Phytoremediation of petroleum-contaminated soils: Pre-screening for suitable plants and rhizospheral fungi

A field study was conducted in a petroleum-contaminated site in Kermanshah refinery (Iran) to find the petroleum-resistant plant species and the rhizospheral fungi for being used in bioremediation. Results showed that the amounts of petroleum pollution in non-vegetated areas is 6.8% and in vegetated areas is 2.2%. Plant samples were collected from petroleum-polluted areas and determined using morphological characters. It was found that eight plant species were growing on the contaminated sites: Polygonum aviculare, Amaranthus retroflexus, Noea mucronata, Alhaji cameleron, Crozophora heirosolymitrana, Poa sp., Convolvulus arvensis and Trifolium repense. The rhizospheral fungi of the plants were collected and determined using microscopic studies and taxonomical keys. The results determined the presence of 21 species in the rhizosphere of the plants growing in the polluted areas; three of these species were common in all of the plants and the others have species-specific distribution within the plants. The highest number of rhizospheral fungi (11 species) were determined for P. aviculare in non-polluted areas and nine species in polluted areas. It seems that the plant is the best candidate for using phytoremediation. However, the variation of fungi in petroleum-polluted areas was more than non-polluted zones. The culture of fungi in oil-contaminated media showed that, although all the studied fungi were resistant to low petroleum pollution (1% v/v), a few species, especially Fusarium species, showed higher resistance to petroleum pollution (10% v/v) and hence they may be suitable for mycoremediation in highly polluted areas.     

An assessment of hematological and biochemical responses in the tropical fish Epinephelus stoliczkae of Chabahar Bay and Gulf of Oman under chromium exposure: ecological and experimental tests

The aim of this investigation was to evaluate the effect of chromium on hematological and biochemical parameters in Epaulet Grouper, Epinephelus stoliczkae of Chabahar Bay and Gulf of Oman by ecological and experimental tests. Spatial evaluation of ecological test results showed these parameters had significant difference among some sampling sites. Examination of hematological and biochemical profiles on Epaulet Grouper was performed after 0.5, 1, 7, 14, and 21 days of chromium exposure (3.6, 7.31 and 14.6 mg/L). Experimental test results of chromium induce indicated the significant decrease in MCV, MCH, neutrophils, basophils, plasma protein and significant increase in MCHC, lymphocytes, monocytes, eosinophils and a biphasic trend in Hb, Ht, RBC, WBC, and glucose (p?<?0.05). Cellular and nuclear axis, cytoplasmic volume, cell and nuclear volume, and surface area were significantly different for ecological and experimental results (p?<?0.05). It was concluded that these parameters are sensitive in monitoring the toxicity of chromium concentrations.     

Optimization of Xanthan Gum/Poly(acrylic acid)/Cloisite 15A Semi-IPN Hydrogels for Heavy Metals Removal

Journal of Polymers and the Environment - Semi-interpenetrating networks (semi-IPNs) of Xanthan gum/poly (acrylic acid) containing Cloisite 15A were prepared via radical polymerization using a...     

Characterization of ionic composition of TSP and PM10 during the Middle Eastern Dust (MED) storms in Ahvaz, Iran

Because of the recent frequent observations of major dust storms in southwestern cities in Iran such as Ahvaz, and the importance of the ionic composition of particulate matters regarding their health effects, source apportionment, etc., the present work was conducted aiming at characterizing the ionic composition of total suspended particles (TSP) and particles on the order of ～10?μm or less (PM(10)) during dust storms in Ahvaz in April-September 2010. TSP and PM(10) samples were collected and their ionic compositions were determined using an ion chromatography. Mean concentrations of TSP and PM(10) were 1,481.5 and 1,072.9?μg/m(3), respectively. Particle concentrations during the Middle Eastern Dust (MED) days were up to four times higher than those in normal days. Ionic components contributed to only 9.5% and 11.3% of the total mass of TSP and PM(10), respectively. Crustal ions were most abundant during dust days, while secondary ions were dominant during non-dust days. Ca(2+)/Na(+) and Cl(-)/Na(+) ratios can be considered as the indicators for identification of the MED occurrence. It was found that possible chemical forms of NaCl, (NH(4))(2)SO(4), KCl, K(2)SO(4), CaCl(2), Ca(NO(3))(2), and CaSO(4) may exist in TSP. Correlation between the anionic and cationic components suggests slight anion and cation deficiencies in TSP and PM(10) samples, though the deficiencies were negligible.     

Bio-based composites from waste agricultural residues

The main objective of this research was to study the potential of waste agricultural residues such as sunflower stalk, corn stalk and bagasse fibers as reinforcement for thermoplastics as an alternative to wood fibers. The effects of two grades (Eastman G-3003 and G-3216) of coupling agents on the mechanical properties were also studied. In the sample preparation, one level of fiber loading (30 wt.%) and three levels of coupling agent content (0, 1.5 and 2.5 wt.%) were used. For overall trend, with addition of both grades of the coupling agents, tensile, flexural and impact properties of the composites significantly improved, as compared with untreated samples. In addition, morphological study revealed that the positive effect of coupling agent on interfacial bonding. The composites treated with G-3216 gave better results in comparison with G-3003. This could be caused by the high melt viscosity of G-3003. In general, bagasse fiber showed superior mechanical properties due to its chemical characteristics.     

Lemon Balm (Melissa officinalis) Stalk: Chemical Composition and Fiber Morphology

This work investigates the potentials of lemon balm (Melissa officinalis L.) stalk (LBS), a massive waste part of medicinal plant, for pulp and papermaking by assessing its fiber characteristics and chemical composition. In addition, LBS properties were compared with some important agro-residues such as bagasse stalk (BS), cotton stalk (CS) and tobacco stalk (TS). There is no information about suitability of the LBS in the open literature. Chemically, LBS fibers contain a relatively high percentage of alpha-cellulose (32.7%), but a low percentage of lignin (25%), which benefits pulping and bleaching. The hemicelluloses in LBS are mainly glucose and xylose. Ash content was about 6%, superior to the average value corresponding to woods, which makes pulping difficult. It was verified that the chemical compositions of the studied agro-residues vary significantly. Morphologically, the LBS fibers are comparable to those of hardwoods. Rather a significant amount of parenchyma cells was found in LBS. The TS has the highest average fiber length, while the LBS has the least, and the lengths of BS and CS fibers fall in between. In general, based on the results of this study, some propositions can be made about the possible applications of LBS as a non-wood renewable source of natural products for use in the production of pulp and paper.     

Prediction of methanol loss in vapor phase during gas hydrate inhibition using Arrhenius-type functions

Gas hydrate formation in natural gas and NGL systems can block pipelines, equipment, and instruments, restricting or interrupting flow leading to safety hazards to production/transportation systems and to substantial economic risks. The amount of hydrate inhibitor to be injected not only must be sufficient to prevent freezing of the inhibitor water phase, but also must be sufficient to provide for the equilibrium vapor phase content of the inhibitor. The vapor pressure of methanol must be high enough so that significant quantities will vaporize. Therefore to estimate methanol vaporization losses, it is necessary to develop a new predictive tool. In this work, a simple correlation, which is a mathematically compact and reasonably accurate equation containing few tuned coefficients, is presented here for the prediction of methanol vaporization loss and vapor pressures of aqueous methanol solutions as a function of temperature and methanol mass fraction in aqueous solutions using a novel and theoretically meaningful Arrhenius-type asymptotic exponential function and Vandermonde matrix. The proposed correlation predicts the vapor pressures of aqueous methanol solutions for temperatures up to 100 °C and methanol vaporization loss for temperature between ?16 and 16 °C. Estimations are found to be in excellent agreement with the reliable data in the literature where the average absolute deviation from data is less than 1.5%. The tool developed in this study can be of immense practical value for the engineers and scientists to have a quick check on the methanol vaporization loss and vapor pressures of aqueous methanol solutions at various conditions without opting for any experimental measurements. In particular, chemical and process engineers would find the approach to be user-friendly with transparent calculations involving no complex expressions.     

Effect of fertilizer application on soil heavy metal concentration

A large amount of chemicals is annually applied at the agricultural soils as fertilizers and pesticides. Such applications may result in the increase of heavy metals particularly Cd, Pb, and As. The objective of this study was to investigate the variability of chemical applications on Cd, Pb, and As concentrations of wheat-cultivated soils. Consequently, a study area was designed and was divided into four subareas (A, B, C, and D). The soil sampling was carried out in 40 points of cultivated durum wheat during the 2006–2007 periods. The samples were taken to the laboratory to measure their heavy metal concentration, soil texture, pH, electrical conductivity, cationic exchange capacity, organic matter, and carbonate contents. The result indicated that Cd, Pb, and As concentrations were increased in the cultivated soils due to fertilizer application. Although the statistical analysis indicates that these heavy metals increased significantly (P value < 0.05), the lead and arsenic concentrations were increased dramatically compared to Cd concentration. This can be related to overapplication of fertilizers as well as the pesticides that are used to replant plant pests, herbs, and rats.