细化搜索
结果 3381-3390 的 4,308
Degradation of streptomycin in aquatic environment: kinetics, pathway, and antibacterial activity analysis 全文
2017
Shen, Yanru | Zhao, Wenyan | Zhang, Chunling | Shan, Yujie | Shi, Junxian
Streptomycin used in human and veterinary medicine is released into the environment mainly through excretions. As such, its elimination in water should be investigated to control pollution. In this study, the degradation of streptomycin in water was studied, and the influence of variables, including light exposure, solution pH, temperature, ionic strength, dissolved organic matter (DOM), and coexisting surfactants, on degradation was investigated. Streptomycin degradation was consistent with the first-order model in aquatic environments. Its degradation rate under light exposure was 2.6-fold faster than that in the dark. Streptomycin was stable under neutral conditions, but it was easily decomposed in acidic and basic environments. Streptomycin degradation was enhanced by high temperature, and its half-life decreased from 103.4 days at 15 °C to 30.9 days at 40 °C. This process was also accelerated by the presence of Ca²⁺ and slightly improved by the addition of HA. Streptomycin degradation was suppressed by high levels of the cationic surfactant cetyltri- methylammonium bromide (CTAB), but was promoted by the anionic surfactant sodium dodecyl benzene sulfonate (SDBS). The main degradation intermediates/products were identified through liquid chromatography–mass spectrometry, and the possible degradation pathway was proposed. The antibacterial activity of streptomycin solution was also determined during degradation. Results showed that STR degradation generated intermediates/products with weaker antibacterial activity than the parent compound.
显示更多 [+] 显示较少 [-]Assessing PAHs pollution in Shandong coastal area (China) by combination of chemical analysis and responses of reproductive toxicity in crab Portunus trituberculatus 全文
2017
Pan, Luqing | Xu, Ruiyi | Wen, Jianmin | Guo, Ruiming
The concentrations of PAHs in seawater and sediments were measured at three selected sites (S1, S2, and S3) along the coastal area of Shandong (China) in April, May, and June, 2015, which ranged from 29.72 to 123.88 ng/L and 82.62 to 232.63 ng/g, respectively. Meanwhile, the reproductive toxicity responses in crab Portunus trituberculatus were also evaluated to assess the pollution of PAHs during the sampling period. Chemical analysis showed that S3 was the most PAH-contaminated area while S1 was the least, and the biochemical parameters concerned with reproduction were efficiently responded to the three sites, especially in S3 (p < 0.05). Moreover, the principal component analyses (PCA) showed that parameters for DNA alkaline unwinding, protein carbonyl content, and lipid peroxidation levels in two genders, 17β-estradiol in female, testosterone and TESK2 gene expression in male crabs, were closely correlated with the concentrations of PAHs (2 + 3 rings, 4 rings, and 5 + 6 rings), which were considered to be good candidate indicators to assess the environmental pollutions resulting from PAHs in the coastal area of Shandong, China.
显示更多 [+] 显示较少 [-]Concentration estimation of heavy metal in soils from typical sewage irrigation area of Shandong Province, China using reflectance spectroscopy 全文
2017
Wang, Fei | Li, Chunfang | Wang, Jining | Cao, Wentao | Wu, Quanyuan
Since sewage irrigation can markedly disturb the status of heavy metals in soils, a convenient and accurate technique for heavy metal concentration estimation is of utmost importance in the cropland using wastewater for irrigation. This study therefore assessed the feasibility of visible and near infrared reflectance (VINR) spectroscopy for predicting heavy metal contents including Cr, Cu, Ni, Pb, Zn, As, Cd, and Hg in the north plain of Longkou city, Shandong Province, China. A total of 70 topsoil samples were taken for in situ spectra measurement and chemical analysis. Stepwise multiple linear regression (SMLR) and principal component regression (PCR) algorithms were applied to establish the associations between heavy metals and reflectance spectral data pretreated by different transformation methods. Based on the criteria that minimal root mean square error (RMSE), maximal coefficient of determination (R ²) for calibration, and greater ratio of standard error of performance to standard deviation (RPD) is related to the optimal model, SMLR model using first deviation data (RD₁) provided the best prediction for the contents of Ni, Pb, As, Cd, and Hg, calibration using SNV data for Cr and continuum removal spectra for Zn, while PCR equation employed RD₁ values was fit for prediction of the contents of Cu. The determination coefficients of all the reasonable models were beyond 0.6, and RPD indicated a fair or good result. In general, first deviation preprocessing tool outperformed other methods in this study, while raw spectra reflectance performed unsatisfactory in all models. Overall, VINR reflectance spectroscopy technique could be applicable to the rapid concentration assessment of heavy metals in soils of the study area.
显示更多 [+] 显示较少 [-]A bibliometric analysis of eutrophication literatures: an expanding and shifting focus 全文
2017
Li, Xia | Nan, Ruiqi
This paper examined the eutrophication literatures from 1998 to 2015 using bibliometric techniques basing on the database of Science Citation Index. Bibliometric techniques, social network analysis, and mapping knowledge domains in this paper were used. The results revealed that article was the most used document type accounting for 94.79% (14,006) of the records. With the rapid development of eutrophication domain after 2004, the annual article publishing amount also grew notably in each country, with the list of US tops. International cooperation was not enough to compare with that between institutions. An author keyword analysis showed that “phosphorus,” “nutrients,” “nitrogen,” “water quality,” “phytoplankton,” and “sediment” were the most popular keywords. And it was also found that climate change, life cycle assessment, and chlorophyll a appear with high frequency in recent years, indicating that the eutrophication mechanism analysis might turn from uni-factor microresearch to multi-factor macroresearch, and the eutrophication management research tends to be whole-process management research. In addition, the future focuses of research directions, including (1) eutrophication and its ecosystem response, (2) eutrophication management, (3) eutrophication and climate change interactions, (4) eutrophication monitoring and forecast, and (5) ecological restoration of eutrophication. These findings are useful for the future endeavor of eutrophication academic research.
显示更多 [+] 显示较少 [-]Organometallic nanoprobe to enhance optical response on the polycyclic aromatic hydrocarbon benzo[a]pyrene immunoassay using SERS technology 全文
2017
Dribek, Mohamed | Rinnert, Emmanuel | Colas, Florent | Crassous, Marie-Pierre | Thioune, Néné | David, Catalina | de la Chapelle, Marc | Compère, Chantal
Organometallic nanoprobe to enhance optical response on the polycyclic aromatic hydrocarbon benzo[a]pyrene immunoassay using SERS technology 全文
2017
Dribek, Mohamed | Rinnert, Emmanuel | Colas, Florent | Crassous, Marie-Pierre | Thioune, Néné | David, Catalina | de la Chapelle, Marc | Compère, Chantal
We demonstrated the use of a new organometallic nanoprobe for competitive surface-enhanced Raman scattering (SERS) immunoassay devoted to the detection of polycyclic aromatic hydrocarbons (PAH) such as benzo[a]pyrene (BaP) in seawater. The nanoprobes are gold nanoparticles (GNPs) labeled by a Raman reporter, the 5,5′-dithiobis(succinimidyl-2-nitrobenzoate) (DSNB) and functionalized with monoclonal antibodies anti-BaP. The antibodies are bound with a high specificity to the analyte while the GNPs enhanced the Raman scattering of the DSNB. This type of immunoassay involved the grafting of BaP onto a sensing surface. Thus, NH₂-terminated self-assembled monolayer is formed on the surface of gold substrate using cysteamine. Amines finally reacted with 6-formylbenzo[a]pyrene. So, this SERS detection involves four steps: (i) the nanoprobes are incubated with the sample; (ii) a drop of the mixture is then put onto the substrate; (iii) the surface is rinsed; and (iv) the surface is analyzed by Raman spectroscopy. To synthesize the nanoprobes, firstly, we prepared GNPs according to Frens’ method. Then, GNPs were spontaneously labeled by the DSNB Raman reporter, thanks to a strong gold-sulfur interaction. Thereafter, BaP antibodies were cross-linked to the DSNB labeled GNPs by reaction of proteins primary amino groups with N-hydroxyl succinimide (NHS). Before use in SERS detection, their activity was controlled by surface plasmon resonance technique. The present method allows us to detect BaP at trace concentration (2 nmol/L). The results demonstrate that the proposed method has a great potential for application in the monitoring of seawater.
显示更多 [+] 显示较少 [-]Organometallic nanoprobe to enhance optical response on the polycyclic aromatic hydrocarbon benzo[a]pyrene immunoassay using SERS technology 全文
2017
Dribek, Mohamed | Rinnert, Emmanuel | Colas, Florent | Crassous, Marie-pierre | Thioune, Nene | David, Catalina | De La Chapelle, Marc | Compere, Chantal
We demonstrated the use of a new organometallic nanoprobe for competitive surface-enhanced Raman scattering (SERS) immunoassay devoted to the detection of polycyclic aromatic hydrocarbons (PAH) such as benzo[a]pyrene (BaP) in seawater. The nanoprobes are gold nanoparticles (GNPs) labeled by a Raman reporter, the 5,5'-dithiobis(succinimidyl-2-nitrobenzoate) (DSNB) and functionalized with monoclonal antibodies anti-BaP. The antibodies are bound with a high specificity to the analyte while the GNPs enhanced the Raman scattering of the DSNB. This type of immunoassay involved the grafting of BaP onto a sensing surface. Thus, NH2-terminated self-assembled monolayer is formed on the surface of gold substrate using cysteamine. Amines finally reacted with 6-formylbenzo[a]pyrene. So, this SERS detection involves four steps: (i) the nanoprobes are incubated with the sample; (ii) a drop of the mixture is then put onto the substrate; (iii) the surface is rinsed; and (iv) the surface is analyzed by Raman spectroscopy. To synthesize the nanoprobes, firstly, we prepared GNPs according to Frens' method. Then, GNPs were spontaneously labeled by the DSNB Raman reporter, thanks to a strong gold-sulfur interaction. Thereafter, BaP antibodies were cross-linked to the DSNB labeled GNPs by reaction of proteins primary amino groups with N-hydroxyl succinimide (NHS). Before use in SERS detection, their activity was controlled by surface plasmon resonance technique. The present method allows us to detect BaP at trace concentration (2 nmol/L). The results demonstrate that the proposed method has a great potential for application in the monitoring of seawater.
显示更多 [+] 显示较少 [-]Soil pollution fingerprints of children playgrounds in Sarajevo city, Bosnia and Herzegovina 全文
2017
Sapcanin, Aida | Cakal, Mirsada | Jacimovic, Zeljko | Pehlic, Ekrem | Jancan, Gordan
This is the first study, 10 years after the war activities, to report about the content of heavy metals and metalloids, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) found in samples of soils from selected playgrounds in Sarajevo. Due to the fact that children are in direct contact with surface soils, it has been recommended that children’s playgrounds should be given special consideration in this respect. Basic properties (pH in H₂O, pH in 1 mol dm⁻³ KCl, humus, and CaCO₃) of the examined soils were determined. Samples for the determination of heavy metals and metalloids were prepared by microwave-assisted acid digestion and determined by using an inductively coupled plasma optical emission spectrometer. Fluorine was determined potentiometrically. Gas chromatography with mass spectrometry was used for determination of PAHs and PCBs. Determined contents (mg kg⁻¹) for Cd, Pb, Hg, Cr, Ni, Cu, Zn, Co, Mo, Fe, Se, As, B, and F were in the ranges from: 0.031 ± 0.03 to 0.52 ± 0.05; 26.1 ± 2.5 to 47.7 ± 4.5; 0.07 ± 0.01 to 0.50 ± 0.08; 26.2 to 50; 19.5 ± 1.6 to 33.3 ± 2.7; 12.8 ± 1.8 to 31.9 ± 4.5; 56.0 ± 4.0 to 89.0 ± 6.5; 6.7 ± 0.6 to10.6 ± 1.0; <0.8; 3.05 to 7.35; 1.98 to 2.60; 6.5 ± 0.8 to 17.2 ± 2.0; 0.4 to 3.6, and 286 to 575, respectively. The total PAHs ranged between 0.184 ± 0.32 mg kg⁻¹ and 7.983 ± 1.389 mg kg⁻¹. The total PCBs was <0.002 mg kg⁻¹. Our preliminary results may contribute to more accurate health risk assessments of the soils, and may be included in projects planning children’s health risk assessments and adopting environmental legislation which has not been sufficiently regulated in Bosnia and Herzegovina so far.
显示更多 [+] 显示较少 [-]Enhanced treatment of coking wastewater containing phenol, pyridine, and quinoline by integration of an E-Fenton process into biological treatment 全文
2017
Xue, Lanlan | Liu, Jiaxin | Li, Meidi | Tan, Liang | Ji, Xiangyu | Shi, Shengnan | Jiang, Bei
In this study, the pyridine and quinoline could be cometabolically degraded by phenol-cultivated Comamonas sp. strain JB(strain JB). The integration of magnetically immobilized cells of JB and an E-Fenton process into one entity has been designed to prepare a novel integration system to improve the treatment efficiency of phenol, pyridine, and quinoline in coking wastewater. The optimal pH for the integration system was 3.5. Degradation rates of phenol, pyridine, quinoline, and COD by the integration system were significantly exceeded the sum degradation rates of the single E-Fenton process and magnetically immobilized cells at the optimal voltage of 1 V. During the 6 cycles, the integration system still showed higher degradation rates than that by the single magnetically immobilized cells for all the compounds. These findings demonstrated that a synergistic effect existed between the biological treatment and the E-Fenton process, and the applied voltage in the integration system played the key roles in the synergistic effect, which not only electrogenerated H₂O₂ but also improved the activity of phenol hydroxylase and strain JB concentration.
显示更多 [+] 显示较少 [-]Environmental exposure and effects on health of children from a tobacco-producing region 全文
2017
Nascimento, Sabrina N. | Göethel, Gabriela | Baierle, Marília | Barth, Anelise | Brucker, Natália | Charão, Mariele F. | Moro, Angela M. | Gauer, Bruna | Sauer, Elisa | Durgante, Juliano | Arbo, Marcelo D. | Thiesen, Flavia V. | Pierre, Tatiana D Saint’ | Gioda, Adriana | Moresco, Rafael | Garcia, Solange Cristina
Children may be environmentally exposed to several hazards. In order to evaluate the health of children living in a tobacco-producing region, different biomarkers of exposure and effect, as well as hematological parameters, were evaluated. Biomarkers of exposure to the following xenobiotics were assessed: pesticides, nicotine, toxic elements, and organic solvents. Oxidative damage markers malondialdehyde (MDA) and protein carbonyls (PCO), vitamin C, microalbuminuria (mALB) levels, and N-acetyl-β-D-glucosaminidase (NAG) activity were also evaluated. Peripheral blood samples and urine were collected from 40 children (6–12 years), at two different crop periods: in the beginning of pesticide applications (period 1) and in the leaf harvest (period 2). The Wilcoxon signed-rank test for paired data was used to evaluate the differences between both periods. Biomarkers of exposure cotinine in urine and blood chromium (Cr) levels were increased in period 1 when compared to period 2. Moreover, a significant reduced plasmatic activity of butyrylcholinesterase (BuChE) was observed in period 2 in relation to period 1. Blood Cr levels were above the recommended by WHO in both evaluations. The biomarkers MDA and PCO as well as the kidney dysfunction biomarker, mALB, presented levels significantly increased in period 1. Additionally, decreased lymphocytes and increased basophils were also observed. Cotinine was positively associated with PCO, and Cr was positively associated with PCO and MDA. The increased Cr levels were associated with decreased lymphocytes and increased basophils. Our findings demonstrate that children environmentally exposed to xenobiotics in rural area may present early kidney dysfunction, hematological alterations, as well as lipid and protein damages, associated with co-exposure to different xenobiotics involved in tobacco cultivation.
显示更多 [+] 显示较少 [-]A preliminary study for conducting a rational assessment of radon exposure levels 全文
2017
Jeon, Hyung-Jin | Kang, Dae-Ryoung | Go, Sang-Baek | Park, Tae-Hyun | Park, Si-Hyun | Kwak, Jung-Eun | Lee, Cheol-Min
The aim of this study was to determine the factors that go into a highly reliable estimate of radon exposure levels for use in setting up the case-control study. To this end, the present study conducted a multi-faceted investigation of the distribution of radon concentrations in the bedrooms and living rooms of 400 households in the target areas during the winter months from December 2014 to February 2015. We determined that taking the mean value of the radon concentration levels detected in the bedroom and living room as the representative value of residential concentration is appropriate, given the usability of previous research data and the difference in the concentration levels between the two. In terms of detector placement, we found that detectors should not inconvenience residents or be affected by an air current. Further, we found that housing type should distinguish between regular housing (single-detached, row, and multiplex housing) and apartments but that the building type was not a key factor in the assessment of radon exposure levels. Houses should be classified into those constructed with soil (red clay) and those with constructed with general building materials for the assessment of radon exposure levels.
显示更多 [+] 显示较少 [-]Control of the pollution of antibiotic resistance genes in soils by quorum sensing inhibition 全文
2017
Lai, Bai-Min | Zhang, Kun | Shen, Dong-Sheng | Wang, Mei-Zhen | Shentu, Jia-Li | Li, Na
To investigate whether pollution from antibiotic resistance genes (ARGs) could be affected by bacterial quorum sensing, the oxytetracycline (OTC)-containing manure was fertilized to establish the ARG-polluted soil environment. Under long-term OTC stress, substantial ARGs in the range from 10⁻⁴ to 10⁻³ RG/16S rRNA (resistance genes/16S rRNA) were detected in the antibiotics control (AC) group, in which OTC-containing manure was fertilized. Meanwhile, 10⁻⁶ RG/16S rRNA was detected in biological control (BC) group, in which non-OTC-containing manure was fertilized. Subsequently, two typical quorum sensing inhibitors, 4-nitropyridine N-oxide (4-NPO) and 3,4-dibromo-2H-furan-5-one (DBF), were used to treat the ARG-polluted soils. These two groups called 4-NPO treatments (NT) and DBF treatments (FT), respectively. There were no significant differences in bacterial growth and OTC degradation in NT and FT groups, compared to AC group. However, acyl-homoserine lactones such as C₄-HSL, C₆-HSL, and C₈-HSL decreased significantly in both NT and FT groups, compared to AC group. Meanwhile, the abundance of most ARGs decreased dramatically. In FT group, the concentrations of tet(L) and tet(Q) were below the detection limits. It was demonstrated that quorum sensing inhibition could be an effective way to prevent and control the pollution of ARGs in soil.
显示更多 [+] 显示较少 [-]