Environmental Soil Samples Research Articles

Detection and differentiation of Burkholderia species with pathogenic potential in environmental soil samples.

The Burkholderia pseudomallei phylogenetic cluster includes B. pseudomallei, B. mallei, B. thailandensis, B. oklahomensis, B. humptydooensis and B. singularis. Regarded as the only pathogenic members of this group, B. pseudomallei and B. mallei cause the diseases melioidosis and glanders, respectively. Additionally, variant strains of B. pseudomallei and B. thailandensis exist that include the geographically restricted B. pseudomallei that express a B. mallei-like BimA protein (BPBM), and B. thailandensis that express a B. pseudomallei-like capsular polysaccharide (BTCV). To establish a PCR-based assay for the detection of pathogenic Burkholderia species or their variants, five PCR primers were designed to amplify species-specific sequences within the bimA (Burkholderia intracellular motility A) gene. Our multiplex PCR assay could distinguish pathogenic B. pseudomallei and BPBM from the non-pathogenic B. thailandensis and the BTCV strains. A second singleplex PCR successfully discriminated the BTCV from B. thailandensis. Apart from B. humptydooensis, specificity testing against other Burkholderia spp., as well as other Gram-negative and Gram-positive bacteria produced a negative result. The detection limit of the multiplex PCR in soil samples artificially spiked with known quantities of B. pseudomallei and B. thailandensis were 5 and 6 CFU/g soil, respectively. Furthermore, comparison between standard bacterial culture and the multiplex PCR to detect B. pseudomallei from 34 soil samples, collected from an endemic area of melioidosis, showed high sensitivity and specificity. This robust, sensitive, and specific PCR assay will be a useful tool for epidemiological study of B. pseudomallei and closely related members with pathogenic potential in soil.

2D Co3O4 stabilizing Rh nano composites developed for visual sensing bioactive urea and toxic p-aminophenol in practice by synergetic-reinforcing oxidase activity

To enlarge the perspective of nanozyme, 2-dimensional Co3O4 stabilizing Rh nano composite (2D Co3O4@Rh NC) was identified and developed first by one-pot surfactant-aided oxido-reduction. By virtue of the synergetic-reinforcing oxidase activity between 2D Co3O4 substrate and Rh nano particles, the obtained 2D Co3O4@Rh NC could catalyze the oxidation of chromogenic substrate 3,3′,5,5,’-tetramethylbenzidine (TMB) to blue oxTMB with quite a low Michaelis-Menten constant (Km) of 0.018 mM and a quick vmax of 6.45 × 10–8 M s–1, expressing superior oxidase-like catalysis with a wide temperature range from 20 to 60 °C. Importantly, either bioactive urea or toxic p-aminophenol (p-Ap) could exclusively alter the existed state of oxTMB with differentiable color changes. Under the optimized conditions, 2D Co3O4@Rh NC was successfully applied for ratiometric colorimetric sensing urea and p-Ap in environmental water, soil and urine samples with low detection limits (1.1 μM for urea and 0.68 μM for p-Ap) and satisfactory recoveries (96.0–105.8%). The synergetic enhanced oxidase-like activity of 2D Co3O4@Rh NC and the different reaction mechanisms of the 2D Co3O4@Rh NC-TMB system to urea and p-Ap were investigated. Not only does the work provide an efficient way for sensing organic pollution of p-Ap, it will offer an efficient potential for diagnosing urea-related diseases on clinical medical testing in future.

Spatial Distribution and Associated Risk Factors of Soil-Transmitted Helminth Infection in a Semi-urban Community in Southwest Nigeria

Parasite distribution exhibit heterogeneity within households and communities. The aim of this study is to identify the spatial distribution, clustering and associated risk factors of Soil-transmitted Helminths infection in a semi-urban area in Southwest Nigeria. Geographical information System (GIS) was used to map the town into three density areas; low, medium and high density areas. Two hundred and thirty six soil samples were obtained from the surroundings of 137 households and stool samples were collected from the inhabitant of the households. Moran index was used to analyze the spatial distribution of STH within the community. A total of 137 households were sampled for human STH and environmental soil samples from the household were analyzed. The prevalence of human STH infection was 41.7% while that of soil parasite was 27.7% within the selected household. Ascaris lumbricoides was the predominant STH infection in the community sampled with 24.1% prevalence followed by Hookworm. Spatial analysis showed that A. lumbricoides infection was significantly clustered only in the GIS mapped medium density area of Igbo-Ora (z-score 2.302, p=0.021), while hookworm infection was randomly distributed in all the GIS mapped areas of Igbo-Ora. There was a statistically significant association between human STH infection and presence of parasite in the household soil (x2 5.74, p-value 0.017). None of the risk factors evaluated was found to have significant association for the clustering pattern of infection found in the medium density area of the community. Meanwhile, factors such as; the physical presence of a popularly patronized local market in the area, lack of any visible public toilet and the use of bushes around the area by the people for defecation contribute to the reasons for the clustering of the Ascaris infection. Also, the ability of Ascaris to withstand environmental conditions than other STH parasite may contribute to the pattern observed. The differences in the pattern of distribution and associated risk factors revealed that environmental conditions and exposure factors are major determinant of STH infection.

A new simple, highly sensitive and selective spectrofluorimetric method for the speciation of thallium at pico-trace levels in various complex matrices using N-(pyridin-2-yl)-quinoline-2-carbothioamide.

A very simple and non-extractive new spectrofluorimetric method for the determination of TlI and TlIII individually and for mixtures of both analytes at pico-trace levels using N-(pyridin-2-yl)-quinoline-2-carbothioamide (PQCTA) has been developed. PQCTA reacts in a slightly acidic (0.0025–0.05 M H2SO4) solution with TlIII in 20% ethanol and is oxidized itself to produce highly fluorescent oxidized product in aqueous solution, which has the excitation and emission wavelengths of λex = 324 nm and λem = 379 nm, respectively. The determination of TlI is based on the rapid oxidation of this ion by bromine water heating for 15 min with the concomitant formation of fluorescent TlIII-PQCTA. Fluorescence due to the sum of TlI and TlIII is measured and TlI is determined from the difference in fluorescence values. Constant and maximum fluorescence intensities were observed for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001–600 μg L−1 of Tl, providing a detection limit of 0.16 ng L−1. The quantification limit of the reaction system was 1.6 ng L−1 and the RSD was 0–2%. A large excess of over 80 cations, anions, and complexing agents (such as chloride, phosphate, azide, tartrate, oxalate, and SCN−) do not interfere in the determination. The developed method was successfully used in the determination of thallium in several Standard Reference Materials (SRM) as well as in some environmental waters, biological fluids, soil and food samples, solutions containing both TlI and TlIII, and complex synthetic mixtures. The results of the proposed method for biological samples, vegetables, food, soil, and water analyses were found to be in excellent agreement with those obtained by ICP-OES, AAS, and ICP-MS.

A highly sensitive and selective spectrophotometric method for the determination of vanadium at nanotrace levels in some environmental, biological, soil, food, and pharmaceutical samples using salicylaldehyde-benzoylhydrazone

A very simple, non-extractive and new spectrophotometric method for the swift determination of trace amount of vanadium using salicylaldehyde-benzoylhydrazone (Sal-BH) has been developed. Sal-BH undergoes a reaction in a slightly acidic solution (0.0016-0.0032 M H2S04) with vanadium to give a light greenish-yellow chelate, which has an absorption maximum at 392 nm. The reaction is instantaneous and absorbance remains stable for over 24 hrs. The average molar absorption co-efficient and Sandell’s sensitivity were found to be 2.5039×105 L/mol.cm and 1.0 ng/cm2 V, respectively. Beer’s law was obeyed for 0.001-30 mg/L of V, providing a detection limit of 0.1 µg/L of V and RSD 0-2 %. The stoichiometric composition of the chelate is 1:1 (V:Sal-BH). Interference study shows that a large excess of over 60 cations, anions, and some common complexing agents (such as chloride, azide, tartrate, EDTA and SCN‑, etc.) satisfy the tolerance limit. The developed method was successfully used in the determination of vanadium in several standard reference materials as well as in some environmental waters, biological fluids, soil, food and pharmaceutical samples and solutions containing both vanadium (IV) and vanadium (V). The results of the proposed method for assessing biological, food and vegetable samples were comparable with ICP-OES and AAS were found to be in excellent agreement. The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L).

Isolation and Identification of Biosurfactant Producing Bacterial Strain from Saline Soil Samples in Iran; Evaluation of Factors on Biosurfactant Production

Background: Biosurfactants are a group of valuable amphiphilic molecules that have been widely used in different industries such as pharmaceuticals and cosmetics. Objectives: The current study aimed to screen and identify a bacterial strain able to produce biosurfactant from environmental soil samples, followed by evaluating factors that contribute to biosurfactant production. Methods: The biosurfactants production was evaluated every 24 hours by emulsification index (EI), oil spreading ability, and surface tension measurement. Thereafter, the sequences of 16S rDNA genes and biochemical tests were performed to identify the isolated bacterial. Furthermore, the effect of different factors, including nitrogen, vegetable oil, and cations on biosurfactant productivity of the selected bacterial strain, was also evaluated. Results: In primary screening, out of the six bacterial strains, only one isolate was found to produce a hemolytic zone on the blood agar plate. The EI index was increased in a time-dependent manner with a maximum EI of 10% after 12h. Surface tension measurement revealed decreased surface tension (51 mN/m) after 12 hours' incubation compared to that of the blank sample. The selected isolate was recognized as Bacillus atrophaeus by 16S rDNA gene sequencing and biochemical test. All applied factors in culture media could decrease the surface tension of culture broth compared to that of the blank sample. Conclusions: This study demonstrated a Bacillus strain able to produce biosurfactants. Such biosurfactant producers would have great potentials in bioremediation activities and microbial enhanced oil recovery.

Dosimetric impact of natural terrestrial radioactivity on residents of lower Himalayas, India.

A comprehensive radio-ecological evaluation of soil samples of Solan and Shimla districts of Himachal Pradesh has been carried out for risk and dose assessment. Twenty-six randomly selected environmental soil samples were analysed for natural radionuclide concentrations (226Ra, 232Th and 40K) using NaI(Tl) scintillator detector. The average concentration of 226Ra, 232Th and 40K was observed as 37, 59 and 430Bqkg-1, respectively, which exceeded the worldwide average of 33, 45 and 412Bqkg-1 reported by UNSCEAR (Sources and effects of ionizing radiation. Report to the general assembly with scientific annexes, New York, 2008). Radium equivalent activity (Raeq), hazard indices (Hex, Hin) and radioactivity level indices (Iϒr, Iα, AUI) and Clark value were checked against their threshold limits, and their mean values were safely below the recommended criteria. This confirms the soil applicability for construction purposes. Indoor and outdoor dose rates (Ḋ), age-dependent annual effective doses (AED), organ-specific doses and lifetime attributable cancer risk (both cancer incidence and cancer mortality) were also computed. Strong positive correlation was established between radon/thoron exhalation rate and their parent radionuclides. Multivariate statistical technique was employed to explore spatial distribution of radionuclides and homogeneity between various radiological parameters.

Determination of Natural Radionuclides and Mineral Contents in Environmental Soil Samples

A study of natural radioactivity levels in environmental samples within the northern coastal region of Egypt and the Eastern Province—Khobar, Dammam, Saudi Arabia, has been evaluated. The samples were analyzed using gamma spectrometry based on HpGe detector. The mean activity concentrations of 238U, 232Th, 235U, 40K in addition to 137Cs were 27.03 ± 6.74 Bq/kg, 19.76 ± 0.92 Bq/kg, 0.83 ± 0.06 Bq/kg, 147.11 ± 1.69 Bq/kg and 0.09 ± 0.01 Bq/kg for the first region and 32.9 ± 6.65 Bq/kg, 28.2 ± 0.78 Bq/kg, 1.10 ± 0.3 Bq/kg, 193.8 ± 1.55 Bq/kg and 0.1 ± 0.001 Bq/kg for the second region, respectively. The radiological hazard parameters such as the absorbed dose rate (D), annual effective dose equivalent (AEDE), gamma-ray hazard index (Iγ) and the annual gonadal dose equivalent of the studied samples were estimated. Also, the current work provided the mineralogical composition and the correlations between them and the distribution of radionuclides.

Real-time PCR-based quantitation of viable Mycobacterium leprae strain from clinical samples and environmental sources and its genotype in multi-case leprosy families of India.

The potential role of environmental M. leprae in the transmission of leprosy remains unknown. We investigated role of environment as a possible source of viable M. leprae responsible for transmission of leprosy. The samples were collected from 10 multi-case leprosy families comprising, slit skin smear (SSS) from 9 multibacillary (MB), 16 paucibacillary cases (PB), 22 household contacts, and 38 environmental soil samples. The quantum of viable M. leprae was estimated by qRT-PCR using 16S rRNA gene from soil and SSS. Genotypes of M. leprae were determined by gene sequencing. We could observe presence of viable M. leprae in 11 (44%) leprosy cases (M. leprae 16S rRNA gene copies range from 1.78 × 102 to 8.782 × 109) and 4 (18%) household contacts (M. leprae 16S rRNA gene copies range from 2.54 × 103 and 7.47 × 104). Remarkably, presence of viable M. leprae was also noted in 10 (53%) soil samples where in M. leprae 16S rRNA gene copies ranged from 4.36 × 102 to 7.68 × 102. M leprae subtype 1D was noted in most of the leprosy cases their household contacts and in the surrounding soil samples indicating source of infection in household contacts could be from environment or patients. M. leprae 16S rRNA copies were approximately similar in both PB cases and soil samples along with presence of SNP type 1 subtype 1D in both samples indicating source of M. leprae from patients to contacts was either from patients or environment or both.

Isolation and Genotypic Characterization of Toxoplasma gondii based on GRA6 Gene from Environmental Soil Samples in Mazandaran Province, North of Iran

Soil is one of the environmental sources of Toxoplasma gondii oocysts. The other hand, genotype of the parasite is one of the important factors for its pathogenicity. Due to the importance of toxoplasmosis on public health, this study aimed to isolation and genotyping of T. gondii in environmental soil samples of Mazandaran Province, north of Iran. Overall, 192 soil samples were collected from different areas in Mazandaran Province from Apr to Sep 2014. The flotation method was used for recovering oocysts. Then, soil samples were investigated for DNA detection of T. gondii using nested PCR of RE gene, genotyping with Semi-nested PCR of GRA6 gene and restriction fragment length polymorphism (RFLP) analysis. Results were analyzed using Chi-squared test. A significant difference was considered with a P<0.05. From 192 soil samples, T. gondii DNA was detected in 150 samples (78.1%). Then genotype of 23 samples was determined (91.3% type I and 8.7% type II). Prevalence of T. gondii in soil samples of Mazandaran province, north of Iran is high and T. gondii GRA6 type I is predominant. Soil can be the most important source of severe toxoplasmosis in this province.

Major enteropathogens in humans, domestic animals, and environmental soil samples from the same locality: prevalence and transmission considerations in coastal Odisha, India.

OBJECTIVESRegions with limited sanitation facilities have higher rates of infections with various enteric pathogens. It is therefore important to identify different hosts and their relative contribution to pathogen shedding into the environment, and to assess the subsequent health risks to humans. METHODSIn this study, human faecal (n=310), animal faecal (n=150), and environmental (soil) samples (n=40) were collected from the same locality and screened for selected enteric pathogens by immunochromatography and/or polymerase chain reaction. RESULTSAt least 1 microbial agent was detected in 49.0%, 44.7%, and 40.0% of the samples from human, animals, and soil, respectively. Among humans, rotavirus was predominantly detected (17.4%) followed by enteropathogenic Escherichia coli (EPEC) (15.4%), Shigella (13.8), and Shiga toxin-producing E. coli (STEC) (9.7%). Among animals, STEC was detected most frequently (28.0%), and EPEC was the major enteric pathogen detected in soil (30.0%). The detection rate of rotavirus was higher among younger children (≤2 years) than among older children. Single infections were more commonly detected than multiple infections in humans (p<0.01), unlike the observations in animal and soil samples. For diarrhoeagenic E. coli and Shigella, most of the human and animal isolates showed close relatedness, suggesting possible cross-infection between humans and domesticated animals in the area studied. CONCLUSIONSThe present study provides an improved understanding of the distribution of major enteric pathogens coexisting in humans and animals in the region, thereby suggesting a high potential for possible transmission among livestock and communities residing in the studied locality.

Co-occurrence of mcr-1, mcr-3, mcr-7 and clinically relevant antimicrobial resistance genes in environmental and fecal samples.

Multidrug-resistant bacteria harboring different antimicrobial resistance genes (ARGs) have been detected worldwide. The association of plasmid-mediated colistin resistance genes (mcr-like) and other ARGs in bacteria isolated from animals is a huge concern worldwide. Therefore, this study aimed to investigate the presence of mcr-like genes and clinically relevant ARGs as well as plasmids in samples from a zoo. Fecal and environmental (soil and water) samples were collected from a zoo and the DNA of cultivable aerobic bacteria was extracted. ARGs were screened by PCR and the plasmids were detected using the PCR-based replicon typing method. A total of 74 amplicons from 27 ARGs [mcr-1, mcr-3, mcr-7.1, blaCTX-M-Gp1, blaCTX-M-Gp2, blaCTX-M-Gp9, blaVEB, blaPER, blaCMY, tetA, tetB, tetC, aadA, aac(6')-Ib, aph(3')-Ia, ant(2'')-Ia, qnrA, qnrB, qnrS, oqxA, oqxB, sul1, sul2, sul3, cmlA, mefAE, ermB] and 21 amplicons from eight plasmid families (IncY, ColE-like, IncFrepB, IncFIA, IncFIB, IncHI1, IncFIC, IncP) were detected. These findings reinforce that the zoo acts as a reservoir of clinically relevant ARGs, including mcr-like, and call attention to the monitoring studies in the zoo. Therefore, to the best of our knowledge, this is the first report of the world of mcr-1, mcr-3 and mcr-7.1 in environmental samples from the zoo.

Identification of a novel archaea virus, detected in hydrocarbon polluted Hungarian and Canadian samples.

Metagenomics is a helpful tool for the analysis of unculturable organisms and viruses. Viruses that target bacteria and archaea play important roles in the microbial diversity of various ecosystems. Here we show that Methanosarcina virus MV (MetMV), the second Methanosarcina sp. virus with a completely determined genome, is characteristic of hydrocarbon pollution in environmental (soil and water) samples. It was highly abundant in Hungarian hydrocarbon polluted samples and its genome was also present in the NCBI SRA database containing reads from hydrocarbon polluted samples collected in Canada, indicating the stability of its niche and the marker feature of this virus. MetMV, as the only currently identified marker virus for pollution in environmental samples, could contribute to the understanding of the complicated network of prokaryotes and their viruses driving the decomposition of environmental pollutants.

Inference-based accuracy of metagenome prediction tools varies across sample types and functional categories

BackgroundDespite recent decreases in the cost of sequencing, shotgun metagenome sequencing remains more expensive compared with 16S rRNA amplicon sequencing. Methods have been developed to predict the functional profiles of microbial communities based on their taxonomic composition. In this study, we evaluated the performance of three commonly used metagenome prediction tools (PICRUSt, PICRUSt2, and Tax4Fun) by comparing the significance of the differential abundance of predicted functional gene profiles to those from shotgun metagenome sequencing across different environments.ResultsWe selected 7 datasets of human, non-human animal, and environmental (soil) samples that have publicly available 16S rRNA and shotgun metagenome sequences. As we would expect based on previous literature, strong Spearman correlations were observed between predicted gene compositions and gene relative abundance measured with shotgun metagenome sequencing. However, these strong correlations were preserved even when the abundance of genes were permuted across samples. This suggests that simple correlation coefficient is a highly unreliable measure for the performance of metagenome prediction tools. As an alternative, we compared the performance of genes predicted with PICRUSt, PICRUSt2, and Tax4Fun to sequenced metagenome genes in inference models associated with metadata within each dataset. With this approach, we found reasonable performance for human datasets, with the metagenome prediction tools performing better for inference on genes related to “housekeeping” functions. However, their performance degraded sharply outside of human datasets when used for inference.ConclusionWe conclude that the utility of PICRUSt, PICRUSt2, and Tax4Fun for inference with the default database is likely limited outside of human samples and that development of tools for gene prediction specific to different non-human and environmental samples is warranted.Bd7sVYy1zvX6J832DpeqhYVideo abstract.

A highly sensitive and rapid spectrophotometric method for the determination of molybdenum at nano-trace levels in some real, environmental, biological, food and soil samples using salicylaldehyde-benzoylhydrazone

A very simple, sensitive and highly selective non-extractive new spectrophotometric method has been developed for the determination of molybdenum at nano-trace levels using salicylaldehyde-benzoylhydrazone (Sal-BH). The method is based on the reaction of non-absorbent Sal-BH in a slightly acidic solution (0.0025-0.0075 M H2S04) with molybdenum (VI) to give a light yellowish chelate, which has an absorption maximum at 440 nm. The reaction is instantaneous and absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell’s sensitivity were found to be 4.32×105 L/mol.cm and 5 ng/cm2 of molybdenum, respectively. Linear calibration graphs were obtained for 0.01-60.00 mg/L of molybdenum having detection limit of 1 µg/L and RSD 0.0-2.0 %. The stoichiometric composition of the chelate is 1:1 (Mo:Sal-BH). A large excess of over 60 cations, anions and some common complexing agents (such as chloride, azide, tartrate, EDTA, SCN- etc.) do not interfere in the determination. The method was successfully used in the determination of molybdenum in several Certified Reference Materials (Alloys, steels, water, hair and bovine liver) as well as in some environmental waters (Potable and polluted), biological samples (Human blood, urine, nails, hair, food and vegetables), soil samples, and solutions containing both molybdenum(VI) and molybdenum(V) as well as complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetables samples were found to be in excellent agreement with those obtained by ICP-OES and AAS. The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L).

Electrochemical aptasensor for ultrasensitive detection of PCB77 using thionine-functionalized MoS2-rGO nanohybrid

The authors describe a PCB77 aptasensor based on the use of thionine (Thi) functionalized MoS2-rGO as a platform for aptamer immobilization. Differential pulse voltammetry and cyclic voltammetry were used to monitor the electrochemical properties of proposed aptasensor and investigated the importance of MoS2-rGO/Thi as an aptasensing platform in the measurement of PCB77, a type of polychlorinated biphenyl, as a model molecule. The electrochemical response is based on a decrease of DPV response of Thi before and after the interaction of aptamer with the target (PCB77). Based on the calibration curve, the very low detection limit of 80 ag mL−1 and a very wide linear range of 0.3 fg mL−1–0.1 ng mL−1 were obtained, which is the widest linear range and lowest detection limit among the previous methods reported in the literature. The reproducibility of this aptasensor was 4.2%. Moreover, the effective determination of the PCB 77 by our MoS2-rGO/Thi-based sensor in the complex environmental water and soil samples was realized, which displays a good application possibility.

Isolation and Culture of Leptospira from Clinical and Environmental Samples.

Leptospires, the etiological agents of leptospirosis, are fastidious slow-growing organisms. Here we describe the isolation and routine maintenance of leptospires from clinical (blood, urine, or tissue) and environmental (water or soil) samples. Using combinations of filtration, agar plating, and selective agents, leptospires can be isolated in pure cultures even from complex contaminated sources in standard EMJH culture medium.

Total mercury bias in soil analysis by CV-AFS: causes, consequences and a simple solution based on sulfhydryl cotton fiber as a clean-up step.

This study examines the matrix effect over the trueness for determining total mercury (THg) using CV-AFS. We demonstrate that matrix interferences in soils and sediment samples cannot be eliminated by acid digestion and establish the use of sulfhydryl cotton fiber (SCF), a malleable, cheap and easy to synthesize fiber, as a mandatory solution capable to overcome this bias. Using the classic CV-AFS approach, an overestimation bias for THg recovery values of >140% in a certified reference material was reported. Interference metals test was conducted, thus discarding any influence of metals in the overestimation bias. Therefore, a clean-up step using SCF was proposed, and tests with synthesized fiber did not present a dispersion of >0.08 ng L-1. Moreover, validation was performed by analyzing three certified reference material and yielding mean recovery percentages of 100% ± 1%. A validated methodology was applied to ten environmental soil samples; THg values obtained varied from 129 to 384 ng g-1. Finally, a comparison between sample results obtained and reference method did not show any significant differences (p > 0.05), thus highlighting the efficacy of SCF-CV-AFS for THg quantification in environmental solid samples.

Natural radioactivity, radon emanating power and mass exhalation rate of environmental soil samples from Karabük province, Turkey

Abstract In this study, content of natural radionuclides (226Ra, 232Th and 40K) and radon emanating power and radon mass exhalation rate of surface soil samples collected around industrial province Karabük in which the first iron steel plant was built in 1937 were determined by high-resolution γ-ray spectrometry with a high purity germanium detector. The average activity concentration of 226Ra, 232Th and 40K in soil samples were measured as 30 ± 2, 28 ± 2 and 251 ± 20 Bq kg−1, respectively. The average value of radon emanating power and mass exhalation rate of soil samples were found as 31 % and 19 μBq kg−l s−l, respectively. Assessment of possible radiation hazards to the people due to external exposure was done by estimating the outdoor absorbed gamma dose rate in the air at 1 m above the soil, the corresponding annual effective dose, and the excess lifetime cancer risk. The average outdoor gamma dose rate, annual effective dose, and lifetime cancer risk were estimated as 41 nGy h−1, 51 μSv y−1 and 2.0 × 10−4, respectively. A comparison of the activity and radiological results obtained for the studied samples with the corresponding worldwide average values indicates that the results are below the world average values.

Azo-linked porous organic polymers/polydimethylsiloxane coated stir bar for extraction of benzotriazole ultraviolet absorbers from environmental water and soil samples followed by high performance liquid chromatography-diode array detection

With 4,4′-diaminoterphenyl and phloroglucinol as the monomers, Azo-linked porous organic polymer (PP) was prepared by a green mild azo reaction. Azo-PP is rich in phenolic hydroxyl groups and benzene rings, which can form intermolecular hydrogen bonds with the phenolic hydroxyl groups in interest benzotriazoles (BZTs). The π-π interaction between the benzene ring and the triazole ring would promote the adsorption of target BZTs on Azo-PP. Azo-PP/polydimethylsiloxane (PDMS) coated stir bar was prepared via sol-gel technique for the extraction of target BZTs. Compared with commercial stir bar, Azo-PP coated stir bar showed superior extraction efficiency (75–88% vs 45–65%) under similar conditions and kinetics (50 min vs 120 or 360 min). A method of stir bar sorptive extraction (SBSE) combined with high performance liquid chromatography (HPLC)-diode array detector (DAD) was developed to analyze six target BZT UltraViolet (UV) absorbers. The optimization of SBSE conditions for extraction of interest BZTs was performed by single-factor test. Under the optimized conditions, the limits of detection within 0.12–0.33 μg/L were achieved for six BZT UV absorbers, with the linear range within 0.5–100 μg/L. The method was applied to detect six BZT UV absorbers in the East Lake water, Yangtze River water, and campus soil samples. No BZT was detected in any of the samples. The recoveries of target BZTs in spiked samples were found in the range of 94.9–118%, 96.2–118%, and 88.2–119%.