Effect of PM2.5 chemical constituents on atmospheric visibility impairment

PM_2.5 sampling was conducted at a curbside location in Delhi city for summer and winter seasons, to evaluate the effect of PM_2.5 and its chemical components on the visibility impairment. The PM_2.5 concentrations were observed to be higher than the National Ambient Air Quality Standards (NAAQS), indicating poor air quality. The chemical constituents of PM_2.5 (the water-soluble ionic species SO₄^2-, NO₃^?, Cl^?, and NH₄⁺, and carbonaceous species: organic carbon, elemental carbon) were analyzed to study their impact on visibility impairment by reconstructing the light extinction coefficient, b_ext. The visibility was found to be negatively correlated with PM_2.5 and its components. The reconstructed b_ext showed that organic matter was the largest contributor to b_ext in both the seasons which may be attributed to combustion sources. In summer season, it was followed by elemental carbon and ammonium sulfate; however, in winter, major contributions were from ammonium nitrate and elemental carbon. Higher elemental carbon in both seasons may be attributed to traffic sources, while lower concentrations of nitrate during summer, may be attributed to volatility because of higher atmospheric temperatures.

Implications: The chemical constituents of PM_2.5 that majorly effect the visibility impairment are organic matter and elemental carbon, both of which are products of combustion processes. Secondary formations that lead to ammonium sulfate and ammonium nitrate production also impair the visibility.     

Modeling seasonal variations of long-term soil CO<Subscript>2</Subscript> emissions in an orchard plantation in a semiarid area,SE Turkey

Emissions of soil CO₂ under different management systems have a significant effect on the carbon balance in the atmosphere. Soil CO₂ emissions were measured from an apricot orchard at two different locations: under the crown of trees (CO₂-UC) and between tree rows (CO₂-BR). For comparison, one other measurement was performed on bare soil (CO₂-BS) located next to the orchard field. Analytical data were obtained weekly during 8 years from April 2008 to December 2016. Various environmental parameters such as air temperature, soil temperature at different depths, soil moisture, rainfall, and relative humidity were used for modeling and estimating the long-term seasonal variations in soil CO₂ emissions using two different methods: generalized linear model (GLM) and artificial neural network (ANN). Before modeling, data were randomly split into two parts, one for calibration and the second for validation, with a varying number of samples in each part. Performances of the models were compared and evaluated using means absolute of estimations (MAE), square root of mean of prediction (RMSEP), and coefficient of determination (R²) values. CO₂-UC, CO₂-BR, and CO₂-BS values ranged from 11 to 3985, from 9 to 2365, and from 8 to 1722 kg ha^?1 week^?1, respectively. Soil CO₂ emissions were significantly correlated (p?<?0.05) with some environmental variables. The results showed that GLM and ANN models provided similar accuracies in modeling and estimating soil CO₂ emissions, as the number of samples in the validation data set increased. The ANN was more advantageous than GLM models by providing a better fit between actual observations and predictions and lower RMSEP and MAE values. The results suggested that the success of environmental variables for estimations of CO₂ emissions using the two methods was moderate.     

Performance evaluation of oil spill software systems in early fate and trajectory of oil spill: comparison analysis of OILMAP and PISCES 2 in Mersin bay spill

The aim of this study is to evaluate the performance level of two advanced oil spill software systems in early transport and fate of oil spill through algorithms accepted in oil spill literature. To do this, the performance level of software systems mostly used in real cases have been compared. OILMAP (the oil spill prediction modeling system) and PISCES 2 (potential incident simulation, control and evaluation system) have been used for spill trajectory in the light of four spill scenarios. The findings reveal that the OILMAP has predicted a relatively larger area of spill. In addition, OILMAP has achieved closer results to the calculations of approaches adopted in the literature for evaporation calculations. Besides, OILMAP software has provided highly reliable results in the evaporation rates of oil compared to the calculations of PISCES 2. On the other hand, as for the determination of the risky area, both software systems have yielded results with high reliability values, which could be used in taking precautions against oil spill in such areas.     

Managing Mediterranean soil resources under global change: expected trends and mitigation strategies

Regional Environmental Change - The soils of the Mediterranean Basin are the products of soil processes that have been governed by a unique convergence of highly differentiated natural and...     

Study of non-revenue water status and enforcement measures to reduce water loss: case study in villages of Kermanshah Province of Iran

In this study, the volume and the cash value of water loss, and reduction of water loss as a result of enforcement action during 2011–2013 in the drinking water network of villages in Kermanshah Province, Iran, have been investigated. Date collected by referring to the different parts of rural water and waste water company of Kermanshah Province and checklist were completed. The study showed the volume of produced water and sold water has increased and the water loss percentage has decreased. High cost of water production compared to revenue of sold water and water loss resulted in significant detriments in terms of the water production costs. Water loss level decreased from 33% to 30% as result of measures taken to reduce water loss but, it is still 15% higher than the world average level. Also the reduction in number of water resources and increase in the number and volume of reservoirs indicates a lack of water and a growing need. As result of high water loss, waste of costs in the contrast of water production cost and also because physical water loss accounts for most of the water loss of villages, necessary measures can be effective in reducing loss and have economic justification.     

Response curves of seventeen woody species to soil factors along a riparian forest in northern Iran

The aim of this study was to determine type of response curves for seventeen woody species (10 tree and 7 shrub species) to soil factors in an intact riparian forest in Safaroud River in northern Iran using HOF function. Data were collected along transects established perpendicular to the water flow on both sides of the river. Results indicated different responses for different woody species. The most common were symmetricunimodal response curves and curves showing an increase in occurrence probability after a certain value in form of a plateau. Bimodal curves were four times more frequent in riverside than forest interior area. It seems that river flow disturbances through frequent floods effect on species tolerance and optimum in riversides.     

Compost and sulfur affect the mobilization and phyto-availability of Cd and Ni to sorghum and barnyard grass in a spiked fluvial soil

Soil reclamation via additives can cause contradictory effects on the mobilization of toxic elements in soils under dry and wet conditions. Therefore, our aim was to investigate the impact of compost and sulfur in two rates (1.25 and 2.5%) on fractionation, mobilization, and phyto-availability of cadmium (Cd) and nickel (Ni) to sorghum (dry soil) and barnyard grass (wet soil) in a fluvial soil spiked with 25 mg Cd or 200 mg Ni/kg soil. Compost decreased the solubility and mobilization of Cd (especially in dry soil) and Ni (in both soils). Sulfur increased the solubility of Cd (31% in dry soil—49% in wet soil) and Ni (4.6% in wet soil—8.7% in dry soil). Sulfur altered the carbonate fraction of Cd to the soluble fraction and the residual fraction of Cd and Ni to the non-residual fraction. Compost decreased Cd and increased Ni in sorghum, but enhanced Cd and degraded Ni in grass. Sulfur increased Cd and Ni in both plants, and the increasing rate of Cd was higher in grass than in sorghum, while Ni was higher in sorghum than in grass. These results suggest that compost can be used as an immobilizing agent for Cd in the dry soil and Ni in the wet soil; however, it might be used as mobilizing agent for Cd in the wet soil and Ni in the dry soil. Sulfur (with rate 2.5%) can be used for enhancing the phyto-extraction of Cd and Ni (especially Cd) from contaminated alkaline soils.     

Bioavailability of polycyclic aromatic hydrocarbons (PAHs) to short-neck clam (<Emphasis Type="Italic">Paphia undulata</Emphasis>) from sediment matrices in mudflat ecosystem of the west coast of Peninsular Malaysia

The bioaccumulation and bioavailability of polycyclic aromatic hydrocarbons (PAHs) were characterized in sediment and Paphia undulata (short-neck clam) from six mudflat areas in the west coasts of Peninsular Malaysia. The concentrations of total PAHs varied from 357.1 to 6257.1 and 179.9 ± 7.6 to 1657.5 ± 53.9 ng g ^?1 dry weight in sediment and short-neck clam samples, respectively. PAHs can be classified as moderate to very high level of pollution in sediments and moderate to high level of pollution in short-neck clams. The diagnostic ratios of individual PAHs and principal component analysis indicate both petrogenic and pyrogenic sources with significant dominance of pyrogenic source. The first PAHs biota-sediment accumulation factors and relative biota-sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. Evaluation of PAH levels in sediments and short-neck clams indicates that short-neck clam could be introduced as a good biomonitor in mudflats. The results also demonstrated that under environmental conditions, the sedimentary load of hydrocarbons appears to be one of the factors controlling their bioavailability to biota.     

Impact of climate factors on cyanobacterial dynamics and their interactions with water quality in South Taihu Lake,China

Cyanobacterial bloom events in South Taihu Lake cause serious water quality problems and disturb aesthetic view of lake’s environment. In this study, correlations between cyanobacterial blooms and hydro-meteorological factors, including water quality, temperature and precipitation were investigated. Results demonstrated that South Taihu Lake was heavily affected by cyanobacteria and the proliferation of cyanobacteria due to variations in hydro-meteorological factors and water quality conditions. Water quality parameters, including COD, NH₃-N, TN and TP improved significantly since 2008 even at an elevated cyanobacterial bloom situation. Correlation analyses have shown that the development of cyanobacterial density and chlorophyll a concentration was sensitive to a wider temperature variation. The optimum temperature for cyanobacteria was 20°C, while extremely low and high temperatures were found to suppress their growth. Moreover, unusual rainfall patterns were measured during the study period (2003–2009), which showed an adverse impact on cyanobacterial development. Findings from this study suggested that seasonal lake’s water quality monitoring; suitable treatment of cyanobacterial blooms and strict policy implementation can solve the water quality issues in highly eutrophic lakes like Taihu.     

Removal of Cr(VI) from aqueous solution using electrosynthesized 4-amino-3-hydroxynaphthalene-1-sulfonic acid doped polypyrrole as adsorbent

Environmental Science and Pollution Research - Polypyrrole (PPy) conducting films, doped with 4-amino-3-hydroxynaphthalene sulfonic acid (AHNSA), were electrosynthesized by anodic oxidation of...