INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY (IJEST)
Year:2011 | Volume:8 | Issue:3 (31)|Papers Count:20

For decades, repeated and widespread use of arsenical pesticides has significantly contributed to arsenic contamination in soils. Residues from the overuse of these arsenicals may result in phytotoxicity to crops, which will depend on soil types, plant species and the toxicity of arsenical pesticides. A greenhouse column study was conducted to evaluate the effect of two pesticides, i.e. one organic (dimethylarsinic acid) and one inorganic (sodium arsenate), on the vegetative response of rice as a function of soil properties. Four soils with varying arsenic retention capabilities at two different pesticide amendment rates (675 and 1500 mg/kg) representing the worst case scenarios in superfund sites were used. Results showed that arsenic availability to rice was mainly influenced by soil physicochemical properties. The soil with the lowest arsenic retention capacity had the highest arsenic concentration in the leachate as well as in the plant tissue. In contrast, for soils with higher arsenic retention capacity, higher concentrations of arsenic were found in the surface soil which resulted in the inhibition of plant growth. There was no significant difference between labile arsenic / plant-available arsenic irrespective of the form of arsenical pesticide used. Plant growth parameters such as biomass, shoot height, root length decreased with increased arsenic concentrations in all soils. A significant negative correlation (P<0.05) was observed between the phytoavailable arsenic and plant growth response. Interestingly, the form of arsenical pesticide used did not impact arsenic uptake or shoot growth but significantly impacted root growth.

Two bacterial strains, i.e. Pseudomonas mendocina and Ochrobactrum sp. were isolated from bilge oil contaminated water of Mormugao harbour, Goa, India and grown in a culture medium with hexadecane as the sole carbon source. Pseudomonas mendocina was used in further studies as it was the dominant strain. This strain effectively degraded tetradecane, hexadecane and octadecane leaving a residual concentration of about 73 %, 54 % and 40 % respectively in 120 h. Sequence analysis of the dominant bands from the denaturing gradient gel electrophoresis profiles revealed the differences between the genera of bilge oil contaminated sea water and its enrichment culture on hexadecane indicating a shift in community structure based on the type of substrate available. Pseudomonas mendocina amplified for the following catabolic genes namely C23O, nid and ndo. Based on the catabolic gene study the potential of the bacterial strain isolated, i.e. Pseudomonas mendocina seems to be interesting as it will be able to degrade polyaromatic hydrocarbons as well. Physicochemical properties of Pseudomonas mendocina indicates production of exopolysaccharides based on the value of its isoelectric point.

A mathematical model to predict the rhamnolipids production by Pseudomonas aeruginosa from oleic acid in a two phase liquid-liquid batch reaction system, was developed in this study. The model was based on two theoretical assumptions: 1) the convective oleic acid mass transfer is coupled to a bioreaction in the aqueous liquid bulk, and 2) the volume of the immiscible oleic acid drops and the saturation concentration at the interface are a function of rhamnolipids production. The model was able to accurately predict the experimental growth of the Pseudomonas aeruginosa strain, and the rhamnolipids production data with oleic acid as carbon source. This mathematical approach indicated a high correspondence between the saturation dimensionless profiles of oleic acid at the interface and the experimental profiles of surface tension difference. This modeling approach may constitute a useful tool in the design and scaling-up of bioreactors applied to the production of biosurfactants with immiscible carbon sources.

Seawater intrusion is a major problem in urbanized coastal regions of India which is due to over exploitation of groundwater for various purposes. This study was carried out with the objective of assessing the zone of mixing between seawater and groundwater in the coastal aquifer in south of Chennai, Tamil Nadu, India using high resolution electrical resistivity tomography. High resolution electrical resistivity tomography was carried out in five profiles perpendicular to the sea using IRIS make SYSCAL Pro-96 system with 2.5 m or 5 m inter-electrode separation. The maximum length of the profile was 170 m which resulted in a depth of investigation of 28.7 m. The apparent resistivity measured in this area varies from 0.3 ohm-m to 30,000 ohm-m. The apparent resistivity of saturated zone decreases towards the sea, indicating the influence of seawater. This was also confirmed by measuring the electrical conductivity of groundwater, which gradually increases from 156 mS/cm to 3430 mS/cm towards the sea. Further, the concentration profiles of electrical conductivity, sodium, chloride and chloride / bicarbonate ratio are compared with the high resolution electrical resistivity tomography profile. The distance of influence of seawater is comparatively high in northern part than in southern part of the area. The high resolution electrical resistivity tomography was effectively used to determine the effect of seawater mixing with groundwater.

The present investigation reports the results of the cadmium accumulated by Salix matsudana, S. alba var. Tristis and S. babylonica in a pot experiment at six different levels of cadmium supply (0, 0.5, 2, 6, 25, 60 mg/kg). All tested Salix species showed the different abilities to remove cadmium, which depend on species and concentrations level. Cadmium accumulated by the leaves, twigs and roots linearly increased with increasing cadmium supply levels. The higher concentration cadmium treatments significantly promoted the cadmium accumulation. S. matsudana always performed the stronger ability of cadmium accumulation under different cadmium supply treatments, while S. alba var. Tristis and S. babylonica had the poorer accumulation ability. Cadmium in soil was more intensively absorbed in the leaves and twigs for all three Salix species, was not retained in roots and was transferred to aboveground plant tissues. The results indicated that Salix has an excellent potential for cadmium phytoremediation because of its high accumulation ability.

A chelating resin is prepared by condensation polymerization of aniline with formaldehyde and characterized by Fourier transform infrared spectrometer, elemental analysis and thermogravimetric analysis and studied for the preconcentration and determination of trace Molybdate ion from environmental water sample using inductive couple plasma atomic emission spectroscopy. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 3.1 mg/g. The chelating sorbent can be reused for 20 cycles of sorptiondesorption without any significant change in sorption capacity. The best desorption of the metal ions from resin was obtained by 0.5 mol/L nitric acid as eluting agent. The profile of molybdenum uptake on this sorbent reflects good accessibility of the chelating sites in the aniline- formaldehyde. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Molybdate ion modified resin were analyzed by five isotherm models such as Langmuir, Freundlich and Temkin. Langmuir isotherm parameters obtained from the four Langmuir linear equations by using linear method. Based on the Langmuir isotherm analysis, the monolayer adsorption capacity was determined to be 4.03 mg/g at 20°C. The method was applied for molybdenum ions determination from river water sample.

A new photosynthetic bacterium isolate was morphologically identified as a non-motile rod-shape gram-negative bacterium. It produced a dark red culture under phototrophic condition, reproduced by budding and formed a lamellar intracytoplasmic membrane system parallel to cytoplasmic membrane, which contained bacteriochlorophyll a and caratenoids. It’s physiological and nutrient requirement tests gave indication that the isolate thrived and multiplied in varied environmental conditions. It was consequently named Z08 and identified as Rhodobacter spheroids by 16SrDNA. Adaptation of Z08 to biodegradation of two environmentally concerned wastewaters, i.e. soybean and pharmaceutical wastewaters, attested its potential in wastewater bioremediation. Z08 adaptation in a suspended batch photobioreactor treating pharmaceutical wastewater at 3500lx radiation recorded best result after wastewater dilution of 1:4 with concomitant chemical oxygen demand reduction, biomass yield and specific growth of 50 %, 780 mg/L and 0.015/h, respectively at the lowest hydraulic retention time of three days. Furthermore, gas chromatography mass spectra analyses of treated and raw pharmaceutical wastewater indicated that high molecular weight recalcitrant compounds found in the pharmaceutical wastewater were transformed to less toxic and acceptable lower molecular weight substances through biodegradation. Whilst Z08 treatment of soybean wastewater under natural light intensity radiation recorded 80 % reduction, 1540 mg/L and 0.025/h for chemical oxygen demand, biomass and specific growth rate respectively regardless of the food to microorganism ratio. This preliminary investigation showed that isolate Z08 has some toxic tolerance level which could detoxify refractory substances with great potential for cell protein recovery in high organic strength wastewater. Therefore, strain Z08 could be employed in biodegradation of contaminated wastewater streams.

Although solar power systems are considered as one of the most promising renewable energy sources, some uncertain factors as well as the high cost could be barriers which create customer resistance. Leasing instead of purchase, as one type of product service system, could be an option to reduce consumer concern on such issues. This study focuses on consumer concerns about uncertainty and willingness to pay for leasing solar power systems. Conjoint analysis method is used to find part worth utilities and estimate gaps of willingness to pay between attribute levels, including various leasing time lengths. The results show the part worth utilities and relative importance of four major attributes, including leasing time. Among concerns about uncertainties, government subsidy, electricity price, reliability, and rise of new generation solar power systems were found to be significantly related to the additional willingness-to-pay for a shorter leasing time. Cluster analysis is used to identify two groups standing for high and low concerns about uncertainty. People with more concerns tend to pay more for a shorter lease time.

Biophysical and socioeconomic conditions of pre and post dam construction were assessed in one of the arid regions of Iran commanded by Minab dam. The methodology used in this study was drawn from the international organizations especially the World Commission on Dams and the United Nations for selection of the indicators for sustainable development relating to water resources projects. Commissioning of the dam in 1986 led to progressive expansion of the irrigated agriculture, which was almost doubled in year 2006. Results of the study revealed that there is significant positive impact of the irrigation infrastructures of the dam; for example literacy rate has increased from 41 % (pre project) to 74 % in 2006. Similarly, significant improvements were observed in health care, sanitation, education and other scopes. Nevertheless, for some of the targets only 50-60 % progress were made, whereas no significant achievements had been made in the others. Therefore, development did not match with the planned goals of the project. Deficiency in achieving the primary objectives, especially after many years of project completion, may be attributed to the management and implementation of the project. For effective project performance, a new institutional framework and guide lines are proposed in this article.

Thin films of titanium dioxide with high surface area are prepared by sol-gel dip-coating technique. In this regards, Titania nano sols with high photocatalytic activity were prepared by dissolving titanium alkoxide in alcohol and water under acidic conditions. Photocatalytic activities of titanium dioxide thin films were measured in the presence of methylene blue. Microstructure and photocatalytic activity of the films, nanopowders and titanium dioxide sols were investigated using X-ray diffraction, scanning electron microscopy, specific surface area, zeta sizer and ultraviolet–visible spectrometry techniques. Particle size analysis of sols showed that the mean particle sizes were 15 to 128 nm. X-ray diffraction analyses revealed that anatase crystal structure was produced with crystallite size below 11 nm. Increasing mass percent of anatase phase and specific surface area, enhance the photocatalytic activity. Scanning electron microscopy images showed that the addition of methylcellulose as a dispersant, not only produced rough texture in the thin film, but also enhanced photocatalytic activity. The thin films prepared by using nitric acid as a stabilizer, revealed higher photocatalytic activity, surface area and sol stability and these data were more than those prepared with acetic acid.

nutrients and contaminants and the biological activity within wetland systems for several decades. The majority of studies considering the redox geochemistry in sediments used measurements of bulked material and single point measurement of biogeochemical parameters for interpretation, yet it remains questionable whether this information is reliable for environments that are very dynamic, such as wetlands. In this study it is evaluated whether variations in redox potential reflect dynamics of denitrification and overall bacterial respiration using continuous measurements of redox potential in time-series experiments in laboratory microcosms, in which the biogeochemical variation was enhanced by bioturbation. The results presented here suggest that measurements of redox potential have predictive potential in approximating rates of denitrification and overall bacterial respiration in aquatic sediments. The data clearly suggest that, while sediment bulk measurements and measurements of single profiles of redox potential, denitrification and bacterial activity often fail to provide ecological relevant information in dynamic systems, measurements of spatial and temporal redox potential profiles provide a useful parameter that reflects biogeochemical processes and functioning of sediments.

Adsorption kinetic and equilibrium studies of two reactive dyes, namely, Reactive Red 31 and Reactive Red 2 were conducted. The equilibrium studies were conducted for various operational parameters such as initial dye concentration, pH, agitation speed, adsorbent dosage and temperature. The initial dye concentration was varied from 10 - 60 mg/L, pH from 2 - 11, agitation speed from 100-140 rpm, adsorbent dosage from 0.5 g to 2.5 g and temperature from 30°C -50°C respectively. The activated carbon of particle size 600 mm was developed from preliminary tannery sludge. The dye removal capacity of the two reactive red dyes decreased with increasing pH. The zero point charge for the sludge carbon was 9.0 and 7.0 for the two dyes, respectively. Batch kinetic data investigations on the removal of reactive dyes using tannery sludge activated carbon have been well described by the lagergren plots. It was suggested that the Pseudo second order adsorption mechanism was predominant for the sorption of the reactive dyes onto the tannery sludge based carbon. Thus, the adsorption phenomenon was suggested as a chemical process. The adsorption data fitted well with Langmuir model than the Freundlich model. The maximum adsorption capacity(q0) from Langmuir isotherm were found to have increased in the range of 23.15-39.37 mg/g and 47.62-55.87 mg/g for reactive dyes reactive red 31 and reactive red 2, respectively.

Vertical distribution of microbial communities in a eutrophic lake sediments of Lake Xuanwu was quantified by phospholipid fatty acids analysis and multivariate statistical analysis was employed to interprete the data. Principle component analysis of sediment characteristics parameters, including total nitrogen, total phosphorus, organic matters and pH produced clustering of sampling sites for two distinct groups. These groups corresponded with the two sampling stations and the levels of nutrient enrichment. Total phospholipid fatty acids concentration, which is indicative of microbial biomass, reduced with depth, however, the relative percentage of anaerobic prokaryotes increased. To assess changes of microbial community along depth, phospholipid fatty acids compositions were analyzed by cluster analysis. Distinct clusters were observed in different sampling stations. Canonical correspondence analysis was carried out to infer the relationship between sediment characteristics and microbial communities. Phospholipid fatty acids samples collected at the same sampling site clustered together. Canonical correspondence analysis revealed that the environmental parameter with the greatest bearing on the phospholipid fatty acids profiles was pH. This study proved the successful application of phospholipid fatty acids and multivariate analysis to investigate the relationship between environment factors and microbial community composition.

Water pollution has become a growing threat to human society and natural ecosystems in the recent decades. Assessment of seasonal changes in water quality is important for evaluating temporal variations of river pollution. In this study, seasonal variations of chemical characteristics of surface water for the Chehelchay watershed in northeast of Iran was investigated. Various multivariate statistical techniques, including multivariate analysis of variance, discriminant analysis, principal component analysis and factor analysis were applied to analyze river water quality data set containing 12 parameters recorded during 13 years within 1995-2008. The results showed that river water quality has significant seasonal changes. Discriminant analysis identified most important parameters contributing to seasonal variations of river water quality. The analysis rendered a dramatic data reduction using only five parameters: electrical conductivity, chloride, bicarbonate, sulfate and hardness, which correctly assigned 70.2 % of the observations to their respective seasonal groups. Principal component analysis / factor analysis assisted to recognize the factors or origins responsible for seasonal water quality variations. It was determined that in each season more than 80 % of the total variance is explained by three latent factors standing for salinity, weathering-related processes and alkalinity, respectively. Generally, the analysis of water quality data revealed that the Chehelchay River water chemistry is strongly affected by rock water interaction, hydrologic processes and anthropogenic activities. This study demonstrates the usefulness of multivariate statistical approaches for analysis and interpretation of water quality data, identification of pollution sources and understanding of temporal variations in water quality for effective river water quality management.

A significantly large volume of effluent is generated during the manufacture of sugar and contains high amount of pollution load. The effluent from sugarcane industry is disposed off on land moves into the wider environment through a number of routes and the soil itself retains the various contaminants in the effluent to a greater or lesser extent depending on the physical nature of the soil. The analysis of contaminant transport through soil used to design of industrial wastewater treatments and disposal systems. This paper discussed the adsorption and diffusion of cations calcium, magnesium, sodium and anions chloride and sulphate by the sorption diffusion permeameter under different hydraulic retentions time of 3 min, 13 min, 27 min and 58 min with a constant diffusion flow rate of 3.6 L/h. In this study, less percentage error found between observed adsorption and diffusion coefficients from the experiments at different hydraulic retentions time and optimum adsorption and diffusion coefficients from the experiments at optimum hydraulic retentions time of 30 min for calcium, magnesium, sodium, choloride and sulphate. The results of regression analysis implied that the adsorption and diffusion coefficients obtained from the equation for cations and anions were good recognizing with the experimental results.

In the past, decision making within the energy sector, especially in Iran, was limited to economic analysis. Lately, multiple criteria decision making has gained great popularity. However, this is not enough to make a right decision by considering sustainability. This paper deals with designing an appropriate multiple criteria decision making method to address the multifaceted nature of such problems. This task is the second precondition to make a decision which meets the sustainability criterion. This is done by revealing new facts about quantitative and qualitative data and the degree of compensation between the criteria. Moreover, this paper illustrates the capability of different methods with regard to sustainable energy planning and management in two steps: 1) comparison of two main approaches in the strategic energy planning context; 2) evaluation of multi attribute decision making methods and combining them. Combining four methods including Analytical hierarchy process, Preference ranking organization method for enrichment evaluation II, geometric mean and weighted sum seems to result in designing an appropriate method which meets the sustainability criterion. These contributions are proposed for comparing the renewable energy technologies with nonrenewable ones. Nevertheless, these seem to be applicable in any comparison between discrete alternatives in the energy sector.

A series of experiments were performed for toluene decomposition from a gaseous influent at normal temperature and atmospheric pressure by nonthermal plasma coupled with a combination of catalysts technology. Nonthermal plasma was generated by dielectric barrier discharge. g-Al2O3 was used to be a sorbent and a catalyst carrier. Nanocatalysts were MnO2/g-Al2O3 coupled with modified ferroelectric of nano-Ba0.8Sr0.2Zr0.1Ti0.9O3. g-Al2O3 played an important role in prolonging reaction time of nonthermal plasma with volatile organic compounds molecules. MnO2/g-Al2O3 has an advantage for ozone removal, while nano-Ba0.8Sr0.2Zr0.1Ti0.9O3 is a kind of good ferroelectric material for improving energy efficiency. Thus these packed materials were incorporated together to strengthen nonthermal plasma power for volatile organic compounds decomposition. The results showed the synergistic technology resulted in greater enhancement of toluene removal and energy efficiencies and a better inhibition for ozone formation in the gas exhaust. Based on the data analysis of the Fourier transforms infrared spectrum, the reaction process of toluene decomposition and the mechanism of synergistic effect are discussed. The results showed in a complex oxidation mechanism of toluene via several pathways, producing either ringretaining or ringopening products. The final products were carbon dioxide and water.

In this study, adsorption of copper and chromium was investigated by residue of brewed tea (Tea Waste) from aqueous solutions at various values of pH. It was shown that adsorbent dose, copper and chromium ion concentrations in such solutions influence the degree of these heavy metal ions’ obviation. The adsorption level of the prepared solutions was measured by visible spectrophotometer. The tea residue adsorbed copper (II) and chromium (VI) ions at initial solution pH by 25 % and 3 %, respectively. During the experiments the peak adsorption occured in hydrated copper nitrate aqueous solution at pH range of 5-6. Likewise the maximum adsorption appeared in potassium chromate aqueous solution at pH range of 2-3. In addition, tea residue adsorbed about 60 mg/g of copper (II) ion at pH=5, while chromium adsorption was registered at about 19 mg/g at pH=2. The data obtained at the equilibrium state, was compared with Langmuir and Freundlich models. Results showed that regarding the kinetics of adsorption, the uptake of copper (II) and chromium (VI) ions by tea residue was comparatively faster, with the adsorption process exhaustion completed within the first 20 min of the experiments. Furthermore, results revealed that adsorption data concerning the kinetic phase is closely correlated with a pseudo-second order model with R2 > 0.99 for copper (II) and chromium (VI) ions.

Phytoremediation is increasingly receiving attention as a cost effective technique that uses plants to remediate contaminants from wastewater, soil and sediments. In this study, the ability of Typha domingensis to uptake heavy metals as well as its potential application for phytoremediation was assessed. Pollutant elements concentrations were measured in samples of wastewater, sediments and Typha domingensis collected from industrial wastewater ponds, El-Sadat city, Egypt. This study specifically focused on the capacity of Typha domingensis to absorb and accumulate aluminum, iron, zinc and lead. Results indicated thatTypha domingensis was capable of accumulating the heavy metal ions preferentially from wastewater than from sediments. The accumulation of metals in plant organs attained the highest values in roots, rhizomes and old leaves. Rhizofiltration was found to be the best mechanism to explain Typha domingensis phytoremediation capability.

In recent years, concerns about the occurrence and fate of active pharmaceutical ingredients, solvents, intermediates and raw materials that could be present in water and wastewater including pharmaceutical industry wastewater has gained increasing attention. Traditional wastewater treatment methods, such as activated sludge, are not sufficient for the complete removal of active pharmaceutical ingredients and other wastewater constituents from these waters. As a result, complementary treatment methods such as membrane filtration, reverse osmosis and activated carbon are often used in conjunction with the traditional methods for treatment of industrial wastewater. Most of the literature published to date has been on the treatment of municipal wastewater. However, there is a growing body of research that looks at the presence of active pharmaceutical ingredients in industrial wastewater, the treatment of these wastewaters and the removal rates. This article, reviews these treatment methods and includes both traditional methods and advanced oxidation processes. The paper concludes by showing that the problem of pharmaceuticals in wastewaters cannot be solved merely by adopting end of pipe measures. At source measures, such as replacement of critical chemicals, reduction in raw material consumption should continue to be pursued as the top priority.