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Oxidation of bisphenol F (BPF) by manganese dioxide Full text
2011
Bisphenol F (BPF), an environmental estrogen, is used as a monomer in plastic industry and its environmental fate and decontamination are emerging concern. This study focused on the kinetics, influencing factors and pathways of its oxidation by MnO₂. At pH 5.5, about 90% of BPF was oxidized in 20min in a solution containing 100μM MnO₂ and 4.4μM BPF. The reaction was pH-dependent, following an order of pH 4.5>pH 5.5>pH 8.6>pH 7.5>pH 6.5>pH 9.6. Humic acids inhibited the reaction at low (≤pH 5.5) and high pH (≥pH 8.6) at high concentrations. In addition, metal ions and anions also suppressed the reaction, following the order Mn²⁺>Ca²⁺>Mg²⁺>Na⁺ and HPO₄ ²⁻>Cl⁻>NO₃ ⁻≈SO₄ ²⁻, respectively. A total of 5 products were identified, from which a tentative pathway was proposed.
Show more [+] Less [-]Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants in air and seawater of the European Arctic Full text
2011
Möller, Axel | Xie, Zhiyong | Sturm, Renate | Ebinghaus, Ralf
The spatial distribution of polybrominated diphenyl ethers (PBDEs) and several alternative non-PBDE, non-regulated brominated flame retardants (BFRs) in air and seawater and the air–seawater exchange was investigated in East Greenland Sea using high-volume air and water samples. Total PBDE concentrations (Ó₁₀PBDEs) ranged from 0.09 to 1.8 pg m⁻³ in the atmosphere and from 0.03 to 0.64 pg L⁻¹ in seawater. Two alternative BFRs, Hexabromobenzene (HBB) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), showed similar concentrations and spatial trends as PBDEs. The air–seawater gas exchange was dominated by deposition with fluxes up to −492 and −1044 pg m⁻² day⁻¹ for BDE-47 and DPTE, respectively. This study shows the first occurrence of HBB, DPTE and other alternative flame retardants (e.g., pentabromotoluene (PBT)) in the Arctic atmosphere and seawater indicating that they have a similar long-range atmospheric transport potential (LRAT) as the banned PBDEs.
Show more [+] Less [-]Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen Full text
2011
Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O₃) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O₃ fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O₃ fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O₃, determined from the mRNA levels of the major allergens. We conclude that O₃ can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase.
Show more [+] Less [-]Plant uptake and dissipation of PBDEs in the soils of electronic waste recycling sites Full text
2011
Huang, Honglin | Zhang, Shuzhen | Christie, Peter
Plant uptake and dissipation of weathered PBDEs in the soils of e-waste recycling sites were investigated in a greenhouse study. Eighteen PBDE congeners (tri- through deca-) were detected in the plant tissues. The proportion of lower brominated PBDEs (mono- through hexa-) in plant roots was higher than that in the soils. A concentration gradient was observed of PBDEs in plants with the highest concentrations in the roots followed by the stems and lowest in the leaves. Reduction rates of the total PBDEs in the soils ranged from 13.3 to 21.7% after plant harvest and lower brominated PBDEs were associated with a higher tendency to dissipate than the higher brominated PBDEs. This study provides the first evidence for plant uptake of weathered PBDEs in the soils of e-waste recycling sites and planting contributes to the removal of PBDEs in e-waste contaminated soils.
Show more [+] Less [-]Changes in the chemistry of acidified Adirondack streams from the early 1980s to 2008 Full text
2011
Lawrence, G.B. | Simonin, H.A. | Baldigo, B.P. | Roy, K.M. | Capone, S.B.
Lakes in the Adirondack region of New York have partially recovered in response to declining deposition, but information on stream recovery is limited. Here we report results of Adirondack stream monitoring from the early 1980s to 2008. Despite a 50% reduction in atmospheric deposition of sulfur, overall increases in pH of only 0.28 and ANC of 13 μeq L⁻¹ were observed in 12 streams over 23 years, although greater changes did occur in streams with lower initial ANC, as expected. In the North Tributary of Buck Creek with high dissolved organic carbon (DOC) concentrations, SO₄ ²⁻ concentrations decreased from 1999 to 2008 at a rate of 2.0 μmol L⁻¹ y⁻¹, whereas in the neighboring South Tributary with low DOC concentrations, the decrease was only 0.73 μmol L⁻¹ y⁻¹. Ca²⁺ leaching decreased in the North Tributary due to the SO₄ ²⁻ decrease, but this was partially offset by an increase in Ca²⁺ leaching from increased DOC concentrations.
Show more [+] Less [-]Modeling short-term variability of semivolatile organic chemicals in air at a local scale: An integrated modeling approach Full text
2011
Morselli, Melissa | Ghirardello, Davide | Semplice, Matteo | Di Guardo, Antonio
Monitoring campaigns from different locations have recently shown how air concentrations of persistent semivolatile contaminants such as polychlorinated biphenyls (PCBs) often exhibit short-term (less than 24 h) variations. The observed patterns have been ascribed to different factors, such as temperature-mediated air–surface exchange and variability of planetary boundary layer (PBL) height and dynamics. Here, we present a new modeling approach developed in order to investigate the short-term variability in air concentrations of organic pollutants at a local scale. A new dynamic multimedia box model is supplied by a meteorological preprocessor (AERMET) with hourly values of air compartment height and wind speed. The resulting model is tested against an existing dataset of PCB air concentrations measured in Zurich, Switzerland. Results show the importance of such modeling approach in elucidating the short- and long-term behavior of semivolatile contaminants in the air/soil system.
Show more [+] Less [-]Transport of copper as affected by titania nanoparticles in soil columns Full text
2011
Fang, Jing | Shan, Xiao-quan | Wen, Bei | Lin, Jin-Ming | Owens, Gary | Zhou, Shuai-ren
The effects of TiO₂ nanoparticles on the transport of Cu through four different soil columns were studied. For two soils (HB and DX), TiO₂ nanoparticles acted as a Cu carrier and facilitated the transport of Cu. For a third soil (BJ) TiO₂ nanoparticles also facilitated Cu transport but to a much lesser degree, but for a fourth soil (HLJ) TiO₂ nanoparticles retarded the transport of Cu. Linear correlation analysis indicated that soil properties rather than sorption capacities for Cu primary governed whether TiO₂ nanoparticles-facilitated Cu transport. The TiO₂-associated Cu of outflow in the Cu-contaminated soil columns was significantly positively correlated with soil pH and negatively correlated with CEC and DOC. During passage through the soil columns 46.6–99.9% of Cu initially adsorbed onto TiO₂ could be “stripped” from nanoparticles depending on soil, where Cu desorption from TiO₂ nanoparticles increased with decreasing flow velocity and soil pH.
Show more [+] Less [-]The performance of passive flow monitors and phosphate accumulating passive samplers when exposed to pulses in external water flow rate and/or external phosphate concentrations Full text
2011
O’Brien, Dominique | Hawker, Darryl | Shaw, Melanie | Mueller, Jochen F.
Passive samplers are typically calibrated under constant flow and concentration conditions. This study assessed whether concentration and/or flow pulses could be integrated using a phosphate passive sampler (P-sampler). Assessment involved three 21-day experiments featuring a pulse in flow rate, a pulse of filterable reactive phosphate (FRP) concentration and a simultaneous concentration and flow pulse. FRP concentrations were also determined by parallel grab sampling and the P-sampler calibrated with passive flow monitors (PFMs) and direct measurement of flow rates. The mass lost from the PFM over the deployment periods predicted water velocity to within 5.1, 0.48 and 7.1% when exposed to a flow rate pulse (7.5–50 cm s⁻¹), concentration pulse (5–100 μg P L⁻¹), or both simultaneously. For the P-sampler, good agreement was observed between the grab and passive measurements of FRP concentration when exposed to a pulse in flow (6% overestimation) or concentration (2% underestimation).
Show more [+] Less [-]Persistent organic pollutant in a fish community of a sub-alpine lake Full text
2011
Villa, Sara | Bizzotto, Elisa Chiara | Vighi, M.
This study investigated the presence of organochlorine pollutants in abiotic and biotic samples from Lake Como (Italy). DDTs and PCBs were found to be the major contaminants, ranging from 0.04 to 4.25 and from 0.25 to 40.8 μg/g lipid respectively. Evidence of biomagnification according to the trophic role of the investigated organisms was highlighted by means of Stable Isotope Analysis. A Trophic Magnification Factor (TMF) was calculated for the chemicals of interest and the applicability of the method for global use was confirmed. Statistically significant correlation has been found between the calculated trophic level and the concentrations of more lipophilic compounds, while for the less lipophilic (e.g., HCH, 3CBs) the relationship is no statistically significant and the TMF is close to 1. The role of the foraging area in affecting PCB and DDT concentrations within aquatic ecosystems has been highlighted by a Principal Component Analysis (PCA).
Show more [+] Less [-]Date palm (Phoenix dactylifera L.) leaves as biomonitors of atmospheric metal pollution in arid and semi-arid environments Full text
2011
Al-Khashman, Omar Ali | Al-Muhtaseb, Ala’a H. | Ibrahim, Khalid A.
The leaves of date palms were evaluated as a possible biomonitor of heavy metal contamination in Ma’an city, Jordan. Concentrations of (Fe), (Pb), (Zn), (Cu), (Ni), and (Cr) were determined in washed and unwashed leaves and soil samples collected from different sites with different degrees of metal contamination (urban, suburban, industrial, highway and rural sites); separate leaves were taken from outside the city to be used as a control sample. Samples collected from industrial sites were found to have high concentrations of all metals except those of Cu, Ni and Pb, which were found at high levels in the highway site samples which is associated with the road traffic. The difference between unwashed and washed samples showed that metal pollutants exist as contaminants, particularly Pb, Zn and Ni, which varied in concentration, depending on the source of the metal.
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