metal(oids) in GS was low-moderate for most studied elements. However, in ALF assays, bioaccessibility was high among the samples: for lead (Pb = 34–100%), arsenic (As = 14.7–100%), copper (Cu = 17.9–100%), and zinc (Zn = 35–52%) possibly related to hydrophobic minerals in dust. SEM and DLS image analysis showed that playground dust particles smaller than 2.5 μm are dominant, particularly particles with a size range of 500–600 nm. The polydispersity detected in these particle sizes showed that most of them might be crystalline compounds (elongated shapes) forming agglomerates instead of combustion particles (spheres). Moreover, the circularity detected varies from 0.57 to 0.79 (low roundness), which corroborates this finding. The presence of agglomerates of ultrafine/nanoparticles containing highly bioaccessible metals in playground sites may have severe implications in children's health. Therefore, further studies are required to characterize the size distribution, structure, shape and composition of such minerals which are essential factors related to the toxicology of inhaled dust particles. Unlabelled Image • High total metal content in playground dust is detected. • High metal bioaccessibility of playground dust in synthetic lung fluids is assessed. • Dynamic Light Scattering in lysosomal fluids show ultrafine particles (<500 nm). • Less than 500 nm-particles appear as crystalline compounds rather than combustion [ABSTRACT FROM AUTHOR]