Concentrations Of Inorganic Ions Research Articles

Vertical Distributional Characteristics of Inorganic Ions of PM2.5 at Mt. Huashan, Inland China

PM2.5 was simultaneously collected using a high-volume sampler at 4 h intervals from the mountainside and the foot of the mountain in the Mt. Huashan region, inland China, during the summer of 2016, and the samples were analyzed for inorganic ions, to investigate the chemical characteristics and vertical distribution of the fine particles in the region. The results showed that the concentrations of PM2.5 were (46.9±38.2) μg·m-3 and (76.0±44.3) μg·m-3 on the mountainside and at the foot of Mt. Huashan, respectively. The concentrations of inorganic ions in PM2.5 was higher at the foot of the mountain than on the mountainside, with the order of the mass concentrations of the major ionic species being SO42- > NO3- > NH4+ > Ca2+. Among all the inorganic ions, SO42-, NO3-, and NH4+ are the dominant species, accounting for 89% and 85% of the total, on the mountainside and at the foot, respectively. The fine particulate NH4+ existed mostly in the forms of (NH4)2SO4 and NH4NO3 on the mountainside, and in the forms of NH4HSO4 and NH4NO3 at the foot of the mountain. Mass concentrations of PM2.5 and its major components on the mountainside showed clear diurnal variations, with maximums between 12:00-16:00, mainly due to the transport of the pollutants from the ground surface by the planetary boundary layer height variation and the valley breeze. In contrast, the diurnal variations of PM2.5 and its major components at the foot are characterized with two maxima, peaking between 08:00-12:00 in the daytime and 00:00-04:00 in the nighttime, respectively, mainly due to the increased emissions from both the morning rush-hour traffic and the nighttime on-road heavy-duty vehicles. Acidity of the fine particles was estimated by using the equivalent ratio of anions to cations and the thermodynamic equilibrium model ISORROPIA Ⅱ. Both methods showed that the acidity of PM2.5 at the ground surface site is stronger than that on the mountainside in the Mt. Huashan region.

The mechanisms and process of acephate degradation by hydroxyl radical and hydrated electron

The degradation process of acephate in aqueous solution with •OH and produced by 60Co-γ irradiation and electron pulse radiolysis was studied in the present paper. In the aqueous solution, acephate reacted with and transformed to transient species which can absorb weakly in the wavelength range of 300–400 nm and decay very fast. According to the decay of hydrated electron, the reaction rate constant of and acephate is (3.51 ± 0.076) × 109 dm3·mol−1·s−1. The transient species produced in the reaction of •OH and acephate do not distinctly absorb the light in the wavelength range of 300–700 nm, so the decay and kinetics of the transient species cannot determinedirectly. The competing reaction of KSCN oracephate with •OH were studied to obtain the reaction rate constant of •OH and acephate, which is (9.1 ± 0.11) × 108 dm3·mol−1·s−1. Although acetylamide and inorganic ions were determined in the products of the reaction of acephate with •OH or , the concentration of inorganic ions in the products of the reaction of acephate with •OH is higher than that in the product of the reaction of acephate with . Moreover, there were sulfide in the products of the reaction of acephatewith . The degradation pathways of acephate by •OH and were also proposed based on the products from GC-MS.

Fog Water Chemical Composition on Ailaoshan Mountain, Yunnan Province, SW China

ABSTRACT Between December 2015 and March 2016, fog water was collected at the subtropical mountain cloud forest site Ailaoshan in SW China at 2476 m above mean sea level. An active fog collector was employed to collect 117 samples during more than 140 hours of fog, covering 6 major fog events. The chemical analysis included acidity and inorganic ion concentrations. The median pH values of the fog events varied between 3.7 and 4.2, characterizing the fog water as acidic (pH < 5.0) to very acidic (pH < 4.0). The ion composition was dominated by H+, NH4+, SO42– and NO3–, which made up more than 86% of the total ionic concentration (TIC). The generally rather high ion concentration levels cannot be explained by nearby emission sources but rather by long-range transport of air pollutants from various sources in East Asia. During one event on February 8, 2016, it is evident that it was the emissions from a large coal-fired power plant in Myanmar that led to high concentrations of sulphuric acid. This pilot study of fog chemistry in rural, mountainous SW China should be complemented by studies spanning the moist summer monsoon season and covering more chemical species.

Biogenic, urban, and wildfire influences on the molecular composition of dissolved organic compounds in cloud water

Abstract. Organic aerosol formation and transformation occurs within aqueous aerosol and cloud droplets, yet little is known about the composition of high molecular weight organic compounds in cloud water. Cloud water samples collected at Whiteface Mountain, New York, during August–September 2014 were analyzed by ultra-high-resolution mass spectrometry to investigate the molecular composition of dissolved organic carbon, with a focus on sulfur- and nitrogen-containing compounds. Organic molecular composition was evaluated in the context of cloud water inorganic ion concentrations, pH, and total organic carbon concentrations to gain insights into the sources and aqueous-phase processes of the observed high molecular weight organic compounds. Cloud water acidity was positively correlated with the average oxygen : carbon ratio of the organic constituents, suggesting the possibility for aqueous acid-catalyzed (prior to cloud droplet activation or during/after cloud droplet evaporation) and/or radical (within cloud droplets) oxidation processes. Many tracer compounds recently identified in laboratory studies of bulk aqueous-phase reactions were identified in the cloud water. Organosulfate compounds, with both biogenic and anthropogenic volatile organic compound precursors, were detected for cloud water samples influenced by air masses that had traveled over forested and populated areas. Oxidation products of long-chain (C10−12) alkane precursors were detected during urban influence. Influence of Canadian wildfires resulted in increased numbers of identified sulfur-containing compounds and oligomeric species, including those formed through aqueous-phase reactions involving methylglyoxal. Light-absorbing aqueous-phase products of syringol and guaiacol oxidation were observed in the wildfire-influenced samples, and dinitroaromatic compounds were observed in all cloud water samples (wildfire, biogenic, and urban-influenced). Overall, the cloud water molecular composition depended on air mass source influence and reflected aqueous-phase reactions involving biogenic, urban, and biomass burning precursors.

Characteristics and Source Apportionment of Water-soluble Inorganic Ions in Road Dust PM2.5 in Selected Cities in Liaoning Province

In order to collect comprehensive information on the characteristics and sources of water-soluble inorganic ions in road dust (RD) PM2.5 in Liaoning Province, samples of road dust were collected in 2014 and 2016 in Anshan and Panjin and then re-suspended on filters using an NK-ZXF sampler. The concentrations of the major water-soluble inorganic ions were analyzed by ion chromatography. A correlation analysis, ratios, and a principal component analysis were used to analyze the sources of RD. The results showed that the total water-soluble inorganic ions in Panjin and Anshan accounted for 5.83%±3.34% and 5.84%±1.15% in RD PM2.5, respectively. NH4+, SO42-, and NO3- in RD PM2.5 coexisted in the forms of (NH4)2SO4, and NH4NO3 in Panjin, and NH4HSO4 and NH4NO3 in Anshan. The average values of NO3-/SO42- were 0.52±0.55 and 0.46±0.13 for Panjin and Anshan, respectively, indicating that the effects of stationary sources (e.g., coal combustion) on PM2.5 were more significant. The main sources of RD PM2.5 in Panjin were biomass burning, sea salt particles, construction dust, and mobile sources, while the main sources of RD PM2.5 in Anshan were coal combustion, biomass burning, sea salt particles, and steel smelting dust.

Seasonal variation of water-soluble inorganic ions in PM10 in a city of northwestern Turkey

ABSTRACTThe objective of this study was to determine the concentrations of inorganic ions present in particulate matter smaller than 10 µm (PM10), released into the environment by industrial, domestic and mobile sources in Duzce. To assess spatial variations, samples were collected from two sampling sites that had urban and suburban characteristics. Further, the process was carried out in two seasons to understand the seasonal variations. An ion chromatography device was used for analyzing the inorganic ion content in the collected samples. The highest levels of inorganic ion concentrations were measured at the urban sampling site during the winter campaign. Furthermore, the highest ion concentrations were measured for SO42− ion at both sampling sites and during both seasons, while the lowest concentrations were measured for Br−. Moreover, there were significant relationships between meteorological parameters and ion concentrations. A comparison of the cation and anion equivalence values using seasonal CE/AE (cation equivalence/anion equivalence) ratios showed that the aerosol matter had alkaline characteristics during both seasons. The mean value for the CE/AE ratios was 1.58 in winter and 2.06 in summer at the urban sampling site and 1.36 in winter and 1.52 in summer at the suburban sampling site. The interrelationships among the ions were determined by Pearson correlation analysis. Based on the correlation analyses, the ions emitted from common sources and those exposed to similar atmospheric conditions displayed strong correlations with each other.

Deconvoluting interrelationships between concentrations and chemical shifts in urine provides a powerful analysis tool

The NMR chemical shifts of a substance in a complex mixture strongly depend on the composition of the mixture itself, as many weak interactions occur that are hardly predictable. Chemical shift variability is the major obstacle to automatically assigning, and subsequently quantitating, metabolite signals in body fluids, particularly urine. Here we demonstrate that the chemical shifts of signals in urine are actually predictable. This is achieved by constructing ca. 4000 artificial mixtures where the concentrations of 52 most abundant urine metabolites—including 11 inorganic ions—are varied, to sparsely but efficiently populate an N-dimensional concentration matrix. A strong relationship is established between the concentration matrix and the chemical shift matrix, so that chemical shifts of > 90 metabolite signals can be accurately predicted in real urine samples. The concentrations of the invisible inorganic ions are also accurately predicted, along with those of albumin and of several other abundant urine components.

Spatiotemporal characteristics of hydrochemistry in Asian arid inland basin-a case study of Shiyang River Basin.

Inland rivers play a key role in supplying water for domestic and agricultural purposes in Asian arid inland basin. This paper investigates the chemical composition of precipitation, river water, and groundwater, providing evidence for the influencing factors the water composition in the Shiyang River Basin. Water samples were collected and analyzed to determine the content of major cations (Ca2+, Mg2+, Na+, K+, and NH+ 4) and anions (HCO- 3, Cl-, NO- 3, NO- 2, F-, and SO2-4), total solid solubility, and pH values. The results showed that precipitation, surface water, and groundwater were mildly alkaline. Ca2+ and SO2-4 were the predominant ions. The content of inorganic ions varied largely in the different seasons, with the highest ion concentration observed in spring and the lowest in summer. The seasonal variations in groundwater were less considerable than those in surface water. Furthermore, anion concentrations increased substantially from upstream to downstream. Regional weathering of carbonates and evaporation were established as the major sources of these ions. In addition, we discovered that anthropogenic inputs had led to light pollution of water in some residential districts.

Chemical composition of polluted mist droplets

Mist events occur frequently worldwide, but the chemical characteristics of the mist droplets has never been investigated because of very low liquid water contents of them. We estimated the concentrations of the mist water, the average concentration of the mist droplets, via the determination of water-soluble components of the coarse aerosol and the observation of the imprints of the droplets on a MgO-coated glass slide. The pH of the mist water was estimated from the equilibrium calculation with the data of the Gran plot of the solution of the dissolved coarse particles, the inorganic ion concentrations of aerosol larger than 10 μm, and the estimated volume of mist water. The mist water was measured as about 1 eq/L total concentration for typical inorganic ions and about pH 4.5 in Yokohama. Such highly concentrated mist droplets may have intense environmental effects.

The contribution of residential coal combustion to atmospheric PM&amp;lt;sub&amp;gt;2. 5&amp;lt;/sub&amp;gt; in northern China during winter

Abstract. A vast area in northern China, especially during wintertime, is currently suffering from severe haze events due to the high levels of atmospheric PM2. 5. To recognize the reasons for the high levels of PM2. 5, daily samples of PM2. 5 were simultaneously collected at the four sampling sites of Beijing city (BJ), Baoding city (BD), Wangdu county (WD) and Dongbaituo (DBT) during the winter and spring of 2014–2015. The concentrations of the typical water-soluble ions (WSIs, such as Cl−, NO3−, SO42− and NH4+) at DBT were found to be remarkably higher than those at BJ in the two winters, but almost the same as those at BJ in the two springs. The evidently greater concentrations of OC, EC and secondary inorganic ions (NO3−, SO42−, NH4+ and Cl−) at DBT than at WD, BD and BJ during the winter of 2015 indicated that the pollutants in the rural area were not due to transportation from neighbouring cities but dominated by local emissions. As the distinct source of atmospheric OC and EC in the rural area, the residential coal combustion also made a contribution to secondary inorganic ions through the emissions of their precursors (NOx, SO2, NH3 and HCl) as well as heterogeneous or multiphase reactions on the surface of OC and EC. The average mass proportions of OC, EC, NO3− and SO42− at BD and WD were found to be very close to those at DBT, but were evidently different from those at BJ, implying that the pollutants in the cities of WD and BD, which are fully surrounded by the countryside, were strongly affected by the residential coal combustion. The OC ∕ EC ratios at the four sampling sites were almost the same value (4.8) when the concentrations of PM2. 5 were greater than 150 µg m−3, suggesting that the residential coal combustion could also make a dominant contribution to atmospheric PM2. 5 at BJ during the severe pollution period when the air parcels were usually from southwest–south regions, where a high density of farmers reside. The evident increase in the number of the species involved in significant correlations (p &lt; 0. 05) from the countryside to the cities further confirmed that residential coal combustion was the dominant source of key species in the rural area. However, the complex sources including local emissions and regional transportation were responsible for the atmospheric species in the cities. Strong correlations among OC, EC, Cl−, NO3− and NH4+ were found at the four sampling sites but only a strong correlation was found between OC (or EC) and SO42− at BJ, implying that the formation rate of SO42− via heterogeneous or multiphase reactions might be relatively slower than those of NO3−, NH4+ and Cl−. Based on the chemical mass closure (CMC) method, the contributions of the primary particle emission from residential coal combustion to atmospheric PM2. 5 at BJ, BD, WD and DBT were estimated to be 32, 49, 43 and 58 %, respectively.

The osmotin of Calotropis procera latex is not expressed in laticifer-free cultivated callus and under salt stress

The latex of Calotropis procera has previously been reported to contain osmotin. This protein (CpOsm) inhibited phytopathogens and this was mechanistically characterized. Here, the time-course profile of CpOsm transcripts was examined in the salt-stressed cultivated callus of C. procera in order to better understand its role in the physiology of the plant. Stressed callus (80 mM NaCl) showed an unbalanced content of organic compounds (proline and total soluble sugar) and inorganic ions (Na+, Cl−, and K+). Under salt treatment, the transcripts of CpOsm were detected after 12 h and slightly increased to a maximum at day seven, followed by reduction. Interestingly, CpOsm was not detected in the soluble protein fraction recovered from the salt-stressed callus as probed by electrophoresis, dot/Western blotting and mass spectrometry. The results suggested that (1) CpOsm is not constitutive in cultivated cells (laticifer-free tissues); (2) CpOsm transcripts appear under salt-stressed conditions; (3) the absence of CpOsm in the protein fractions of stressed cultivated cells indicated that salt-induced transcripts were not used for protein synthesis and this accounts to the belief that CpOsm may be a true laticifer protein in C. procera. More effort will be needed to unveil this process. In this study we show evidences that CpOsm gene is responsive to salt stress. However the corresponding protein is not produced in cultivated cells. Therefore, presently the hypothesis that CpOsm is involved in abiotic stress is not fully supported.

Fine particles at a background site in Central France: Chemical compositions, seasonal variations and pollution events

To expand our knowledge of regional fine particles in Central France (Centre-Val de Loire region), a field observation study of PM2.5 was carried out at Verneuil site (46.81467N, 2.61012E, 180m.a.s.l.) from 2011 to 2014. The mass concentrations of water-soluble inorganic ions (WSIIs), organic carbon (OC), elemental carbon (EC) and biomass burning tracer (Levoglucosan) in PM2.5 were measured. Annual average PM2.5 mass concentrations were 11.8, 9.5, 12.6 and 10.2μg·m−3 in 2011, 2012, 2013 and 2014, respectively, three of four higher than the WHO guideline of 10μg·m−3. Secondary inorganic aerosol (SIA) and organic matter (OM) appeared to be the major components in PM2.5 in Verneuil, contributing 30.1–41.8% and 36.9–46.3%, respectively. Main chemical species were observed in the following order: winter≥spring>autumn>summer. Backward atmospheric trajectories were performed using Hysplit model and suggested that the PM2.5 pollutants caused by atmospheric transport were mainly originated from European inland, mainly east to north-east areas. During the observation period, five pollution events were reported and indicated that not only the polluted air masses from central Europe but also the biomass burning from East Europe significantly influenced the air quality in Verneuil site.

The remarkable effect of Al–Fe pillaring on the adsorption and catalytic activity of natural Tunisian bentonite in the degradation of azo dye

Four Al–Fe–PILC catalysts were prepared by pillaring process and tested for the degradation of diazo dye in heterogeneous Fenton-like process. The synthesized catalysts were characterized using XRD, N2 sorption, XRF and TEM techniques in order to study the influence of iron and Al loading on structure and texture. In this work, at Fe loading of 10%, pillared clay was studied and investigated in catalytic test. The effects of major parameters, such as initial pH, H2O2 concentration and catalyst dose were tested on the activity as well as iron leaching from catalyst. Results of this study show that dye degradation rate increased with an increase in dosages of catalyst and concentration of H2O2 up to a certain limit. However, the degradation rate decreased with an increase in the pH. Mineralization and comparison with different catalysts prepared were evaluated by analyzing color removal and inorganic ions (SO4 2−, NO3 −) concentrations. The kinetic studies revealed that the degradation profile is well fitted by the first-order kinetic model.

Formation and Size Distribution of the Secondary Aerosol Inorganic Ions in Different Intensity of Haze in Qingdao, China

Size-segregated atmospheric aerosol samples were collected from September 2015 to February 2016 at a coastal site in Qingdao, and the concentrations of major water-soluble inorganic ions were analyzed by ion chromatography. Characteristics and variation of size distribution of secondary inorganic components in aerosol were discussed, as well as the formation process and influencing factors of SNA(sulfate, nitrate and ammonium). The results indicated that the concentrations of NO3-, SO42-, NH4+, NO2-, Cl- in the aerosols were in the range of 10.32-193.46, 4.42-74.05, 2.21-57.75, 0.05-2.22 and 1.35-17.39 μg·m-3 respectively. And the mass concentration of SNA increased with the intensity of haze pollution. The concentrations of NO3- on the slight, mild, moderate and severe haze days were 55%, 77%, 240% and 537% higher than that on non-haze days respectively, while concentrations of SO42- increased by 4.7%, 35%, 77% and 262% respectively, and concentrations of NH4+ increased by 72%, 83%, 201% and 526% respectively. The contribution of these water-soluble ions to PM2.5 showed that the proportion of sum of NO3-, SO42-, NH4+, NO2- and Cl- to PM2.5 was in range of 62.03%-80.93%. The proportion of ion to PM2.5 decreased in the order of NO3- > SO42- > NH4+ > Cl- > NO2-. With the enhancement of haze pollution, the proportion of NO3- in PM2.5 increased from 29.53% to 45.54%. The correlation analysis showed that NO3- and SO42- in the fine particle were significantly correlated with gaseous precursors NO2 and SO2, and also showed good correlations with relative humidity, visibility, wind speed and other weather conditions. These results indicated that the formation of SNA in fine particles was one of the main reasons for visibility decrease and the formation of air pollution in haze days. Meanwhile, high concentration of gaseous precursors, high relative humidity and low wind speed were the important influencing factors of haze formation. Except for slight haze days, SOR and NOR in the haze days were higher than those on the non-haze days, and increased significantly with the intensifying of haze, especially for 0.43-0.65 and 0.65-1.1 μm particle size. Conversion rates of nitrogen and sulfur in severe haze days were 1.5 times that in non-haze days, which showed nitrate and sulfate in these fine mode were mainly from gas-to-particle conversion. NO3-, SO42-, NH4+ and NO2- increased in haze significantly, which mainly existed in the fine particles. The cloud process played a more important role on haze days. While on non-haze day, cloud process and the heterogeneous reaction were both the main factors. And the highest proportion of fine mode concentration to total one was observed for NO3-(79.4%) and SO42-(74.4%) on severe haze days respectively. NO3- showed a bimodal distribution with peaks in the size-bin of 0.43~0.65 μm and 3.3-4.7 μm on non-haze, slight, mild haze days, and the fine peak moved to 0.65-1.1 μm on moderate haze days, however the bimodal distribution changed to unimodal distribution with peak at 0.65-1.1 μm on severe hazy days. SO42- showed a bimodal distribution with peaks at 0.43-0.65 μm and 2.1-3.3 μm in the non-haze weather, while the size distribution changed to unimodal distribution on hazy days. But the peak sizes were different in different intensity of haze, with peak at 0.43-0.65 μm on mild and slight haze and 0.65-1.1 μm in moderate and severe haze days. NH4+ showed a single peak distribution in the fine mode, with the peak in the particle size of 0.43-0.65 μm on slight and non-hazy days, and 0.65-1.1 μm on mild, moderate and severe hazy days. Therefore, haze has a great influence on the size distribution of SNA.

H and O isotopic differences in typhon and urban-induced heavy rain in Tokyo

Stable isotope ratios of hydrogen and oxygen of water are useful tracers of the hydrological cycle. For example, isotopes monitor the evapotranspiration in vegetated areas, local snow ice processes and stream water flow processes. δ18O and δD in rainwater reflect the processes of evaporation, condensation and precipitation. Heavy rains thus modify the stable isotope ratio of ground water, stream water and transpiration water vapor. However, the controlling factors of δ18O and δD are not clear. Here we analyzed the inorganic ion concentration and stable isotope ratio in 38 normal rainwater and 15 heavy rainwater samples were collected in Shinjuku, Tokyo, Japan, during four years from October 2012 to December 2015. Results show a decrease in δ18O and δD values with the total rainfall amount, thus highlighting the amount effect. δ18O and δD volume-weighted mean values in typhoon heavy rain were higher than the values estimated from amount effect, whereas δ18O and δD volume-weighted mean values in urban-induced heavy rain were lower. Typhoon heavy rain has high Na+ ratio and stable isotope ratios, while urban-induced heavy rain has low Na+ ratio and stable isotope ratio.

Changes in the chemical compositions of leaf litter in the canopy of a Japanese cedar plantation

ABSTRACTCanopy leaf litter is typically unevenly distributed due to interception by branches and epiphytes and/or due to attachment to branches and tree trunks. Japanese cedar (Cryptomeria japonica) trees hold a large amount of canopy litter that stays attached to foliage and branches for several years before litterfall. Litter retention in the canopy is predicted to affect the chemical composition of litterfall and throughfall. We analyzed the chemical compositions of water-soluble materials washed from the leaves and those of the leaf residues with different leaf litter ages to clarify the effect of leaf-litter retention in the canopy of Japanese cedar trees. Chemical components of the leaf litter after the washing procedure show temporal changes in total carbon, total nitrogen, and carbon/nitrogen ratio just after senescence and prior to litterfall. Higher inorganic ion concentrations in soluble materials from old dead leaves (ODL) dead for more than 2 years suggest the importance of ODL in leaching and catching chemical components in the canopy. Our results show that Japanese cedar canopies retain the various qualities of leaf litter, which are produced by senescence, leaching, and catching dry deposition, and that a large amount of dissolved components leach from dead leaves that are still attached to the canopy.

A colorimetry based, semi-automated portable sensor device for the detection of arsenic in drinking water

A portable colorimetric device is presented for arsenic ion detection in drinking water. The main purpose of this device – which was developed to complement a commercial water dearsenating station demanding regular (weekly to monthly) regeneration runs depending on its saturation – is to provide regular field measurements and easy, semi-automatic operation designed specifically for untrained, typically illiterate users e.g. the population of developing countries. The device exploits a commercially available, well established reagent kit, which is widely used in arsenic field-testing in many developing countries. The hereby presented custom-designed microfluidic system enhances the user-friendliness, the functionality and reliability of the test-strip based kit. The response for total inorganic arsenic ion concentrations (As(III) and As(V)) is linear in the 5–20μg/l (ppb) range with a sensitivity of 1μg/l, thus the device is capable to distinguish drinkable water based on the World Health Organization (WHO) guidelines of 10μg/l. The average relative standard deviation of the measurements is 8% in the linear range and it is below 2% for higher arsenic concentrations (above 20μg/l). The hardware construction of the device and the custom microfluidic system is presented in detail. The effect of elevated water sample temperature on the kinetics and performance of the device was also investigated in order to reduce the required time for the measurements. Stable and reliable arsenic concentration values were obtained after 60min at 22°C (ambient temperature) and after only 25min at 50°C water sample temperature, but at a cost of an increased relative standard deviation to 16%, in the linear range.

Variability in inorganic As, Sb and Tl species concentrations in waters and bottom sediments of the Kłodnica River (Poland)

ABSTRACTThe study describes the application of new methodologies for the simultaneous determination of As(III)/As(V), Sb(III)/Sb(V) and Tl(I)/Tl(III) ions in waters and bottom sediments of the Kłodnica River (Poland) with the hyphenated technique of high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) . Time and spatial correlations were determined in the changes of total and speciation concentrations of the above-mentioned analytes in Kłodnica river in 2012. The developed methodologies demonstrate high selectivity and limits of quantification at the level of 0.009–0.120 µg/L. Their repeatability, precision and recovery are appropriate for trace analyses of environmental samples. Time and spatial correlations, and concentrations of inorganic As, Sb and Tl ions demonstrated high variability both in water and bottom sediments.

Chemical characteristics and source apportionment of PM2.5 between heavily polluted days and other days in Zhengzhou, China

PM2.5 samples were collected in Zhengzhou during 3years of observation, and chemical characteristics and source contribution were analyzed. Approximately 96% of the daily PM2.5 concentrations and annual average values exceeded the Chinese National Ambient Air Quality Daily and Annual Standards, indicating serious PM2.5 pollution. The average concentration of water-soluble inorganic ions was 2.4 times higher in heavily polluted days (daily PM2.5 concentrations>250μg/m3 and visibility <3km) than that in other days, with sulfate, nitrate, and ammonium as major ions. According to the ratio of NO3−/SO42−, stationary sources are still the dominant source of PM2.5 and vehicle emission could not be ignored. The ratio of secondary organic carbon to organic carbon indicated that photochemical reactivity in heavily polluted days was more intense than in other days. Crustal elements were the most abundant elements, accounting for more than 60% of 23 elements. Chemical Mass Balance results indicated that the contributions of major sources (i.e., nitrate, sulfate, biomass, carbon and refractory material, coal combustion, soil dust, vehicle, and industry) of PM2.5 were 13%, 16%, 12%, 2%, 14%, 8%, 7%, and 8% in heavily polluted days and 20%, 18%, 9%, 2%, 27%, 14%, 15%, and 9% in other days, respectively. Extensive combustion activities were the main sources of polycyclic aromatic hydrocarbons during the episode (Jan 1−9, 2015) and the total benzo[a]pyrene equivalency concentrations in heavily polluted days present significant health threat. Because of the effect of regional transport, the pollution level of PM2.5 in the study area was aggravated.

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators' preferences than organic acids and inorganic ions.

Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino acids are more strongly correlated with the preferences of predominant pollinators than organic acids and inorganic ions.