Measurements of polycyclic aromatic hydrocarbons at an industrial site in India

Polycyclic Aromatic Hydrocarbon (PAH) concentrations were measured in Total Suspended Particulate Matter (TSPM) from December 2005 to August 2006 at Nunhai, an industrial site in Agra (India). Particulate matter samples were collected on glass fibre filters using High Volume Sampler (HVS-430) and were extracted using dichloromethane with ultrasonication and analyzed by GC. Total PAH concentration varies between 0.04 to 2.5 microg m(-3) accounting only 1.6 x 10(-3)% of TSPM. The mass distribution in air was dominated by high molecular weight DbA, BghiP, BaP, BkF and IP. Combustion PAH (CPAH) except BeP represents 58% of the total PAH mass and IARC classified total carcinogenic PAH accounting 63% of TPAH concentration. Correlation studies between PAH revealed the contribution of low molecular weight PAH was mainly due to primary emission from diesel exhaust while high molecular weight PAH were formed during combustion. The presence of specific tracers and calculation of characteristic molecular diagnostic ratios Fla/(Fla + Pyr), BaP/(BaP + Chy), BaA/(BaA + Chy), IP/(IP + BghiP), BaP/BghiP and IP/BghiP) were used to identify the sources of the emissions of PAHs in the atmospheric samples. Seasonal variation in atmospheric PAH showed four fold increase in winter concentration than summer. The BaP and relative BaP amount calculated from the measurements suggested that photo-oxidation may also be responsible for the variation in PAH concentrations during winter and summer. Seasonal trends in atmospheric PAH concentration in the study area were influenced by fossil fuel usage for domestic heating, boundary height and temperature.     

Effect of selected organic and inorganic snow and cloud components on the photochemical generation of nitrite by nitrate irradiation

The effect of selected organic and inorganic compounds, present in snow and cloudwater was studied. Photolysis of solutions of nitrate to nitrite was carried out in the laboratory using a UVB light source. The photolysis and other reactions were then modelled. It is shown that formate, formaldehyde, methanesulphonate, and chloride to a lesser extent, can increase the initial formation rate of nitrite. The effect, particularly significant for formate and formaldehyde, is unlikely to be caused by scavenging of hydroxyl radicals. The experimental data obtained in this work suggest that possible causes are the reduction of nitrogen dioxide and nitrate by radical species formed on photooxidation of the organic compounds. Hydroxyl scavenging by organic and inorganic compounds would not affect the initial formation rate of nitrite, but would protect it from oxidation, therefore, increasing the concentration values reached at long irradiation times. The described processes can be relevant to cloudwater and the quasi-liquid layer on the surface of ice and snow, considering that in the polar regions irradiated snow layers are important sources of nitrous acid to the atmosphere. Formate and (at a lesser extent) formaldehyde are the compounds that play the major role in the described processes of nitrite/nitrous acid photoformation by initial rate enhancement and hydroxyl scavenging.     

Structure characterization and thermal stabilities of the isomers of the brominated flame retardant 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane

1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) is used primarily as an additive flame retardant. 1H NMR spectroscopy and an X-ray structure determination have revealed that a technical mixture consists largely of two (of the four possible) diastereomers, rac-(1R,2R)-1,2-dibromo-(4S)-4-((1S)-1,2-dibromoethyl)cyclohexane (alpha-TBECH) and rac-(1R,2R)-1,2-dibromo-(4S)-4-((1R)-1,2-dibromoethyl)cyclohexane (beta-TBECH), in a mole ratio of approximately 1:1. The two other possible isomers, gamma- and delta-TBECH, were not detected in a technical mixture. The TBECH isomers are thermally sensitive and can easily interconvert at temperatures of 125 degrees C. A thermal equilibrium mixture of alpha-, beta-, gamma- and delta-TBECH consists of approximately 33%, 33%, 17% and 17% of these isomers, respectively. Separation of all four TBECH diastereomers, with minimal thermal interconversion of the isomers, was achieved by careful selection of GC-capillary column length and injector temperature. Although technical TBECH does not contain the gamma- and delta-isomers, they may still be relevant environmental contaminants since manufacturing processes utilize thermal processes which may induce their formation.     

Optimal Carbon Capture and Storage Policies

The IPCC recommends the use of carbon capture and sequestration (CCS) technologies in order to achieve the Kyoto environmental goals. This paper sheds light on this issue by assessing the optimal strategy regarding the long-term use of CCS technologies. The aim is to analyze the optimal CCS policy when the sequestration rate is endogenous, being therefore one specific tool of the environmental policy. We develop a simple growth model to identify the main driving forces that should determine the optimal CCS policy. We show that, under some conditions on the cost of extractions, CCS may be a long-term solution to curb carbon emissions. We also show that over time the social planner will choose to decrease the rate of capture and sequestration. We then derive the decentralized equilibrium outcome by considering the programs of the fossil resource-holder and of the representative consumer. Finally, we determine the optimal environmental policy, i.e. the carbon tax scheme, as well as the dynamics of the fossil fuel price needed to implement it.     

Two sampling strategies for an overview of pesticide contamination in an agriculture-extensive headwater stream

Two headwaters located in southwest France were monitored for 3 and 2 years (Auvézère and Aixette watershed, respectively) with two sampling strategies: grab and passive sampling with polar organic chemical integrative sampler (POCIS). These watersheds are rural and characterized by agricultural areas with similar breeding practices, except that the Auvézère watershed contains apple production for agricultural diversification and the downstream portion of the Aixette watershed is in a peri-urban area. The agricultural activities of both are extensive, i.e., with limited supply of fertilizer and pesticides. The sampling strategies used here give specific information: grab samples for higher pesticide content and POCIS for contamination background noise and number of compounds found. Agricultural catchments in small headwater streams are characterized by a background noise of pesticide contamination in the range of 20–70 ng/L, but there may also be transient and high-peak pesticide contamination (2000–3000 ng/L) caused by rain events, poor use of pesticides, and/or the small size of the water body. This study demonstrates that between two specific runoff events, contamination was low; hence the importance of passive sampler use. While the peak pesticide concentrations seen here are a toxicity risk for aquatic life, the pesticide background noise of single compounds do not pose obvious acute nor chronic risks; however, this study did not consider the risk from synergistic “cocktail” effects. Proper tools and sampling strategies may link watershed activities (agricultural, non-agricultural) to pesticides detected in the water, and data from both grab and passive samples can contribute to discussions on environmental effects in headwaters, an area of great importance for biodiversity.     

Downscaling scenarios of future land use and land cover changes using a participatory approach: an application to mountain risk assessment in the Pyrenees (France)

Regional Environmental Change - Better understanding the pathways through which future socioeconomic changes might influence land use and land cover changes (LULCCs) is a crucial step in accurately...     

Fe(III)–EDDS complex in Fenton and photo-Fenton processes: from the radical formation to the degradation of a target compound

The present work compares the efficiency of homogenous Fenton and photo-Fenton processes in the presence of Fe(III)–EDDS complex under different experimental conditions. 4-tert-Butylphenol (4-t-BP), which is one of the endocrine disrupting chemicals, was used as a model pollutant to investigate the Fenton and photo-Fenton application. The efficiency of homogenous photo-Fenton process was significantly much higher than homogenous Fenton process, which is due to the rapid formation of Fe²⁺ under UV irradiation of the iron complex and the photochemical formation of HO^? from the photolysis of the complex Fe(III)–EDDS. Through the degradation of 4-t-BP, the effect of Fe(III)–EDDS concentration, H₂O₂ concentration, pH, and oxygen was investigated in both processes. Such trend was also correlated with pH calculating the polychromatic Fe²⁺ quantum yield formation at pH 4.0, 6.0, and 8.6. The results showed that at high Fe(III)–EDDS and H₂O₂ concentrations, a negative effect was found. By the way, the Fenton process was found to be enhanced at basic pH. These results can be very useful for the use and optimization of such iron complex in water treatment process as function of different physico-chemical conditions.     

Biochemical biomarkers in environmental studies—lessons learnt from enzymes catalase,glutathione <Emphasis Type="Italic">S</Emphasis>-transferase and cholinesterase in two crustacean species

Background, aim and scope  

For reliable environmental risk assessment of pollutants, knowledge on the effects at different levels of biological organisation is needed. During the early days of biomarker research in environmental studies approximately two decades ago, biochemical biomarkers were considered as the most promising tool for such purposes. Among these, three enzymes have often been studied: catalase (CAT), glutathione S-transferase (GST) and cholinesterase (ChE). However, despite their intensive research, their measurements in invertebrates have not been commonly applied in environmental risk assessment (ERA) or for regulatory purposes.     

Characterization of major pollution events (dust, haze, and two festival events) at Agra, India

Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO₂, SO₂, and O₃) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca²⁺, Cl^?, NO₃ ^?, and SO₄ ^2? were the most abundant ions and Ca²⁺ alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO₃ ^?, SO₄ ^2?, and NH₄ ⁺, were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO₄ ^2? concentration (17.8 μg?m^?3) was highest followed by NO₃ ^?, K⁺, and Cl^? while the Holi samples were strongly enriched with Cl^? and K⁺ which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched with particles of crustal origin.