Vascular function and short-term exposure to fine particulate air pollution

Exposure to fine particulate air pollution has been implicated as a risk factor for cardiopulmonary disease and mortality. Proposed biological pathways imply that particle-induced pulmonary and systemic inflammation play a role in activating the vascular endothelium and altering vascular function. Potential effects of fine particulate pollution on vascular function are explored using controlled chamber exposure and uncontrolled ambient exposure. Research subjects included four panels with a total of 26 healthy nonsmoking young adults. On two study visits, at least 7 days apart, subjects spent 3 hr in a controlled-exposure chamber exposed to 150-200 microg/m3 of fine particles generated from coal or wood combustion and 3 hr in a clean room, with exposure and nonexposure periods alternated between visits. Baseline, postexposure, and post-clean room reactive hyperemia-peripheral arterial tonometry (RH-PAT) was conducted. A microvascular responsiveness index, defined as the log of the RH-PAT ratio, was calculated. There was no contemporaneous vascular response to the few hours of controlled exposure. Declines in vascular response were associated with elevated ambient exposures for the previous 2 days, especially for female subjects. Cumulative exposure to real-life fine particulate pollution may affect vascular function. More research is needed to determine the roles of age and gender, the effect of pollution sources, the importance of cumulative exposure over a few days versus a few hours, and the lag time between exposure and response.     

Nitrated monoaromatic hydrocarbons (nitrophenols,nitrocatechols, nitrosalicylic acids) in ambient air: levels,mass size distributions and inhalation bioaccessibility

Environmental Science and Pollution Research - Nitrated monoaromatic hydrocarbons (NMAHs) are ubiquitous in the environment and an important part of atmospheric humic-like substances (HULIS) and...     

The Great Recession or progressive energy policies? Explaining the decline in US greenhouse gas emissions forecasts

This paper evaluates the causes of the 23% decline in 2030 US greenhouse gas emissions forecasts between 2007 and 2011. Dynamic regression modeling predicts that the Great Recession contributed to about 67% of the 2008–2009 emissions decline, but then fell to about an 18% share for the 2030 emissions forecast. An analysis of electricity generation forecasts show that switching from coal to gas contributed only 6% to the total 2030 decline. In contrast, regulatory impact assessments and policy analysis showed that state and federal policies were responsible for 46% of the 2030 decline in emissions.     

A better method for standardizing vitellogenin content of fish tissues

Vitellogenin (vtg) concentrations were measured in plasma and liver samples from 12 hybrid Tilapia oreochromis niloticus x O. aureus to compare concentrations in these tissues. The results were calculated under two different normalizations: volume per gram of sample used (similar to normalization usually published in the literature and typically used for ELISA) and volume per total protein (similar to normalization used in polyacrylamide gel electrophoresis; PAGE). It was observed that the normalization procedure used in PAGE (per gram total protein) minimized the method detection limit by about 1000 and 2500 times in plasma and liver respectively, compared to the normalization usually reported in the literature. It was also observed that normalizing per gram total protein makes it possible to eliminate a potential problem of accidental dilution of plasma samples during sample collection. Moreover, the normalization on a per gram of total protein makes it possible even to compare results from the two different methods namely PAGE and ELISA. It also allows comparison between different tissues. Using the normalization procedures as used in PAGE (per gram total protein) for liver and the normalization method as reported in literature for ELISA (per volume of sample used), it was observed that liver samples had higher vtg levels (mean: 62 microg vtg/g) compared to the corresponding plasma samples (mean: 0.24 microg vtg/ml). However, when both results were normalized per gram total protein all but one liver sample were lower (62 microg vtg/g) than the corresponding plasma concentrations (mean = 246 microg vtg/g).     

High-capacity adsorbents from stainless steel slag for the control of dye pollutants in water

Environmental Science and Pollution Research - Adsorbent materials for the control of dye pollutants in water were synthetized from stainless steel slag (SSS) using different acid-base treatments....     

Geochemistry of street dust in Tyumen,Russia: influence of traffic load

Environmental Science and Pollution Research - This study investigates the elemental composition, organic carbon content, pH values, and particle size characteristics in 50 road dust samples...     

Toxicity of emerging energetic soil contaminant CL-20 to potworm Enchytraeus crypticus in freshly amended or weathered and aged treatments

We investigated the toxicity of an emerging polynitramine energetic material hexanitrohexaazaisowurtzitane (CL-20) to the soil invertebrate species Enchytraeus crypticus by adapting then using the Enchytraeid Reproduction Test (ISO/16387:2003). Studies were designed to develop ecotoxicological benchmark values for ecological risk assessment of the potential impacts of accidental release of this compound into the environment. Tests were conducted in Sassafras Sandy Loam soil, which supports relatively high bioavailability of CL-20. Weathering and aging procedures for CL-20 amended into test soil were incorporated into the study design to produce toxicity data that better reflect soil exposure conditions in the field compared with the toxicity in freshly amended soils. Concentration-response relationships for measurement endpoints were determined using nonlinear regressions. Definitive tests showed that toxicities for E. crypticus adult survival and juvenile production were significantly increased in weathered and aged soil treatments compared with toxicity in freshly amended soil, based on 95% confidence intervals. The median effect concentration (EC50) and EC20 values for juvenile production were 0.3 and 0.1 mg kg-1, respectively, for CL-20 freshly amended into soil, and 0.1 and 0.035 mg kg-1, respectively, for weathered and aged CL-20 soil treatments. These findings of increased toxicity to E. crypticus in weathered and aged CL-20 soil treatments compared with exposures in freshly amended soils show that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information on ecotoxicological effects of emerging energetic contaminants in soil.     

Observation and origin of organochlorine compounds and polycyclic aromatic hydrocarbons in the free troposphere over central Europe

On Zugspitze (2670 m a.s.l.), Alps, higher concentrations were observed during a winter than during a summer measurement campaign of PAHs, chlorobenzenes (43.6 vs. 2.0 pg m⁻³) and DDTs (3.7 vs. 1.2 pg m⁻³), while hexachlorocyclohexanes and PCBs were found at similar levels. The PCB, HCH and DDT levels are among the lowest ever reported from outside the Arctic. Mostly lower levels were found in samples collected in summer than in winter despite a significant boundary layer air influence, but no such influence on samples collected during the winter campaign. Boundary layer influence was quantified by Lagrangian particle dispersion model retroplume analyses. Photochemical lifetimes corresponding to k_OH < 1.5 × 10⁻¹² cm³ molec⁻¹ s⁻¹ are found for p,p′-DDT, k_OH < 0.75 × 10⁻¹² cm³ molec⁻¹ s⁻¹ for p,p′-DDE and k_OH < 1.0 × 10⁻¹² cm³ molec⁻¹ s⁻¹ for p,p′-DDD.     

Competitive sorption of cis-DCE and TCE in silica gel as a model porous mineral solid

The competitive sorption of 1,2-cis-dichloroethene (cis-DCE) and trichloroethene (TCE) was investigated by means of column experiments using a model porous mineral solid represented by silica gel. The experimental isotherms were obtained by employing a chromatographic method. The competitive sorption isotherms were modelled with the extended Freundlich and extended Langmuir isotherms, using the parameters from single-solute experiments. The breakthrough curves were modelled with the advection-dispersion transport equation coupled with the lumped pore diffusion model. The best results were obtained when the extended Freundlich isotherm was employed. The competitive sorption was revealed with the presence of an overshoot in the breakthrough curve of cis-DCE and a decrease in the degree of sorption of cis-DCE (20%) and TCE (12%). A linear dependency of the overshoot with an increase in the concentration of cis-DCE at a fixed concentration of TCE was observed, between 16% and 20%, and at least at concentrations <6 mg L(-1) in the liquid phase. The displaced molecules of cis-DCE by TCE were accumulated through the column causing its overshoot; thus short columns may hinder its observation. Thermodynamic analysis shows an exothermic adsorption process of -34 to -41 kJ mol(-1), which is enhanced by sorption in micropores. The Gibbs free energy is positive for cis-DCE in the multi-component case, due to its displacement by TCE.