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Inactivation of antibiotic resistance genes in municipal wastewater by chlorination, ultraviolet, and ozonation disinfection Texte intégral
2015
Zhuang, Yao | Ren, Hongqiang | Geng, Jinju | Zhang, Yingying | Zhang, Yan | Ding, Lili | Xu, Ke
This study investigated the inactivation of two antibiotic resistance genes (ARGs)—sul1 and tetG, and the integrase gene of class 1 integrons—intI1 by chlorination, ultraviolet (UV), and ozonation disinfection. Inactivation of sul1, tetG, and intI1 underwent increased doses of three disinfectors, and chlorine disinfection achieved more inactivation of ARGs and intI1 genes (chlorine dose of 160 mg/L with contact time of 120 min for 2.98–3.24 log reductions of ARGs) than UV irradiation (UV dose of 12,477 mJ/cm²for 2.48–2.74 log reductions of ARGs) and ozonation disinfection (ozonation dose of 177.6 mg/L for 1.68–2.55 log reductions of ARGs). The 16S rDNA was more efficiently removed than ARGs by ozone disinfection. The relative abundance of selected genes (normalized to 16S rDNA) increased during ozonation and with low doses of UV and chlorine disinfection. Inactivation of sul1 and tetG showed strong positive correlations with the inactivation of intI1 genes (for sul1, R ² = 0.929 with p < 0.01; for tetG, R ² = 0.885 with p < 0.01). Compared to other technologies (ultraviolet disinfection, ozonation disinfection, Fenton oxidation, and coagulation), chlorination is an alternative method to remove ARGs from wastewater effluents. At a chlorine dose of 40 mg/L with 60 min contact time, the selected genes inactivation efficiency could reach 1.65–2.28 log, and the cost was estimated at 0.041 yuan/m³.
Afficher plus [+] Moins [-]Ionome and expression level of Si transporter genes (Lsi1, Lsi2, and Lsi6) affected by Zn and Si interaction in maize Texte intégral
2015
Bokor, Boris | Bokorová, Silvia | Ondoš, Slavomír | Švubová, Renáta | Lukačová, Zuzana | Hýblová, Michaela | Szemes, Tomáš | Lux, Alexander
Zinc (Zn) is an essential microelement involved in various plant physiological processes. However, in excess, Zn becomes toxic and represents serious problem for plants resulting in Zn toxicity symptoms and decreasing biomass production. The effect of high Zn and its combination with silicon (Si) on ionome and expression level of ZmLsi genes was investigated in maize (Zea mays, L; hybrid Novania). Plants were cultivated hydroponically in different treatments: control (C), Zn (800 μM ZnSO₄ · 7H₂O), Si5 (5 mM of sodium silicate solution), and Si5 + Zn (combination of Zn and Si treatments). Growth of plants cultivated for 10 days was significantly inhibited in the presence of high Zn concentration and also by Zn and Si interaction in plants. Based on principal component analysis (PCA) and mineral element concentration in tissues, root ionome was significantly altered in both Zn and Si5 + Zn treatments in comparison to control. Mineral elements Mn, Fe, Ca, P, Mg, Ni, Co, and K significantly decreased, and Se increased in Zn and Si5 + Zn treatments. Shoot ionome was less affected than root ionome. Concentration of shoot Cu, Mn, and P decreased, and Mo increased in Zn and Si5 + Zn treatments. The PCA also revealed that the responsibility for ionome changes is mainly due to Zn exposure and also, but less, by Si application to Zn stressed plants. Expression level of Lsi1 and Lsi2 genes for the Si influx and efflux transporters was downregulated in roots after Si supply and even more downregulated by Zinc alone and also by Zn and Si interaction. Expression level of shoot Lsi6 gene was differently regulated in the first and second leaf. These results indicate negative effect of high Zn alone and also in interaction with Si on Lsi gene expression level and together with ionomic data, it was shown that homeostatic network of mineral elements was disrupted and caused negative alterations in mineral nutrition of young maize plants.
Afficher plus [+] Moins [-]Polycyclic aromatic hydrocarbons in the largest deepwater port of East China Sea: impact of port construction and operation Texte intégral
2015
Li, Juan-Ying | Cui, Yu | Su, Lei | Chen, Yiqin | Jin, Ling
PAHs were analyzed for samples of seawater, sediment, and oyster (Saccostrea cucullata) collected from Yangshan Port, East China between 2012 and 2013. Concentrations of ∑PAHs in seawater (180–7,700 ng/L) and oyster (1,100–29,000 ng/g dry weight (dw)) fell at the higher end of the global concentration range, while sediment concentrations (120–780 ng/g dw) were generally comparable to or lower than those reported elsewhere. PAHs in the particulate phase accounted for 85 % (52–93 %) of the total PAHs in seawater. Congener profile analysis revealed that PAHs in waters originate mainly from petrogenic sources, while high-temperature combustion processes are the predominant sources for sediment. ∑PAHs in oyster well correlated with ∑PAHs in the particulate phase, suggesting particle ingestion as an important pathway for bioaccumulation of PAHs. Cancer risk assessment of PAHs in oyster indicated high human health risks posed by these chemicals to the coastal population consuming this seafood.
Afficher plus [+] Moins [-]Electrochemical impedance immunosensor for rapid detection of stressed pathogenic Staphylococcus aureus bacteria Texte intégral
2015
Bekir, Karima | Barhoumi, Houcine | Braiek, Mohamed | Chrouda, Amani | Zine, Nadia | Abid, Nabil | Maaref, Abdelrazek | Bakhrouf, Amina | Ouada, Hafedh Ben | Jaffrezic-Renault, N. (Nicole) | Mansour, Hedi Ben
In this work, we report the adaptation of bacteria to stress conditions that induce instability of their cultural, morphological, and enzymatic characters, on which the identification of pathogenic bacteria is based. These can raise serious issues during the characterization of bacteria. The timely detection of pathogens is also a subject of great importance. For this reason, our objective is oriented towards developing an immunosensing system for rapid detection and quantification of Staphylococcus aureus. Polyclonal anti-S. aureus are immobilized onto modified gold electrode by self-assembled molecular monolayer (SAM) method. The electrochemical performances of the developed immunosensor were evaluated by impedance spectroscopy through the monitoring of the charge transfer resistance at the modified solid/liquid interface using ferri-/ferrocyanide as redox probe. The developed immunosensor was applied to detect stressed and resuscitate bacteria. As a result, a stable and reproducible immunosensor with sensitivity of 15 kΩ/decade and a detection limit of 10 CFU/mL was obtained for the S. aureus concentrations ranging from 10¹ to 10⁷ CFU/mL. A low deviation in the immunosensor response (±10 %) was signed when it is exposed to stressed and not stressed bacteria.
Afficher plus [+] Moins [-]Removal of BrO3 − from drinking water samples using newly developed agricultural waste-based activated carbon and its determination by ultra-performance liquid chromatography-mass spectrometry Texte intégral
2015
Naushad, Mu | Khan, Mohammad R. | ALOthman, Zeid A. | AlSohaimi, Ibrahim | Rodriguez-Reinoso, Francisco | Turki, Turki M. | Ali, Rahmat
Activated carbon was prepared from date pits via chemical activation with H₃PO₄. The effects of activating agent concentration and activation temperature on the yield and surface area were studied. The optimal activated carbon was prepared at 450 °C using 55 % H₃PO₄. The prepared activated carbon was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer, Emmett, and Teller (BET) surface area. The prepared date pit-based activated carbon (DAC) was used for the removal of bromate (BrO₃ ⁻). The concentration of BrO₃ ⁻ was determined by ultra-performance liquid chromatography-mass tandem spectrometry (UPLC-MS/MS). The experimental equilibrium data for BrO₃ ⁻ adsorption onto DAC was well fitted to the Langmuir isotherm model and showed maximum monolayer adsorption capacity of 25.64 mg g⁻¹. The adsorption kinetics of BrO₃ ⁻ adsorption was very well represented by the pseudo-first-order equation. The analytical application of DAC for the analysis of real water samples was studied with very promising results.
Afficher plus [+] Moins [-]Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China Texte intégral
2015
Chen, Kai | Liao, Qi Lin | Ma, Zong Wei | Jin, Yang | Hua, Ming | Bi, Jun | Huang, Lei
Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005–2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km²were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population.
Afficher plus [+] Moins [-]Alluvial and riparian soils as major sources of lead exposure in young children in the Philippines: the role of floods Texte intégral
2015
Ostrea, Enrique M. | Ostrea, Angelo M. | Villanueva-Uy, Ma Esterlita | Chiodo, Lisa | Janisse, James
The objective of this paper was to determine the prevalence and sources of high lead (Pb) exposure among children in Bulacan, Philippines. A total of 150 children (6–7 years old) and their caregivers were studied. Lead was analyzed in children hair and deciduous teeth. Sources of lead exposure were determined by caregiver interview and Pb analysis of house soil, drinking faucet water, air, and water from seven Bulacan rivers. Lead was positive in 91.3 % of children’s hair (MC or median concentration = 8.9 μg/g; range = 0–38.29), in 46.2 % of the teeth (MC = 0.000 μg/mg in positive samples; range = 0.00–0.020), in 100 % of soil (MC = 27.06 mg/kg; range = 3.05–1155.80), in 21.1 % of air (MC = 0 μg/Ncm; range = 0–0.10), in 4 % of house, faucet water (MC = 0.0 ppm; range = 0–40). There was a significant correlation (Spearman’s rho) between Pb in children’s hair and soil (r = 0.195; p = 0.017) and between Pb in house water and outdoor air (r = 0.616; p = 0.005). There is no significant correlation between Pb in children’s hair and teeth. None of the potential sources of Pb from interview were related to lead exposure in the children. Water from seven Bulacan rivers was 100 % positive for lead (MC = 70.00 ppb; range = 30–90). Widespread flooding with river overflow occurred in Bulacan in 2009 which likely caused lead contamination of the soil. There was no significant difference in the lead concentration of the soil whether near or far from the river (p = 0.205, Mann-Whitney U test). High lead exposure in children in Bulacan is likely from soil contaminated by lead-polluted rivers during flooding. In areas where flooding is common, alluvial and riparian soils from polluted rivers are important sources of lead exposure in children.
Afficher plus [+] Moins [-]Effect of nitrate and ammonium fertilization on Zn, Pb, and Cd phytostabilization by Populus euramericana Dorskamp in contaminated technosol Texte intégral
2015
Qasim, Bashar | Motelica-Heino, Mikael | Bourgerie, Sylvain | Gauthier, Arnaud | Morabito, Domenico
This study aimed at assessing the effect of nitrogen addition under two forms, nitrate and ammonium, on the stabilization of Zn, Pb, and Cd by Populus euramericana Dorskamp grown in contaminated soils for 35 days under controlled conditions. Temporal changes in the soil pore water (SPW) were monitored for pH, dissolved organic carbon (DOC), and total dissolved concentrations of metals in the soils rhizosphere. Rhizospheric SPW pH decreased gradually with NH₄ ⁺ addition and increased with NO₃ ⁻ addition up to one unit, while it slightly decreased initially then increased for the untreated control soil DOC increased with time up to six times, the highest increase occurring with NH₄ ⁺ fertilization. An increase in the metal concentrations in the rhizospheric SPW was observed for NH₄ ⁺ addition associated with the lowest rhizospheric SPW pH, whereas the opposite was observed for the control soil and NO₃ ⁻ fertilization. Fertilization did not affect plant shoots or roots biomass development compared to the untreated control (without N addition). Metals were mostly accumulated in the rhizosphere and N fertilization increased the accumulation for Zn and Pb while Cd accumulation was enhanced for NH₄ ⁺ addition. Collectively, our results suggest metal stabilization by P. euramericana Dorskamp rhizosphere with nitrogen fertilization and are potential for phytostabilization of contaminated technosol.
Afficher plus [+] Moins [-]Kinetics of tetracycline, oxytetracycline, and chlortetracycline adsorption and desorption on two acid soils Texte intégral
2015
Fernández-Calviño, David | Bermúdez-Couso, Alipio | Arias-Estévez, Manuel | Nóvoa-Muñoz, Juan Carlos | Fernández-Sanjurjo, Maria J. | Álvarez-Rodríguez, Esperanza | Núñez Delgado, Avelino
The purpose of this work was to quantify retention/release of tetracycline, oxytetracycline, and chlortetracycline on two soils, paying attention to sorption kinetics and to implications of the adsorption/desorption processes on transfer of these pollutants to the various environmental compartments. We used the stirred flow chamber (SFC) procedure to achieve this goal. All three antibiotics showed high affinity for both soils, with greater adsorption intensity for soil 1, the one with the highest organic matter and Al and Fe oxides contents. Desorption was always <15 %, exhibiting strong hysteresis in the adsorption/desorption processes. Adsorption was adequately modeled using a pseudo first-order equation with just one type of adsorption sites, whereas desorption was better adjusted considering both fast and slow sorption sites. The adsorption maximum (q ₘₐₓ) followed the sequence tetracycline > oxytetracycline > chlortetracycline in soil 1, with similar values for the three antibiotics and the sequence tetracycline > chlortetracycline > oxytetracycline in soil 2. The desorption sequences were oxytetracycline > tetracycline > chlortetracycline in soil 1 and oxytetracycline > chlortetracycline > tetracycline in soil 2. In conclusion, the SFC technique has yielded new kinetic data regarding tetracycline, oxytetracycline, and chlortetracycline adsorption/desorption on soils, indicating that it can be used to shed further light on the retention and transport processes affecting antibiotics on soils and other media, thus increasing knowledge on the behavior and evolution of these pharmaceutical residues in the environment.
Afficher plus [+] Moins [-]Urinary heavy metals, phthalates and polyaromatic hydrocarbons independent of health events are associated with adult depression: USA NHANES, 2011–2012 Texte intégral
2015
Shiue, Ivy
Links between environmental chemicals and human health have emerged, but the effects on mental health such as depression were less studied. Therefore, it was aimed to study the relationships between different sets of urinary environmental chemical concentrations and adult depression in a national and population-based setting in recent years. Data was retrieved from the US National Health and Nutrition Examination Survey in 2011–2012 including demographics, serum measurements, lifestyle factors, self-reported health conditions and urinary chemical concentrations. Depression was determined by using the Patient Health Questionnaire with a cutoff point at 9/10. Chi-square test, t test and survey-weighted logistic regression modeling were performed. Among 5560 American adults aged 20–80 years, 363 (7.8 %) people were classified as having depression (Patient Health Questionnaire score ≥ 10). They tended to have history of health events. After full adjustment including urinary creatinine; demographic characteristics; lifestyle factors; health conditions (such as cardiovascular, neurological, respiratory, digestive and bone diseases, and injury); and subsample weighing; and higher levels of manganese, tin, and phthalates including mono-2-ethyl-5-carboxypentyl, mono-n-butyl, mono-isobutyl, and mono-benzyl were associated with adult depression. Similarly, urinary polyaromatic hydrocarbons including 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, 1-hydroxypyrene, 1-hydroxynaphthalene (1-naphthol), 2-hydroxynaphthalene (2-naphthol) and 4-hydroxyphenanthrene were associated with depression. There were no associations observed in urinary arsenic, phenols, parabens, pesticides, perchlorate, nitrate, thiocyanate and polyfluorinated compounds. Urinary heavy metal, phthalates and polyaromatic hydrocarbons were associated with adult depression, being independent of health events. Further elimination of such harmful chemicals might need to be considered in future mental health and environmental policies.
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