IRANIAN JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE AND ENGINEERING (IJEHSE)
Year:2007 | Volume:4 | Issue:4|Papers Count:10

In recent years, hormones and hormone–like compounds have been frequently used in vegetable and livestock production to obtain a high yield performance in a shorter period of time, but depending on the use of anabolics in animal feed, anabolic residues that may occur in meat and meat products would present the risks to the human health. The present study was undertaken to detect and quantify the levels of trenbolone residues (a potent synthetic analog of testosterone) in the market meat in Iran. Cattle meat samples were collected from the markets in Tehran. A total of 120 samples of cattle meat were analyzed for level of trenbolone by Enzyme-Linked Immunosorbant Assay method. The average experimental values of trenbolone in cattle meat were 3.76±5.26ng/kg. This value gave no evidence for the illegal use of hormones in Tehran, but these results do not exclude the possibility of misuse of these potentially harmful chemicals in future. There is, therefore, need to routinely monitor these chemicals as a food quality and health control measure.

This paper presents the results of an experimental research undertaken to evaluate different purging solutions to enhance the removal of cadmium from spiked contaminated field soil by electrokinetic remediation. Three experiments were conducted when soil was saturated with deionised water and subsequently deionised water, ammonium citrate and sodium citrate were used as purging solutions at anode end. One experiment was conducted when the soil was saturated with ammonium citrate and itself was used as the purging solution. Results showed that 49% reduction of cadmium concentration was achieved in the case of soil saturated (washed) with ammonium citrate as well as purging solution also was ammonium citrate. The soil pH and washing solutions were the most important factors in controlling the removal of cadmium in electrokinetic remediation process.

The oxygenate methyl tert-butyl ether is added to gasoline to increase the octane level and to reduce carbon monoxide and hydrocarbon emissions by vehicles. The high mobility, water solubility, and resistance to natural attenuation associated with methyl tert-butyl ether may result in contamination of ground and surface waters. In this research the degradation of aqueous methyl tert-butyl ether at relatively high concentrations was investigated by UV-vis/TiO2/H2O2 photocatalytic process. The effect of important operational parameters such as pH, amount of H2O2, catalyst loading, and irradiation time were also studied. Concentrations of methyl tert-butyl ether and intermediates such as tert-butyl formate and tert-butyl alcohol were measured over a 180 min period using a gas chromatograph equipped with flame ionization detector and combined with headspace sampler. Results showed that the time required for complete degradation increased from 30 to 180min, when the initial concentration was increased from 10 to 500mg/L. The first order rate constant for degradation of methyl tert-butyl ether from the hydroxyl radical was estimated to be 0.177 to 0.022 1/min as the concentration increased from 10 to 500mg/L. Study on the overall mineralization monitored by total organic carbon (TOC) analysis showed that in the initial concentration of 100mg/L methyl tert-butyl ether, complete mineralization was obtained after 110min under UV-vis/TiO2/H2O2 photocatalytic process.

The amount of solid wastes generated in developing countries such as Nigeria has steadily increased over the last two decades as a result of population explosion and continuous growth of industries and agricultural practices. In agriculture, particularly cattle rearing, large quantities of cow wastes are generated, which could be used as biogas inputs to compliment the fuel usage alternative. In addition, a large number of families generate heavy wastes in the kitchen on a daily basis, which could be converted to economic benefits. In this work, a comparative study of biogas production from poultry droppings, cattle dung, and kitchen wastes was conducted under the same operating conditions. 3kg of each waste was mixed with 9L of water and loaded into the three waste reactors. Biogas production was measured for a period of 40 days and at an average temperature of 30.5°C. Biogas production started on the 7th day, and attained maximum value on the 14th days for reactor 1. Production reached its peak on the 14th day with 85×10-3dm3 of gas produced in reactor 2. For reactor 3, biogas production started on the 8th day and production reached a peak value on the 14th day. The average biogas production from poultry droppings, cow dung and kitchen waste was 0.0318dm3/day, 0.0230dm3/day and 0.0143 dm3/day, respectively. It is concluded that the wastes can be managed through conversion into biogas, which is a source of income generation for the society.

The performance of an up flow anaerobic packed-bed reactor in the upgrading of Parkandabad (Mashhad, north east of Iran) wastewater treatment plant was studied in a pilot plant. The experiments were performed at hydraulic retention times of 6, 12, 18 and 24h based on empty reactor volume and the performance of the reactor was evaluated based on the removal of organic matter (BOD5 and COD) and SS. The average BOD5 and COD removal efficiencies were in the ranges of 79.0-89.3% and 75.7-87.2%, respectively, depending on HRT. The relationship between the organic loading rate and organic removal rate was linear in the loading range of 0.52-2.10kg BOD5/m3.d. The average SS removal efficiencies at hydraulic retention times of 6, 12, 18 and 24h were obtained to be 82.9, 83.6, 81.2 and 87.4%, respectively. The results indicated that the reactor in combination with existing biological treatment process (completely mixed aerated lagoon) can produce a high quality effluent.

A Microsoft Windows based ventilation software package is developed to reduce time-consuming and boring procedure of exhaust ventilation system design. This program Assure accurate and reliable air pollution control related calculations. Herein, package is tentatively named Exhaust Ventilation Design Software which is developed in VB6 programming environment. Most important features of Exhaust Ventilation Design Software that are ignored in formerly developed packages are Collector design and fan dimension data calculations. Automatic system balance is another feature of this package. Exhaust Ventilation Design Software algorithm for design is based on two methods: Balance by design (Static pressure balance) and design by Blast gate. The most important section of software is a spreadsheet that is designed based on American Conference of Governmental Industrial Hygienists calculation sheets. Exhaust Ventilation Design Software is developed so that engineers familiar with American Conference of Governmental Industrial Hygienists datasheet can easily employ it for ventilation systems design. Other sections include Collector design section (settling chamber, cyclone, and packed tower), fan geometry and dimension data section, a unit converter section (that helps engineers to deal with units), a hood design section and a Persian HTML help. Psychometric correction is also considered in Exhaust Ventilation Design Software. In Exhaust Ventilation Design Software design process, efforts are focused on improving GUI (graphical user interface) and use of programming standards in software design. Reliability of software has been evaluated and results show acceptable accuracy.

Tea is the most popular beverage in the world and contains several essential nutrients, which are beneficial for human health. The contamination of tea leaves by heavy metals may pose a serious threat to human, because they are not biodegradable and remain in environment and pass to food chain. In this study, the concentration of heavy metals of Cd, Pb, Ni, and Al and macro-elements of Fe, Zn, Cu, and Mn were determined by atomic absorption spectrometry on 30 samples of black tea cultivated in Iran and compared with the results for 30 samples of imported black tea in 2006. The results of analysis showed that the mean level of Al was 699.2±172.7mg/kg for Iranian and 388.3±98.3mg/kg for imported black tea. However, the values for Cd, Pb, and Ni were non-detectable. The most abundant nutritive metal was manganese with 155.2-214.2mg/kg and 96.7-332.9mg/kg in Iranian and imported black tea, respectively. The average contents of detectable heavy metals were significantly (p<0.05) higher in Iranian black tea. According to the results of this study, it is justifiable to set maximum residue level for heavy metals in tea, such as Al which appears to be very high in concentration.

Sub-lethal toxicity of lead nitrate solution (46.25mg/L, 5% of 96h LC50 value) on the air-breathing organ (suprabranchial chamber) of Channa striata was analysed for 60 days. Because air-breathing organs of C. striata remain in direct contact with waterborne xenobiotics, any change in the aquatic ecosystem was directly reflected in them. Concentration of lead accumulation in the air-breathing organ fluctuated at different stages of exposure. Due to extensive secretory activity, the mucous cells very often got exhausted and disappeared followed by their regeneration. This causes periodic fluctuations in the density of the mucous cells. A significant increase in the gross DNA contents in relation to the respective control is noticed at many stages of exposure. Increases in the RNA and protein contents with simultaneous increase in the mucogenic activity of the mucous cells were also observed. The total lipid contents also showed a periodic fluctuation in their concentration.

A comprehensive investigation was conducted in order to evaluate the quality of the groundwater in Zarand plain of Chatrood region which supplies drinking water of Zarand city. Zarand plain with longitude of 55°, 46- 57°,7 and latitude of 30°,20 -31°,44 is one of Iran’s plains located in sub-basin of Daranjir desert. Groundwater of Zarand plain supplies drinking water of many cities and villages located in and near the plain. Samples were collected from 11 water wells used as drinking water sources in Zarand plain "Chatrood region", at least once at the middle of each month. By means of the standard methods, a number of parameters were analyzed for each sample for the period of 7 years from 1996 to 2003. Tests included measuring pH, electrical conductivity, total dissolved solid, total hardness, calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride, and nitrate ions. Data analysis was done by using t and Z-Test. Results indicated that water quality of water wells during studied period did not show any undesirable change. The quality of each parameter in drinking water wells of Zarand plain was within permissible limit and did not exceed neither the Iran’s standards nor WHO guidelines. Meanwhile, the quality of raw water resources of the plain in the final year of experiment was within "good" potability limit based on Schuller’s diagram; it means raw water resources still kept its quality. Although the quality of Zarand plain water resources comply with Iran’s standards and WHO guidelines increasing trend of water consumption and consecutive droughts in the studied region as well as severe water shortage, ask for conservation, preservation and monitoring of water resources.

Gold nanoparticle is the active catalyst for CO oxidation at low temperature. This feature of gold base catalysts is suitable to overcome the problem of cold-start problem of automobile exhaust TWC converters. In this study gold nanoparticle were deposited on modified NH4-Y type zeolite. The activity of synthesized catalyst was measured in a fixed-bed quartz-tubular reactor (7mm i.d.) under atmospheric pressure. In order to investigate the catalytic activities toward CO oxidation reaction, 31mL/min of air and 0.155mL/min of carbon monoxide were mixed and then passed through the reactor. It was found that activity of Au/Y catalyst was 100% at 20°C. The thermal stability of Au/Y catalyst was measured at 400°C for 4h. The activity of the catalyst was decreased to 65% at 20°C after thermal stability test. Results of Energy Dispersive Analysis by X-rays before and after thermal stability have showed that Au content of these samples were 3.89% and 1.76, respectively. It was found that the amount of Au content decreased after thermal stability process. Fourier Transform Infrared (FT-IR) spectra showed no changes in framework structure of zeolite during thermal stabilization process of the catalyst.