Spring Samples Research Articles

Relationship between algae diversity and water quality- a case study: Chah Niemeh reservoir Southeast of Iran.

Algae are known with many detrimental impacts on drinking water quality. Discharge of municipal and agricultural wastewater into the receiving water resources make desirable conditions for algae growth and consequently cause eutrophication phenomena. Water samples were withdrawn monthly from 5 stations in Zabol City within spring and summer seasons. To identify algae species, micronutrients, and physical parameters such as temperature, depth of Secchi disk (SD) and pH on their growth were evaluated. The average phosphate in spring and summer were observed to be 0.034 and 0.028mg/L, respectively. The results obtained from the present study indicated that the volume and depth of the water reservoirs were less critical on total phosphorus compared with the concentration of algal cells and total nitrogen. The mean pH for water samples taken from Chah Niemeh (CN) in spring and summer were observed to be 8.4 which is suitable for algae growth. Furthermore, the mean temperature (>20°C) in both seasons were found to be desirable for the growth of algae, especially cyanobacteria in the CN. Moreover, the mean SD in spring and summer samples was 96.16m and 119.83m, respectively. As a result, the reservoir had low transparency in terms of algal growth. Totally, most of the identified algae were green algae (50%), algal flagella (19%), cyanobacteria (15.4%) and diatoms (15%). Therefore, cyanobacteria are most possible responsible for the taste and odor in the CN water reservoir. Future efforts should be directed toward preventive measurements for protecting water reservoirs from municipal and agricultural wastewaters and algae control.

Phytoplankton community structure changes during autumn and spring in response to environmental variables in Methana, Saronikos Gulf, Greece

Phytoplankton community was investigated during two contrasting periods using offshore plankton samples in the volcanic area of Methana peninsula (Saronikos Gulf): the first at early autumn (warm period, September 2016) and the second one at early spring (cold period, March 2017). In order to investigate the phytoplankton community structure in the complex geo-biochemical conditions of the area, samples were collected from stations near the CO2 hydrothermal vents, at the hydrothermal sulfur and radioactive springs and at a fishery nearby Methana town. Three major phytoplankton groups, Bacillariophyceae, Dinophyceae, and Prymnesiophyceae, were studied, using inverted microscopy. In early autumn, Dinophyceae were dominant in the majority of the stations with cell concentrations of Prorocentrum spp. up to ~ 35.5 × 103 cells l-1. In early spring, the dominant class was Bacillariophyceae with dominant genus Nitzschia/Pseudo-nitzschia presenting cell concentrations up to ~ 33.9 × 103 cells l-1. Furthermore, Prymnesiophyceae appeared in both spring and autumn samples with small fluctuations. Total phytoplankton cell concentrations followed a seasonal trend, presenting slightly lower values in the hydrothermal-effected area in comparison with the broader Saronikos Gulf, confirming the prevalence of oligotrophic conditions. Seasonal variation was very strong, revealing an association with water temperature and nutrient content. Those environmental variables proved to have a strong effect that was reflected in the phytoplankton community structure.

Genomic Insights of "Candidatus Nitrosocaldaceae" Based on Nine New Metagenome-Assembled Genomes, Including "Candidatus Nitrosothermus" Gen Nov. and Two New Species of "Candidatus Nitrosocaldus".

“Candidatus Nitrosocaldaceae” are globally distributed in neutral or slightly alkaline hot springs and geothermally heated soils. Despite their essential role in the nitrogen cycle in high-temperature ecosystems, they remain poorly understood because they have never been isolated in pure culture, and very few genomes are available. In the present study, a metagenomics approach was employed to obtain “Ca. Nitrosocaldaceae” metagenomic-assembled genomes (MAGs) from hot spring samples collected from India and China. Phylogenomic analysis placed these MAGs within “Ca. Nitrosocaldaceae.” Average nucleotide identity and average amino acid identity analysis suggested the new MAGs represent two novel species of “Candidatus Nitrosocaldus” and a novel genus, herein proposed as “Candidatus Nitrosothermus.” Key genes responsible for chemolithotrophic ammonia oxidation and a thaumarchaeal 3HP/4HB cycle were detected in all MAGs. Furthermore, genes coding for urea degradation were only present in “Ca. Nitrosocaldus,” while biosynthesis of the vitamins, biotin, cobalamin, and riboflavin were detected in almost all MAGs. Comparison of “Ca. Nitrosocaldales/Nitrosocaldaceae” with other AOA revealed 526 specific orthogroups. This included genes related to thermal adaptation (cyclic 2,3-diphosphoglycerate, and S-adenosylmethionine decarboxylase), indicating their importance for life at high temperature. In addition, these MAGs acquired genes from members from archaea (Crenarchaeota) and bacteria (Firmicutes), mainly involved in metabolism and stress responses, which might play a role to allow this group to adapt to thermal habitats.

A multi-omic screening approach for the discovery of thermoactive glycoside hydrolases.

Next-generation sequencing and computational biology have facilitated the implementation of new combinatorial screening approaches to discover novel enzymes of biotechnological interest. In this study, we describe the successful establishment of a multi-omic approach for the identification of thermostable hydrolase-encoding genes by determination of gene expression levels. We applied this combinatorial approach using an anaerobic enrichment culture from an Azorean hot spring sample grown on green coffee beans as recalcitrant substrate. An in-depth analysis of the microbial community resulted in microorganisms capable of metabolizing the selected substrate, such as the genera Caloramator,Dictyoglomus and Thermoanaerobacter as active and abundant microorganisms. To discover glycoside hydrolases, 90,342 annotated genes were screened for specific reaction types. A total number of 106 genes encoding cellulases (EC 3.2.1.4), beta-glucosidases (EC 3.2.1.21) and endo-1,4-beta-mannosidases (EC 3.2.1.78) were selected. Mapping of RNA-Seq reads to the related metagenome led to expression levels for each gene. Amongst those, 14 genes, encoding glycoside hydrolases, showed highest expression values, and were used for further cloning. Four proteins were biochemically characterized and were identified as thermoactive glycoside hydrolases with a broad substrate range. This work demonstrated that a combinatory omic approach is a suitable strategy identifying unique thermoactive enzymes from environmental samples.

Broad-scale geographic and temporal assessment of northern long-eared bat (Myotis septentrionalis) maternity colony-landscape association

As the federally threatened northern long-eared bat Myotis septentrionalis continues to decline due to white-nose syndrome (WNS) impacts, the application of effective conservation measures is needed but often hindered by the lack of ecological data. To date, recommended management practices have been adopted in part from other federally listed sympatric species such as the endangered Indiana bat M. sodalis. During the maternity season, these measures have largely focused on conservation of known day-roost habitat, often with little consideration for foraging habitat, particularly riparian areas. We examined acoustic activity of northern long-eared bats relative to day-roost and capture data at coastal and interior sites in the District of Columbia, New York, Pennsylvania, Virginia, and West Virginia, USA, over the course of 6 summers (2015-�2020), where maternity activity was still documented after the initial arrival and spread of WNS. Acoustic activity of northern long-eared bats relative to forest cover decreased at the acoustic site level (fine scale) but increased at the sampling region level (coarse scale). We observed a positive association of northern long-eared bat acoustic activity with riparian areas. Additionally, we observed higher levels of activity during pregnancy through early lactation period of the reproductive cycle prior to juvenile volancy. Our findings suggest the need for more explicit inclusion of forested riparian habitats in northern long-eared bat conservation planning. Acoustic sampling in spring and early summer rather than mid- to late summer and in forested riparian areas is the most effective strategy for identifying potential active northern long-eared bat maternity colonies on the local landscape.

Identification of Cu in <i>Crassostrea virginica</i> Tissue Using the Technique of Laser-Induced Breakdown Spectroscopy (LIBS)

The analysis of metals in aquatic organisms is of great importance due to the health problems they can cause to be consumed by human beings. In this study, the Laser-Induced Plasma Spectroscopy (LIBS) technique is evaluated as an alternative method to identify Cu in Crassostrea virginica oysters’ tissue. It focuses on the characterization of oysters caught a natural bank and the identification of different Cu concentrations. To carry out experimentation, oyster samples were collected in autumn (October 2017) and spring (May 2018) from San Andres Lagoon, Aldama, Tamaulipas. A single pulse Nd:YAG laser (1064 nm) was used, and tissue was contaminated with 0, 2, 10, 20, 50, and 100 μg/g of Cu. In tissue were identified atomic lines for Ca, Cr, Mg, Mn, Na, N, O, and H. However, the intensities of emission lines for autumn samples were greater than spring samples. Cu emission lines at 324.6, 327.1, 510.3, 515.1, and 521.5 nm were found for contaminated pills. The intensity of emission lines showed a linear increase with the concentration; whereby, they can be used as calibration curves to quantify Cu concentrations in oyster tissue.

Analytical determination of oestrogenic endocrine disruptors: the method of choice for wastewater treatment plant effluents

Environmental context Endocrine disrupting compounds (EDCs) are among the most recently targeted micropollutants detected in wastewater treatment plant (WWTP) effluents and in aquatic environments. There is a need for the development of robust analytical methods for most relevant estrogenic EDCs. This study provides optimisation of analytical techniques and addresses several relevant aspects that are often overlooked in the literature. The method was finally successfully employed for the analysis of WWTP effluents. Abstract Two analytical approaches – liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) methods – were compared for the simultaneous determination of the 19 most important oestrogenic endocrine disrupting chemicals (EDCs), such as 17β-oestradiol, oestrone, 17α-ethinyloestradiol, bisphenol A and triclosan in wastewater treatment plant effluents. To lower the instrument limits of detection (ILODs), a derivatisation step preceded detection in both methods. The stability, sensitivity and ease of use of dansylation (Dns) for LC-MS/MS and trimethylsilylation (TMS) for GC-MS/MS derivatives were evaluated before method validation. TMS derivatisation products were highly unstable over time. Parameters such as susceptibility to matrix effects and the stability of monodansylated and didansylated derivatisation products of phytohormones are discussed. Lower ILODs of highly potent EDCs (0.11 ng mL−1 for 17β-oestradiol, 0.01 ng mL−1 for 17α-ethinyloestradiol and 0.22 ng mL−1 for oestrone) and stability of derivatisation products within 7 days were achieved using LC–MS/MS; therefore, further validation of this method at environmentally relevant concentrations was conducted. The method limits of detection (MLODs) met the requirements of the European Union defined in Directive 2008/105/ES for 17α-ethinyloestradiol (0.035 ng L−1) and 17β-oestradiol (0.4 ng L−1). Twenty samples of wastewater treatment plant effluent from the Czech Republic were screened using LC-MS/MS. Fifteen of the EDCs were detected in at least one sample. The most abundant EDCs were bisphenol A, with a concentration up to 1107 ng L−1, and triclosan, with a concentration up to 76 ng L−1. No seasonal trend between late spring and autumn samples was observed in the frequency or quantity of analytes.

Speciation, Preconcentration and Determination of Inorganic Chromium Species in Spring, Drinking, and Waste Water Samples

In general, chromium is existed in stable oxidation states, such as Cr(III) and Cr(VI) in the environment. While a certain amount of Cr(III) is required for human metabolism, Cr(VI) is known to have toxic and carcinogenic effects for all living species. Chromium compounds are widely used in different fields, such as electroplating, dyeing, photographic and textile industries. Owing to this reason, it and its compounds can easily interfere with the water resources. Because of differences in toxicity, it is important to develop a sensitive analytical method for the speciation, preconcentration and determination of chromium species in the water resources. In this work, speciation and preconcentration of Cr(III) and Cr(VI) were performed using Amberlite CG-120 resin before detection step by flame atomic absorption spectrometry. The experimental conditions for model solutions were optimized so that Cr(III) was adsorbed in a column while Cr(VI) was not. To perform this, some experimental parameters, such as pH, eluent’ type/concentration/flow rate, sample solution flow rate and adsorbent amount were optimized. Furthermore, Cr(VI) was reduced to Cr(III) to determine total chromium. Then, Cr(VI) was calculated by the differences between total chromium and Cr(III). The limit of detection (3 s) and preconcentration factor were found to be 0.3 μg L–1 and 600, respectively. This proposed method was successfully applied for the determination of inorganic chromium species in the different spring waters supplied from Isparta province (Eyupler Village), Burdur province (Aglasun County), the commercial drinking water samples purchased from local market in Burdur province, and the waste water supplied from Isparta province (Suleyman Demirel Organized Industrial Region) at Turkey. The accuracy of the method was successfully checked by certified reference material (TMDA-70.2 Ontario Lake water) at 95% confidence level.

Effect of ensiling time on apparent total tract starch digestibility in Southern Brazilian dairy herds

Ensiling corn for longer periods is a strategy used to increase rumen bacteria access to starch. In fact, when corn is ensiled for insufficient periods, starch digestibility decreases, as evidenced by excreted starch. This study investigates the effects of corn silage ensiling time on starch digestibility of dairy cows through fecal starch analysis. The trial was conducted during the spring of 2013 and the fall of 2014 on twenty dairy herds located in the state of Paraná, southern Brazil. Total mixed ration (TMR), whole-plant corn silage (WPCS) and fecal samples were collected for determination of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin and starch. Apparent total tract starch digestibility (ATTSD) was calculated using equations developed by Fredin et al. (2014) and Bal et al. (1997). Data were analyzed using the CORR, REG and GLM procedures of SAS. Spring and fall WPCS were ensiled for 260 and 132 days, respectively (p < 0.01). There was no difference (p > 0.05) in ATTSD-Fredin from season to season though there was a trend (p = 0.11) towards greater ATTSD-Bal for spring samples. ATTSD-Bal was positively correlated with ensiling days (r = 0.31). Starch digestibility was not negatively affected by WPCS harvesting maturity. Differences in post-ruminal starch digestion, variation between farms in DM intake and diets, limitations of the equations, influence of uncontrolled factors, and the small number of experimental units might have contributed to the absence of significant results. Overall, Bal et al. (1997) equation was more efficient in distinguishing ATTSD from different ensiling periods.

Comparison of hydrogeological characteristics and genesis of the Xiaguan Hot Spring and the Butterfly Spring in Yunnan of China

The Xiaguan Hot Spring and the Butterfly Spring near Dali in Yunnan of China were sampled 5 and 3 times, respectively and their hydrogeological characteristics are discussed in this study. The TDS and hydrochemical type of these two springs are 1360 mg/L and HCO3-SO4-Na type, and 246 mg/L and HCO3-Ca-Mg type, respectively. The Butterfly Spring is enriched in Ca2+, Mg2+ and HCO3− due to dissolution of carbonate rocks. In contrast, the Xiaguan Hot Spring is enriched in Na+, K+, HCO3− and SO42− due to dissolution of albite, halite and ion exchange. The concentrations of the rare earth elements (REEs) in the Xiaguan Hot Spring and the Butterfly Spring range from 0.033 μg/L to 0.071 μg/L and 0.013 μg/L to 0.018 μg/L, respectively. The absolute concentrations of the medium rare earth elements (MREEs) and heavy rare earth elements (HREEs) are relatively higher than those of the light rare earth elements (LREEs) in the Xiaguan Hot Spring. The concentrations of the LREEs in the Butterfly Spring are relatively high. The δ2H and δ18O values of the Xiaguan Hot Spring and the Butterfly Spring vary from −102‰ to −107‰ and −11.6‰ to −13.8‰, respectively, showing negative trends due to altitude effect. The data points of δ2H and δ18O of the two spring samples are close to the Global Meteoric Water Line and the Local Meteoric Water Line with a slight 18O shift, indicating that the springs are meteoric in origin with a slight 18O exchange with the surrounding rocks. The geothermal reservoir temperature of the Xiaguan Hot Spring estimated with SiO2 geothermometers ranges from 107.4 °C to 114.6 °C. The Xiaguan Hot Spring occurs in the metamorphic rocks of the Paleoproterozoic Cangshan Group, and is recharged from infiltration of precipitation and snow-melting water. After undergoing a deep circulation, the groundwater is heated by heat flow and rises along the Tangzipu fault to form a hot spring of deep groundwater circulation type. The Butterfly Spring emerges in the Silurian limestone. Groundwater receives recharge from precipitation and snow-melting water in the western mountainous area, flows eastward along the fissures, and emerges on the lower slopes as a spring of shallow groundwater circulation type with ambient temperature.

Seasonal Variations of Picoeukaryote Community Structure in Zhoushan Fishing Ground, East China Sea

Picoeukaryotes (<2–3 µm) are major oceanic primary producers and play a crucial role for the functioning of marine ecosystems. However, the community structure of such communities remains poorly understood, especially in the East China Sea (ECS). We investigated the seasonal variations of abundance and diversity of picoeukaryotes, and recorded environmental variables, along a transect in Zhoushan Fishing Ground. High-throughput sequencing was used for sequencing the V4–V5 variable region within the 18S rRNA gene to analyze genetic diversity and relative abundance of picoeukaryotes. A total of 40 phyla, 68 classes, 99 orders, 126 families, and 140 genera were observed. The estimated richness and diversity indices were both higher in each season. The composition and dominant picoeukaryotes changed significantly at the class level with the seasons alternating. Basidiomycota, Ciliophora, Ascomycota and Cryptomonadales were observed throughout the year. The Linear Discriminant Analysis (LDA) revealed the predominant discriminant taxa of four seasonal groups. Redundancy analysis (RDA) showed that NO2− and salinity played very important roles to picoeukaryotes for all the spring samples and DS5 sample in winter, PO43− and pH affected mostly picoeukaryotes for winter samples and autumn samples.

Optically and Microwave-Induced Magnetization Precession in [Co/Pt]/NiFe Exchange Springs.

Microwave and heat-assisted magnetic recordings are two competing technologies that have greatly increased the capacity of hard disk drives. The efficiency of the magnetic recording process can be further improved by employing non-collinear spin structures that combine perpendicular and in-plane magnetic anisotropy. Here, we investigate both microwave and optically excited magnetization dynamics in [Co/Pt]/NiFe exchange spring samples. The resulting canted magnetization within the nanoscale [Co/Pt]/NiFe interfacial region allows for optically stimulated magnetization precession to be observed for an extended magnetic field and frequency range. The results can be explained by formation of an imprinted domain structure, which locks the magnetization orientation and makes the structures more robust against external perturbations. Tuning the canted interfacial domain structure may provide greater control of optically excited magnetization reversal and optically generated spin currents, which are of paramount importance for future ultrafast magnetic recording and spintronic applications.

Effect of pH on Different Strains of Phytase Producing Bacteria from Malaysia’s Hot Spring

In the recent research, the optimisation of culture condition for phytase production rarely done for Acetinobacter baumanii. The optimisation of the phytase production from the bacterial strains largely contributed by Bacillus sp. The study on the phytase originated from hot spring are limited and the species that identified from the hot spring samples are not in the same species from the previous study and mainly the species isolated from Bacillus sp. In this study, four potential strains of bacteria producing phytase isolated from hot spring in several regions in Malaysia. For enrichment of the bacterial, Nutrient Agar was used, meanwhile for batch culture optimisation, the bacteria producing phytase grown in modified liquid Phytase Screening Media with soy extract as agro residual substrate as a replacement for sodium phytate, the chemical substrate. The bacteria were screened for their ability to produce clear zone in solid PSM with sodium phytate as substrate. Optimisation of media through its physical factor that is pH of the media carried out using shake flask scale in laboratory. The growth of the bacterial strains and phytase activity measured quantitatively through the two different pH of media at pH 5.5 and pH 7. The analysis of colony-forming unit and pH determination after fermentation was carried out in this study. From the study, bacterial strain L3 from Labis, Johor has the highest phytase activity in the two parameters studied where the inorganic phosphate released at pH 5.5 (0.21953 U/mL) and pH 7 (0.2047 U/mL). Optimisation carried out through manipulating the culture condition that is pH of the media to determine at which condition has the highest phytase production. Several effects on enzyme activity caused by culture conditions identified. The optimisation of the fermentation medium able to contribute to the less cost production of the industrial enzyme as phytase has potential production for feed additives for poultry feeding. In the future research, molecular identification of the bacterial strains from the better-quality bacteria producing phytase grown in optimised culture media to investigate the molecular identity of the bacterial.

Determination of nitroaromatic explosive residues in water by stir bar sorptive extraction-gas chromatography-tandem mass spectrometry.

Nitroaromatic compounds were massively used in the formulation of explosives during both world wars. Even several decades after the end of these wars, their residues are suspected to be widely present in the environment. Their occurrence and effect on ecosystems and human health are still not fully determined. This paper describes the development of a method for the determination of 28 nitroaromatic compounds in water, including isomers of nitrotoluene (NT), dinitrotoluene (DNT), trinitrotoluene (TNT), nitrobenzene (NB), dinitrobenzene (DNB), chloronitrobenzene (ClNB), chlorodinitrobenzene (DNCB), nitronaphthalene (NN), dinitronaphthalene (DNN), nitroaniline (NA), dinitroanisole (DNAN), diphenylamine (DPA), and nitrodiphenylamine (nitro-DPA). In order to separate and individually quantify all the analytes with the best possible sensitivity, stir bar sorptive extraction (SBSE) was chosen as the extraction and pre-concentration step prior to gas chromatography (GC) separation and tandem mass spectrometry detection (MS/MS). Our SBSE optimization efforts focused on parameters such as the type of stir bar, ionic strength, addition of organic solvent, and extraction and desorption times. After these optimizations, the analytical method enabled us to reach limits of quantification (LOQs) between 1 and 50ng/L in tap water, groundwater, and surface water. The method was applied to the determination of targeted nitroaromatic explosive residues in spring and groundwater samples collected in an area where mine warfare had raged during World War I. Up to 16 different nitroaromatic compounds were detected in the same sample. The highest concentrations were recorded for 2,4-DNT and 1,3-DNB (1700 and 2690ng/L respectively).

Separation/Preconcentration and Determination of Lead(II) in Drinking, Spring and Lake Water Samples

Pb(II) ions were separated/preconcentrated and detected by a two-step preconcentration method (Amberlite CG-120 resin and slotted quartz tube (SQT) flame atomic absorption). The first preconcentration step was the adsorption of Pb(II) on Amberlite CG-120 resin in the drinking, spring and lake water samples before detection and then its elution using 5 mL of 3 M nitric acid. The second preconcentration step was conducted using SQT device with flame atomic absorption detection. Using a two-step preconcentration method, enrichment factor of 560 was found and detection and quantitation limits were 0.23 and 0.8 µg/L, respectively. The accuracy of the method was tested by analysis of standard reference material (Environmental Matrix Reference Material, Lake Water, TMDA-70.2) at a 95% confidence level.

The conceptual model of Wae Sano Geothermal field based on geology and geochemistry data

Wae Sano volcano is included in the inner Banda arc, Mount Wae Sano is a type C volcano and formed the Sano Nggoang crater lake. The magmatism activity produces geothermal manifestations such as; hot spring, rock alteration, and sulfur deposits, the hottest water temperature is 81 0C, with neutral pH, but the Sano Nggoang Lake water has acid pH. It becomes interesting to examine the characteristics of the geothermal system in that area. The research was conducted by Volcanostratigraphic studies to reconstruct the geological process and Geochemical sampling of hot springs, lake water, ground air, and the soil side to understand the subsurface characterization. The result showing some period of volcano products, with the youngest come from the product of Sano Nggoang 2 that spills its product to on the north-east side of Poco Dedeng volcano. The geochemical analysis shows all manifestations originate from one reservoir, chloride water type, NaCl type of the lake water with a few SO4 influence, presumably, the hot springs supply is influenced by seawater, the estimation of the reservoir has a temperature about ± 230 0C, with dacite and the rich organic sedimentary rock, and located at ± 1456 m from the manifestation, the isothermal section shows the rate of temperature increase at 97.07 m / 10 0C. The hypothetical resource is counted about 1,488.6 kWe.

Breakage of Spring Steel During Manufacturing: A Metallurgical Investigation

Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. High carbon of HC82BCr grade steel is drawn in the range of 4.0–3.0 mm as per customer’s requirement for production of spring mainly in automobile components. This spring steel grade is produced from continuous cast billet of size 150 mm × 150 mm and then hot rolled into the size of 5.5 mm diameter wire rod. Quality aspects of these spring are significant as any inherent abnormality in the material could lead to unwanted productivity losses or quality claims or sometimes serious safety issues. In this present study, spring samples broken during coiling stage were collected from plants for understanding their quality aspect and potential causes of breakage during production. Detailed microstructural investigation revealed that the root cause of breakage of the spring is related to the segregation of phosphorous and chromium in the billet which leads to the formation of martensite (brittle and less ductile) in wire rod during rolling process. This volume change due to formation of martensite increases the stress level at the interface of pearlite and martensite. During wire drawing, this increased stress level causes formation of internal crack in subsequent passes causing breakage during spring formation.

Phylogenetic Processes and Key Driving Factors of Bacterial Communities in Jinze Reservoir

To investigate the ecological mechanisms of the bacterial response to human disturbance in micro-polluted water ecosystems, we studied the relationship between the environmental factors and bacterial community development in the incoming water and various areas of a reservoir based on an ecological null model. The results showed that the phylogenetic clustering of bacterial communities was more dispersed than expected (the single-sample t-test of SES.MNTD has a 95% lower confidence limit of 9.79). Temperature is an important environmental factor affecting community phylogeny. The relative importance of stochastic and deterministic processes in the bacterial community succession of different samples showed seasonal characteristics. The bacterial community succession in spring, summer, and autumn samples was dominated by random and deterministic processes. NH4+-N is the main environmental factor affecting the relative importance of random and deterministic processes. When the concentration of NH4+-N is 0.06-0.40 mg ·L-1, the bacterial community succession is dominated by random processes; when the concentration is 0.40-0.80 mg ·L-1, it is dominated by both random and deterministic processes. Dispersal limitation (61.68%) and heterogeneous selection (26.65%) played important roles in bacterial community changes at different sampling points in the study area.

Utilize gadolinium as environmental tracer for surface water-groundwater interaction in Karst

The rare earth element (REE) group is widely used for geochemical prospection and the hydrochemical differentiation of waters. Most of the currently applied methods use normalized REE patterns to determine enrichments or depletions of certain REE in comparison to standard materials, which are caused by specific environmental conditions. Contrast agents containing Gadolinium (Gd), which are used for magnetic resonance imaging (MRI), have been emitted into surface waters since the 1980s. Patients excrete these contrast agents shortly after ambulant medication in hospitals or at home. Sewage treatment is currently unable to hold back Gd from this anthropogenic source. Therefore, the Gd concentration in the receiving channel increases significantly and creates a Gd peak in the REE pattern. This anthropogenic peak propagates into adjacent groundwater bodies. In a karst aquifer showing a connection between a river/ponor (input) and three springs (output), such an anthropogenic Gd anomaly has been traced, the local Gd background quantified, and surface water groundwater interaction evaluated. In two sampling campaigns, water samples were taken every day at the input and output side during one week in February and three weeks in May. Sampling of springs and brooks in the vicinity of the karst aquifer proved excessive Gd from anthropogenic sources. The evaluation of concentration, mass flow and total mass of Gd show that Gd can be an environmental tracer to monitor surface water-groundwater interaction as well as the anthropogenic influence on water bodies. Further anthropogenic pollutants - diclofenac, carbamazepine, galaxolide, caffeine, and acesulfame-K - representing different classes of common organic substances were tested as co-indicators to Gd. However, out of these only acesulfame-K was detected and is related with the Gd-anomaly. Our results indicate that Gd is a more powerful indicator of surface water- groundwater interaction than most organic pollutants.

Extraction and ICP-OES determination of heavy metals using tetrabutylammonium bromide aqueous biphasic system and oleophilic collector

Preconcentration of Cd(II), Co(II), Cu(II), Ni(II), Pb(II), and Zn(II) in aqueous biphasic system tetrabutylammonium bromide (TBAB) – H2O – (NH4)2SO4 followed by ICP-OES determination is reported for the first time. All metal ions extracted quantitatively with 4-(2-pyridylazo)-resorcinol. Nonwoven polypropylene collector was used to capture the extract and to assist phase separation. The concentrate was eluted with 0.3 mol L−1 nitric acid and introduced directly into ICP-OES sampling line. Detection limits for cadmium, cobalt, copper, nickel, lead, and zinc were 0.012, 0.2, 0.17, 0.11, 0.2, and 0.4 μg L−1, respectively; preconcentration factor was 150. The method accuracy was verified by the analysis of certified reference materials samples of waste waters and surface water, as well as the real samples of spring and well water. The use of oleophilic polypropylene collector allowed to handle small volume extract, attain high preconcentration factor and significantly decrease detection limits for ICP-OES determination of heavy metals.