Quinoline-derived electron-donating/withdrawing fluorophores for hydrazine detection and applications in environment and bioimaging

Substitution can be employed to competently tune the photophysical properties of chemosensors. The effect of substituents on the absorption and emission properties of quinoline probes was investigated. Therefore, salicylaldehyde (S), N-diethylamino-salicylaldehyde (D), and nitro-salicylaldehyde (W)-based quinoline Schiff base derivatives were investigated with hydrazine and studied for their photophysical properties. The nucleophilic substitution reaction was used as a sensing mechanism between the probes and hydrazine and investigated with 1H NMR, HR-MS characterizations, and DFT calculations. The sensitivity of QW-R is greater than that of QS-R and QD-R because of the stronger intramolecular charge transfer (ICT) in QW-R. The calculated LOD values are 28 nM for QS-R, 30 nM for QD-R, and 9 nM for QW-R. The probes were employed to monitor gaseous hydrazine using a smartphone and analyze solution forms of hydrazine in soil, water, and food samples, and living cells. Moreover, the in situ hydrazine release was monitored with bioimaging by administering an isoniazid drug. Significantly, the electronic effect of substituents over fluorescence showing, ranging from electron-donating to electron-withdrawing was investigated. We anticipate that this approach may be a promising strategy for the rational design of fluorescent sensors.

Spatial distribution and risk assessment of polycyclic aromatic hydrocarbons in soils from contaminated sites in Eastern China

A total of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in 28 soil column samples from two contaminated industrial sites in Eastern China. The total concentration of 16 PAHs (∑PAHs) in the surface soil (0-20 cm) was measured up to 52,600 ng/g (dry weight basis) with a remarkable spatial difference in the studied contaminated sites. The concentrations of the ∑PAHs in soils decreased with the increase in soil depth (0-10 m). The surface and subsurface soil presented a tenfold higher concentration than the soil with depth greater than 4 m. Additionally, the vertical migration tendency of the PAHs was found to be correlated significantly with their hydrophobicity (R2 = 0.79, P < 0.01). Naphthalene (with lowest octanol-water partition coefficient among the studied PAHs) showed the greatest average soil depth at which its peak concentration occurred. Furthermore, risk quotient analysis by using benzo[a]pyrene as reference compound showed that 71.4% of the samples exhibited high ecological risk for soil. Moreover, the total carcinogenic risk of the PAHs in the surface soil samples was assessed at 5.61 × 10-5-1.28 × 10-4 and 4.41 × 10-6-9.43 × 10-5 for male and female workers, respectively, in which 67.9%-71.4% of the samples showed potential risk. Generally, these results suggest a further consideration of ecological and health risks associated with PAHs in contaminated sites in Eastern China.

Perennial Existence of Organochlorine Pesticides in the Soils of Amghara, Kuwait

A comprehensive study from the surface soil samples of 14 locations from Amghara, Kuwait were assessed for the investigation of organochlorine pesticides (OCPs). There is limited information regarding the distribution pattern of OCPs in the soil samples of Kuwait. The total concentration of OCPs was in the range of 209.39 pg/g -7449.18 pg/g with an average value of 1313.04 pg/g. DDT had higher concentrations in soil samples (969.52 pg/g) than the other pesticides, according to the findings. The distribution pattern of OCPs in the Amghara soils revealed their origin as both historical and recent applications of pesticides. The study extended, how residual quantities could be used to determine health risks of both children and adults. Children and adults in all the locations were subject to negligible cancer risk, according to the health risk evaluation.

Molecular identification of Acanthamoeba spp., Balamuthia mandrillaris and Naegleria fowleri in soil samples using quantitative real-time PCR assay in Turkey; Hidden danger in the soil!

Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri are pathogenic free-living amoeba (FLA) and are commonly found in the environment, particularly soil. This pathogenic FLA causes central nervous system-affecting granulomatous amebic encephalitis (GAE) or primary amebic meningoencephalitis (PAM) and can also cause keratitis and skin infections. In the present study, we aimed to determine the quantitative concentration of Acanthamoeba spp., B. mandrillaris, and N. fowleri in soil samples collected from places where human contact is high by using a qPCR assay in Izmir, Turkey. A total of 45.71% (n=16) of Acanthamoeba spp., 20% (n=7) of B. mandrillaris, and 17.4% (n=6) of N. fowleri were detected in five different soil sources by the qPCR assay. The quantitative concentration of Acanthamoeba spp., B. mandrillaris, and N. fowleri in various soil sources was calculated at 10 × 10⁵ - 6 × 10², 47 × 10⁴ to 39 × 10³, and 9 × 10³ - 8 × 10² plasmid copies/gr, respectively. While the highest quantitative concentration of Acanthamoeba spp. and B. mandrillaris was determined in garden soil samples, N. fowleri was detected in potting soil samples. Three different genotypes T2 (18.75%), T4 (56.25%), and T5 (25%) were identified from Acanthamoeba-positive soil samples. Acanthamoeba T4 genotype was the most frequently detected genotype from soil samples and is also the most common genotype to cause infection in humans and animals. To the best of our knowledge, the present study is the first study to identify genotype T5 in soil samples from Turkey. In conclusion, people and especially children should be aware of the hidden danger in the garden and potting soil samples that come into contact most frequently. Public health awareness should be raised about human infections that may be encountered due to contact with the soil. Public health specialists should raise awareness about this hidden danger in soil.

DIVERISTY and enzymatic potential of indigenous bacteria from unexplored contaminted soils in Faisalabad

Bacteria residing in contaminated waste soil degrade and utilize organic and inorganic material as a source of nutrients as well as reduce environmental contamination through their enzymatic machinery. This enzymatic potential of indigenous bacteria can be exploited at industrial level through detailed screening, characterization, optimization and purification. In present study, diversity and enzymatic potential of indigenous bacteria was investigated through qualitative and quantitative screening methods from unexplored contaminated soil waste sites in Faisalabad. Shannon diversity (H') index revealed that twenty-eight soil samples from four contaminated sites were highly diverse of amylase, protease and lipase producing bacteria. Maximum protease producing bacteria were detected in fruit waste (1.929 × 10⁷), whereas amylase and lipase producing bacteria were found in industrial (1.475 × 10⁷) and (5.38 × 10⁶), in household waste soil samples. Most of the indigenous bacterial isolates showed potential for multiple enzymes. An isolate OC5 exhibited capability for amylase production and optimization at a wider range of cultural conditions; pH (6-8), temperature (25 °C, 37 °C, 45 °C), incubation time (24-72 h), and NaCl concentrations 0.5-13%, using (1%) starch and lactose as substrates. An isolate OC5 was identified by molecular identification and phylogenetic analysis showed 99% sequence similarity with Bacillus spp. ANOVA was used to analyzed all data statistically. This study enhances the importance of initial screening and reporting of industrially potent indigenous bacteria from unexplored contaminated waste soils. In future, indigenous bacteria in contaminated wastes may be good candidates to solve various environmental pollution problems.

Comparison of different approaches of soil sampling uncertainty determination

The ISO/IEC 17025 standard requires that all significant contributions have to be propagated to the measurement uncertainty, including also sampling uncertainties. We evaluated soil sampling uncertainties for gamma-ray spectrometry by using in-house and split-sample methods. By in-house method, the sampling uncertainty was determined by comparing standard deviations of measurement results and average analytical uncertainty. With split-sample method, it was calculated using between-sample and between-analysis variances. If analytical uncertainty is reliably determined, the in-house method is recommended because fewer measurements are needed.

Evaluation of sample processing methods to improve the detection of Bacillus anthracis in difficult sample matrices

Large area sampling approaches have been developed and implemented by the US Environmental Protection Agency (EPA) to increase sample sizes, and potentially representativeness, in outdoor urban environments (e.g., concrete, asphalt, grass/landscaping). These sampling approaches could be implemented in response to an outdoor biological contamination incident or bioterrorism attack to determine the extent of contamination and for clearance following remediation. However, sample collection over large areas often contains an extensive amount of co-collected debris and native background microorganisms that interfere with the detection of biological threat agents. Sample processing methods that utilize basic laboratory equipment amenable to field deployment were selected and applied to turbid aqueous samples (TAS) to reduce particulates and native environmental organisms prior to culture and rapid viability-polymerase chain reaction (RV-PCR) analytical methods. Bacillus anthracis Sterne (BaS) spores were spiked into TAS collected by soil grab, wet vacuum collection from an outdoor concrete surface, or storm water runoff from an urban parking lot. The implementation of a sample processing method improved the sensitivity of culture and RV-PCR analytical methods for BaS spore detection in soil and wet vacuum TAS samples compared to baseline (minimal to no field processing methods applied). For soil, when the processing method was applied, samples with 15 colony forming units (CFU)/ml (60 CFU/g) and 1.5 CFU/mL (6 CFU/g) BaS spore load were detected using culture and RV-PCR, respectively. Most notably, the processing methods greatly improved the sensitivity of the RV-PCR analytical method for the wet vacuum TAS from no detection at the 1500 CFU/mL BaS spore load level to as low as 1.5 CFU/mL BaS spore load.

Determination of tire wear markers in soil samples and their distribution in a roadside soil

Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0-2, 2-5, 5-10, and 10-20 cm. Four fine fractions, 1 000-500, 500-100, 100-50, and <50 μm, were analyzed. TW contents based on SBR ranged from 155 to 15 898 mg kg^-1. TW contents based on zinc were between 413 and 44 812 mg kg^-1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance. The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.

Improving integrated management of weed control by determination of weed seed bank in sandy and clay soil

Knowledge of soil weed seed bank is important for population dynamics studied, establishment of appropriate weed management programs, a little effort in understanding weed seed bank can give valuable information about what weeds to expect in growing season, weed density, and when most weed germination will take place. In this study, a two - year's, two sites were carried out with the aim of assessing weed seed bank status of the soil throughout 2018 and 2019. A site was worked out in Sakha Agriculture Research farm act as a clay soil, Kafr El-Sheikh Governorate, Agriculture Research Center (ARC). Another site was worked out in El-Ismailia Agr; Res; farm act as sandy soil, El-Ismailia Governorate, ARC. At each site, soil samples were selected from nine different places as like three Zigzag shapes divided into three, six and nine sites, "W" to act the whole soil area (30 faddan in Sakha farm, and 15 faddan in El-Ismailia farm). The soil samples were taken from topsoil 0-10 cm depth with an auger (core) 10 cm diameter the soils without tillage and before sowing the summer crop. The result of present the study in two different stations and soils, revealed that the number of soil samples to estimate weed seed banks should be either six or nine sites; each sample weighted 0.50 Kg soil with zigzag shape act a direct seed extraction technique to able recognize the abundance of weed species into the soil and their seed density. The aim is to improve integrated weed control.

Digital mapping of soil texture in ecoforest polygons in Quebec, Canada

Texture strongly influences the soil’s fundamental functions in forest ecosystems. In response to the growing demand for information on soil properties for environmental modeling, more and more studies have been conducted over the past decade to assess the spatial variability of soil properties on a regional to global scale. These investigations rely on the acquisition and compilation of numerous soil field records and on the development of statistical methods and technology. Here, we used random forest machine learning algorithms to model and map particle size composition in ecoforest polygons for the entire area of managed forests in the province of Quebec, Canada. We compiled archived laboratory analyses of 29,570 mineral soil samples (17,901 sites) and a set of 33 covariates, including 22 variables related to climate, five related to soil characteristics, three to spatial position or spatial context, two to relief and topography, and one to vegetation. After five repeats of 5-fold cross-validation, results show that models that include two functionally independent values regarding particle size composition explain 60%, 34%, and 78% of the variance in sand, silt and clay fractions, respectively, with mean absolute errors ranging from 4.0% for the clay fraction to 9.5% for the sand fraction. The most important model variables are those observed in the field and those interpreted from aerial photography regarding soil characteristics, followed by those regarding elevation and climate. Our results compare favorably with those of previous soil texture mapping studies for the same territory, in which particle size composition was modeled mainly from rasterized climatic and topographic covariates. The map we provide should meet the needs of provincial forest managers, as it is compatible with the ecoforest map that constitutes the basis of information for forest management in Quebec, Canada.

Detection and identification of polyaromatic hydrocarbons (PAHs) contamination in soil using intrinsic fluorescence

Polyaromatic hydrocarbons (PAHs), such as pyrene, benzo[a]pyrene, phenanthrene, and anthracene induce toxic, carcinogenic, and mutagenic effects on living organisms and are considered as primary pollutants. Traditional methods for their identification are often laborious and time-consuming and do not account for the heterogeneous nature of their distribution. Here we present confocal microscopy as a rapid and accurate technique for direct analysis of PAHs in soil samples without the complexity of sample pre-processing which might delay results for several days. The method uses the intrinsic fluorescence of PAHs for detection and their emission spectra for the identification of different PAHs. A clear difference was observed in the fluorescence spectral properties of phenanthrene, pyrene and naphthalene in real-time environmental samples. The post-processing of confocal scans obtained in the detection stage of PAHs was completed through the application of ImageJ software. Intrinsic fluorescence-based detections of PAHs may open new avenues in terms of rapid detection and identification of PAHs in heterogeneous complex soil samples.

Correction of the chemical composition effect for soil samples in gamma spectrometry

Correction of the chemical composition effect for soil samples in gamma spectrometry is very important to perform at low emission energy (<100 keV). This study presents an intensive Monte Carlo simulation using Geant4 code of CERN which investigates several items in this subject. First, it is confirmed that for soil samples, in presence of chemical composition effect, correction of the density effect at low energy is not sufficient to produce an accurate efficiency calibration of the detector. Chemical composition effect must also be corrected. Second, it was found that the slope of the linear fit to the decrease of the efficiency as a function of % of average chemical composition for a given emission energy is density independent. This is a new result which could be used to develop new efficiency correction methods against chemical composition effect. Finally, the usual method of correcting the efficiency using the simple ratio between the self absorption factor of the gamma ray inside the sample and inside the calibration standard, was found unable to correct the chemical composition effect for soil samples.

A practical approach to determining soil-sample detection efficiency in field gamma-ray spectroscopy

Field measurements of radionuclide activities in soil samples via gamma spectroscopy measurements are conducted for many applications. One example application space is on-site inspection for the Comprehensive Nuclear-Test-Ban Treaty. To extract isotopic activities from observed peak counting rates, it is necessary to understand the absolute efficiency of the detector system for a sample. In principle, this efficiency is a function of many parameters, such as sample geometry, soil elemental composition, and soil density. The demands of field measurements within the context of on-site inspections, however, places a premium on an easy-to-implement approach at the possible expense of accuracy given the need to process many samples in a short period of time. This paper presents a semi-empirical approach, using a calibrated standard and a correction that depends only on the relative differences in density of the sample and the standard. Field measurements were conducted to demonstrate the validity of the approach.

Uncovering a hidden diversity: optimized protocols for the extraction of dsDNA bacteriophages from soil

BACKGROUND

Bacteriophages (phages) are the most numerous biological entities on Earth and play a crucial role in shaping microbial communities. Investigating the bacteriophage community from soil will shed light not only on the yet largely unknown phage diversity, but may also result in novel insights towards their functioning in the global biogeochemical nutrient cycle and their significance in earthbound ecosystems. Unfortunately, information about soil viromes is rather scarce compared to aquatic environments, due to the heterogeneous soil matrix, which rises major technical difficulties in the extraction process. Resolving these technical challenges and establishing a standardized extraction protocol is, therefore, a fundamental prerequisite for replicable results and comparative virome studies.

RESULTS

We here report the optimization of protocols for the extraction of phage DNA from agricultural soil preceding metagenomic analysis such that the protocol can equally be harnessed for phage isolation. As an optimization strategy, soil samples were spiked with Listeria phage A511 (Myovirus), Staphylococcus phage 2638AΔLCR (Siphovirus) and Escherichia phage T7 (Podovirus) (each 10⁶ PFU/g soil). The efficacy of phage (i) elution, (ii) filtration, (iii) concentration and (iv) DNA extraction methods was tested. Successful extraction routes were selected based on spiked phage recovery and low bacterial 16S rRNA gene contaminants. Natural agricultural soil viromes were then extracted with the optimized methods and shotgun sequenced. Our approach yielded sufficient amounts of inhibitor-free viral DNA for shotgun sequencing devoid of amplification prior library preparation, and low 16S rRNA gene contamination levels (≤ 0.2‰). Compared to previously published protocols, the number of bacterial read contamination was decreased by 65%. In addition, 379 novel putative complete soil phage genomes (≤ 235 kb) were obtained from over 13,000 manually identified viral contigs, promising the discovery of a large, previously inaccessible viral diversity.

CONCLUSION

We have shown a considerably enhanced extraction of the soil phage community by protocol optimization that has proven robust in both culture-dependent as well as through viromic analyses. Our huge data set of manually curated soil viral contigs substantially increases the amount of currently available soil virome data, and provides insights into the yet largely undescribed soil viral sequence space.

Ratiometric SERS detection of polycyclic aromatic hydrocarbons assisted by β-cyclodextrin-modified gold nanoparticles

A surface-enhanced Raman scattering (SERS) method is described for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in the environment efficiently and economically. Detection sensitivity is improved by modifying gold nanoparticles (AuNPs) with 4-mercaptophenylboronic acid (4-MPBA) conjugated to β-cyclodextrin (β-CD) as a new method for ratiometric determination of PAHs in solution. Pyrene (with a Raman band at 580 cm^-1) and anthracene (750 cm^-1) were used as the model analytes, while 4-MPBA (1570 cm^-1) was used as the internal reference to normalize the SERS signals. The intensity ratios of pyrene/4-MPBA increase linearly in the 2 to 10 nM pyrene concentration range, and the intensity ratios of anthracene/4-MPBA increase linearly in the 10 to 100 nM anthracene concentration range. The detection limits are 0.4 nM for pyrene and 4.4 nM for anthracene. This method was applied to the determination of the two analytes in soil sample extracts and the recoveries of pyrene (at levels of 236 ng∙g^-1 and 170 ng∙g^-1) and anthracene (334 ng∙g^-1 and 510 ng∙g^-1) agreed well with the results from GC-MS analyses. The good recovery rates (101.8% and 102.5% for pyrene and 106.4% and 101.7% for anthracene) confirmed the reliability of the method. Graphical abstract Schematic illustration of SERS signal enhancement of pyrene, as an example of polycyclic aromatic hydrocarbons, by β-cyclodextrin modified gold nanoparticles.

The prevalence and distribution of Burkholderia pseudomallei in rice paddy within Hainan, China

Melioidosis is an infectious disease caused by Burkholderia pseudomallei, mainly found in Southeast Asia and northern Australia. In Hainan, sporadic cases were first described in 1990; since then, more cases have been identified. No systematic study has yet been done to detect the environmental source of the organism and its true extent in Hainan. This study is aimed to confirm the prevalence of B. pseudomallei in soil samples in Hainan. 1080 soil samples from 18 different counties were collected from 3 sampling points of 360 sites. They were screened for the presence of B. pseudomallei by Ashdown selective media. Suspected colonies of B. pseudomallei were confirmed by biochemical test and a specific PCR assay. 48 of 360 sites (13.3%) were positive for B. pseudomallei, including all coastal counties in Hainan Island. This study revealed the prevalence and distribution of B. pseudomallei in the soil environment in Hainan Island of southern China and may be helpful to understand the distribution of B. pseudomallei and to access its epidemiological importance.

Determination of glyphosate residues in Egyptian soil samples

A sensitive linker-assisted enzyme-linked immunosorbent assay (L'ELISA) was developed for the analysis of glyphosate in Egyptian soil samples. Polyclonal glyphosate antibodies were produced from rabbits immunized with glyphosate protein conjugate. The conjugate was prepared by activating the carboxylic groups of proteins; thyroglobulin or bovine serum albumin with 1-ethyl-3- (3-diaminopropyl) carbodiimide hydrochloride and N-hydroxysulfosuccinimide followed by directly coupled to the amino group of glyphosate. The L'ELISA used succinic anhydride to derivatize glyphosate, which mimics the epitopic attachment of glyphosate to thyroglobulin. L'ELISA recognized the derivatized glyphosate with a limit of detection (LOD) of 0.8 ng g-1 and sensitivity (IC50 value) of 0.018 μg g-1. The recovery values of the spiked soil samples with different concentrations of glyphosate were in the range of 87.4-97.2%. Good correlation was achieved between L'ELISA and conventional high-pressure liquid chromatography (HPLC) with fluorescence detection. This study demonstrated the utility and convenience of the sensitive, simple, practical and cost-effective L'ELISA method for glyphosate analysis in soil samples. Also, it is ideal for rapid screening of a large number of environmental samples.

Measurements of 106Ru in Sweden during the autumn 2017: Gamma-ray spectrometric measurements of air filters, precipitation and soil samples, and in situ gamma-ray spectrometry measurement

During the last days of September to the first days of October in 2017, a unique detection of ¹⁰⁶Ru was observed in air filters sampled at different locations in Sweden via the national air monitoring network. Furthermore, measurements of precipitation also showed the presence of ¹⁰⁶Ru. This initiated soil sampling and in situ gamma-ray spectrometry at one of the locations.

Comparative study of dioxin contamination from forest soil samples (BZE II) by mass spectrometry and EROD bioassay

Dioxins and dioxin-like compounds can be analyzed by bioanalytical screening methods to evaluate their biotoxicity. In vitro bioassays, based on 7-ethoxyresorufin-O-deethylase (EROD) and the activity of cytochrome P450 1A1 and the aryl hydrogen receptor (AhR) pathway, are employed for the evaluation of bioanalytical equivalents (BEQ) of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) from a wide variety of sample matrices. Here, we present the evaluation of 11 humic soil samples derived from forest stands across Germany and a comparison of the BEQ values against toxic equivalents (TEQ, PCDD/Fs+PCBs) derived by chemical analysis. BEQ values ranged from 8.8 to 34.1 while TEQ values from 13.9 to 60.5 pg/g dry weight. Additional two subsequent mineral layers were analyzed to identify the BEQ/TEQ gradient vertically, showing a TEQ decrease of 85.1 and 93.8 % from the humic to the first and second mineral layers, respectively. For BEQ values, a decrease as well as an increase was detected. BEQ measurements were performed with and without sample clean-up. Omitting clean-up revealed about 20 times increased BEQ values presumably due to non-persistent bioactive compounds not detected by chemical analysis. The results we present suggest that the EROD assay can be used for the screening of large sample quantities for the identification of samples showing dioxin and dioxin-like contaminations even at low levels, which can then be further analyzed by chemical analysis to identify the congener composition. The study also shows that EROD results give a qualitative image of the contamination. EROD seems to be interfered with cross-contaminants specifically for soils with high biological activity as forest layers.

Polyphasic taxonomic characterisation of a novel strain as Pararhizobium haloflavum sp. nov., isolated from soil samples near a sewage treatment tank

A Gram-stain negative, aerobic, motile and ovoid- to rod-shaped bacteria strain, designated XC0140^T, was isolated from soil samples near the sewage treatment tank of a chemical factory in Zhejiang Province, China, and subjected to polyphasic taxonomic investigation. Strain XC0140^T grew at 10-37 °C and pH 6.0-9.0 (optimum, 35 °C and pH 7.5) and with 0-17% (w/v) NaCl (optimum, 1%). According to phylogenetic analysis based on 16S rRNA gene sequences, strain XC0140^T was assigned to the genus Pararhizobium with high 16S rRNA gene sequence similarity of 95.97% to "Pararhizobium helanshanense CCNWQTX14^T", followed by Pararhizobium sphaerophysae CCNWGS0238^T (95.95%). Chemotaxonomic analysis showed that strain XC0140^T contains ubiquinone-10 as the predominant respiratory quinone and possessed summed feature 8 (comprising C_{18: 1} ω7c and/or ω6c), 11-methyl C_18:1 ω7c, C_{18: 0} and C_{16: 0} as predominant forms of fatty acids. The polar lipids of strain XC0140^T consisted of seven phospholipids (PL), two aminolipids (AL), one glycolipid (GL) and three unidentified lipids (L1, L2 and L3). The DNA G+C content was 62.7 mol%. Based on the polyphasic taxonomic characterization, strain XC0140^T is considered to represent a novel species of the genus Pararhizobium, for which the name Pararhizobium haloflavum sp. nov. is proposed. (type strain XC0140^T = MCCC 1K03228^T = KCTC 52582^T).

Homologue distribution patterns of 2,3,7,8-chloro-substituted PCDD/F in Bavarian soils

BACKGROUND

Soil-background values of PCDD/F concentrations are usually conveniently displayed as toxic equivalent (TEq), being a bulk parameter of all relevant 7 PCDD- and 10 PCDF-congeneres, chloro-subsidized at the 2nd, 3rd, 7th and 8th carbon atom. Data here are ample, not so survey on congenere/homologue patterns occurring in soils. The sufficient number of samples taken within this analysis allowed first a well-grounded evaluation.

RESULTS

OCDD proved to be the dominant congenere in all samples (forest and agriculture), however, in considerably different concentrations. As expected, highest level was detected in forest organic layers, followed by forest top soils, cropland- and grassland top soils. Although highest in concentration, OCDD only contributes to 0.17% (both forest organic- and top soil layer), respectively, 0.4% (cropland) and 0.3% (grassland) to TEq. The influence of lower chlorinated homologues on TEq is strongest in forest top soils (72%) followed by 67% (forest organic layers), cropland top soil (63%) and grassland (61%). Although all homologue patterns (forest and agriculture) give a fairly similar picture, a test of significance (χ²) proved a different population of forest samples.

CONCLUSIONS

The resemblance of the homologue patterns throughout all utilization suggests that agent levels are explained mainly by diffuse atmospheric depositions rather than by specific land use input.

Pioneering particle-based strategy for isolating viable bacteria from multipart soil samples compatible with Raman spectroscopy

The study of edaphic bacteria is of great interest, particularly for evaluating soil remediation and recultivation methods. Therefore, a fast and simple strategy to isolate various bacteria from complex soil samples using poly(ethyleneimine) (PEI)-modified polyethylene particles is introduced. The research focuses on the binding behavior under different conditions, such as the composition, pH value, and ionic strength, of the binding buffer, and is supported by the characterization of the surface properties of particles and bacteria. The results demonstrate that electrostatic forces and hydrophobicity are responsible for the adhesion of target bacteria to the particles. Distinct advantages of the particle-based isolation strategy include simple handling, enrichment efficiency, and the preservation of viable bacteria. The presented isolation method allows a subsequent identification of the bacteria using Raman microspectroscopy in combination with chemometrical methods. This is demonstrated with a dataset of five different bacteria (Escherichia coli, Bacillus subtilis, Pseudomonas fluorescens, Streptomyces tendae, and Streptomyces acidiscabies) which were isolated from spiked soil samples. In total 92% of the Raman spectra could be identified correctly.

Heterogeneous areas-identification of outliers and calculation of soil sampling uncertainty using the modified RANOVA method

We modified the robust analysis of variance (RANOVA) method to calculate sampling uncertainty of selected trace elements determined in soil samples from two heterogeneous remote historic metal ore mining areas. Classical RANOVA is down-weighting the outlying values by replacing them during the calculation process with mean ± c·σ _r . Because the arithmetic mean is greatly influenced by outliers, it cannot represent a robust statistic. The main novel contribution of this work is use of median value that is independent on outliers and replace all extreme values during the calculation process with median ± 2·σ _r . In our work, 18 duplicate, composite soil samples were collected, digested with aqua regia in a closed microwave system, and analyzed twice for selected trace elements. To extract homogenous groups within sampling areas and make the results more accessible for interpretation, a cluster analysis was done. Subsequently, histograms of each element were prepared and statistical tests were applied to determine the normal distribution of datasets. For abnormally distributed elements, the outlying values were identified by four different methods: boxplot, mean ± c·σ _r , mean ± c·σ, and median ± 2·σ _r . For five elements, the amount of outliers identified by the median ± 2·σ _r procedure was less than 10 %, and for these elements, the sampling uncertainty was computed using a modified RANOVA method. The sampling uncertainty computed with this method was 28.9 % for Cd, 15.2 % for Co, 14.5 % for Mn, 12.7 % for Ni, and 16.3 % for Zn, whereas that computed with a traditional model was 16.7 % for Cd, 9.2 % for Co, 20.5 % for Mn, 17.9 % for Ni, and 16.3 % for Zn.

Determination of n-alkanes contamination in soil samples by micro gas chromatography functionalized by multi-walled carbon nanotubes

A new method for separation of 11 n-alkanes: octane, o-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentdecne, n-hexadecath, heptadecane, n-octadecane in soil samples was developed. Kuderna-Danish (K.D.) concentrator enrichment prior to ultrasonic extraction and the silicone chromatography column purification and with gas chromatography flame ionization detection (GC-FID) could be used for n-alkanes determination. The micro channels of open tubular column were fabricated onto a silicon wafer to replace the quartz capillary chromatographic column. The column structure and analysis parameters that affected the column separation were investigated and optimized. Under optimal conditions, the extract reagent was centrifuged and collected. A silicone chromatography column and a K.D. concentrator were used for further clean-up and enrichment. Using this method, the limits of detection (LOD) and limits of quantification (LOQ) were obtained in the range of 0.03-0.15 and 0.1-0.5 mg kg(-1) in soil samples, respectively. The relative standard deviation (RSD) was under 12%. The optimized procedure that presented good analytical performance (with recoveries ranging from 56.5% to 89.2%), was successfully applied to determine n-alkane content in farmland soil samples adjacent to a highway. The results showed that the MWCNTs-functionalized column is capable of separating the alkane contaminations with high resolution in about 3 min, which is much shorter than that of GC-MS and other conventional analytical methods, demonstrating its great potential for rapid analysis.

A robust X-ray fluorescence technique for multielemental analysis of solid samples

X-ray fluorescence (XRF) quantitation software programs are widely used for analyzing environmental samples due to their versatility but at the expense of accuracy. In this work, we propose an accurate, robust, and versatile technique for multielemental X-ray fluorescence analytical applications, by spiking solid matrices with standard solutions. National Institute of Standards and Technology (NIST)-certified soil standards were spiked with standard solutions, mixed well, desiccated, and analyzed by an energy dispersive XRF. Homogenous targets were produced and low error calibration curves, for the added and not added, neighboring, elements, were obtained. With the addition of few elements, the technique provides reliable multielemental analysis, even for concentrations of the order of milligram per kilogram (ppm). When results were compared to the ones obtained from XRF commercial quantitation software programs, which are widely used in environmental monitoring and assessment applications, they were found to fit certified values better. Moreover, in all examined cases, results were reliable. Hence, this technique can also be used to overcome difficulties associated with interlaboratory consistency and for cross-validating results. The technique was applied to samples with an environmental interest, collected from a ship/boat repainting area. Increased copper, zinc, and lead loads were observed (284, 270, and 688 mg/kg maximum concentrations in soil, respectively), due to vessels being paint stripped and repainted.

Uranium ((234)U, (235)U and (238)U) contamination of the environment surrounding phosphogypsum waste heap in Wiślinka (northern Poland)

The aim of this work was to determine the uranium concentration ((234)U, (235)U and (238)U) and values of the activity ratio (234)U/(238)U in soil samples collected near phosphogypsum waste heap in Wiślinka (northern Poland). On the basis of the studies it was found that the values of the (234)U/(238)U activity ratio in the analyzed soils collected in the vicinity of phosphogypsum dump in Wiślinka are in most cases close to one and indicate the phosphogypsum origin of the analyzed nuclides. The obtained results of uranium concentrations are however much lower than in previous years before closing of the phosphogypsum stockpile. After this process and covering the phosphogypsum stockpile in Wiślinka with sewage sludge, phosphogypsum particles are successfully immobilized. In the light of the results the use of phosphate fertilizers seems to be a major problem. Prolonged and heavy rains can cause leaching accumulated uranium isotopes in the phosphogypsum stockpile, which will be washed into the Martwa Wisła and on the fields in the immediate vicinity of this storage.

Suitability of a Saccharomyces cerevisiae-based assay to assess the toxicity of pyrimethanil sprayed soils via surface runoff: comparison with standard aquatic and soil toxicity assays

The present study is aimed at evaluating whether a gene expression assay with the microbial eukaryotic model Saccharomyces cerevisiae could be used as a suitable warning tool for the rapid preliminary screening of potential toxic effects on organisms due to scenarios of soil and water contamination with pyrimethanil. The assay consisted of measuring changes in the expression of the selected pyrimethanil-responsive genes ARG3 and ARG5,6 in a standardized yeast population. Evaluation was held by assessing the toxicity of surface runoff, a major route of pesticide exposure in aquatic systems due to non-point-source pollution, which was simulated with a pyrimethanil formulation at a semifield scale mimicking worst-case scenarios of soil contamination (e.g. accident or improper disposal). Yeast cells 2-h exposure to the runoff samples led to a significant 2-fold increase in the expression of both indicator genes. These results were compared with those from assays with organisms relevant for the aquatic and soil compartments, namely the nematode Caenorhabditis elegans (reproduction), the freshwater cladoceran Daphnia magna (survival and reproduction), the benthic midge Chironomus riparius (growth), and the soil invertebrates Folsomia candida and Enchytraeus crypticus (survival and reproduction). Under the experimental conditions used to simulate accidental discharges into soil, runoff waters were highly toxic to the standard test organisms, except for C. elegans. Overall, results point out the usefulness of the yeast assay to provide a rapid preview of the toxicity level in preliminary screenings of environmental samples in situations of inadvertent high pesticide contamination. Advantages and limitations of this novel method are discussed.

Comparison of the TriCarb and Hidex 300 SL technique using measurements of (241)Pu and (90)Sr on various samples

Soil and radioactive slurries were analyzed for the presence of beta emitting (241)Pu and (90)Sr. The comparison study between two different LSC apparatus, TriCarb 2200/2550 and Hidex 300 SL, shows good agreement for the quench corrected (241)Pu activity concentrations. The (90)Sr activity concentrations of most soil samples were in agreement, and were confirmed by the recommended IAEA-375 value. The Hidex 300 SL is an excellent apparatus to measure pure β-emitters of routine samples.

Methyl parathion imprinted polymer nanoshell coated on the magnetic nanocore for selective recognition and fast adsorption and separation in soils

Core-shell magnetic methyl parathion (MP) imprinted polymers (Fe3O4@MPIPs) were fabricated by a layer-by-layer self-assembly process. In order to take full advantage of the synergistic effect of hydrogen-binding interactions and π-π accumulation between host and guest for molecular recognition, methacrylic acid and 4-vinyl pyridine were chosen as co-functional monomers and their optimal proportion were investigated. The core-shell and crystalline structure, morphology and magnetic properties of Fe3O4@MPIPs were characterized. The MP-imprinted nanoshell was almost uniform and about 100nm thick. Binding experiments demonstrated that Fe3O4@MPIPs possessed excellent binding properties, including high adsorption capacity and specific recognition, as well as fast adsorption kinetics and a fast phase separation rate. The equilibration adsorption capacity reached up to 9.1mg/g, which was 12 times higher than that of magnetic non-imprinted polymers, while adsorption reached equilibrium within 5min at a concentration of 0.2mmol/L. Furthermore, Fe3O4@MPIPs successfully provided selective separation and removal of MP in soils with a recovery and detection limit of 81.1-87.0% and 5.2ng/g, respectively.

Rapid method for plutonium-241 determination in soil samples

A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied to soil samples contaminated with Chernobyl fallout.

Aptamer-based colorimetric sensing of acetamiprid in soil samples: sensitivity, selectivity and mechanism

A simple and selective aptamer-based colorimetric method was developed for highly sensitive detection of acetamiprid, taking advantages of the sensitive target-induced colour changes that arisen from the interparticle plasmon coupling during the aggregation of Au nanoparticles (NPs). The results showed that the established method could be applied to detect acetamiprid in the linear range between 75 nM to 7.5 μM, with a low detection limit of 5 nM. Meanwhile, by employing an "artificial antibody" acetamiprid-binding aptamer (ABA) as recognition element, highly selective and specific colorimetric visualization of acetamiprid was obtained. It indicated that pesticides which may coexist with acetamiprid could not interfere with the detection of acetamiprid even that had similar structure with acetamiprid, such as imidacloprid and chlorpyrifos. Mechanism study suggested that it could be attributed to the specific supramolecular interaction between ABA and acetamiprid, as well as the resulted target-binding event induced conformation changes of ABA from random coil to hairpin structure. The practical application of the colorimetric method was realized for detecting acetamiprid in real soil samples and monitoring its natural degradation process.

AN EVALUATION OF RESIDUES AT AN OIL REFINERY SITE FOLLOWING FIRES

Soil pollution at the oil refinery at Novi Sad following destruction of crude oil and its products in storage tanks during the Kosovo conflict was investigated. More than 100, 000 t of crude oil and its products were destroyed, and about 90% of these were burnt off, 10% leached and 130 t recovered. The acute injection of polycyclic aromatic hydrocarbons (PAHs) to the air of the town was widespread depending on the weather conditions and ranged from 1-431, 000 ng/m³. The presence of PAHs, polychlorinated biphenyls (PCBs), and elements in the surface zone and soil core samples taken from various sites were determined up to a depth of 100 cm. Concentrations of PAHs were in the range between 0.75 and 86.19 µg/g dry soil. The contaminated soil can be expected to act as a permanent pollution source, while the mobile constituents are likely to cause groundwater pollution.