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Levels, isomer profiles and chiral signatures of particle-bound hexabromocyclododecanes in ambient air around Shanghai, China
2012
Li, Huiru | Mo, Ligui | Yu, Zhiqiang | Sheng, Guoying | Fu, Jiamo
Hexabromocyclododecanes (HBCDs) have been considered candidate persistent organic pollutants, however, environmental data on their presence in China, a major world market, are limited. In this study, airborne particle-bound HBCDs in Shanghai, China were quantified with liquid chromatography–tandem mass spectrometry, and their total concentrations varied from 3.21 to 123 pg/m³. The industrial area showed about three times higher HBCD levels than the urban areas. Gamma-HBCD dominated in particle-associated HBCDs in the industrial area, while α-HBCD was the major diastereomer of the urban areas, which is quite different from the pattern of technical products. Besides α-, β- and γ-HBCDs, δ-HBCD was also detected in all samples (0.09–6.31 pg/m³), while no ɛ-HBCD was found. Airborne β- and γ-HBCDs were racemic in most studied areas due to their chiral signatures showing no significant difference from commercial mixture. Fractions of (+)-α-HBCD (0.417–0.467), however, suggested the enrichment of (−)-α-HBCD and the involvement of enantioselective bioprocesses.
Show more [+] Less [-]Imaging of metal bioaccumulation in Hay-scented fern (Dennstaedtia punctilobula) rhizomes growing on contaminated soils by laser ablation ICP-MS
2012
Koelmel, Jeremy | Amarasiriwardena, Dulasiri
Understanding Pb removal from the translocation stream is vital to engineering Pb hyperaccumulation in above ground organs, which would enhance the economic feasibility of Pb phytoextraction technologies. We investigated Cu, Pb, Sb and Zn distributions in Hay-scented fern (Dennstaedtia punctilobula) rhizomes on shooting range soils by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), analyzing digested rhizomes, stems, and fronds using ICP-MS. Nutrients Cu and Zn concentrated in fronds while toxic elements Pb and Sb did not, showing potential Pb and Sb sequestration in the rhizome. Frond and rhizome concentration of Pb was 0.17 ± 0.10% and 0.32 ± 0.21% of dry biomass, respectively. The ²⁰⁸Pb/¹³C and ¹²¹Sb/¹³C determined by LA-ICP-MS increased from inner sclerotic cortex to the epidermis, while Pb concentrated in the starchy cortex only in contaminated sites. These results suggest that concentration dependent bioaccumulation in the rhizome outer cortex removes Pb from the vascular transport stream.
Show more [+] Less [-]Surface-bound humic acid increased Pb²⁺ sorption on carbon nanotubes
2012
Lin, Daohui | Tian, Xiaoli | Li, Tingting | Zhang, Zhiyong | He, Xiao | Xing, Baoshan
Solid humic acid (HA) particles were dissolved and subsequently coated on a type of multiwalled carbon nanotubes (MWCNTs). Pb²⁺ sorption from water by the solid HA, the MWCNTs and the obtained HA-MWCNT complexes was compared. The underlying mechanism of the difference in the sorption was discussed with the data at different pHs, results of desorption in the presence and absence of Ca²⁺ and the characterizations using inductively coupled plasma mass spectrometry, X-ray energy dispersion spectroscopy and X-ray absorption fine structure spectroscopy. The effect of MWCNT-contained impurities on the sorption was also examined. It was shown that the surface-bound HA introduced oxygen-containing functional groups and negative charges on the MWCNTs, thus greatly increasing Pb²⁺ sorption on the MWCNTs. Pb²⁺ could be electrostatically attracted into outer-sphere of the electric double layer of the HA-MWCNT complexes, a fraction of which would form coordination complexes with carboxyl groups in the inner- and/or outer-sphere.
Show more [+] Less [-]Spatial distribution of per- and polyfluoroalkyl compounds in coastal waters from the East to South China Sea
2012
Cai, Minghong | Zhao, Zhen | Yang, Haizhen | Yin, Zhigao | Hong, Qingquan | Sturm, Renate | Ebinghaus, Ralf | Ahrens, Lutz | Cai, Minggang | He, Jianfeng | Xie, Zhiyong
The spatial distribution of per- and polyfluoroalkyl compounds (PFCs) were investigated in coastal waters collected onboard research vessel Snow Dragon from the East to South China Sea in 2010. All samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(−)ESI-MS/MS). Concentrations of 9 PFCs, including C₄ and C₈ (PFBS, PFOS) perfluoroalkyl sulfonate (PFSAs), C₅–C₉ and C₁₃ (PFPA, PFHxA, PFHpA, PFOA, PFNA, PFTriDA) perfluoroalkyl carboxylates (PFCAs), and N-ethyl perfluorooctane sulfonamide (EtFOSA) were quantified. The ΣPFC concentrations ranged from 133 pg/L to 3320 pg/L, with PFOA (37.5–1541 pg/L), PFBS (23.0–941 pg/L) and PFHpA (0–422 pg/L) as dominant compounds. Concentrations of PFCs were greater in coastal waters along Shanghai, Ningbo, Taizhou, Xiamen and along coastal cities of the Guangdong province compared to less populated areas along the east Chinese coast. Additionally, the comparison with other seawater PFC measurements showed lower levels in this study.
Show more [+] Less [-]Use of species sensitivity distributions to predict no-effect concentrations of an antifouling biocide, pyridine triphenylborane, for marine organisms
2012
Mochida, Kazuhiko | Onduka, Toshimitsu | Amano, Haruna | Ito, Mana | Ito, Katsutoshi | Tanaka, Hiroyuki | Fujii, Kazunori
We used species sensitivity distributions (SSDs) and a Bayesian statistical model to carry out a primary risk assessment for pyridine triphenylborane (PTPB) in Hiroshima Bay, Japan. We used SSDs derived from toxicity values, such as EC₅₀ and LC₅₀, obtained from this study and previous work to calculate hazardous concentrations that should protect 95% and 99% of species (HC₅ and HC₁) and demonstrated that the medians of the HC₅ and HC₁ were 0.78 and 0.17μg/L, respectively. We also used liquid chromatography/mass spectrometry to investigate the occurrence of PTPB in seawater from several coastal sites of Hiroshima Bay and detected PTPB at concentrations of 4.8–21pg/L. Comparison of environmental concentrations to the HC values suggests that the current ecological risk posed by PTPB in Hiroshima Bay is low. This is the first report of the detection of PTPB in the natural marine environment.
Show more [+] Less [-]Levels and spatial distribution of trace elements in macroalgae species from the Todos os Santos Bay, Bahia, Brazil
2012
Brito, Geysa B. | de Souza, Thaís L. | Bressy, Fernanda C. | Moura, Carlos W.N. | Korn, Maria Graças A.
Concentrations of elements (As, Ba, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, V, and Zn) were determined in ten species of macroalgae collected from six sites in the Todos os Santos Bay, Brazil, between May and July of 2010. An optimized microwave-assisted digestion procedure was used to digest the samples. The elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). A wide range of metal concentrations were observed between the species analysed. Somewhat higher concentrations of Cd (5.99μgg⁻¹), Co (372μgg⁻¹), Mn (640μgg⁻¹), Ni (17.2μgg⁻¹) and Zn (51.4μgg⁻¹) were found in the brown macroalgae species Padina spp., whereas elements, such as As (19.7μgg⁻¹) and Pb (8.27μgg⁻¹), were mainly concentrated in the species Sargassum spp. and Bostrychia montagnei, respectively. Statistical analyses (ANOVA) of the Padina data showed significant inter-site differences for all metals examined except nickel.
Show more [+] Less [-]Analysis of Pacific oyster larval proteome and its response to high-CO₂
2012
Dineshram, R. | Wong, Kelvin K.W. | Xiao, Shu | Yu, Ziniu | Qian, Pei Yuan | Thiyagarajan, Vengatesen
Most calcifying organisms show depressed metabolic, growth and calcification rates as symptoms to high-CO₂ due to ocean acidification (OA) process. Analysis of the global expression pattern of proteins (proteome analysis) represents a powerful tool to examine these physiological symptoms at molecular level, but its applications are inadequate. To address this knowledge gap, 2-DE coupled with mass spectrophotometer was used to compare the global protein expression pattern of oyster larvae exposed to ambient and to high-CO₂. Exposure to OA resulted in marked reduction of global protein expression with a decrease or loss of 71 proteins (18% of the expressed proteins in control), indicating a wide-spread depression of metabolic genes expression in larvae reared under OA. This is, to our knowledge, the first proteome analysis that provides insights into the link between physiological suppression and protein down-regulation under OA in oyster larvae.
Show more [+] Less [-]Solventless Microextraction Techniques for Determination of Trihalomethanes by Gas Chromatography in Drinking Water
2012
Rosero, Milton Moreano | Aguirre, Mauricio | Pezo, Davinson | Taborda, Gonzalo | Dussán, Carmen | Nerin, Cristina
Three different solventless sample preparation techniques based on microextraction, membrane extraction, and headspace extraction have been developed and optimized for determination of trihalomethanes in drinking water by gas chromatography electron capture detector and mass spectrometry detection. The techniques employed were headspace (HS) solid-phase microextraction, hollow fiber liquid-phase microextraction (HFLPME) and HS extraction. All techniques used were optimized with different experimental designs in order to select the most relevant variables which significantly affect the different processes. The different analytical figures of merit such as limit of detection (LOD), limit of quantification, reproducibility, accuracy, and linear dynamic range were obtained. The new HFLPME method applied used a hollow fiber membrane of polypropylene and the optimized variables were extraction time, extraction temperature, and salting-out effect. The software MODDE 6.0 was used and its design was one central composite on face with a total of 17 runs. The best conditions for the HFLPME were 20 min, 40°C, and 10% NaCl, respectively. The LODs ranged from 0.018 μg·L−1 (for CHClBr2) to 0.049 μg·L−1 (for CHBr3), being this technique the most sensitive one among those studied. Finally, after having optimized the sample preparation techniques and chromatographic conditions, several water samples were taken in two different water treatment plants in Spain (Zaragoza) and Colombia (Viterbo, Caldas). The results obtained are shown and discussed.
Show more [+] Less [-]Effect of pH on the Analysis of 2-MIB and Geosmin in Water
2012
Hsieh, Wen-Hsing | Hung, Wei-Nung | Wang, Gen-Shuh | Hsieh, Shu-Ting | Lin, Tsair-Fuh
2-Methylisoborneol (2-MIB) and trans-1,10-dimethyl-trans-9-decalol (geosmin) are two commonly observed taste and odor compounds present in drinking water sources. The effects of pH on the analysis of the two chemicals are investigated using a gas chromatograph and mass spectrometric detector (GC/MSD) coupled with three pre-concentration methods, namely solid-phase micro-extraction (SPME), purge-and-trap concentration (PTC), and liquid–liquid extraction (LLE). At neutral and alkaline pH conditions, the concentrations detected for both compounds remain constant. However, a substantial reduction of concentration for both chemicals is observed when the water solution pH is less than 5. Under acidic conditions (pH ≅ 2.5), the 2-MIB concentrations detected by GC/MSD coupled with SPME, PTC, and LLE are 87%, 16%, and 37% lower than those measured at pH 6–7, respectively. For geosmin, a decrease in concentration is only observed when using GC/MSD-SPME, presumably due to the higher extraction temperature compared to the other two techniques. The pH-dependent behavior was attributed to dehydration of the tertiary alcohols of 2-MIB and geosmin under acidic conditions. The dehydration for 2-MIB and geosmin is reversible, and the analysis can be mitigated by adjusting the water solution pH back to a neutral condition.
Show more [+] Less [-]Formation of Tebuconazole Complexes with Cadmium(II) Investigated by Electrospray Ionization Mass Spectrometry
2012
Norková, Renáta | Dytrtová, Jana Jaklová | Jakl, Michal | Schröder, Detlef
The formation of complexes between tebuconazole (Teb) and cadmium in simplified model solutions as well as soil solutions was studied using electrospray ionization mass spectrometry. Teb and cadmium form two types of complexes with the general formulas [Cd(Teb) â ]²+ (nâ=â1–4) and [CdI(Teb) â ]+ (mâ=â1–3), where iodine corresponds to the counterion used. The most intense Teb/cadmium complex is [CdI(Teb)₂]+, and the most stable one is [Cd(Teb)(Teb − H)]+. Another detected complex, the dication [Cd(Teb)₄]²+, was considered as the origin complex for the iodine-free complexes and was found in a sample prepared from forest soil solution naturally contaminated with cadmium ions.
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