Analytical study of 226Ra activity concentration in market consuming foodstuffs of Ramsar, Iran.

BACKGROUND: Ramsar, a city of Iran located on the coast of the Caspian Sea, has been considered to be enormously important due to its high natural radioactivity levels. People living in High Level Natural Radiation Areas (HLNRAs) have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been conducted in all stapled consumed foods yet. This study was dedicated to determine 226Ra activity concentration in the daily diets of Ramsar residents as a probable exposure. METHODS: Approximately 70 different market samples were collected during the four seasons based on the daily consumption patterns of residents which have the highest consumption and their availability in the seasons. All samples, after washing, drying and pretreatment, were analyzed for 226Ra radionuclide determination by α-spectrometry. RESULTS: The mean radioactivity concentration of 226Ra ranged between 7 ± 1 mBq Kg-1 wet weight in meat, and 318 ± 118 mBq Kg-1 for tea dry leaves. The 226Ra activity concentrations in collected samples varied from below the minimum detectable activity up to 530 ± 30 mBq Kg-1. To compare the results with United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) reference values, the 226Ra activity concentrations concluded from the results appear to be higher in milk, chicken and eggs and less in grain products, vegetables, fruits and fish products. These results indicate that no significant 226Ra contamination is present in market foodstuffs and provide reference values for the foodstuffs in Ramsar. CONCLUSIONS: Of the total daily dietary 226Ra exposure from market consuming foodstuffs for adults in Ramsar, the largest percentage was from wheat. The residents consuming wheat and manufacturing wheat products such as bread, pasta, porridge, crackers, biscuits, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, breakfast cereals and so on may receive an elevated dose in the diet. In conclusion, with regards to presence of 226Ra in foodstuffs it is necessary to monitor regularly the activity of 226Ra in foodstuffs including market and local foods.

Integrated assessment of air pollution in tehran, over the period from september 2008 to september 2009.

BACKGROUND: Air pollution is a major problem in urban\industrial areas, like Tehran, and has several impacts on human health. This study aimed at assessing concentrations of criteria air pollutants (CO, SO(2), NO(2), O(3), PM(10)) in Tehran, extracting patterns of hourly, daily, weekly, and monthly variations of concentrations, and making comparisons to National Standards and WHO Guidelines. METHODS: Air quality data were taken from Air Quality Control Corporation and 5 sampling stations (out of 13) were selected for analysis according to data availability. Microsoft Excel 2003 was used for data analysis and plotting the charts. RESULTS: Patterns of temporal variation (hourly, daily, weekly, and monthly) of air pollutant concentrations were extracted. In some cases extracted patterns matched with the patterns proposed by other researchers. Pollutant concentrations were compared to National Standards and WHO Guidelines and it was observed that in most of the days, we exceeded the limit values. CONCLUSION: Air pollution in Tehran is quite high and there are many days that we exceed the standards; therefore appropriate control strategies are needed. Although the number of sampling stations is high enough to be representative of whole city, it is proposed that an independent sampling station is setup to check the validity of the measurements.

Evaluating the efficiency of lettuce disinfection according to the official protocol in iran.

BACKGROUND: The objective of this study was to evaluate the efficacy of Sanitization of Lettuce according to the protocols set forth by Iranian Ministry of Health and Medical Education for reducing populations of total coliform, fecal coliform, and helminth eggs present on lettuce. METHODS: In the present study, we determined the load of total coliform, fecal coliform, and parasites of lettuce. The lettuce was sanitized by protocol of Iranian Ministry of Health and Medical Education. The protocol consists of 3 levels to disinfect the fruits and vegetables. The procedure was as follows: first washing stage. The leaves of leafy vegetables washed with tap water, second stage, separation of helminth eggs by 3 to 5 droplets of detergent per liter for 5 min; third stage, disinfection of vegetables by calcium hypochlorite solution (with 200 mg/l free chlorine) for 5 min; and finally the disinfected vegetables were washed with tap water. RESULTS: The average initial levels of total coliform and fecal coliform in the samples were 3.36 log(10) cfu/g and 2.31 log(10) cfu/g, respectively. Helminth eggs were not detected in any of the samples tested. The efficiency of total coliform and fecal coliform removal were 78.1% (0.75 log(10)cfu/g) and 79.6% (0.67 log(10)cfu/g), respectively, after washing. This increased up to 94.8(1.44 log(10)cfu/g) and 98.5% (1.90 log(10)cfu/g) after the use of detergent. Chlorine disinfection rose these amounts up to 98.3% (2.18 log(10)cfu/g) and 100% (2.31 log(10)cfu/g), respectively. CONCLUSION: By applying the protocol large parts of microorganisms existing on lettuce have indeed been removed.

Bioassay of methyl tertiary-butyl ether (MTBE) toxicity on rainbow trout fish.

Methyl tertiary-butyl ether (MTBE) has been widely used as a gasoline additive. Water resource contamination due to spillage and accidental leakage of gasoline during fuel transportation may cause an important threat to aquatic life. In this work, the bioassay of MTBE toxicity on rainbow trout was performed. MTBE solutions of 250, 500, 750, 1000, and 1250 mg L(-1) were prepared in five aquariums and aerated for 96 h. LC50 values of each experiment were measured according to probit analysis. A mathematical relationship between time exposure and LC50 of MTBE for rainbow trout was developed. The relative toxicity of MTBE to rainbow trout and to other organisms was also reviewed. It was shown that the toxicity of MTBE does not change significantly in the time exposure between 24 and 72 h varying from 878 to 831 mg L(-1), respectively. After 72 h of rainbow trout exposure to MTBE, LC50 value gradually decreased and reached 773 mg L(-1) in 96 h of contact time. In conclusion, the result of this work showed that the toxicity of MTBE to rainbow trout was relatively low.

The removal of H2S from process air by diffusion into activated sludge.

Emissions of H2S from publicly owned treatment works is a serious problem, therefore collection and treatment of these emissions is essential. In this work, the performance of a bench scale activated sludge system used for the removal of H2S from foul air was investigated, and the effects of H2S concentration (5 to 50 ppm,) on COD reduction and biomass settleability were studied. After biomass acclimation, the reactor was operated in a continuous mode at a hydraulic retention time of 5 h and a mean cell residence time of 6 days. Results showed that COD and H2S removal were 93.5 and 94.5%, respectively. Furthermore, H2S concentration up to 50 ppm, did not significantly affect the COD reduction. H2S loading rates of up to 7.5 mg(H2S) g(-1)MLSS, d(-1) were treated with greater than 94% efficiency. The only adverse effect of H2S that was observed was an increase in the sludge volume index at loading rates over 4.5 mg(H2S) g(-1)MLSS d(-1), at which bulking of the sludge occurred. Overall, the results indicate that H2S at concentrations usually emitted from wastewater treatment processes (lower than 50 ppm(v)), can be efficiently treated by diffusion into activated sludge without compromising the performance of the activated sludge process.

Water quality trend analysis for the Karoon River in Iran.

The Karoon River basin, with a basin area of 67,000 km(2), is located in the southern part of Iran. Monthly measurements of the discharge and the water quality variables have been monitored at the Gatvand and Khorramshahr stations of the Karoon River on a monthly basis for the period 1967-2005 and 1969-2005 for Gatvand and Khorramshahr stations, respectively. In this paper the time series of monthly values of water quality parameters and the discharge were analyzed using statistical methods and the existence of trends and the evaluation of the best fitted models were performed. The Kolmogorov-Smirnov test was used to select the theoretical distribution which best fitted the data. Simple regression was used to examine the concentration-time relationships. The concentration-time relationships showed better correlation in Khorramshahr station than that of Gatvand station. The exponential model expresses better concentration - time relationships in Khorramshahr station, but in Gatvand station the logarithmic model is more fitted. The correlation coefficients are positive for all of the variables in Khorramshahr station also in Gatvand station all of the variables are positive except magnesium (Mg2+), bicarbonates (HCO3-) and temporary hardness which shows a decreasing relationship. The logarithmic and the exponential models describe better the concentration-time relationships for two stations.

The treatment of wastewater containing crude oil with aerated submerged fixed-film reactor.

An aerated submerged fixed-film (ASFF) bioreactor was developed to treat an artificial wastewater based on crude oil. Bee-Cell 2000 was used as support media having porosity of 87% and a specific surface area of 650 m2 m(-3). The system was able to achieve 70.87-93.12% removal efficiencies of Chemical Oxygen Demand (COD) in the organic loading rate range of 1.310 to 15.797 g COD m(-2) day(-1). Data gained exhibited that the effluent COD concentration ranged between 68.68 and 292.60 mg L(-1) at organic loadings experienced. Therefore, an ASFF process showed that it was feasible to treat high oily wastewater in order to meet the discharge standards.