[Risk assessment of welders' exposure to total fume in an automobile industry]

Risk assessment of Toxic or hazardous chemicals enables the Industrial Hygienists to make the appropriate decision in providing healthy work place. This project was conducted in an assembling plant, [4workshop] of an Automobile Industry in IRAN with 2 types of welding operations, including GMAW [CO[2] welding] and Spot resistance welding operations. Welders exposures were assessed via collecting 143 breathing zone air samples based on NIOSH 0500 method. Risk assessment was carried out using Singapore recommended method. Finding showed that the mean of welders exposure in GMAW and Spot resistance welding operations 5.61 +/- 5.78 and 2.38 +/- 2.15 mg/m[3], respectively [p<0.05]. The results showed that in GMAW welders had the high exposure in comparison with Spot resistance welders [p<0.05]. The findings also demonstrated that the risk rate of GMAW welders were high, while this rate for Spot resistance was low. More hygienic attention is needed for GTAW welders. Control approaches are required including effective engineering control, conduct air monitoring, biological monitoring training, adopt respiratory protection program, develop and implement safe and correct work procedures and finally reassess the risk after all the controls have been done

Comparison of iran power plants air pollutants before and after shifting to natural gas

In a three years period, 24 fossil fueled thermal power plants located in different parts of the country were extensively examined for discharge of pollutants into the environment and their potential effects on surrounding. During this investigation emission to air, discharge to receiving waters and l and as well as electromagnetic fields were measured using relevant st and ard methods. This paper will focus on air pollution emissions and recent reinvestigation that was done after shifting the fuel from residual oil to natural gas. In our first studies that most of the plants were consuming residual oil, high level of SO2 emission in some areas was the main cause of losses to vegetations and fruit gardens. It was concluded that a serious problem threats the environment and health of people living near these areas. Based on the results some mitigation plans were recommended to the authorities, and after some times they started to shift to natural gas consumption. Our recent investigation that was after this action, showed a good improvement of air pollution reduction. This was almost 100% for SO2 and from 32 to 73% for NOx

Comparision of Langmuir and Freundich equilibriums in Cr, Cu and Ni adsorption by sargassum

Heavy metals are present in different types of industrial effluents, being responsible for environmental pollution. Biosorption is a promising alternative method to treat industrial effluents, mainly because of its low cost and high metal binding capacity. In this work application of Langmuir and Freundlich sorption models for chromium, copper and nickel biosorption process by Sargassum seaweed biomass was studied in batch system. The work considered the effects of some important parameters such as retention time and initial concentration on remained concentration of heavy metals. Dried Sargassum was contacted with metal solution on different retention times [10, 20, 30, 45 and 60 min] and variation of initial concentration [10, 25, 50, 75 and100mg/l] at constant pH and temperature. The obtained charts were linear for Langmuir and Freundlich equilibriums and their slopes and y-intercepts were calculated [Constants a, b, n, k]. Results showed that the constants were in a same range; therefore Langmuir and Freundlich sorption models were in good agreement with experimental results

Mottled enamel in a military educational center in Teheran, Iran

A survey of mottled enamel in a military educational center in Karaj area of metropolitan Tehran was conducted from August to September 1978, on a population of 1789 student, aged 18-23 gathered from 32 areas of Iran. Dean clinical standards used for diagnosing dental fluorsis and Orion lonalyzer Fluoride Electrode was used to determine the fluoride content of communal waters of endemic areas. The conclusion asserted is that the index of dental fluorsis in the population under the study is 0.04. The survey showed 15 mottled enamel area in Iran, with fluouide concentration of domestic and drinking water from 0.7 to 3.8 ppm