International Journal of Environmental Science and Technology

Spatial pattern of variation in populations of Acacia nilotica in semi-arid environment

1S. Mahmood, 1A. Ahmed, 2A. Hussain and 3 *M. Athar

Variability among populations was analyzed in five provenances of Acacia nilotica from spatially variable habitats. Populations of A. nilotica developed in response to their habitat conditions. The level of variability was significantly high among the populations. Phenotypic variability was extremely high for leaf and stipular spine characteristics. The nature of morphological variability for vegetative traits appeared environmentally controlled. The differentiation of leaf and stipular spine expression seems to have an adaptive significance for the species in terms of water economy. Although, seed and pod characteristics are genetically controlled showing a lower proportion of variability but these traits supported r and k-selection that may allow the species to survive under a wide array of contrasting habitats. The study suggested that populations of A. nilotica are differentiated in relation to the heterogeneity of environment. These populations became adapted to their habitat through the variability of morphological expressions. The morphologically differentiated populations of the species had allowed them to maintain themselves in a wide array of environmental situations enabling A. nilotica to occupy ample ecological ranges.

Nitrate reductase activity: A solution to nitrate problems tested in free and Immobilized algal cells in presence of heavy metals

*M. Awasthi

Every organism has different potential to accumulate NO3- from the environment. Nitrate reduction processes are perhaps most significant in maintaining water quality by alteration of nitrate to nitrite. A comparative study between the nitrate reductase NR activity of green and blue green algae in presence of heavy metals is being conducted to present a situation where nitrate reductase process may be affected in presence of heavy metals. Metals interacted negatively with the nitrate reductase activity of a blue green alga, Anacystis nidulans and green algae, Chlorella vulgaris in both free and immobilized state. The activity was more repressed in C. vulgaris in presence of Ni compared to Zn and Cd. However, Cd was more toxic to NR activity in A. nidulans (free state). Metal dependent variation between free and immobilized cells were found to be significant (P< 0.01) however, the concentration dependent pattern in the activity between free and immobilized state was non significant in both the test organisms. C.vulgaris is more efficient in conversion of nitrate to nitrite compared to A.nidulans in presence of heavy metals.

Modeling of packed absorption tower for volatile organic compounds emission control

*1M. S. Rahbar and 2T. Kaghazchi

Development of chemical industry and high vapor pressure of volatile organic compounds (VOCs) have been caused that these materials recently be considered as a source of air pollution. These are different methods for separation of VOC from air that absorption by suitable and selective solvent is an efficient method. In this research, mathematical modeling of a packed absorption tower for separation of VOCs from air has been presented. Then, acetone vapors separation in this tower and with Intalox saddle packing has been investigated. Concentration of acetone in inlet air stream was 1.5 mol % which has reduced to 150 ppm (0.015 mol %) in effluent air stream. The results show that the packed absorption tower with this type of packing can separate 99% of acetone vapors. Comparison of the results obtained by Intalox saddle packing with the results obtained by another type of packing (with trade mark of Kerapak patented by Sulzer Company) shows that the tower gives the same efficiency for acetone separation. Thus, the efficiency of absorption process, mainly, depends on solvent type, composition of VOC in feed air, desired composition of VOC in outlet air (or percentage of VOC separation) and pressure drop.

Assessment of ambient air quality in Bishnumati corridor, Kathmandu metropolis

K. Simkhada, *K. Murthy V and S. N. Khanal

The Kathmandu valley urban area is growing as a metropolis. Bishnumati corridor in Kathmandu valley is is a target of increased pollution. The unabated solid waste land-filling on either side of the river-bank and animal slaughter houses and biological waste arising from these activities, busy commercial and high residential density characterize the corridor. Six areas, namely Teku Dovan, Kalimati Bridge, Kankeswori, Shova Bhagwati, Balaju and New Bus Park areas, all areas falling within the Bishnumati corridor were selected to measure air quality representing corridor. The pollutants quantified were respirable particulate matter - PM10, sulphur dioxide and oxides of nitrogen. The air-borne microbial flora and fungi load quantification were also carried out. Teku Dovan (918.92 µg/m3) and Shovabhagavati areas (847.45 µg/m3) showed higher levels of particulates. Kankeswori area showed highest levels of aerial bacterial (3.7x107 cfu/m3) and fungal load (4.8x108 cfu/m3). The PM10 levels at all the sites are substantial and fall in the categories of ‘Harmful' and ‘Hazardous' quality of air suggesting that the corridor needing intervention to minimize the risk from air pollution. Non-judicious open-air combustion of the solid waste contributes to air pollution. Heavy traffic and few roads not clad with asphalt; perceivable mal-odor and persistent stench emanating from the indiscriminate disposal and consequent putrefaction processes, dense population and increased commercial activities are other principal contributing sources to the resulting pollution of the corridor. In view of this status, mitigating measures to minimize exposure to the toxicants in the corridor is a necessity.

Genotypic and environmental interaction in advanced lines of wheat under salt-affected soils environment of Punjab

*Y. Ali, Z. Aslam, G . Sarwar and F. Hussain

Wheat cultivars of diverse origin including approved varieties of different provinces of Pakistan i.e. Punjab, NWFP and Sindh were tested against different salinity levels in laboratory as well as in naturally saline fields in different ecological zones. Initially, 16 genotypes were studied for germination test at 6 different salinity levels ranging from 0-25 dS/m (2, 5, 10, 15, 20, 25, EC= dS/m). Then, out of 16 cultivars, 11 were studied for the relative growth rate at different levels of salinity and after their study in the laboratory, 9 genotypes were selected for testing in the naturally saline areas of Punjab province. Under germination percentage study, the varieties viz. Pasban-90, Sarsabz, Bakhtawar, 93032 and 933118 were less affected than other varieties. As regards the relative plant growth, varieties viz. Sarsabz, Bakhtawar, and Pasban-90 were tolerant to salinity at seedling stage while Inqlab was graded as sensitive to salt stress. Regarding field performance, significant differences were observed in the varieties grown under different saline environments and varieties x environment interaction. Varieties x environment (Lin) interaction was non significant while nonlinear interaction (pooled deviation) was significant. Based on overall yield performance, the Sarsabz variety produced the highest seed yield (4.37 T/ha) followed by Bakhtawar (4.24 T/ha) and Pasban-90 (3.93 T/ha). Regression coefficient values showed non significant differences to unity while standard deviation to regression showed significant differences to zero. These results indicated that the genotypes viz. Sarsabaz, Bakhtawar and Pasban-90 are better tolerant to saline environment as compared to others. The two genotypes, Marvi and 25219 had low regression values and can fit under stress environment.

Comparative study of body composition of different fish species from brackish water pond

1M. Ali, 1F. Iqbal, 1A. Salam, 1S. Iram, and 2*M. Athar

Seven species of fish (Catla catla, Cirrhinus mrigala, Cyprinus carpio, Hypophthalmicthys molitrix, Labeo rohita, Mori-Rahu Hybrid and Thalla-Rahu Hybrid) were collected from a brackish water pond near Muzaffargarh, Pakistan for the comparison of body composition. All the seven species were found relatively well adapted to the saline environment though some of them showed significant differences in body composition. Results obtained did not show any adverse effect of salinity on these fish species. The mean values of body constituents, except for protein content (dry and wet body weight) differed significantly (P<0.05) among various fish species. Minimum amount of water content and maximum amount of lipids, organic content and condition factor were observed in Cyprinus carpio indicating that Cyprinus carpio show overall better growth in brackish water as compared to other species. Cyprinus carpio may be recommended for culturing in such water bodies and farmers may be encouraged to farm this species on mass scale.

Potassium induced salinity tolerance in wheat (Triticum aestivum L.)

1M. U. Shirazi, 2*M. Y. Ashraf, 1M. A. Khan and 1M. H. Naqvi

Water culture experiments were conducted to study the response of ten wheat genotypes to external K application (10 mmol KCI dm^_3) at seedling stage under saline condition (0 and 100 mmol NaCl dm^_3). The data showed that there was an increase in the shoot and root length with the application of external K. The increase was more pronounced under control than under saline conditions. The better performing genotypes under two treatments were Bhitai, NIAB-41, NIAB-I076 and Khirman. The enhanced growth of these genotypes under saline condition might be due to the quick response to external K application, resulting in high K/Na ratio. The results indicated that the genotypes, which have the ability of enhanced K/Na discrimination, might perform better under saline conditions when sufficient potassium is applied in the rooting medium.

Assessment of the impact of industrial effluents on water quality of receiving rivers in urban areas of Malawi

O. Phiri, *P. Mumba, B. H. Z. Moyo and W. Kadewa

A study was carried out in Malawi to assess the extent of chemical pollution in a receiving river as affected by industrial effluents. Both the effluents and the water at selected points in the river were analysed for pH, dissolved oxygen, biochemical oxygen demand, electrical conductivity, suspended solids, nitrate, alkalinity, hardness, chloride and phosphate in the dry and rainy seasons. The results showed that the effluents were acidic in both the dry season (range: 4.2  0.02-6.5  0.02) and in the rainy season (range: 4.2  0.05 - 5.6  0.01). While the levels of dissolved oxygen, biological oxygen demand, electrical conductivity, suspended solids, alkalinity and chloride were relatively high in the dry and rainy seasons, the concentration of phosphate and nitrate were low in both seasons. The water upstream was neutral (average pH, 7.40  0.04) with high dissolved oxygen but low in the levels of the other parameters in both seasons. The water after the effluent receiving points was acidic and the levels of the other parameters were high, especially downstream. The results suggested that the water in the river was polluted and not good for human consumption. It is therefore recommended that the careless disposal of the wastes should be discouraged and although the values in some cases were lower than the allowable limits, the continued discharge of the effluents in the river may result in severe accumulation of the contaminants and, unless the authorities implement the laws governing the disposal of wastes, this may affect the lives of the people.

Decolorization of simulated spent reactive dye bath using solar / TiO₂ / H₂O₂

1*S. Sreedhar Reddy and 2B. Kotaiah

Different parameters were investigated to evaluate their effect on the process removal efficiency of reactive dye from simulated spent reactive dye bath, by solar / TiO₂ / H₂O₂, including H₂O₂ concentration, TiO₂ loading and pH. As a result 99% of reactive dye can be removed at a TiO₂ loading of 400mg/l, H₂O₂ concentration of 150 mg/l and of pH: 5.2. The effect of photo-catalytic deactivation of TiO₂on reactive dye removal was studied for ten number of cycles, and found that the extent of deactivation was high for each consecutive repeated use.

Flood occurrence hazard forecasting based on geographical information system

1*K. Solaimani, 2H. Mohammadi, 3M. Z. Ahmadi and 1M. Habibnejad

The application of Geographical Information system (GIS) in modeling flood and its prediction in catchments offers considerable potential. Several examples illustrate simple GIS techniques to produce flood hazard indices or its zonation using hydrologic-type models. Existing flood models can also be loosely coupled to a GIS, such as the HMS (Hydrological Modeling System) model. Forethermore, models can be fully integrated into a GIS by embedded coupling, such as the SCS (Soil Conservation Service) model. Installation of flood forecasting systems in watersheds with incomplete hydrometric data may reduce the flood-induced damages. In this study Geographical Information system used to up to date the watershed data and estimation of SCS model parameters which is sensible to considered the real time flood forecasting in Kasilian catchment of Mazandaran province. The main aim of this paper is to investigate the possibility of the linkage between GIS with a comprehensive hydrologic model, especially HMS. The use of GIS could produce a suitable agreement between observed results (extracted rainfall and runoff data of 1992, 1995 and 1996 from the related stations) with the calculated results of the hydrological model. The obtained results from rainfall-runoff process simulations of the model in this research showed that submergibility of the main watershed, Kasillian, does not depend on the outlet discharge rate of each one of its watershed independently. But it is related to how those two outlet hydrographs from main river watershed are combined. The model is capable of showing the flood characteristics temporally and spatially in each cross section of the channel network.

Daily air pollution time series analysis of Isfahan City

1R. Modarres and 2*A. Khosravi Dehkordi

Different time series analysis of daily air pollution of Isfahan city were performed in this study. Descriptive analysis showed different long-term variation of daily air pollution. High persistence in daily air pollution time series were identified using autocorrelation function except for SO₂ which seemed to be short memory. Standardized air pollution index (SAPI) time series were also calculated to compare fluctuation of different time series with different levels. SAPI time series indicated that NO and NO₂, CH₄ and non-CH₄ have similar time fluctuations. The effects of weather condition and vehicle accumulation in Isfahan city in cold and warm seasons are also distinguished in SAPI plots.

Germination and seedling growth of corn (Zea mays l.) under varying levels of copper and zinc

1S. Mahmood, 2A. Hussain, 1Z. Saeed and 3M. Athar

The heavy metal tolerance in corn (Zea mays L.) var. ‘Neelum' was assessed at germination and seedling growth after having subjected it to different concentrations of CuSO₄ and ZnSO₄. Germination was not affected by any of the metal tested, whereas initial growth was strongly inhibited by increasing concentrations of ZnSO₄. Seedlings developed toxicity symptoms in the presence of both metals but more chlorotic and necrotic regions were observed at varying levels of ZnSO₄ than CuSO₄. The metal accumulation was concentration dependent. Z. mays seedlings accumulated more copper in roots but greater contents of zinc in their shoots. On the basis of results presented here, it can be concluded that the cultivar of the species tested has shown a marked sensitivity to the presence of small amounts of metals present in the growth medium. The data support the assumption that metal sensitivity is probably due to strong tendency of the species to accumulate them. This justifies that the corn variety ‘Neelum' is not suitable for the cultivation under situations where water and soil suffer from occasional and/ or transitory metal pollution.

Sample preparation and analytical techniques for determination of polyaromatic hydrocarbons in soils

2*Z. Khan, 1, 2J. Troquet and 1, 2C. Vachelard

Polyaromatic Hydrocarbons (PAHs) have been determined in soil samples for many years. PAHs can arise in the environment from natural sources, oil and petroleum products and combustion processes. Although oil spills influence PAHS concentrations in local areas, the major sources of PAHS are anthropogenic and derived from land based combustion sources. PAHs are globally distributed and the highest concentrations generally occur close to urban centres. Monitoring is essential during the assessment and remediation. It makes further demands on the analytical methods used, since the transformation products are often present in lower concentrations than the parent PAHs and they may be difficult to identify in the complex mixtures found in these samples. It is therefore essential to use powerful analytical tools to fractionate, separate and identify the analyses in the samples. In this paper we review those aspects relating to the analysis and monitoring of PAHs in soils. The aim is to provide an overview of current knowledge, so as to assess the need for future monitoring of PAHs and the present capability for their analysis. Further monitoring of PAHs is justified because of their ubiquity in the environment, their persistence and bioaccumulative properties and their potential for toxicity both to aquatic organisms and human consumers.

European red spider mite - an environmental consequence of persistent chemical pesticide application