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Occurrence, source identification and ecological risk evaluation of metal elements in surface sediment: toward a comprehensive understanding of heavy metal pollution in Chaohu Lake, Eastern China Texte intégral
2016
Wang, Ji-Zhong | Peng, Shu-Chuan | Chen, Tian-Hu | Zhang, Liu
In the present study, surface sediment samples from 48 sites covering the whole water area and three main estuaries of Chaohu Lake were collected to determine the concentrations of 25 metal elements using microwave-assisted digestion combined with ICP-MS. Spatial variation, source appointments, and contamination evaluation were examined using multivariate statistical techniques and pollution indices. The results show that for the elements Cd, Pb, Zr, Hf, U, Sr, Zn, Th, Rb, Sn, Cs, Tl, Bi, and Ba, which had higher coefficients of variation (CV), the concentrations were significantly higher in the eastern lake than in the western lake, but other elements with low CV values did not show spatial differences. The accumulation of Cu, Zn, Rb, Sr, Zr, Cd, Sn, Cs, Ba, Hf, Ta, Tl, Pb, Bi, U, and Th in the surface sediments was inferred as long-term agricultural cultivation impact, but that of Ti, V, Cr, Mn, Co, and Ni may have been a natural occurrence. The contribution from industrial and municipal impact was negligible, despite the rapid urbanization around the studied area. Principal component analysis-multiple linear regression (PCA-MLR) predicted the contribution from agricultural activities to range from 0.45 ± 1.31 % for Co to 92.7 ± 17.7 % for Cd. The results of the pollution indices indicate that Chaohu Lake was weakly to moderately affected by Ti, V, Cr, Mn, Co, and Ni but was severely contaminated by Hf and Cd. The overall pollution level in the eastern lake was higher than that in the western lake with respect to the pollution level index (PLI). Therefore, our results can help comprehensively understand the sediment contamination by metals in Chaohu Lake.
Afficher plus [+] Moins [-]Effect of benzoic acid on the removal of 1,2-dichloroethane by a siderite-catalyzed hydrogen peroxide and persulfate system Texte intégral
2016
Li, Shengpin | Li, Mengjiao | Luo, Ximing | Huang, Guoxin | Liu, Fei | Chen, Honghan
Benzoic acid can affect the iron-oxide mineral dissolution and react with hydroxyl radical. This study investigated its effect on 1,2-dichloroethane removal process by siderite-catalyzed hydrogen peroxide and persulfate. The variation of benzoic acid concentrations can affect pH value and soluble iron concentrations; when benzoic acid varied from 0 to 0.5 mmol/L, pH increased while Fe²⁺ and Fe³⁺ concentrations decreased, resulting in 1,2-dichloroethane removal efficiency which decreased from 91.2 to 5.0 %. However, when benzoic acid varied from 0.5 to 10 mmol/L, pH decreased while Fe²⁺ and Fe³⁺ concentrations increased, resulting in 1,2-dichloroethane removal efficiency which increased from 5.0 to 83.4 %.
Afficher plus [+] Moins [-]Screening of phthalate esters in 47 branded perfumes Texte intégral
2016
Al-Saleh, Iman | Elkhatib, Rola
In the last few years, the use of phthalates in perfumes has gained attention because these chemicals are sometimes added intentionally as a solvent and a fixative. Five phthalate esters, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), and diethyl hexyl phthalate (DEHP), were measured in 47 branded perfumes using headspace solid phase microextraction (SPME) followed by gas chromatography–mass spectrometry (GC-MS). The results revealed considerable amounts of phthalate in all 47 brands with detection frequencies > limit of quantitation in the following order: DEP (47/47) > DMP (47/47) > BBP (47/47) > DEHP (46/47) > DBP (23/45). Of the 47 brands, 68.1, 72.3, 85.1, 36.2, and 6.7 % had DEP, DMP, BBP, DEHP, and DBP levels, respectively, above their reported threshold limits. Of these phthalates, DEP was found to have the highest mean value (1621.625 ppm) and a maximum of 23,649.247 ppm. The use of DEP in the perfume industry is not restricted because it does not pose any known health risks for humans. DMP had the second highest level detected in the perfumes, with a mean value of 30.202 ppm and a maximum of 405.235 ppm. Although DMP may have some uses in cosmetics, it is not as commonly used as DEP, and again, there are no restrictions on its use. The levels of BBP were also high, with a mean value of 8.446 ppm and a maximum of 186.770 ppm. Although the EU banned the use of BBP in cosmetics, 27 of the tested perfumes had BBP levels above the threshold limit of 0.1 ppm. The mean value of DEHP found in this study was 5.962 ppm, and a maximum was 147.536 ppm. In spite of its prohibition by the EU, 7/28 perfumes manufactured in European countries had DEHP levels above the threshold limit of 1 ppm. The DBP levels were generally low, with a mean value of 0.0305 ppm and a maximum value of 0.594 ppm. The EU banned the use of DBP in cosmetics; however, we found three brands that were above the threshold limit of 0.1 ppm, and all were manufactured in European countries. The results of this study are alarming and definitely need to be brought to the attention of the public and health regulators. Although some phthalate compounds are still used in cosmetics, many scientists and environmental activists have argued that phthalates are endocrine-disrupting chemicals that have not been yet proven to be safe for any use, including cosmetics. Phthalates may also have different degrees of estrogenic modes of action. Furthermore, we should not dismiss the widespread use of phthalates in everyday products and exposure to these chemicals from sources such as food, medications, and other personal care products.
Afficher plus [+] Moins [-]Silicon alleviates Cd stress of wheat seedlings (Triticum turgidum L. cv. Claudio) grown in hydroponics Texte intégral
2016
Rizwan, M. | Meunier, J.-D. | Davidian, J.-C. | Pokrovsky, O. S. | Bovet, N. | Keller, C.
Silicon alleviates Cd stress of wheat seedlings (Triticum turgidum L. cv. Claudio) grown in hydroponics Texte intégral
2016
Rizwan, M. | Meunier, J.-D. | Davidian, J.-C. | Pokrovsky, O. S. | Bovet, N. | Keller, C.
We investigated the potential role of silicon in improving tolerance and decreasing cadmium (Cd) toxicity in durum wheat (Triticum turgidum L. durum) either through a reduced Cd uptake or exclusion/sequestration in non-metabolic tissues. For this, plants were grown in hydroponic conditions for 10 days either in presence or absence of 1 mM Si and for 11 additional days in various Cd concentrations (0, 0.5, 5.0 and 50 μM). After harvesting, morphological and physiological parameters as well as elemental concentrations were recorded. Cadmium caused reduction in growth parameters, photosynthetic pigments and mineral nutrient concentrations both in shoots and roots. Shoot and root contents of malate, citrate and aconitate increased, while contents of phosphate, nitrate and sulphate decreased with increasing Cd concentrations in plants. Addition of Si to the nutrient solution mitigated these adverse effects: Cd concentration in shoots decreased while concentration of Cd adsorbed at the root cell apoplasmic level increased together with Zn uptake by roots. Overall, total Cd uptake decreased in presence of Si. There was no co-localisation of Cd and Si either at the shoot or at the root levels. No Cd was detected in leaf phytoliths. In roots, Cd was mainly detected in the cortical parenchyma and Si at the endodermis level, while analysis of the outer thin root surface of the plants grown in the 50 μM Cd + 1 mM Si treatment highlighted non-homogeneous Cd and Si enrichments. These data strongly suggest the existence of a root localised protection mechanism consisting in armoring the root surface by Si- and Cd-bearing compounds and in limiting root–shoot translocation.
Afficher plus [+] Moins [-]Silicon alleviates Cd stress of wheat seedlings (Triticum turgidum L. cv. Claudio) grown in hydroponics Texte intégral
2016
Rizwan, M. | Meunier, Jean-Dominique | Davidian, J. -C. | Pokrovsky, O. S. | Bovet, N. | Keller, Catherine | Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE) ; Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) | Department of Environmental Sciences [Faisalabad] ; Government College University of Faisalabad (GCUF) | Biochimie et Physiologie Moléculaire des Plantes (BPMP) ; Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Géosciences Environnement Toulouse (GET) ; Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) ; Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) | Tomsk State University [Tomsk] | NanoGeoScience ; University of Copenhagenn
International audience | We investigated the potential role of silicon in improving tolerance and decreasing cadmium (Cd) toxicity in durum wheat (Triticum turgidum L. durum) either through a reduced Cd uptake or exclusion/sequestration in non-metabolic tissues. For this, plants were grown in hydroponic conditions for 10 days either in presence or absence of 1 mM Si and for 11 additional days in various Cd concentrations (0, 0.5, 5.0 and 50 mu M). After harvesting, morphological and physiological parameters as well as elemental concentrations were recorded. Cadmium caused reduction in growth parameters, photosynthetic pigments and mineral nutrient concentrations both in shoots and roots. Shoot and root contents of malate, citrate and aconitate increased, while contents of phosphate, nitrate and sulphate decreased with increasing Cd concentrations in plants. Addition of Si to the nutrient solution mitigated these adverse effects: Cd concentration in shoots decreased while concentration of Cd adsorbed at the root cell apoplasmic level increased together with Zn uptake by roots. Overall, total Cd uptake decreased in presence of Si. There was no co-localisation of Cd and Si either at the shoot or at the root levels. No Cd was detected in leaf phytoliths. In roots, Cd was mainly detected in the cortical parenchyma and Si at the endodermis level, while analysis of the outer thin root surface of the plants grown in the 50 mu M Cd + 1 mM Si treatment highlighted non-homogeneous Cd and Si enrichments. These data strongly suggest the existence of a root localised protection mechanism consisting in armoring the root surface by Si- and Cd-bearing compounds and in limiting root-shoot translocation.
Afficher plus [+] Moins [-]Effect of carbon sources on the aggregation of photo fermentative bacteria induced by L-cysteine for enhancing hydrogen production Texte intégral
2016
Xie, Guo-Jun | Liu, Bing-Feng | Ding, Jie | Wang, Qilin | Ma, Chao | Zhou, Xu | Ren, Nan-Qi
Poor flocculation of photo fermentative bacteria resulting in continuous biomass washout from photobioreactor is a critical challenge to achieve rapid and stable hydrogen production. In this work, the aggregation of Rhodopseudomonas faecalis RLD-53 was successfully developed in a photobioreactor and the effects of different carbon sources on hydrogen production and aggregation ability were investigated. Extracellular polymeric substances (EPS) production by R. faecalis RLD-53 cultivated using different carbon sources were stimulated by addition of L-cysteine. The absolute ζ potentials of R. faecalis RLD-53 were considerably decreased with addition of L-cysteine, and aggregation barriers based on DLVO dropped to 15–43 % of that in control groups. Thus, R. faecalis RLD-53 flocculated effectively, and aggregation abilities of strain RLD-53 cultivated with acetate, propionate, lactate and malate reached 29.35, 32.34, 26.07 and 24.86 %, respectively. In the continuous test, hydrogen-producing activity was also promoted and reached 2.45 mol H₂/mol lactate, 3.87 mol H₂/mol propionate and 5.10 mol H₂/mol malate, respectively. Therefore, the aggregation of R. faecalis RLD-53 induced by L-cysteine is independent on the substrate types, which ensures the wide application of this technology to enhance hydrogen recovery from wastewater dominated by different organic substrates.
Afficher plus [+] Moins [-]An ultrasound-assisted procedure for fast screening of mobile fractions of Cd, Pb and Ni in soil. Insight into method optimization and validation Texte intégral
2016
Leśniewska, Barbara | Krymska, Marta | Świerad, Ewelina | Wiater, Józefa | Godlewska-Żyłkiewicz, Beata
A fast ultrasound-assisted sequential extraction (UASE) procedure for the determination of cadmium, lead and nickel fractions in soil was developed and fully validated. The working parameters of an ultrasound probe were optimized by comparing the content of metals in soil extracts obtained by the UASE procedure with that obtained by the conventional (with the aid of a vertical rotor) modified Community Bureau of Reference (BCR) procedure. The content of metals in soil fractions was determined by electrothermal atomic absorption spectrometry. The total time of extraction of metals from soil was shorten from 48 h to 27 min (total sonication time). The trueness of the developed method was confirmed by analysis of the certified reference material BCR-701. In order to indicate critical points of the developed UASE method, uncertainties of fractionation results were calculated and compared with those calculated for conventional modified BCR procedure. The method usefulness was tested for the determination of metal fractions in different types of soil collected in the Podlasie Province (Poland). The proposed procedure could be used for fast screening of mobile fractions of several heavy metals in soil.
Afficher plus [+] Moins [-]Monitoring of emerging pollutants in Guadiamar River basin (South of Spain): analytical method, spatial distribution and environmental risk assessment Texte intégral
2016
Garrido, Eva | Camacho-Muñoz, Dolores | Martin, Julia | Santos, Antonio | Santos, Juan Luis | Aparicio, Irene | Alonso, Esteban
Guadiamar River is located in the southwest of the Iberian Peninsula and connects two protected areas in the South of Spain: Sierra Morena and Doñana National Park. It is sited in an area affected by urban, industrial and agriculture sewage pollution and with tradition on intensive mining activities. Most of the studies performed in this area have been mainly focused on the presence of heavy metals and, until now, little is known about the occurrence of other contaminants such as emerging organic pollutants (EOPs). In this work, an analytical method has been optimized and validated for monitoring of forty-seven EOPs in surface water. The analytical method has been applied to study the distribution and environmental risk of these pollutants in Guadiamar River basin. The analytical method was based on solid-phase extraction and determination by liquid chromatography-triple quadrupole–tandem mass spectrometry. The 60 % of the target compounds were found in the analyzed samples. The highest concentrations were found for two plasticizers (bisphenol A and di(2-ethyhexyl)phthalate, mean concentration up to 930 ng/L) and two pharmaceutical compounds (caffeine (up to 623 ng/L) and salicylic acid (up to 318 ng/L)). This study allowed to evaluate the potential sources (industrial or urban) of the studied compounds and the spatial distribution of their concentrations along the river. Environmental risk assessment showed a major risk on the south of the river, mainly due to discharges of wastewater effluents.
Afficher plus [+] Moins [-]Mercury toxicity to terrestrial snails in a partial life cycle experiment Texte intégral
2016
Gimbert, Frédéric | Perrier, Fanny | Caire, Ange-Lyne | de Vaufleury, Annette
Despite growing concerns about the potential adverse effects of elevated mercury (Hg) concentrations in the terrestrial environment, only a few toxicity data are available for soil invertebrates. The chronic toxicity of inorganic Hg—Hg(II)—through food or soil contaminations was therefore assessed for the snail Cantareus aspersus, a well-recognized soil quality bioindicator. The 28-day EC₅₀s (the concentrations causing 50 % effect) for the snail growth were 600 and 5048 mg Hg kg⁻¹ for food and soil, respectively. A survey of growth over its entire duration (91 days) allowed to show that the effects took place rapidly after the beginning of exposure and persisted in the long term. Reproduction was also impaired, and we established 28-day EC₅₀s for sexual maturation and fecundity of 831 and 339 mg Hg kg⁻¹, respectively, for food and 1719 and 53 mg Hg kg⁻¹, respectively, for soil. Total Hg analyses in snails exposed to contaminated matrices revealed important bioaccumulation capacities up to 2000 mg Hg kg⁻¹ viscera. Critical limits in internal Hg concentration of about 500 and 1000 mg Hg kg⁻¹ were determined as thresholds for the induction of growth toxicity through food and soil exposure, respectively. These different values underlined differences in the uptake and toxicological dynamics of Hg according to its bioavailability in the source of exposure.
Afficher plus [+] Moins [-]Benchmark dose for cadmium exposure and elevated N-acetyl-β-D-glucosaminidase: a meta-analysis Texte intégral
2016
Liu, CuiXia | Li, YuBiao | Zhu, ChunShui | Dong, ZhaoMin | Zhang, Kun | Zhao, Yanbin | Xu, YiLu
Cadmium (Cd) is a well-known nephrotoxic contaminant, and N-acetyl-β-D-glucosaminidase (NAG) is considered to be an early and sensitive marker of tubular dysfunction. The link between Cd exposure and NAG level enables us to derive the benchmark dose (BMD) of Cd. Although several reports have already documented urinary Cd (UCd)-NAG relationships and BMD estimations, high heterogeneities arise due to the sub-populations (age, gender, and ethnicity) and BMD methodologies being employed. To clarify the influences that these variables exert, firstly, a random effect meta-analysis was performed in this study to correlate the UCd and NAG based on 92 datasets collected from 30 publications. Later, this established correlation (Ln(NAG) = 0.51 × Ln(UCd) + 0.83) was applied to derive the UCd BMD₅ of 1.76 μg/g creatinine and 95 % lower confidence limit of BMD₅ (BMDL₅) of 1.67 μg/g creatinine. While the regressions for different age groups and genders differed slightly, it is age and not gender that significantly affects BMD estimations. Ethnic differences may require further investigation given that limited data is currently available. Based on a comprehensive and systematic literature review, this study is a new attempt to quantify the UCd-NAG link and estimate BMD.
Afficher plus [+] Moins [-]Determination of personal care products and hormones in leachate and groundwater from Polish MSW landfills by ultrasound-assisted emulsification microextraction and GC-MS Texte intégral
2016
Kapelewska, Justyna | Kotowska, Urszula | Wiśniewska, Katarzyna
Determination of the endocrine disrupting compounds (EDCs) in leachate and groundwater samples from the landfill sites is very important because of the proven harmful effects of these compounds on human and animal organisms. A method combining ultrasound-assisted emulsification microextraction (USAEME) and gas chromatography–mass spectrometry (GC-MS) was developed for simultaneous determination of seven personal care products (PCPs): methylparaben (MP), ethylparaben (EP), propylparaben (PP), buthylparaben (BP), benzophenone (BPh), 3-(4-methylbenzylidene)camphor (4-MBC), N,N-diethyltoluamide (DEET), and two hormones: estrone (E1) and β-estradiol (E2) in landfill leachate and groundwater samples. The limit of detection (LOD)/limit of quantification (LOQ) values in landfill leachate and groundwater samples were in the range of 0.003–0.083/0.009–0.277 μg L⁻¹ and 0.001–0.015/0.002–0.049 μg L⁻¹, respectively. Quantitative recoveries and satisfactory precision were obtained. All studied compounds were found in the landfill leachates from Polish municipal solid waste (MSW) landfills; the concentrations were between 0.66 and 202.42 μg L⁻¹. The concentration of pollutants in groundwater samples was generally below 0.1 μg L⁻¹.
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