IRANIAN JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE AND ENGINEERING (IJEHSE)
Year:2010 | Volume:7 | Issue:2|Papers Count:10

Biomonitoring is a method of observing the impact of external factors on ecosystems and their development over a long period. In this research the level of Zn, Cu, Cd and Pb has been determined in samples of the moss Racomitrium crispulum from the area of Almora, Nainital and Pithoragarh of Kumaon hills. High metallic load was observed in locations near proximity of higher traffic density area, which integrated due to enhanced tourism during summer, followed by winter and monsoon season; while in rural area high value of Zn, Cu and Cd attributes to their use in fertilizers. Positive significant correlations obtained between Pb-Zn and Zn-Cu suggest a common origin of these metals. Elemental concentration in Racomitrium.crispulum was in the order of Zn> Pb ~ Cu> Cd in summer, Zn> Cu > Pb > Cd in winter season and Zn> Cu > Pb > Cd in monsoon which reflect atmospheric trace elemental load. Bioaccumulation ability of this moss was evaluated statistically using DMR test and cartographically presented on contour maps obtained from SURFER program.

In this study, the potential of a membrane bioreactor for treating styrene contaminated synthetic wastewater, with COD that simulated a petrochemical wastewater, was evaluated and compared with previous studies. At hydraulic retention times of 18 and 24 hours, the removal efficiency of COD and styrene was consistently higher than 99%. More significantly no styrene was detected in the exhaust air, which meant that, at both hydraulic retention times, the mechanism of styrene removal in the membrane bioreactor was exclusively through biodegradation. The lower contribution of stripping to overall styrene removal obtained in the present work compared to that previously reported for traditional activated sludge processes was attributed to the higher Mixed Liquor Suspended Solids (MLSS) that can be achieved in a membrane bioreactor. Decrease of hydraulic retention time from 24 h to 18 h also resulted in significant increase in the rate of membrane fouling as quantified by transmembrane pressure gradiant. This was attributed to decrease in extracellular polymeric substance concentration which resulted in sludge deflocculation. As a consequence, the particle size distribution of the activated sludge shifted to lower mean particle sizes and the increase in the percentage of smaller particles resulted in increase in the rate of membrane fouling.

Previous researches have demonstrated that presence of some carbohydrates in the culture medium will cause callus induction and frond regeneration in Lemna minor, and it is expected that presence of carbohydrates will affect the uptake of organics by this plant. However, limited studies have investigated the uptake of organics by this plant. The aim of this study was to clarify the effect of conventional carbohydrates such as glucose and lactose on uptake of phenol by Lemna- minor. Experiments were carried out in the presence and absence of glucose and lactose in the growth solution. The growth solution was fresh water collected from river and phenol was added to it. The initial concentrations of phenol were 20, 50 and 100 mg/L and density of Lemna minor (fresh weight) were 50, 100 and 150 g/m2. The plants were contacted with growth solutions for 4 weeks. Control bottles (without plants) were examined with the same manner. The bottles were placed under white cool light with 12h photo periods at room temperature. Every four days sample was taken and the concentration of phenol was determined by spectrophotometer. Uptake of phenol by lemna-minor increased with increasing the contact time and decreased by increasing phenol concentration. In the presence of glucose and lactose in the growth solutions, uptake of phenol was decreased. Phenol uptake was dependent to plant density and when Lemna minor completely covered the surface of the water, uptake decreased. In the presence of glucose and lactose, uptake of phenol by Lemna minor was decreased. Uptake of phenol by lemna minor was affected by density of plant.

The present study is an attempt to treat the coffee processing wastewater using upflow anaerobic hybrid reactor which offers the advantage of both suspended and attached growth anaerobic reactor systems. Upflow anaerobic hybrid reactor with a volume of 19.5 L was operated at 24 h hydraulic retention time. After the startup period, the reactor was evaluated by operating at different hydraulic retention times of 24, 18, 12 and 6 h. The reactor performed better at HRT=18 h with short period of time. At 18 h retention time, reduction of chemical oxygen demand, biochemical oxygen demand and total solids were 61.0, 66.0 and 58.0 per cent, respectively, with organic loading rate of 9.55 kg/m3/day. The maximum quantity of biogas produced were 840, 775 and 430 L/kg of TS, BOD and COD removal, respectively, with the methane content of 60.7% at HRT=18 h. The finding of the study helps to design low cost and compact onsite treatment systems with a very short retention period.

Humic acids, which are derived mainly from decaying organic matter, are considered as complex macromolecules having various functional groups and are very effective in the binding and removal of different cations including heavy metals. Two lentic water bodies selected for the comparative analysis of humic acids and cadmium content in this study are the Devarajan lake (polluted lake) and Srinivasapuram lake (reference lake) located in the Denkanikottai taluk of Krishnagiri district, Tamil Nadu, India. Water and soil samples were collected on every alternate month for one year from Feb. 2008 to Feb. 2009 from five fixed sites in both the lakes. While water samples were collected in polyethylene bottles, sediment samples were collected using a core sampler. In addition to the determination of cadmium in the water and sediment samples using atomic absorption spectrophotometer, the humic acids contents in the sediment samples were also quantified on a bimonthly interval. The dissolved oxygen (DO) content and biochemical oxygen demand (BOD) of the two water bodies were also monitored. BOD and DO showed considerable variations between the two lakes indicating the pollution load of the Devarajan lake. Both the lakes exhibited significant differences between their humic acids contents as well as cadmium contents. In both the lakes, the amount of cadmium in the sediments was positively correlated to the respective humic acids contents indicating the possible interaction and complex formation between humic acids and cadmium. Such interactions may be responsible for the reduction of the bioavailability of toxicants including cadmium especially in the polluted lake leading to the survival of the aquatic fauna in it.

The presence of arsenic in drinking water is one of the greatest threats to public health. The aim of this experimental investigation was to study the removal efficiency of As(v) from water by application of iron-impregnated activated carbon(Fe-AC). Coating of activated carbon with iron salt was carried out by impregnation method and thermo-chemical reactions with using of 100 mM FeCl3 solution. The Fe-AC was pulverized using ASTM standard sieves with the range of 16-20 mesh. The solid structure and surface characteristics of Fe-AC were determined using conventional techniques. Batch adsorption experiments were carried out with 300 and 600mg/L arsenate. Langmuir, Freundlich and Dubinin-Radushkevich models were used to describe the isotherm and energy of adsorption. The results of this study showed that 2.5 h contact time was enough to achieve the equilibrium. The adsorption of As(v) had a good compliance with Langmuir model (R2 = 0.995) and the maximum adsorption capacity was obtained as 0.024 mg/g. The results of kinetic studies showed that As(v) adsorption on Fe-AC may be limited by film diffusion step (m=0.26). The mean free energy of adsorption (E) calculated from Dubinin-Radushkevich isotherm was found to be 1.52 kj/mol which implies that the adsorption of As(v) on Fe-AC is a physical adsorption. The results indicated that Fe-AC is one of the suitable adsorbents which can be used for the treatment of arsenic contaminated waters.

In order to characterize polybrominated diphenyl ether (PBDE) contamination in vehicle interiors, airborne concentrations of polybrominated diphenyl ethers were investigated using PUF disk passive air samplers in 25 private cars. Passive air samplers were fixed inside the selected cars for a period of 4 to 6 weeks. SPBDE concentrations (sum of the 10 congeners) ranged between 0.01 and 8.2 ng/m3 with respective arithmetic and geometric mean concentrations of 0.71 and 0.091 ng/m3. High concentrations of polybrominated diphenyl ethers found in cars might provide an important source of human exposure to PBDEs either via inhalation or dust ingestion. A driver spending 8 hours a day inside a contaminated car (the worst scenario) would receive a daily inhalation intake of 54 ng. Age of the vehicles was found to be the most influential factor affecting polybrominated diphenyl ether emission in car interiors (R=0.47, r<0.01). Furthermore, significant variations were observed in polybrominated diphenyl ether concentrations between cars from same manufacturer with similar ages. The median ratio of BDE 47:99 for air samples was 1.7 comparing with the respective values of ~1 and ~0.7 reported for BK 70-5DE and DE-71, suggesting these commercial formulations to be likely sources of polybrominated diphenyl ethers in the car indoor environments.

Although the asbestos application is band in most developed countries but it is still used in many developing countries, escalating the mortality rate due to cancer among the workers exposed to asbestos fibers. In the present work, occupational exposure to airborne asbestos fibers in production line of an asbestos-cement products manufacturing factory were assessed, using OSHA method ID-160. For this purpose, 106 personal air samples were collected from breathing zones of workers in various processes of the factory. Cancer-related mortalities were also predicted by extrapolation of OSHA risk assessment data to the data obtained from the factory in question. The results revealed that physically disturbing processes such as mills, drilling and cutting are the most deadly processes. It was also shown that mills have the highest mortality rate due to asbestos fibers exposure, expecting 1198 deaths per 100,000 workers after one year exposure and 14665 deaths per 100,000 workers after 20 years occupational exposure. Relative risk (RR) of lung cancer after 1, 20 and 45 years working in the factory in question versus public community of Iran would be 11.6, 206.5 and 324, respectively. Cancer-related mortality predicted for dry cutting process was more than wet cutting process(RR=3.6). Finally it was recommended that job rotation and isolation of high risk operations could lead to lower cancer-related mortality due to occupational exposure to asbestos airborne fibers.

This paper presents an overview of current solid waste management practices in Kohima, Nagaland, India and suggests solutions to some of the major problems. The levels of socio-economic development determine the quantity and composition of solid waste. Higher the level of economic development, greater the proportion of waste composition. The total population of the city is 1,32,836, among those, 90% population is predominantly tribal. Hence, solid waste is not that much problem in rural economy compared to urban areas. As a result of that, the problem of municipal solid waste management is not yet felt in the rural areas of Nagaland. Compared to that, the concentration of population with higher densities in Kohima towns as well as unmanaged growth of settlements are among major causes leading to the problem of municipal solid waste affecting public health and natural environmental systems. So the total elimination of the waste is an impractical suggestion, rather than it should be managed in an effective manner. The surveys have shown that the collection process is deficient in terms of manpower and vehicle availability. Bin capacity provided is adequate but locations were found to be inappropriate, thus contributing to the inefficiency of the system. At this time, no treatment is provided to the waste and waste is dumped on open land at Dhapa after collection. Lack of suitable facilities (equipment and infrastructure) and underestimates of waste generation rates, inadequate management and technical skills, improper bin collection, and route planning are responsible for poor collection and transportation of municipal solid wastes. This study was on field visit, secondary data collection, interviews with different individuals who were directly or indirectly involved with the project and also through the discussions with the relevant Kohima Town Committee officials to get a clear idea about the present situation of the town. The effective management of municipal solid waste has become a monumental challenge in the town with high population density and experiencing the problem of rapid urbanization. This study mainly focuses on the issue of management of municipal solid waste in Kohima town and also describes its existing systems, the way of dealing with the present upcoming problems and also suggests new innovative approach for effective management of municipal solid waste in Kohima town. The overall objective was to create an efficient, reliable and holistic system for management of municipal solid waste, so as to achieve a cleaner environment and improve the quality of life.

Nowadays, people are highly concerned about the effects of high voltage transmission lines on their health. Probable risk for leukemia, breast cancer, neuropsychological disorders and reproductive outcomes has been reported due to this exposure. In this study, several measurements around different areas such as overhead transmission lines, GIS compartments and some appliances have been conducted and compared with the standard tolerances. The emphasis of this research is on high voltage substations and publics. Field magnitudes above 10kV/m have been measured under wires. Results show that there is no serious concern for the people living near the transmission lines but for the individuals who are beneath those lines for long. Recent achievements about electric fields’ effect on human health are reviewed in the present paper. In a case study, three types of 230kV structures are analyzed and the best phase arrangement for reducing the electric and magnetic fields is determined (the circular arrangement). It is concluded that the most effective solution is for the governments to use the best phase arrangement and replace outdoor substations with GIS to reduce the radiations and for the people to be near the high voltage overhead lines as rarely as possible.