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In this study, a new simulation-optimization approach is proposed for solving the areal groundwater pollution source identification problems which is an ill-posed inverse problem. In the simulation part of the proposed approach, groundwater flow and pollution transport processes are simulated by modeling the given aquifer system on MODFLOW and MT3DMS models. The developed simulation model is then integrated to a newly proposed hybrid optimization model where a binary genetic algorithm and a generalized reduced gradient method are mutually used. This is a novel approach and it is employed for the first time in the areal pollution source identification problems. The objective of the proposed hybrid optimization approach is to simultaneously identify the spatial distributions and input concentrations of the unknown areal groundwater pollution sources by using the limited number of pollution concentration time series at the monitoring well locations. The applicability of the proposed simulation-optimization approach is evaluated on a hypothetical aquifer model for different pollution source distributions. Furthermore, model performance is evaluated for measurement error conditions, different genetic algorithm parameter combinations, different numbers and locations of the monitoring wells, and different heterogeneous hydraulic conductivity fields. Identified results indicated that the proposed simulation-optimization approach may be an effective way to solve the areal groundwater pollution source identification problems. © 2016 Elsevier B.V..

Consideration is given to production and decomposition processes in herbaceous communities exposed to chemical pollution with heavy metals in the Middle Urals. High variation in the aboveground phytomass of agrobotanical groups (legumes, forbs, grasses) is due to spatial heterogeneity of soil pollution levels and consequent changes in the species composition of plant communities in the areas studied. Therefore, nonparametric statistical methods have been used (Kruskal–Wallis test with subsequent pairwise comparisons by Wilcoxon–Mann–Whitney with Bonferroni correction for multiple comparisons). The phytomass of legumes remains unchanged in the increasing pollution gradient, while the contribution of forbs to the total phytomass decreases and that of grasses increases. Soils rich in nutrient elements can maintain a high rate of plant debris decomposition, counterbalancing the adverse effect of increased heavy metal concentrations on relevant processes. The balance between production and mineralization processes provides for the sustainable, long-term existence of herbaceous communities under conditions of intense pollution of the natural environment. © 2016, Pleiades Publishing, Ltd.

This study investigates the concentration, cloud condensation nuclei (CCN) activity and hygroscopic properties of particles influenced by biomass burning in the eastern Mediterranean and their impacts on cloud droplet formation. Air masses sampled were subject to a range of atmospheric processing (several hours up to 3 days). Values of the hygroscopicity parameter, κ, were derived from CCN measurements and a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA). An Aerosol Chemical Speciation Monitor (ACSM) was also used to determine the chemical composition and mass concentration of non-refractory components of the submicron aerosol fraction. During fire events, the increased organic content (and lower inorganic fraction) of the aerosol decreases the values of κ, for all particle sizes. Particle sizes smaller than 80 nm exhibited considerable chemical dispersion (where hygroscopicity varied up to 100 % for particles of same size); larger particles, however, exhibited considerably less dispersion owing to the effects of condensational growth and cloud processing. ACSM measurements indicate that the bulk composition reflects the hygroscopicity and chemical nature of the largest particles (having a diameter of ∼ 100 nm at dry conditions) sampled. Based on positive matrix factorization (PMF) analysis of the organic ACSM spectra, CCN concentrations follow a similar trend as the biomass-burning organic aerosol (BBOA) component, with the former being enhanced between 65 and 150 % (for supersaturations ranging between 0.2 and 0.7 %) with the arrival of the smoke plumes. Using multilinear regression of the PMF factors (BBOA, OOA-BB and OOA) and the observed hygroscopicity parameter, the inferred hygroscopicity of the oxygenated organic aerosol components is determined. We find that the transformation of freshly emitted biomass burning (BBOA) to more oxidized organic aerosol (OOA-BB) can result in a 2-fold increase of the inferred organic hygroscopicity; about 10 % of the total aerosol hygroscopicity is related to the two biomass-burning components (BBOA and OOA-BB), which in turn contribute almost 35 % to the fine-particle organic water of the aerosol. Observation-derived calculations of the cloud droplet concentrations that develop for typical boundary layer cloud conditions suggest that biomass burning increases droplet number, on average by 8.5 %. The strongly sublinear response of clouds to biomass-burning (BB) influences is a result of strong competition of CCN for water vapor, which results in very low maximum supersaturation (0.08 % on average). Attributing droplet number variations to the total aerosol number and the chemical composition variations shows that the importance of chemical composition increases with distance, contributing up to 25 % of the total droplet variability. Therefore, although BB may strongly elevate CCN numbers, the impact on droplet number is limited by water vapor availability and depends on the aerosol particle concentration levels associated with the background.

Polychlorinated biphenyls (PCBs) were measured in ambient air samples (n = 48) that were collected for a 2- to 3-day period in each season (winter, spring, summer, fall) of 2013. The samples were collected on the Campus of Uludag University, which is in a semirural region. The samples were collected using a high-volume air sampler. The gas and particle phase concentrations of 87 PCB congeners (I 87PCB) pound were measured in these samples. The average gas and particle phase concentrations of the I 87PCB pound were calculated to be 293 +/- 257 and 52 +/- 56 ng/m(3), respectively. However, the results of short-term measurements showed that the variation among the measurements in the gas phase was up to 39-fold and up to 84-fold in the particle phase. These results demonstrated that the ambient air PCB concentrations were not stable and changed dramatically on a daily basis. Therefore, it was clear that a small number of samples could not be representative of the entire region. Furthermore, the obtained concentrations showed differences that depended on the meteorological conditions and long distance transportation. The sampling indicated that PCB homologues with 3 or 4 chlorines were dominant.

Bu çalışma, 2015 tarihlerinde Caparica[Portekiz]’ da düzenlenen 1. International Caparica Conference on Pollutant Toxic Ions and Molecules (PTIM) Kongresi‘nde bildiri olarak sunulmuştur. Wet deposition fluxes of organochlorine pesticides (OCPs) were determined for rain samples collected in a coastal area of Turkey. Seventeen precipitation samples were collected over a 1-year period from 2008 to 2009. Rainwater was accumulated at the beginning of rain events using real time monitoring. Atmospheric concentrations were also measured in parallel with deposition samples. Both atmospheric concentrations and deposition fluxes were determined as particle and gas phases. The particle phase and dissolved phase deposition fluxes were 794.26 +/- 756.70 ngm(-2) day(-1) and 800.77 +/- 672.63 ngm(-2) day(-1), respectively. The washout ratios for OCP compounds were calculated separately for the particle and dissolved phases using the atmospheric concentrations and rain concentrations. The minimum washout ratio for the particle phase was 2339.47 for Endrin aldehyde, whereas the maximum washout ratio was 497593.34 for Methoxychlor. The maximum washout ratio for the dissolved phase was 247523.89 for Endosulfan beta, whereas the minimum washout ratio was 10169.69 for p,p'-DDT. The dry deposition velocities ranged from 0.01 to 1.67 cms(-1). The partitioning of wet deposition between the particle and dissolved phases was 50 % in terms of total OCP deposition.

Recent studies have indicated that sewer systems and landfills contain polychlorinated biphenyls (PCBs). In this study, 18 surface soil samples were collected from five areas near wastewater treatment plants and landfills to investigate PCB levels. The observed PCB congener numbers and levels in the samples varied. The total PCB values were 5558 +/- 2856 pg g(-1) dry weight (dw) (Sigma 61PCB) for the marine outfall of the Buski Pretreatment Plant (Bursa Water and Sewerage Administration), 5386 +/- 1627 pg g(-1) dw (Sigma 45PCB) for the Hamitler Landfill Area, 3901 +/- 281 pg g(-1) dw (Sigma 35PCB) for the Western Wastewater Treatment Plant, 1824 +/- 448 pg g(-1) dw (Sigma 42PCB) for the Yesil Cevre Wastewater Treatment Plant, and 725 +/- 220 pg g(-1) dw (Sigma 17PCB) for the Eastern Wastewater Treatment Plant. These results show that the soils near the treatment plants were not completely contaminated by PCBs. At the sampling sites, with the biphenyls between 2 and 7 chlorine molecules and in particular, an abundance of homologue groups with 3, 4, and 5 chlorines were found. Moreover, dioxin-like PCBs (PCB#77, 81, 105, 114, 118, 123, and 126) were detected in all samples.

Bulk aerosol samples collected during cruise M91 of FS Meteor off the coast of Peru in December 2012 were analysed for their soluble trace metal (Fe, Al, Mn, Ti, Zn, V, Ni, Cu, Co, Cd, Pb, Th) and major ion (including NO3− and NH4+) content. These data are among the first recorded for trace metals in this relatively poorly studied region of the global marine atmosphere. To the north of ∼ 13° S, the concentrations of several elements (Fe, Ti, Zn, V, Ni, Pb) appear to be related to distance from the coast. At the south of the transect ( ∼ 15–16° S), elevated concentrations of Fe, Cu, Co, and Ni were observed, and we calculated dry deposition fluxes of soluble Cu approximately an order of magnitude higher than a recent model-based estimate of total Cu deposition to the region. The model did not take account of emissions from the large smelting facilities in the south of Peru and northern Chile, and our results may indicate that these facilities constitute an important source of trace metals to the region. Calculated dry deposition fluxes (3370–17800 and 16–107 nmol m−2 d−1 for inorganic nitrogen and soluble Fe respectively) indicated that atmospheric input to the waters of the Peru upwelling system contains an excess of Fe over N, with respect to phytoplankton requirements. This may be significant as primary production in these waters has been reported to be limited by Fe availability, but atmospheric deposition is unlikely to be the dominant source of Fe to the system.

Tropospheric O3 remains a major air-quality issue in the Mediterranean region. The combination of large anthropogenic emissions of precursors, transboundary contributions, a warm and dry aestival climate, and topographical features results in severe cases of photochemical pollution. Chemical transport models (CTMs) are essential tools for studying O3 dynamics and for assessing mitigation measures, but they need to be evaluated specifically for each air basin. In this study, we present an optimisation of the LOTOS-EUROS CTM for the Madrid air basin. Five configurations using different meteorological datasets (from the European Centre for Medium-Range Weather Forecast, ECMWF; and the Weather Research and Forecasting Model, WRF), horizontal resolution and number of vertical levels were compared for July 2016. LOTOS-EUROS responded satisfactorily in the five configurations reproducing observations of surface O3 with notable correlation and reduced bias and errors. However, the best-fit simulations for surface O3 were obtained by increasing spatial resolution and using a large number of vertical levels to reproduce vertical transport phenomena and the formation of reservoir layers. Using the optimal configuration obtained in the evaluation, three characteristic events have been described: recirculation (REC) episodes and northern and southern advection (NAD and SAD, respectively) events. REC events were found to produce the highest O3 due to the reduced ventilation associated with low wind speeds and the contribution of reservoir layers formed by vertical transport of O3 formed near the surface in the previous days of the event. NAD events, usually associated with higher wind speeds, present the lowest ground-level O3 concentrations in the region. During SAD episodes, external contributions along with low wind speeds allow O3 to increase considerably but not as much as in REC events because steady southerly winds disperse local emissions and hinder the formation of reservoir layers. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.

International audience; Simultaneous measurement of C 2 H 6 and CH 4 concentrations, and of the δ 13 C-CH 4 isotope ratio is demonstrated using a cavity-enhanced absorption spectroscopy technique in the mid-IR region. The spectrometer is compact and has been designed for field operation. It relies on optical-feedback-assisted injection of 3.3 µm radiation from an inter-band cascade laser (ICL) into a V-shaped high-finesse optical cavity. A minimum absorption coefficient of 2.8×10 −9 cm −1 is obtained in a single scan (0.1 s) over 0.7 cm −1. Preci-sions of 3 ppbv, 11 ppbv, and 0.08 ‰ for C 2 H 6 , CH 4 , and δ 13 C-CH 4 , respectively, are achieved after 400 s of integration time. Laboratory calibrations and tests of performance are reported here. They show the potential for the spectrometer to be embedded in a sensor probe for in situ measurements in ocean waters, which could have important applications for the understanding of the source and fate of hydrocarbons from the seabed and in the water column.

Tropospheric O3 remains a major air-quality issue in the Mediterranean region. The combination of large anthropogenic emissions of precursors, transboundary contributions, a warm and dry aestival climate, and topographical features results in severe cases of photochemical pollution. Chemical transport models (CTMs) are essential tools for studying O3 dynamics and for assessing mitigation measures, but they need to be evaluated specifically for each air basin. In this study, we present an optimisation of the LOTOS-EUROS CTM for the Madrid air basin. Five configurations using different meteorological datasets (from the European Centre for Medium-Range Weather Forecast, ECMWF; and the Weather Research and Forecasting Model, WRF), horizontal resolution and number of vertical levels were compared for July 2016. LOTOS-EUROS responded satisfactorily in the five configurations reproducing observations of surface O3 with notable correlation and reduced bias and errors. However, the best-fit simulations for surface O3 were obtained by increasing spatial resolution and using a large number of vertical levels to reproduce vertical transport phenomena and the formation of reservoir layers. Using the optimal configuration obtained in the evaluation, three characteristic events have been described: recirculation (REC) episodes and northern and southern advection (NAD and SAD, respectively) events. REC events were found to produce the highest O3 due to the reduced ventilation associated with low wind speeds and the contribution of reservoir layers formed by vertical transport of O3 formed near the surface in the previous days of the event. NAD events, usually associated with higher wind speeds, present the lowest ground-level O3 concentrations in the region. During SAD episodes, external contributions along with low wind speeds allow O3 to increase considerably but not as much as in REC events because steady southerly winds disperse local emissions and hinder the formation of reservoir layers., Funding text #1 1Centro Universitario de la Defensa (CUD) de Zaragoza, Academia General Militar, Ctra. de Huesca s/n, 50090 Zaragoza, Spain 2TNO, P.O. Box 80015, 3584 TA, Utrecht, the Netherlands 3Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain 4Department of Chemical and Environmental Engineering, Technical University of Madrid (UPM), c/José Gutiérrez Abascal 2, 28006 Madrid, Spain 5Escuela Técnica Superior de Ingeniería de Bilbao, Departamento de Ingeniería Química y del Medio Ambiente, Universidad del País Vasco (UPV/EHU), Urkixo Zumarkalea, s/n, 48013 Bilbao, Spain Funding text #2 Acknowledgements. This work was funded by the Ministry of Economy, Industry and Competitiveness and FEDER funds through the project HOUSE (CGL2016-78594-R); the Ministry of Agriculture, Fishing, Food and Environment; the Madrid City Council; the Madrid Regional Government; and by the Department of Research, Innovation and University of the Aragón Regional Government and the European Social Fund (project E23_17D). The study was also partially supported by the scientific programme TECNAIRE-CM funded by the Directorate General for Universities and Research of the Greater Madrid Region (S2013/MAE-2972). The authors gratefully acknowledge air-quality data provision by the following entities: Ministry for the Ecological Transition (MITECO); Madrid City Council; AEMET; and the autonomous communities of Madrid, Castilla y León and Castilla–La Mancha. Miguel Escudero received a grant from the José Castillejo programme of the Ministry of Education and Science of Spain (ref. CAS17/00108) for a 6-month research visit at TNO.View less Funding text #3 Ministry of Economy, Industry and Competitiveness of Spain and FEDER (grant no. CGL2016-78594-R); the Department of Research, Innovation and University of the Aragón Regional Government and the European Social Fund (grant no. E23_17D); the Directorate General for Universities and Research of the Greater Madrid Region (grant no. S2013/MAE-2972); and the Ministry of Education and Science of Spain (grant no. CAS17/00108).

© 2019 The Authors. Background Bisphenols and triclosan are considered as potential thyroid disruptors. While mild alterations in maternal thyroid function can result in adverse pregnancy and child developmental outcomes, there is still uncertainty whether bisphenols or triclosan can interfere with thyroid function during pregnancy. Objectives We aimed to investigate the association of urinary bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF) and triclosan with early pregnancy thyroid function. Methods This study was embedded in the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy study (SELMA), a population-based prospective pregnancy cohort. In total, 1996 participants were included in the current study. Maternal urinary concentrations of three bisphenols and triclosan, collected at median (95% range) 10 (6–14) weeks of pregnancy as well as serum concentrations of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were measured. Results Higher BPA levels were associated with lower TT4 concentrations (non-monotonic, P = 0.03), a lower FT4/FT3 ratio (β [SE] -0.02 [0.01], P = 0.03) and a lower TT4/TT3 ratio (β [SE] -0.73 [0.27], P = 0.008). Higher BPF levels were associated with a higher FT3 (β [SE] 0.01 [0.007], P = 0.04). There were no associations between other bisphenols or triclosan and absolute TSH, (F)T4 or (F)T3 concentrations. The association of BPA with thyroid function differed with gestational age. The negative association of BPA with FT4/FT3 and TT4/TT3 ratios was only apparent in early but not late gestation (P for interaction: 0.003, 0.008, respectively). Conclusion These human data during pregnancy substantiate experimental findings suggesting that BPA could potentially affect thyroid function and deiodinase activities in early gestation. European Union of Medical Specialists; European Union's Horizon 2020 Programme for research; echnological development and demonstration; Swedish Research Council; County Council of Värmland, Sweden

WOS: 000459235700050, Heavy metal concentration in soils is crucial for environmental quality and agricultural ecosystems' health. Intensive agricultural practices and changing land use can induce their availability and mobility in agricultural ecosystems. Amik Lake which was drained-out to gain aglands have significant portion in the Amik Plain, one of the largest plains of Turkey, where agricultural activities were intensified in the last four decades. Therefore, the aim of this study was to investigate potentially plant available and/or mobile fraction heavy metals in the Amik Plain. For this purpose, 179 surface soil samples (0-30 cm) were taken by setting 2 km the grid system. Routine soil properties along with DTPA extractable lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), cobalt (Co), aluminium (Al), iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn) were analysed by using microwave plasma atomic emission spectroscopy (MP-AES). The range of heavy metal concentrations were: Pb 0-4.03 mg/kg, Cd 0-0.270 mg/kg, Ni 0-25.19 mg/kg, Cr 0-0.780 mg/kg, Co 0-1.83 mg/kg, Al 0-0.930 mg/kg, Fe 1.47-22.8 mg/kg, Cu 0.400-5.43 mg/kg, Mn 0-36.4 mg/kg and Zn 0-4.26 mg/kg on the soil samples. The identified main sources of heavy metals were parent materials, traffic, agricultural practices, and overall pedotransfer function as non-point sources; settlements and industrial organisations as point sources. It can be concluded that the accumulation and translocation of the heavy metals in the field were likely to be operated by the slope, erosion, pH, Na, Ca, drainage, and organic matter.

—The aggregation and sedimentation of ultradispersed diamonds (UDDs) in a citrate copper-plating electrolyte (CCPE) used to fabricate composite electrochemical coatings are investigated. The sedimentation and aggregation stability is investigated in order to select the UDD concentration in the CCPE. This is necessary to fabricate composite copper coatings with improved operational characteristics (increased hardness, wear resistance, and corrosion resistance), as well as impart them new properties (antifriction and catalytic). The UDD content in the electrolyte varies in limits from 0.2 to 2.0 g/L. The size distribution of the UDD particles in the electrolyte immediately after the suspension preparation and after the 10-day holding is determined using a Malvern Mastersizer 2000 laser diffraction analyzer. The aggregation and sedimentation stability of the UDD suspension in the CCPE is investigated by the gravimetric method with the continuous weighing of a quartz small cap immersed into this suspension. The quartz cap is associated with a Sartorius R200D analytical balance with the help of a quartz wire. The experimentally determined time dependence of the weight of settling UDD particles is Q = f(t). The relative size distribution of the particles is determined from this dependence. It is established that the sedimentation stability is substantially affected by the aggregation of the particles, the intensity of which increases with an increase in the UDD concentration. The results satisfying the requirements on the aggregation and sedimentation stability are found for the UDD suspension in the CCPE with a concentration of 1.0 g/L. In this case, the high content of the dispersed phase is combined with aggregation and sedimentation stability, which makes it possible to fabricate copper composite coatings with improved operational properties. © 2019, Allerton Press, Inc.

WOS: 000459235700060, In this study, seasonal variations of some heavy metal concentrations (Fe, Zn, Cd, Cu, Co, Ni, Al, Mn, Pb, and Cr) were determined. A total of 108 sea-water samples were taken in three different stations with depths of about (0-5 m, 5-10 m, and 10-15 m) in Iskenderun Bay from June 2012 to September 2013. It was determined that he highest concentration of Pb was found (0.2697 +/- 0.0309 ml/l) at the 1st station in summer, while the lowest concentration was Cr (0.0167 +/- 0.0057 ml/l) was found in spring at the 2nd station. The annual average heavy metal concentrations in the seawater of Iskenderun Bay was determined as Pb>Cu>Al>Zn>Cd>Co>Ni>Fe>Mn>Cr. Heavy metal concentrations in seawater should be monitored in terms of water quality and the sustainability of the healthy ecosystem in terms of fisheries management., Mustafa Kemal University Scientific Project Office [8281], This research was supported by the funding from Mustafa Kemal University Scientific Project Office (Project No: 8281).

The nighttime boundary layer was studied in an urban area surrounded by tropical forest by use of a copter-type unmanned aerial vehicle (UAV) in central Amazonia during the wet season. Fifty-seven vertical profiles of ozone concentration, potential temperature, and specific humidity were collected from surface to 500 m above ground level (a.g.l.) at high vertical and temporal resolutions by use of embedded sensors on the UAV. Abrupt changes in ozone concentration with altitude served as a proxy of nighttime boundary layer (NBL) height for the case of a normal, undisturbed, stratified nighttime atmosphere, corresponding to 40% of the cases. The median height of the boundary layer was 300 m. A turbulent mixing NBL constituted 28% of the profiles, while the median height of the boundary layer was 290 m. The remaining 32% of profiles corresponded to complex atmospheres without clear boundary layer heights. The occurrence of the three different cases correlated well with relative cloud cover. The results show that the standard nighttime model widely implemented in chemical transport models holds just 40% of the time, suggesting new challenges in modeling of regional nighttime chemistry. The boundary layer heights were also somewhat higher than observed previously over forested and pasture areas in Amazonia, indicating the important effect of the urban heat island. © 2019 by the authors.

The study of dissolved organic matter (DOM) in natural waters is hindered by its complex structure and low concentration. Spectroscopic methods (e.g. UV-Vis spectrometry) can be used for the characterization of its chromophoric fraction (CDOM) due to their simplicity, rapid response, low price and high sensitivity. The absorption spectrum of CDOM is unstructured with an exponential decrease in absorbance at increasing wavelength. Absorbance intensity gives an indirect estimate of CDOM concentration, whereas the shape of the spectrum provides insights into its composition. Changes in absorbance spectra can therefore be useful indicators of sources, degree of degradation as well as interactions of DOM with metals. There are over 20 different parameters that can be derived from the UV-Vis spectra in order to gain information on CDOM in natural waters. Only few of these parameters are commonly used (e.g. S275-290, S350-400, SR, SUVA, a254), the others are proposed based on "well correlated" relationship with other DOM specific parameters. Analysis and interpretation of UV-Vis spectra are challenging since there are numerous possibilities to treat the raw spectra and there is still no general agreement among scientists on the interpretation of all these parameters. Here we present ASFit, a new, windows-based "all-inclusive" software tool, for the basic and advanced treatment of CDOM UV/Vis spectra. It computes the most used parameters in few seconds and presents data in interactive graphs. ASFit can also be used to study trace metals complexation with DOM based on differential spectra. © 2019 Elsevier Ltd

The silicon isotopic composition (30Si) of deep sea sponges' skeletal element - spicules - reflects the silicic acid (DSi) concentration of their surrounding water and can be used as natural archives of bottom water nutrients. In order to reconstruct the past silica cycle robustly, it is essential to better constrain the mechanisms of biosilicification, which are not yet well understood. Here, we show that the apparent isotopic fractionation (30Si) during spicule formation in deep sea sponges from the equatorial Atlantic ranges from ĝ'6.74 ‰ to ĝ'1.50 ‰ in relatively low DSi concentrations (15 to 35 μM). The wide range in isotopic composition highlights the potential difference in silicification mechanism between the two major classes, Demospongiae and Hexactinellida. We find the anomalies in the isotopic fractionation correlate with skeletal morphology, whereby fused framework structures, characterised by secondary silicification, exhibit extremely light 30Si signatures compared with previous studies. Our results provide insight into the processes involved during silica deposition and indicate that reliable reconstructions of past DSi can only be obtained using silicon isotope ratios derived from sponges with certain spicule types. © Author(s) 2018. Acknowledgements. We acknowledge the science team and the crew of JC094 and Laura Robinson for cruise organisation. We would also like to thank Paul Curnow for constructive comments, Stuart Kearns for his SEM training and assistance, and Maria López-Acosta for her help. Finally, the funding from the Royal Society (grant code RG130386) and from the European Research Council is acknowledged. Joana R. Xavier received support from the European Union’s Horizon 2020 research and innovation program through the SponGES project (grant agreement no. 679849).

As part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon 2014/5) Experiment, detailed aerosol and trace gas measurements were conducted near Manaus, a metropolis located in the central Amazon Basin. Measurements of aerosol particles and trace gases were done downwind Manaus at the sites T2 (Tiwa Hotel) and T3 (Manacapuru), at a distance of 8 and 70 km from Manaus, respectively. Based on in-plume measurements closer to Manaus (site T2), the chemical signatures of city emissions were used to improve the interpretation of pollutant levels at the T3 site. We derived chemical and physical properties for the city's atmospheric emission ensemble, taking into account only air masses impacted by the Manaus plume at both sites, during the wet and dry season Intensive Operating Periods (IOPs). At T2, average concentrations of aerosol number (CN), CO and SO2 were 5500 cm−3 (between 10 and 490 nm), 145 ppb and 0.60 ppb, respectively, with a typical ratio ΔCN/ΔCO of 60–130 particles cm−3 ppb−1. The aerosol scattering (at RH < 60%) and absorption at 637 nm at T2 ranged from 10 to 50 M m−1 and 5–10 M m−1, respectively, leading to a mean single scattering albedo (SSA) of 0.70. In addition to identifying periods dominated by Manaus emissions at both T2 and T3, the plume transport between the two sampling sites was studied using back trajectory calculations. Results show that the presence of the Manaus plume at site T3 was important mainly during the daytime and at the end of the afternoons. During time periods directly impacted by Manaus emissions, an average aerosol number concentration of 3200 cm−3 was measured at T3. Analysis of plume evolution between T2 and T3 indicates a transport time of 4–5 h. Changes of submicron organic and sulfate aerosols ratios relative to CO (ΔOA/ΔCO and ΔSO4/ΔCO, respectively) indicate significant production of secondary organic aerosol (SOA), corresponding to a 40% mass increase in OA and a 30% in SO4 mass concentration. Similarly, during air mass arrival at T3 the SSA increased to 0.83 from 0.70 at T2, mainly associated with an increase in organic aerosol concentration. Aerosol particle size distributions show a strong decrease in the Aitken nuclei mode (10–100 nm) during the transport from T2 to T3, in particular above 30 nm, as a result of efficient coagulation processes into larger particles. A decrease of 30% in the particle number concentration and an increase of about 50 nm in geometric mean diameter were observed from T2 to T3 sites. The study of the evolution of aerosol properties downwind of the city of Manaus improves our understanding of how coupling of anthropogenic and biogenic sources may be impacting the sensitive Amazonian atmosphere. © 2018 The Authors

In this study, axenic cultures of sulfate-reducing (SRB) and nitrate-reducing (NRB) bacteria were examined for their ability to methylate inorganic tin and to methylate or dealkylate butyltin compounds. Environmentally relevant concentrations of natural abundance tributyltin (TBT) and 116Sn-enriched inorganic tin were added to bacterial cultures to identify bacterial-mediated methylation and dealkylation reactions. The results show that none of the Desulfovibrio strains tested was able to induce any transformation process. In contrast, Desulfobulbus propionicus strain DSM-6523 degraded TBT either under sulfidogenic or non-sulfidogenic conditions. In addition, it was able to alkykate 116Sn-enriched inorganic tin leading to the formation of more toxic dimethyltin and trimethyltin. A similar capacity was observed for incubations of Pseudomonas but with a much greater dealkykation of TBT. As such, Pseudomonas sp. ADR42 degraded 61% of the initial TBT under aerobic conditions and 35% under nitrate-reducing conditions. This is the first work reporting a simultaneous TBT degradation and a methylation of both inorganic tin species and TBT dealkykation products by SRB and NRB under anoxic conditions. These reactions are environmentally relevant as they can control the mobility of these compounds in aquatic ecosystems; as well as their toxicity toward resident organisms. © 2018 Elsevier P.R.G. would like to acknowledge the postdoctoral fellowship from the “Secretaria de Estado de Universidades e Investigacion” of the Spanish Ministry of Education and Science. P.N. would like to acknowledge the Doctoral fellowship from the Basque Country. This project was funded by French National Research Agency ( ANR – Jeune Chercheur program) in the framework of the MINAMETA project ( JCJC2006-0044 ). T. Stoichev is grateful to the Foundation for Science and Technology for fellowship SFRH/BPD/88675/2012 , co-financed by Programa Operacional Potencial Humano (POPH) /Fundo Social Europeu (FSE). Appendix A

Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Stable water isotopes (δ2H, δ18O) were used to trace hydrological processes and tritium (3H) to evaluate the relative contribution of modern water in samples. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal groundwater, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO3-type. It originates as recharge at "La Primavera" caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal groundwater is characterized by high salinity, temperature, Cl, Na and HCO3, and the presence of minor elements such as Li, Mn and F. It is a mixed-HCO3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural return flow. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Twenty-seven groundwater samples contain at least a small fraction of modern water. The application of a multivariate mixing model allowed the mixing proportions of hydrothermal fluids, polluted waters and cold groundwater in sampled water to be evaluated. This study will help local water authorities to identify and dimension groundwater contamination, and act accordingly. It may be broadly applicable to other active volcanic systems on Earth.

The estimated global CO2 emission rates and the measured atmospheric CO2 concentrations show that only a certain share of the emitted CO2 accumulates in the atmosphere. For given atmospheric emissions of CO2, the effective lifetime determines its accumulation in the atmosphere and, consequently, its impact on the future global warming. We found that on average the inferred effective lifetime of CO2 decreases as its atmospheric concentration increases, reducing the rate of its accumulation in the atmosphere. We derived a power function that fits the varying lifetimes. Based on this fitting function, we calculated the increase of CO2 for different scenarios of future global emission rates.

Meteorological conditions, gas-phase precursors, and aerosol acidity (pH) can influence the formation of secondary inorganic aerosols (SIA) in fine particulate matter (PM2.5). Most works related to the influence of pH and gas-phase precursors on SIA have been laboratory research, but field observation research is very scarce, especially in arid environments. The relationship among SIA, pH, gas-phase precursors, and meteorological conditions are investigated in Hohhot, a major city in China with an arid environment. Secondary inorganic species, e.g., SO4 2−, NO3 −, were typically found at low levels, reflecting the low level of secondary aerosol. It is interesting to note that the level of SO2 in Hohhot was higher than in other cities while SO4 2− was relatively lower than in other cities. Multiple receptor models were used to explore the contributions to the SIA and quantify the source impacts on the SIA. Annual average aerosol pH in Hohhot was 5.6 (range 1.1-8.4) which was estimated by a thermodynamic equilibrium model. Additionally, a statistical method was used to evaluate the influence of SIA sources on ambient aerosol concentrations. Aerosol water content and particulate acidity were found to be positively associated with secondary SO4 2−, while NO2 and RH had a significant impact on secondary NO3 − in an arid atmosphere. The findings explain the relationship between gaseous precursors, relative humidity, aerosol pH and temperature in the arid city of Hohhot. © 2018 Elsevier B.V.

In situ measurements using unmanned aerial vehicles (UAVs) and remote sensing observations can independently provide dense vertically resolved measurements of atmospheric aerosols, information which is strongly required in climate models. In both cases, inverting the recorded signals to useful information requires assumptions and constraints, and this can make the comparison of the results difficult. Here we compare, for the first time, vertical profiles of the aerosol mass concentration derived from light detection and ranging (lidar) observations and in situ measurements using an optical particle counter on board a UAV during moderate and weak Saharan dust episodes. Agreement between the two measurement methods was within experimental uncertainty for the coarse mode (i.e. particles having radii >0.5 µm), where the properties of dust particles can be assumed with good accuracy. This result proves that the two techniques can be used interchangeably for determining the vertical profiles of aerosol concentrations, bringing them a step closer towards their systematic exploitation in climate models.

WOS: 000432019600015, Although the water chemistry in saline lakes can differ drastically due to subtle differences in inflowing water conditions, the concentrations, distributions, and geochemical behaviors of trace elements in such environments are poorly understood. In this study, the influence of major-ion chemistry on the trace element distribution in saline lakes is examined based on major and trace element concentrations and geochemical modeling in three carbonate-rich saline lakes located in Mongolia and Turkey. The results are compared to data reported from other carbonate-rich and carbonate-depleted lakes. The concentrations of U and oxyanions (V, Mo, and W) in carbonate-rich saline lakes are several orders of magnitude higher than their contributing rivers and seawater. By contrast, their concentrations in carbonate-depleted saline lakes are lower than those in rivers and oceans. The high U concentrations in carbonate-rich saline lakes are possibly attributed to the formation of (magnesium-)uranyl-carbonate complexes, and the high oxyanion concentrations are likely a result of the high pH of lake water preventing them from being adsorbed onto solid phases such as suspended particulate matter and sediment. Strontium and Ba concentrations are lower in carbonate-rich saline lakes than in river water and seawater, but relatively higher in carbonate-depleted lakes. Incorporation into aragonite and/or calcite, adsorption onto solid phases, and formation of carbonate minerals are possible mechanisms that may account for the lower concentrations of these elements in carbonate-rich lakes. These results help elucidate the influence of water chemistry on trace element distribution in saline lakes., Japan Society for the Promotion of Science KAKENHI [15H05114, 21255002], We are grateful to Prof. Y. Sohrin of Kyoto University for providing the inductively coupled plasma mass spectrometry facilities. We are also grateful to the two anonymous reviewers for their constructive comments and invaluable suggestions. This work was partly supported by Japan Society for the Promotion of Science KAKENHI grant numbers 21255002 and 15H05114.

The hydroxyl radical (OH) removes most atmospheric pollutants from air. The loss frequency of OH radicals due to the combined effect of all gas-phase OH reactive species is a measureable quantity termed total OH reactivity. Here we present total OH reactivity observations in pristine Amazon rainforest air, as a function of season, time-of-day and height (0–80 m). Total OH reactivity is low during wet (10 s−1) and high during dry season (62 s−1). Comparison to individually measured trace gases reveals strong variation in unaccounted for OH reactivity, from 5 to 15% missing in wet-season afternoons to mostly unknown (average 79%) during dry season. During dry-season afternoons isoprene, considered the dominant reagent with OH in rainforests, only accounts for ∼20% of the total OH reactivity. Vertical profiles of OH reactivity are shaped by biogenic emissions, photochemistry and turbulent mixing. The rainforest floor was identified as a significant but poorly characterized source of OH reactivity., The degree to which biogenic volatile organic compounds released by the Amazon canopy impact oxidation capacity remains uncertain. Here, the authors evaluate the vertical distribution of total hydroxyl radical reactivity and individual trace gases in the Amazon rainforest, and determine seasonal variations.

A comprehensive grid-based study of indoor Rn concentration in all accessible urban areas of the Republic of Cyprus, where 67.3% of the population resides, is presented. During the years 2004-2012, a total of 407 measurements of indoor Rn in the four highly-populated urbanised areas of Lefkosia, Lemesos, Larnaka, and Pafos districts were conducted, using high-sensitivity active Rn portable detectors. The four districts were subdivided into 189 grid cells, each of 1km2 in area. The grid cell mean indoor Rn concentration is in the range of 1.7 to 86.4Bq/m3, with an overall geometrical mean of 14.3±10.0Bq/m3, and a median of 14.3±3.9. The Rn mean in Cyprus is almost two-and-a-half times lower than the estimated world average of 39Bq/m3. The equivalent annual effective dose rate for each measurement was also calculated and compared to the corresponding world value. The spatial distribution and variation of Rn concentration values are also shown on maps of the urban areas of these districts. The conclusion of the present extensive and systematic Rn survey is that the Rn risk in the highly populated areas of Cyprus is low. © 2015 Elsevier B.V. 159 20 32

Article, Cloud condensation nuclei counter (CCNC) measurements performed at 14 locations around the world within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) framework have been analysed and discussed with respect to the cloud condensation nuclei (CCN) activation and hygroscopic properties of the atmospheric aerosol. The annual mean ratio of activated cloud condensation nuclei (NCCN) to the total number concentration of particles (NCN), known as the activated fraction A, shows a similar functional dependence on supersaturation S at many locations – exceptions to this being certain marine locations, a free troposphere site and background sites in south-west Germany and northern Finland. The use of total number concentration of particles above 50 and 100 nm diameter when calculating the activated fractions (A50 and A100, respectively) renders a much more stable dependence of A on S; A50 and A100 also reveal the effect of the size distribution on CCN activation. With respect to chemical composition, it was found that the hygroscopicity of aerosol particles as a function of size differs among locations. The hygroscopicity parameter κ decreased with an increasing size at a continental site in south-west Germany and fluctuated without any particular size dependence across the observed size range in the remote tropical North Atlantic and rural central Hungary. At all other locations κ increased with size. In fact, in Hyytiälä, Vavihill, Jungfraujoch and Pallas the difference in hygroscopicity between Aitken and accumulation mode aerosol was statistically significant at the 5 % significance level. In a boreal environment the assumption of a size-independent κ can lead to a potentially substantial overestimation of NCCN at S levels above 0.6 %. The same is true for other locations where κ was found to increase with size. While detailed information about aerosol hygroscopicity can significantly improve the prediction of NCCN, total aerosol number concentration and aerosol size distribution remain more important parameters. The seasonal and diurnal patterns of CCN activation and hygroscopic properties vary among three long-term locations, highlighting the spatial and temporal variability of potential aerosol–cloud interactions in various environments., published version, http://purl.org/eprint/status/PeerReviewed

Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious, there is a need to supplement long-term observations with automated techniques such as those provided by digital repeat photography at high temporal and spatial resolution. We present the first synthesis from a growing observational network of digital cameras installed on towers across Europe above deciduous and evergreen forests, grasslands and croplands, where vegetation and atmosphere CO2 fluxes are measured continuously. Using colour indices from digital images and using piecewise regression analysis of time series, we explored whether key changes in canopy phenology could be detected automatically across different land use types in the network. The piecewise regression approach could capture the start and end of the growing season, in addition to identifying striking changes in colour signals caused by flowering and management practices such as mowing. Exploring the dates of green-up and senescence of deciduous forests extracted by the piecewise regression approach against dates estimated from visual observations, we found that these phenological events could be detected adequately (RMSE < 8 and 11 days for leaf out and leaf fall, respectively). We also investigated whether the seasonal patterns of red, green and blue colour fractions derived from digital images could be modelled mechanistically using the PROSAIL model parameterised with information of seasonal changes in canopy leaf area and leaf chlorophyll and carotenoid concentrations. From a model sensitivity analysis we found that variations in colour fractions, and in particular the late spring `green hump' observed repeatedly in deciduous broadleaf canopies across the network, are essentially dominated by changes in the respective pigment concentrations. Using the model we were able to explain why this spring maximum in green signal is often observed out of phase with the maximum period of canopy photosynthesis in ecosystems across Europe. Coupling such quasi-continuous digital records of canopy colours with co-located CO2 flux measurements will improve our understanding of how changes in growing season length are likely to shape the capacity of European ecosystems to sequester CO2 in the future.

The discarded materials from different sources can be utilized as effective materials in wastewater remediation. This proposed study was aimed mainly to investigate the possibility of Effective Microorganisms based compost (EMKC), which is derived from the kitchen solid waste, as a non-conventional low cost adsorbent for the removal of malachite green from aqueous solution. Batch experiments were carried out to evaluate the optimum operating parameters like pH (2-9), initial dye concentration (50-1000mg/L), adsorbent particle size (0.6-2.36mm) and adsorbent dosage (2-12g/L). EMKC recorded maximum uptake of 136.6mg/g of MG at pH 8, initial dye concentration 1000mg/L, adsorbent particle size 1.18mm and adsorbent dosage 4g/L. Two and three parameter adsorption models were employed to describe experimental biosorption isotherm data. The results revealed that the Sips model resulted in better fit than other models. The pseudo-first and -second order models were applied to describe kinetic data, of which the pseudo-second order described experimental data better with high correlation coefficient. This investigation suggested that EMKC could be an effective and low cost material for the removal of malachite green dye from aqueous solution. � 2015 Elsevier Inc.

Indian cities feature high human population density, heterogeneous traffic, mixed land-use patterns and mostly tropical meteorological conditions. Characteristics of ambient CO2 concentrations under these distinctive features are very specific and the related studies are limited. This paper presents the characteristics of ground level CO2 concentrations at three contrasting land uses (residential, commercial and industrial) in a tropical urban area of India. The CO2 concentrations were monitored in Chennai city for 31 days at each land use during June-September, 2013. Emissions of CO2 from all the major anthropogenic sources present at the three study sites were also quantified. Results indicated that the daily average CO2 concentrations were high at commercial (467�35.15ppm) and industrial (464�31.68ppm) sites than at residential site (448�33.45 ppm). The quantified CO2 emissions were also showed high levels at commercial (1190 tons/day) and industrial sites (8886 tons/day) than at residential site (90tons/day). On a diurnal scale, CO2 concentrations were low during afternoons and high during the late evenings and early morning hours at all the three types of land use sites. At the urban residential site, the domestic sector had a strong impact on the day time CO2 concentrations, while soil and plant respiration phenomena had a greater control over the night time CO2 concentrations. Further, the CO2 concentrations were high during the stagnation and stable meteorological conditions than the ventilation and unstable conditions. � 2015 Elsevier Ltd.

Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NOx under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OSc), and mass yield. The OA oxidation state generally increased during photo-oxidation, and the final OA OSc ranged from -0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. There was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA. © Author(s) 2015.

To better understand the photochemical processing of dicarboxylic acids and related polar compounds, we conducted batch UV irradiation experiments on two types of aerosol samples collected from India, which represent anthropogenic (AA) and biogenic (BA) aerosols, for time periods of 0.5 to 120 h. The irradiated samples were analyzed for molecular compositions of diacids, oxoacids and ?-dicarbonyls. The results show that photochemical degradation of oxalic (C2), malonic (C3) and other C8-C12 diacids overwhelmed their production in aqueous aerosols, whereas succinic acid (C4) and C5-C7 diacids showed a significant increase (ca. 10 times) during the course of irradiation experiments. The photochemical formation of oxoacids and ?-dicarbonyls overwhelmed their degradation during the early stages of experiment except for ?-oxooctanoic acid (?C8), which showed a similar pattern to that of C4. We also found a gradual decrease in the relative abundance of C2 to total diacids and an increase in the relative abundance of C4 during prolonged experiment. Based on the changes in concentrations and mass ratios of selected species with the irradiation time, we hypothesize that iron-catalyzed photolysis of C2 and C3 diacids controls their concentrations in Fe-rich atmospheric waters, whereas photochemical formation of C4 diacid (via ?C8) is enhanced with photochemical processing of aqueous aerosols in the atmosphere. This study demonstrates that the ambient aerosols contain abundant precursors that produce diacids, oxoacids and ?-dicarbonyls, although some species such as oxalic acid decompose extensively during an early stage of photochemical processing. � Author(s) 2015.

The sensitivity and specificity of current Giardia cyst detection methods for foods are largely determined by the effectiveness of the elution, separation, and concentration methods used. The aim of these methods is to produce a final suspension with an adequate concentration of Giardia cysts for detection and a low concentration of interfering food debris. In the present study, a microfluidic device, which makes use of inertial separation, was designed and fabricated for the separation of Giardia cysts. A cyclical pumping platform and protocol was developed to concentrate 10-ml suspensions down to less than 1 ml. Tests involving Giardia duodenalis cysts and 1.90-μm microbeads in pure suspensions demonstrated the specificity of the microfluidic chip for cysts over smaller nonspecific particles. As the suspension cycled through the chip, a large number of beads were removed (70%) and the majority of the cysts were concentrated (82%). Subsequently, the microfluidic inertial separation chip was integrated into a method for the detection of G. duodenalis cysts from lettuce samples. The method greatly reduced the concentration of background debris in the final suspensions (10-fold reduction) in comparison to that obtained by a conventional method. The method also recovered an average of 68.4% of cysts from 25-g lettuce samples and had a limit of detection (LOD) of 38 cysts. While the recovery of cysts by inertial separation was slightly lower, and the LOD slightly higher, than with the conventional method, the sample analysis time was greatly reduced, as there were far fewer background food particles interfering with the detection of cysts by immunofluorescence microscopy.

Particle water and pH are predicted using meteorological observations (relative humidity (RH), temperature (T)), gas/particle composition, and thermodynamic modeling (ISORROPIA-II). A comprehensive uncertainty analysis is included, and the model is validated. We investigate mass concentrations of particle water and related particle pH for ambient fine-mode aerosols sampled in a relatively remote Alabama forest during the Southern Oxidant and Aerosol Study (SOAS) in summer and at various sites in the southeastern US during different seasons, as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study. Particle water and pH are closely linked; pH is a measure of the particle H+ aqueous concentration and depends on both the presence of ions and amount of particle liquid water. Levels of particle water, in turn, are determined through water uptake by both the ionic species and organic compounds. Thermodynamic calculations based on measured ion concentrations can predict both pH and liquid water but may be biased since contributions of organic species to liquid water are not considered. In this study, contributions of both the inorganic and organic fractions to aerosol liquid water were considered, and predictions were in good agreement with measured liquid water based on differences in ambient and dry light scattering coefficients (prediction vs. measurement: slope = 0.91, intercept = 0.5 μg m−3, R2 = 0.75). ISORROPIA-II predictions were confirmed by good agreement between predicted and measured ammonia concentrations (slope = 1.07, intercept = −0.12 μg m−3, R2 = 0.76). Based on this study, organic species on average contributed 35% to the total water, with a substantially higher contribution (50%) at night. However, not including contributions of organic water had a minor effect on pH (changes pH by 0.15 to 0.23 units), suggesting that predicted pH without consideration of organic water could be sufficient for the purposes of aqueous secondary organic aerosol (SOA) chemistry. The mean pH predicted in the Alabama forest (SOAS) was 0.94 ± 0.59 (median 0.93). pH diurnal trends followed liquid water and were driven mainly by variability in RH; during SOAS nighttime pH was near 1.5, while daytime pH was near 0.5. pH ranged from 0.5 to 2 in summer and 1 to 3 in the winter at other sites. The systematically low pH levels in the southeast may have important ramifications, such as significantly influencing acid-catalyzed reactions, gas–aerosol partitioning, and mobilization of redox metals and minerals. Particle ion balances or molar ratios, often used to infer pH, do not consider the dissociation state of individual ions or particle liquid water levels and do not correlate with particle pH.

In this paper, a new way to apportion the absorption coefficient (babs) of carbonaceous atmospheric aerosols starting from a multi-wavelength optical analysis is shown. This methodology can disentangle and quantify the contribution to total absorption of equivalent black carbon (EBC) emitted by wood burning (EBCWB) and fossil fuel (EBCFF) as well as brown carbon (BrC) due to incomplete combustion. The method uses the information gathered at five different wavelengths in a renewed and upgraded version of the approach usually referred to as Aethalometer model. Moreover, we present the results of an apportionment study of carbonaceous aerosol sources performed in a rural area and in a coastal city, both located in the North-West of Italy. Results obtained by the proposed approach are validated against independent measurements of levoglucosan and radiocarbon. At the rural site the EBCWB and EBCFF relative contributions are about 40% and 60% in winter and 15% and 85% in summer, respectively. At the coastal urban site, EBCWB and EBCFF are about 15% and 85% during fall. The OC contribution to the wood burning source at the rural site results approximately 50% in winter and 10% in summer and about 15% at the coastal urban site in fall. The new methodology also provides a direct measurement of the absorption Angstrom exponent of BrC (αBrC) which resulted αBrC = 3.95 ± 0.20.

This paper presents the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). An increasing gradient of σsp is observed when moving from remote environments (arctic/mountain) to regional and to urban environments. At a regional level in Europe, σsp also increases when moving from Nordic and Baltic countries and from western Europe to central/eastern Europe, whereas no clear spatial gradient is observed for other station environments. The SAE does not show a clear gradient as a function of the placement of the station. However, a west-to-east-increasing gradient is observed for both regional and mountain placements, suggesting a lower fraction of fine-mode particle in western/south-western Europe compared to central and eastern Europe, where the fine-mode particles dominate the scattering. The g does not show any clear gradient by station placement or geographical location reflecting the complex relationship of this parameter with the physical properties of the aerosol particles. Both the station placement and the geographical location are important factors affecting the intraannual variability. At mountain sites, higher σsp and SAE values are measured in the summer due to the enhanced boundary layer influence and/or new particle-formation episodes. Conversely, the lower horizontal and vertical dispersion during winter leads to higher σsp values at all low-altitude sites in central and eastern Europe compared to summer. These sites also show SAE maxima in the summer (with corresponding g minima). At all sites, both SAE and g show a strong variation with aerosol particle loading. The lowest values of g are always observed together with low σsp values, indicating a larger contribution from particles in the smaller accumulation mode. During periods of high σsp values, the variation of g is less pronounced, whereas the SAE increases or decreases, suggesting changes mostly in the coarse aerosol particle mode rather than in the fine mode. Statistically significant decreasing trends of σsp are observed at 5 out of the 13 stations included in the trend analyses. The total reductions of σsp are consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe. © Author(s) 2018.

Aerosol-cloud interactions (ACI) constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce the uncertainties and gain more confidence in the simulation of ACI, models need to be evaluated against observations, in particular against measurements of cloud condensation nuclei (CCN). Here we present a data set - ready to be used for model validation - of long-term observations of CCN number concentrations, particle number size distributions and chemical composition from 12 sites on 3 continents. Studied environments include coastal background, rural background, alpine sites, remote forests and an urban surrounding. Expectedly, CCN characteristics are highly variable across site categories. However, they also vary within them, most strongly in the coastal background group, where CCN number concentrations can vary by up to a factor of 30 within one season. In terms of particle activation behaviour, most continental stations exhibit very similar activation ratios (relative to particles 20nm) across the range of 0.1 to 1.0% supersaturation. At the coastal sites the transition from particles being CCN inactive to becoming CCN active occurs over a wider range of the supersaturation spectrum. Several stations show strong seasonal cycles of CCN number concentrations and particle number size distributions, e.g. at Barrow (Arctic haze in spring), at the alpine stations (stronger influence of polluted boundary layer air masses in summer), the rain forest (wet and dry season) or Finokalia (wildfire influence in autumn). The rural background and urban sites exhibit relatively little variability throughout the year, while short-term variability can be high especially at the urban site. The average hygroscopicity parameter, calculated from the chemical composition of submicron particles was highest at the coastal site of Mace Head (0.6) and lowest at the rain forest station ATTO (0.2-0.3). We performed closure studies based on -Kohler theory to predict CCN number concentrations. The ratio of predicted to measured CCN concentrations is between 0.87 and 1.4 for five different types of . The temporal variability is also well captured, with Pearson correlation coefficients exceeding 0.87. Information on CCN number concentrations at many locations is important to better characterise ACI and their radiative forcing. But long-term comprehensive aerosol particle characterisations are labour intensive and costly. Hence, we recommend operating migrating-CCNCs to conduct collocated CCN number concentration and particle number size distribution measurements at individual locations throughout one year at least to derive a seasonally resolved hygroscopicity parameter. This way, CCN number concentrations can only be calculated based on continued particle number size distribution information and greater spatial coverage of long-term measurements can be achieved. © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License.

International audience; We analyzed helium and neon in 24 samples from between 3,607 and 3,767 m (i.e., down to 2 m above the lake-ice interface) of the accreted ice frozen to the ceiling of Lake Vostok. Within uncertainties, the neon budget of the lake is balanced, the neon supplied to the lake by the melting of glacier ice being compensated by the neon exported by lake ice. The helium concentration in the lake is about 12 times more than in the glacier ice, with a measured 3He/4He ratio of 0.12 ± 0.01 Ra. This shows that Lake Vostok's waters are enriched by a terrigenic helium source. The 3He/4He isotope ratio of this helium source was determined. Its radiogenic value (0.057 × Ra) is typical of an old continental province, ruling out any magmatic activity associated with the tectonic structure of the lake. It corresponds to a low geothermal heat flow estimated at 51 mW/m2.

Management of groundwater requires a sufficient coverage of accurate groundwater quality data. These data are usually collected from monitoring wells which are spatially distributed in the river basin or the groundwater body that is studied. A minimum number of monitoring wells with an optimum spatial distribution is desired to ensure a cost-effective observation of the groundwater body. Therefore, the configuration of groundwater monitoring networks and the number of required wells becomes an important engineering optimization problem. The goal of this study is to find an optimum monitoring network with the fewest wells that provides sufficient spatial coverage on groundwater quality. With the presented method redundant wells in an already existing network are identified. Here, a genetic algorithm (GA) based optimization approach is used in which each monitoring well in the watershed is represented with a binary GA bit to evaluate if the corresponding monitoring well will be selected for the network. The proposed approach can solve the problem by simultaneously optimizing two conflicting objectives. The first objective is the maximization of the match between the interpolated groundwater quality concentration distributions obtained using data from all available monitoring wells and the wells from the newly generated network. The match is primarily evaluated using the Nash-Sutcliffe (NS) model efficiency. Groundwater quality is represented by the water quality index WQI that aggregates several quality parameters. The second objective deals with the minimization of the number of monitoring wells in the newly generated network by considering cost-related constraints. These two objectives are integrated in a single objective function where different combinations of both objectives are investigated by considering two cases. The applicability of the proposed approach is evaluated for the groundwater monitoring network of the Gediz River Basin (GRB) which is one of the most important river basins in Turkey. Findings indicate that the proposed approach significantly reduces the number of monitoring wells with a relatively small deviation of the spatial distribution of the WQI values. Also, the monitoring network is optimized such that sampling points are removed from less polluted areas and selected in areas with higher pollutant concentrations.

This paper presents the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). An increasing gradient of σsp is observed when moving from remote environments (arctic/mountain) to regional and to urban environments. At a regional level in Europe, σsp also increases when moving from Nordic and Baltic countries and from western Europe to central/eastern Europe, whereas no clear spatial gradient is observed for other station environments. The SAE does not show a clear gradient as a function of the placement of the station. However, a west-to-east-increasing gradient is observed for both regional and mountain placements, suggesting a lower fraction of fine-mode particle in western/south-western Europe compared to central and eastern Europe, where the fine-mode particles dominate the scattering. The g does not show any clear gradient by station placement or geographical location reflecting the complex relationship of this parameter with the physical properties of the aerosol particles. Both the station placement and the geographical location are important factors affecting the intraannual variability. At mountain sites, higher σsp and SAE values are measured in the summer due to the enhanced boundary layer influence and/or new particle-formation episodes. Conversely, the lower horizontal and vertical dispersion during winter leads to higher σsp values at all low-altitude sites in central and eastern Europe compared to summer. These sites also show SAE maxima in the summer (with corresponding g minima). At all sites, both SAE and g show a strong variation with aerosol particle loading. The lowest values of g are always observed together with low σsp values, indicating a larger contribution from particles in the smaller accumulation mode. During periods of high σsp values, the variation of g is less pronounced, whereas the SAE increases or decreases, suggesting changes mostly in the coarse aerosol particle mode rather than in the fine mode. Statistically significant decreasing trends of σsp are observed at 5 out of the 13 stations included in the trend analyses. The total reductions of σsp are consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe. © Author(s) 2018., Acknowledgements. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 654109, ACTRIS (project no. 262254), ACTRIS-PPP (project no. 739530). We thank the International Foundation High Altitude Research Stations JFJ (Jungfraujoch) and Gornergrat (HFSJG), which made it possible to carry out the experiments at the High Altitude Research JFJ Station and the support of MeteoSwiss within the Swiss programme of the Global Atmosphere Watch (GAW) of the WMO. The MAD (Madrid) station is co-financed by the PROACLIM (CGL2014-52877-R) project. The SMR (Hyytiälä) station acknowledges BACCHUS (project no. 603445), CRAICC (project no. 26060) and the Academy of Finland (project no. 3073314). The UGR (Granada) station is co-financed by the Spanish Ministry of Economy and Competitiveness through project CGL2016-81092-R. Measurements at MSY (Montseny) and MSA (Montsec) stations were supported by the MINECO (Spanish Ministry of Economy, Industry and Competitiveness) and FEDER funds under the PRISMA project (CGL2012-39623-C02/00) and under the HOUSE project (CGL2016-78594-R), by the MAGRAMA (Spanish Ministry of Agriculture, Food and Environment) and by the Generalitat de Catalunya (AGAUR 2014 SGR33, AGAUR 2017 SGR41 and the DGQA). Measurements at IZO (Izaña) were supported by the AEROATLAN project (CGL2015-17 66229-P), co-funded by the Ministry of Economy and Competitiveness of Spain and the European Regional Development Fund. Station KOS (Košetice) is supported by the Ministry of Education, Youth and Sports of the Czech Republic within the project to support the national research infrastructure ACTRIS – participation of the Czech Republic (ACTRIS-CZ – LM2015037). Measurements at PUY (Puy de Dôme) were partly supported by CNRS-INSU, University Clermont-Auvergne, OPGC and the french CLAP programme. The PAL (Pallas) station acknowledges KONE Foundation, Academy of Finland (project no. 269095 and no. 296302). CHC (Mt Chacaltaya) station received support from Institut de Recherche pour le Développement (IRD) under both Jeune Equipe programme attributed to LFA and support to ACTRIS-FR programme. CHC received grants from Labex OSUG@2020 (Investissements d’avenir – ANR10 LABX56). Marco Pandolfi is funded by a Ramón y Cajal Fellowship (RYC-2013-14036) awarded by the Spanish Ministry of Economy and Competitiveness. The authors would like to express their gratitude to David Carslaw and Karl Ropkins for providing the OpenAir software used in this paper (Carslaw and Ropkins, 2012; Carslaw, 2012). We also thank the co-editor Andreas Petzold and two anonymous reviewers for their constructive comments.

An understanding of how anthropogenic emissions affect the concentrations and composition of airborne particulate matter (PM) is fundamental to quantifying the influence of human activities on climate and air quality. The central Amazon Basin, especially around the city of Manaus, Brazil, has experienced rapid changes in the past decades due to ongoing urbanization. Herein, changes in the concentration and composition of submicron PM due to pollution downwind of the Manaus metropolitan region are reported as part of the GoAmazon2014/5 experiment. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a suite of other gas-and particle-phase instruments were deployed at the "T3" research site, 70 km downwind of Manaus, during the wet season. At this site, organic components represented 79 +/- 7% of the non-refractory PM1 mass concentration on average, which was in the same range as several upwind sites. However, the organic PM1 was considerably more oxidized at T3 compared to upwind measurements. Positive-matrix factorization (PMF) was applied to the time series of organic mass spectra collected at the T3 site, yielding three factors representing secondary processes (73 +/- 15% of total organic mass concentration) and three factors representing primary anthropogenic emissions (27 +/- 15 %). Fuzzy c-means clustering (FCM) was applied to the afternoon time series of concentrations of NOy, ozone, total particle number, black carbon, and sulfate. Four clusters were identified and characterized by distinct air mass origins and particle compositions. Two clusters, Bkgd-1 and Bkgd2, were associated with background conditions. Bkgd-1 appeared to represent near-field atmospheric PM production and oxidation of a day or less. Bkgd-2 appeared to represent material transported and oxidized for two or more days, often with out-of-basin contributions. Two other clusters, Pol-1 and Pol-2, represented the Manaus influence, one apparently associated with the northern region of Manaus and the other with the southern region of the city. A composite of the PMF and FCM analyses provided insights into the anthropogenic effects on PM concentration and composition. The increase in mass concentration of submicron PM ranged from 25% to 200% under polluted compared with background conditions, including contributions from both primary and secondary PM. Furthermore, a comparison of PMF factor loadings for different clusters suggested a shift in the pathways of PM production under polluted conditions. Nitrogen oxides may have played a critical role in these shifts. Increased concentrations of nitrogen oxides can shift pathways of PM production from HO2-dominant to NO-dominant as well as increase the concentrations of oxidants in the atmosphere. Consequently, the oxidation of biogenic and anthropogenic precursor gases as well as the oxidative processing of preexisting atmospheric PM can be accelerated. This combined set of results demonstrates the susceptibility of atmospheric chemistry, air quality, and associated climate forcing to anthropogenic perturbations over tropical forests. Atmospheric Radiation Measurement (ARM) Climate Research Facility; United States Department of Energy (DOE), Office of ScienceUnited States Department of Energy (DOE) [DE-SC0006680]; Office of Biological and Environmental Research; Atmospheric System Research (ASR), program of that office [DE-SC0011115, DE-SC0011105]; Amazonas State Research Foundation [FAPEAM 062.00568/2014, 134/2016]; Sao Paulo State Research FoundationFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [FAPESP 2013/05014-0]; USA National Science FoundationNational Science Foundation (NSF) [1106400, 1332998]; Brazilian Scientific Mobility Program (CsF/CAPES); US EPA STAR Graduate FellowshipUnited States Environmental Protection Agency [FP-91761701-0]; Brazilian National Council for Scientific and Technological Development (CNPq)National Council for Scientific and Technological Development (CNPq) [001030/2012-4] Institutional support was provided by the Central Office of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA), the National Institute of Amazonian Research (INPA), and Amazonas State University (UEA). We acknowledge support from the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a user facility of the United States Department of Energy (DOE; grant no. DE-SC0006680), Office of Science, sponsored by the Office of Biological and Environmental Research, and support from the Atmospheric System Research (ASR; grant no. DE-SC0011115, DE-SC0011105) program of that office. Additional funding was provided by the Amazonas State Research Foundation (grant no. FAPEAM 062.00568/2014 and 134/2016), the Sao Paulo State Research Foundation (grant no. FAPESP 2013/05014-0), the USA National Science Foundation (grant nos. 1106400 and 1332998), and the Brazilian Scientific Mobility Program (CsF/CAPES). Suzane S. de Sa. acknowledges support from the Faculty for the Future Fellowship of the Schlumberger Foundation. Brett B. Palm is grateful for a US EPA STAR Graduate Fellowship (grant no. FP-91761701-0). The authors thank Paulo Castillo for his assistance in quality checking the black carbon data from MAOS. Data access from the Sistema de Protecao da Amazonia (SIPAM) is gratefully acknowledged. The research was conducted under scientific license 001030/2012-4 of the Brazilian National Council for Scientific and Technological Development (CNPq).

The objective of this study was to evaluate the effects of seven nitrogen (N2)-fixing and/or phosphorus (P)-solubilizing and siderophore-producing microorganism based bio-fertilizers in single and triple strain combinations isolated from the acidic rhizospheric soil of native tea, grapevine, and wild red raspberries. As a result of this study, bacterial efficiency was found to be variable and depended on the bacterial strains and evaluated growth parameters. Plant growth-promoting rhizobacteria (PGPR) has improved macro- and micro-nutrient concentrations in grapevine leaves, and stimulated plant growth. Triple inoculation and single inoculation based bio fertilizers were found to stimulate overall plant growth, including shoot and leaf weight, main shoot length, leaf ground index, chlorophyll, nitrogen, zinc and iron content of grapevine cv ‘Italy’. Bio-fertilizers increased the nutrients such as nitrogen, zinc and iron concentrations and consequently increased the chlorophyll content of the leaves. © 2018, © 2018 Taylor & Francis.

The major and trace element component of 48 recent sediment samples in three distinct intervals (0–10, 10–20, and 20–30 cm) from Lake Acıgöl is described to present the current contamination levels and grift structure of detrital and evaporate mineral patterns of these sediments in this extreme saline environment. The spatial and vertical concentrations of major oxides were not uniform in the each subsurface interval. However, similar spatial distribution patterns were observed for some major element couples, due mainly to the detrital and evaporate origin of these elements. A sequential extraction procedure including five distinct steps was also performed to determine the different bonds of trace elements in the < 60-µ particulate size of recent sediments. Eleven trace elements (Ni, Fe, Cd, Pb, Cu, Zn, As, Co, Cr, Al and Mn) in nine surface and subsurface sediment samples were analyzed with chemical partitioning procedures to determine the trace element percentage loads in these different sequential extraction phases. The obtained accuracy values via comparison of the bulk trace metal loads with the total loads of five extraction steps were satisfying for the Ni, Fe, Cd, Zn, and Co. While, bulk analysis results of the Cu, Ni, and V elements have good correlation with total organic matter, organic fraction of sequential extraction characterized by Cu, As, Cd, and Pb. Shallow Lake Acıgöl sediment is characteristic with two different redox layer a) oxic upper level sediments, where trace metals are mobilized, b) reduced subsurface level, where the trace metals are precipitated. © 2018, Springer International Publishing AG, part of Springer Nature.