Indoor radon measurements in residential dwellings in Qom, Iran

Background: inhalation of radon and its short-lived decay products is one of the most significant sources of exposure to natural radiation. Radon is the second cause of lung cancer in the populations. The present study was carried out under the projects of national radon, with the aim of determining the concentration of indoor in the city of Qom located in the central semi-arid region of Iran

Materials and Methods: radon measurements were carried out in 123 dwellings using passive sampling with CR-39 detectors for 90 days. The map of radon concentration distribution was prepared using Arc GIS software and the statistical analysis was performed with SPSS version 20

Results: indoor radon concentrations in Qom dwellings ranged from 15-259 Bq m[-3]. The arithmetic mean of indoor radon concentrations on basement, ground floors, first floors and second and upper floors were 123.43, 87.94, 63.72 and 40.69 Bq m[-3], respectively

Conclusion: a correlation was found between the distances from fault zones and measured indoor radon concentration. In most of cases, radon values were lower in well- ventilated dwellings in comparison with poorly-ventilated ones. Moreover, high radon concentration levels were observed in basements. The results indicated that in 30 places [24.3% of cases], the radon concentrations were higher than the reference levels recommended by the World Health Organization [100 Bq m[-3]]

Comparison the efficacy of fenton and "nZVI + H[2]O[2]" processes in municipal solid waste landfill leachate treatment [case study: Hamadan landfill leachate]

Leachate contains large amounts of pollutants, including organic and inorganic materials as well as the types of pathogens. This study was performed with the aim of determining the efficiency of Fenton and" nZVI[nanoparticles of zero valent iron] + H[2]O[2]" processes for reducing chemical oxygen demand [COD], 5-day biological oxygen demand [BOD[5]], total solids [TS]and color of Hamadan city landfill leachate. Experiments were performed in batch reactor and main affected factors; pH, reaction time, concentration of iron and H[2]O[2] were investigated. Also the efficiency of processes was analyzed using One-Way ANOVA statistical test and SPSS-13 software. The highest removal efficiencies obtained with "nZVI + H[2]O[2]" process [48.67%, 52%, 10.44% and 53% for COD, BOD[5], TS and color, respectively in 2.5 g/L iron nanoparticles concentration, 29137 mg/L H[2]O[2], pH = 2.5 and 60 min reaction time]. Based on the results, the nZVI + H[2]O[2] process can be applied as Hamadan city landfill leachate treatment to correct the BOD[5]/COD ratio to increase the biodegrability of this type of wastewater

[Electricity generation from synthetic wastewater treatment in microbial fuel cell]

Microbial fuel cell [MFC] used for electricity generation and wastewater treatment, simultaneously. In MFC, microorganisms act as a catalyst to convert chemical energy stored in organic materials into electrical energy. This study was performed with the aim of electricity generation from synthetic wastewater treatment in microbial fuel cell. A dual chambered microbial fuel cell was operated in continuous flow for 720 hours at temperature 20 +/- 4 °C at different organic loading rates and hydraulic retention times. Organic loading rate and hydraulic retention time were effective factors for the power production and removal of organic loading rate. Maximum COD removal efficiency was observed as 49% for a period of 1.5 to 2.5 hours that this range of time can be used as optimum retention time for operation of microbial fuel cell reactor. Maximum voltage and power production were obtained 700 mV and 1700 mW/m[2], respectively. Considering the advantages such as direct electricity generation from wastewater and considerable removal efficiency of organic loading rate, wastewater treatment in a microbial fuel cell, application of industrial scale microbial fuel cell for wastewater treatment is recommended after complementary studies and economic assessment

[Optimum operating conditions in the phytoremediation of contaminated soils with Lead and Cadmium by native plants of Iran]

In recent decade, phytoremediation technology is regarded very important because of its simplicity, inexpensiveness and use of natural resources and solar energy. In this study, we investigated the efficiency of remediation of contaminated soil with Lead and Cadmium by using native plants of Iran. We selected three native plants of Iran [Abutilon theophrasti, Amaranthus retoflexus and Zea maize] for this study. Extraction of soil and plant samples was performed by use of HNO3 ,HCl and HNO3, HClO4 and H2SO4 respectively. Concentrations of Lead and Cadmium in soil and plants were determined by Perkin-Elmer 603 atomic absorption spectrophotometer. Lead concentration in the roots of plants [Alkaline soil] was more than those in their shoots. In acidic soil [with exception of Zea maize], concentration of Lead in the shoots was more than its concentration in the roots of the plants. Concentrations of lead in the roots and shoots of Abutilon theophrasti, Amaranths and Zea maize in alkaline soil were [54.5 and 25.5 mg/kg], [69 and 37.6mg/kg] and [47 and 32mg/kg] respectively, and its respective concentrations in acidic soil were [71.4 and 92.5 mg/kg], [89 and 120.5mg/kg] and [85 and 66.7 mg/kg]. Cadmium concentrations in alkaline soil were [6.5 and 4mg/kg], [8 and 6.2 mg/kg] and [5.6 and 3.4 mg/kg] and in acidic soil were [5.8 and 4.5 mg/kg], [7.6 and 5.4mg/ kg] and [6 and 4.8 mg/kg] respectively. Plants in group 3 produced less biomass than those in control group, group 1 and group 2. Considering the increased rate of absorption of Lead and Cadmium and the amount of biomass produced by Zea maize and Amaranthus retoflexus in the acidic and alkaline soil, use of these native plants is recommended for refining the soil contaminated with heavy metals

Integrated assessment of air pollution in Tehran, over the priod from September 2008 to September 2009

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, SO2, NO2, O3, PM10] in Tehran, extracting patterns of hourly, daily, weekly, and monthly variations of concentrations, and making comparisons to National Standards and WHO Guidelines. 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. 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. 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

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. 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/1 free chlorine] for 5 min; and finally the disinfected vegetables were washed with tap water. The average initial levels of total coliform and fecal coliform in the samples were 3.36 Iog[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 Iog[10]cfu/g] and 79.6% [0.67 Iog[10]cfu/g], respectively, after washing. This increased up to 94.8[1.44 Iog[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 Iog[10]cfu/g] and 100% [2.31 Iog[10]cfu/g], respectively. By applying the protocol large parts of microorganisms existing on lettuce have indeed been removed

Optimization of operational parameters for decolorization and degradation of c l reactive blue 29 by ozone

Because conventional wastewater treatment of effluent containing anthraquinone dye causes notable environmental problems, it is important to find effective alternative methods for dye removal. This study evaluated the efficacy of ozonation for dye removal and Chemical Oxygen Demand reduction and identified optimal operational conditions for parameters such as pH, contact time and concentration of C.I. Reactive Blue 29 dye in a semi-batch reactor. Values of pH between 3 and 11 and contact times between 15 and 120 minutes were investigated. Dye concentrations were based on the American Dye Manufacture Institute standards and ranged from 1000 to 5000. Although results showed that Chemical Oxygen Demand removal by ozone alone was not very efficient [58%], ozonation proved to be an efficient method for decolorizing Reactive Blue 29 [96%]. pH was found to significantly influence the effectiveness of Chemical Oxygen Demand removal, and optimal pH conditions [95% confidence interval] were between 9 and 11. For decolorization, pH adjustment was not necessary. Degradation and decolorization of dye were found to be strongly influenced by the contact time, optimal conditions [95% confidence interval] for degradation and decolorization were 60 and 30 minutes, respectively. The optimal dye concentration was 1000 American Dye Manufacture Institute

[ effect of nanosilver paint on reducing fungal contamination in hospitals]

Nanosilver-based paint is a new technology with antimicrobial and antifungal characteristics. These characteristics were investigated in this study with regard to fungal contamination in hospitals. Regarding hospitalization of transplant patients and their sensitivity to hospital infections, two similar rooms were selected in nephrology ward. One of them was painted with Nanosilver paint and the other one with ordinary paint. Sampling was done via Swap Sterile and Open Plate. A total of 350 samples was obtained and colony-forming units in Open Plate and Surface Culture methods in case and control rooms were compared. Mean colony- forming units in case and control groups showed significant difference in both open plate and surface culture methods [P<0.000, P<0.001 respectively]. In studying the effect of time passing on the effectiveness of nanosilver paint, P values were 0.165 and 0.644 for open plate and surface culture methods respectively. It was found that Nanosilver paint is indeed effective in reducing both air and surface fungal contamination, but it is more effective on surface. Moreover, the passing of time had no effect on the effectiveness of the paint

[Air pollution quality index [AQI] and density of PM1, PM2.5 and PM10 in the air of Qom]

Air pollution has broad social, economical, political and technical aspects. one of the major issues in this regard is taking measures to prevent its increase. Since suspended particles are among the standard pollutants, the present study was carried out with the aim of measuring the amounts of these particles. In the present study, the suspended particles [PM1, PM2.5 and PM10] were measured at two sites in Qom city. For each of them, 60 samples were selected with the Enviro Check during five consecutive months during summer [2 months] and fall. During sampling, PM10 in the period between October 22'th to November 22[nd] 2007 had the maximum amount with the mean of 117microg/m[3] and in the period between September 22'th to October 22[nd] 2007 it had the minimum amount with the mean of 83microg/m[3]. PM2.5 in the period between November 22[nd] to December 22[nd] 2007 with the mean of 33microg/m[3] had the maximum amount and in the period between July 22[nd] to October 22[nd] 2007 it had the minimum amount with the mean of 8microg/m[3]. Based on the findings of this study, the densities of suspended particles PM1, PM2.5 and PM10 were below the standard levels on most occasions. The amounts of AQI for them were normal and acceptable

Photocatalytic degradation of linear alkyl benzene solfunate from aqueous solution by TIO[2] nanoparticles

The possibility of linear alkyl benzene solfunate [LAS] photocatalytic degradation through application of TIO[2] nanoparticles was investigated. 10[mg/L] of LAS has been affected by either UV or TIO[2] and simultaneous use of both of them in separated experiments. Moreover, the effect of initial concentrations of LAS and TIO[2], pH, present various anions and different UV power was studied to determine the optimal operating conditions for LAS degradation in water. The amount of mineralization of LAS was reported by measuring the primary and final COD of the solution that was irradiated under optimized conditions. Maximum degradation was obtained at acidic pH, 50 mg/L of TIO[2] and 30 minute irradiation time. It was also shown that 99.5% of LAS was degraded in optimal conditions. Kinetic analysis indicated that photo catalytic degradation rates of LAS can be approximated by pseudo-first order model. Measuring the initial and final COD of illuminated solution under optimized conditions, indicated that almost complete mineralization of LAS was occurred. Based on the results, UV/TIO[2] process may be effectively applied in LAS removal in low concentrations but this process is not economically efficient in high concentrations

Investigation of indoor and outdoor air bacterial density in Tehran subway system

The wide use of subway system by citizens underlines the importance of hygienic issues including indoor air pollution in these public places especially in metro stations. The aim of this study was to investigate the bacterial contamination in indoor and outdoor air of two metro stations [Imam Khomeini and Sadeghiyeh stations] in Tehran subway system. In this cross sectional study, three sampling locations were selected in each station. Also, sampling was conducted in indoor air of two types [old and new] of trains. The range of bacterial colony count was 35-1501 CFU/m[3]. Maximum and minimum bacterial contamination levels in Imam Khomeini and Sadeghiyeh platform stations were averagely 1073 CFU/m[3] and 242 CFU/m[3], respectively. 14 bacterial species and genera were isolated; among them the dominant species were Staphylococcus epidermidis, Micrococcus luteus and Bacillus spp. Results showed that bacterial concentrations in indoor air were higher than the outdoor air; also the bacterial counts correlated significantly with number of the passengers [p<0.001] and air temperature [p<0.001]

[Bioassay for toxicity assessment of zinc oxide and titanium oxide to escherichia coli ATCC 35218 and staphylococcus aureus ATCC 25923 bacteria]

This study was conducted to investigate the toxicity of Titanium Oxide [TiO2] and Zinc Oxide [ZnO] nanoparticles as two of most widely used nanoparticles. The result of this study can help to designing environmental standard and legislations for nanoparticles. Different concentrations of nano ZnO and TiO2 nanoparticles were added to nutrient Agar culture media. Then, definite numbers of Escherichia coli and Staphylococcus aureus bacteria were added to culture media and inhibition of these bacteria growth was measured in comparison to controls. Obtained data were analyzed to determine nanoparticles' EC50 and NOEC [No Observed Effect Concentration] using SPSS ver.16 and Probit standard test. 24-hours EC50 of nano ZnO using E. coli and S. aureus determined to be 5.47 mg/L and 2.38 mg/L respectively. In addition, 24-hours EC50 of nano TiO2 using E. coli and S. aureus determined to be 5366 mg/L and 3471 mg/L respectively. In the case of ZnO nanoparticles, no observed effect concentration determined to be 1.15 and 3.28 mg/L for E. coli and S. aureus respectively and in the case of TiO2 nanoparticles no observed effect level determined to be 1937 and 1184 mg/L for E. coli and S. aureus respectively. This study showed that acute toxicity of nano ZnO is by farmore than that of nano TiO2. Regarding the EPA acute toxicity criteria, nano ZnO is categorized as moderately toxic and nano TiO2 is categorized as practically non toxic. Hence, regarding the acute toxicity, in recommending exposure criteria and environmental disposal standards, compared to nano TiO2, nano ZnO requires more attention

[Effect of phenol in aqueous solutions on toxicity ofnano-TiO2 and nano-Fe/TiO2 particles]

Specific and unique characteristics of nanoparticles may entail specific and unique hazards. In addition, they may also exhibit toxicity under certain conditions. This study was conducted to investigate the toxicity of phenol-exposed and phenol-unexposed nano-TiO[2] and nano-Fe/TiO[2] particles. Stock solutions of the afore-mentioned nanoparticles were prepared at different concentrations and a sample of each was exposed to phenol. This was followed by exposing Daphnia Magna to the phenol- and non-phenol-exposed nanoparticles. LC[50], NOEC and the concentrations at which mortality rates were 100% were determined 12 to 96 hours after exposure, while for the determination of the mortality rate of Daphnia the Probit model in SPSS version16 software was used. The results revealed that [1]. The 48-hr LC[50] values for phenol-unexposed nano-TiO[2] and nano-Fe/TiO2 particles were 2705 and over 15000 mg/m[3], respectively. The corresponding values for the phenol-exposed samples were 414 and 1253. [2]. The 48-hr NOEC values for the phenol-exposed TiO[2] and FeTiO[2] were 41 and 789, respectively, the corresponding values for unexposed samples being 1253 and over 15000 mg/m[3]. [3]. In addition, the 48-hr 100% mortality rates for phenol-unexposed nano-TiO[2] and nano-Fe/TiO2 particles were, respectively, 1253 and over 15000 mg/m[3], while for the phenol-exposed samples the corresponding rates were 1090 and over 2108. With regard to 48-hr LC[50], the findings show that the toxicity of both nano-Fe: TiO[2] and TiO[2] increases as a result of exposure to phenol, the increase being 12-fold for the former and 6.5-fold for the latter. In general, however, based on LC[50], it can be said that the toxicity of Fe:TiO2 nanoparticles, which has better catalytic characteristics, is lower in comparison to TiO[2] nanoparticles. Thus, using Fe:TiO2 in preference to pure TiO[2] should be investigated further, as it will be less hazardous to the environment

[Removal of reactive blue 29 dye from water by single-wall carbon nanotubes]

Anthraquinone dyes such as reactive blue29 in water resources and industrial wastewater effluents are one of the most environmental setbacks in many countries. Various methods have been considered to remove these dyes One of which is adsorption. All adsorption experiments were conducted in different pHs and various concentrations of adsorbents. The initial concentration of reactive blue 29 chosen in this study was 30mg/L.Adsorption isotherms were determined and correlated with Longmuir, Freundlich and BET models. The maximum adsorption capacity of reactive blue 29 onto single wall carbon nanotubes was 496mg/g.Results showed that the best pH for adsorption was 5 followed by pH3 and 8. Kinetic study showed that the equilibrium time for adsorption of RB 29 to SWCNT is 4 hr. According to the results obtained BET isotherm fitted well the experiment. It shows the adsorption of reactive blue 29 onto single wall carbon nanotubes is multilayers and the mechanism of SWCNTs adsorption toward RB29 is based on weak van der waals forces

Survey on degradation rates of trichloroethylene in aqueous solutions by ultrasound

Sonochemical degradation of different compounds such as chlorinated aliphatic hydrocarbons is one of the recent advanced oxidation processes and it may be effective for removing low concentration organic pollutants from aqueous streams. Trichloroethylene [TCE] is one of these compounds that is mainly used as a degreaser. Important studies about TCE sonolysis have been focused at millimolar levels and natural pH, but in this study the ultrasonic degradation of TCE at different micromolar initial concentrations [30, 300 and 3000 micro g/L] and 4 different initial pH with a 35 kHz frequency was investigated. Furthermore, the degradation of TCE by ultrasound with different concentrations of hydrogen peroxide at pH= 7 was also performed. Gas chromatography with FID detector was used for analyses of TCE. Results showed that the degradation of TCE increased with decrease in the initial concentration of TCE from 3000 to 30 micro g/L at all initial pH. Initial pH of solution and different concentrations of H[2]O[2] did not affect significantly the TCE destruction

[Determination and emission factories of SO[2], CO[2], CO, NO, NO[]2, NO[x] gases in the fanavaran petrochemical]

Fanavaran petrochemical company is located on the shore of Persian Gulf on west south of Iran, Imam Khomeini Bandar, petrochemical special economic zone with of 25 hectares area. Two units of this company, methanol unit with production capacity 1000000 tons/ years andmonoxide carbon unit with 140000 tons/years were studied for determination and emission factories of SO[2], CO[2], CO, NO, NO[2], NO[x] Gases. With attention to project goals, for implementation of this project 14 months took into from April 2008 till June2009. For goals provide of mentioned research on this basis, 32 case sampling were done from 3 emission sources by using of direct reading device of gas concentration according to standard methods of United State Environmental Protection Agency Results of the study indicate that concentration of issued pollutant gases from these units is in the level lower than Iran department of environment standard level. The total amount of emission Factory of SO[2], CO[2], CO, NO, NO[2], NO[x] gases diffused from these units are11.7 X 10[-6], 81/8 X 10[-6], 0.14 X 10[-6], 431.5 X 10[-6], 19.2 X 10[-6], 681.2 X 10[-6] kg /tons million production in a year respectively. Parameters which optimization is performed in accordance with them, include of additional air percentage, exit air temperature from pre heater, and fuel type, in fact with regarding these 3 factor's. effects, the work is done in a manner that the amount of pollutants diffusion is near to minimum and the selected best fuel

[Evaluation of the relationship between global ultraviolet index in different regions of Iran and skin cancer in 1383]

Skin cancer is the most frequent malignancy in Iran. Exposure to the excessive ultraviolet radiation is an important factor in creating skin tumors. The purpose of this study is to determine how the ultraviolet index has been distributed in all townships throughout the country, to determine different kinds of skin cancer and to evaluate a geographical distribution of skin cancers with regard to the UV geographical distribution. This study is ecologic, descriptive and analytical in nature. A total number of 6921 skin cancer cases registered at the Center for Disease Control of Iran in 2004 were thoroughly analyzed and UV data were collected from the world wide web. With the help of ArcGIS software and SPSS, the statistical analysis was done. The incidence rates were 10.13 for the total skin cancer, 7.53 for basal cell carcinoma, 1.79 for squamous cell carcinoma and 0.39 for malignant melanoma per 100000 population of Iran. The mean ultraviolet index differed from 9 in July to 3 in January. The correlation between the skin cancer incidence at the level of districts and ultraviolet index was not significantly observed. Skin cancer is a public health problem in Iran. Further research in this regard would lead to skin cancer registration improvement and more understanding of different climatic, cultural and behavioral factors in developing skin tumors. With this knowledge the possibility of more effective prevention of the most prevalent cancer in Iran can be created

Influence of bioaugmentation in biodegradation of PAHs-contaminated soil in bio-slurry phase reactor

Polycyclic Aromatic Hydrocarbons [PAHS] are important pollutants which have toxic, carcinogenic and mutagenic properties and are considered as a serious hazard to human health and environment. Bioremediation of PAHs contaminated soil was studied in the soil slurry phase bioreactor. For enhancement of biodegradation, bioaugmentation [which is the process of adding microorganisms with the potential of pollution biodegradation to the bio-slurry reactor] was applied. Phenanthrene [C[14]H[10]], a three-benzene ring PAHs, was added in concentration of 100mg/kg soil. Two isolated species and consortium of bacteria were inoculated to the medium in density of 7_10[7] CFU/mL. The analysis of variance [ANOVA] was used for finding of optimum levels of type of bacterial culture and presence effect of endogenous factors. The base of the bacteria was petroleum-contaminated soil from around Tehran petroleum Refinery. Control reactor [killed bacteria] showed 5% loss of phenanthrene and biodegradation in the non-augmented reactor [endogenous microorganisms] in a slurry bioreactor was about 17%. In the case of bioaugmentation with Pseudomonas.spp, Pseudomonas aeruginosa and consortium, phenanthrene degradation efficiency were 87.8%, 85.5% and 92.8%, respectively, presenting the positive effect of biodegradation in consortium augmented compared to the isolated one. Colony forming units [CFUs] variation showed good conformity and agreement with the performance of the reactors with respect to phenanthrene degradation. Hence, the results of this experiment show that bioaugmentation may be considered as an effective method to enhance the bioremediation in removal of PAHs from contaminated soils

Effect of nanosilver painting on control of hospital air-transmitted microorganisms

Microorganisms, including bacteria and fungi, are among air-transmitted infectious agents at hospitals, which in addition to patients, can afflict hospital employees and visitors, and may result in economic burden and impact on human health. Although application of physical and chemical methods for control of microbial growth is not a new subject, but the use of nanotechnology and especially nanosilver painting is a new method applied in this area. This study was aimed to assess antibacterial and antifungal effects of nano-silver painting. Three rooms were selected in an infectious diseases unit of a university-based tertiary referral hospital affiliated to Tehran University of Medical Sciences. One of the rooms was painted with ordinary paint having no nano-particle [as control room] and the other two rooms were painted with two different 2% nanosilver paints [one locally produced and other provided from abroad] provided from two different companies [as case rooms]. Air sampling was carried out using a portable air pump [Quick Take 30 with constant rate between 10 and 30 L/min from 1 to 999 minutes] at pre-planned schedule. Each sampling was done in two minutes with the rate of 28.3 L/min. Samples were transferred on Blood agar [for total bacterial growth], EMB agar [for Gram negative bacterial growth] and Sabouraud>s Dextrose agar [for fungi detection] medias to study the culture results and Colony Forming Unit [CFU] count. Results, tested by ANOVAs and Kruskal-Wallis methods, indicated that there was no statistically significant reduction in the bacterial and fungal bio- burden between the control and case rooms and also between two types of paints by active sampling method. Moreover, there was no selective statistically significant change in bacterial and fungal species CFUs collected from the painted rooms by the above mentioned method. Study also revealed that there is no time trend change in bacterial bio- burden of the under study case and control rooms except for the first time zone [one month] of study duration

Optimization of reactive blue 19 decolorization by ganoderma SP. using response surface methodology

Synthetic dyes are extensively used in different industries. Dyes have adverse impacts such as visual effects, chemical oxygen demand, toxicity, mutagenicity and carcinogenicity characteristics. White rot fungi, due to extracellular enzyme system, are capable to degrade dyes and various xenobiotics. The aim of this study was to optimize decolorization of reactive blue 19 [RB19] dye using Ganoderma sp. fungus. Response Surface Methodology [RSM] was used to study the effect of independent variables, namely glycerol concentration [15, 20 and 25 g/L], temperature [27, 30 and 33 °C] and pH [5.5, 6.0 and 6.5] on color removal efficiency in aqueous solution. From RSM-generated model, the optimum conditions for RB19 decolorization were identified to be at temperature of 27°C, glycerol concentration of 19.14 mg/L and pH=6.3. At the optimum conditions, predicted decolorization was 95.3 percent. The confirmatory experiments were conducted and confirmed the results by 94.89% color removal. Thus, this statistical approach enabled to improve reactive blue 19 decolorization process by Ganoderma sp. up to 1.27 times higher than non-optimized conditions