Nitrate removal from aqueous solution by almond shells activated with magnetic nanoparticles

Magnetic activated carbons from almond shells were prepared, characterized, and used to remove nitrate from aqueous environments. The magnetic carbon was prepared by mixing of activated carbon in aqueous suspensions with an aqueous Fe3+/Fe2+ solution followed by treatment with sodium hydroxide. The morphologies and surface chemistries of magnetic activated carbon were studied by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray microanalysis, pHpzc, and Brunauer–Emmett–Teller (BET) analyses. The BET area of magnetic activated carbon was 105.480 m2 /g. The effects of adsorbent dosage, the pH of the solution, initial nitrate ion concentration, and contact time on the removal process were investigated. The amount of remaining nitrate ion was measured by spectrophotometer UV–Vis after filtration. At optimum pH of 4 and equilibrium time of 20 min, adsorption efficiency increased with both increasing of absorbent concentration to 1 g/L and reduction of initial concentration of nitrate ions (76.29%). The equilibrium adsorption was best described by the Langmuir isotherm model (R2 = 0.924). The almond shell activated with magnetic nanoparticles has a good ability to remove nitrate ions from aqueous solutions. Therefore, the use of this relatively easy and simple technology is an effective step in removing nitrate from water

Environmental epidemiology: An introduction

Epidemiology is increasingly coping with problems correlated with exposures which may have small relative risks. In fact, many chronic diseases, as the most recent common diseases all over the world, may have unknown etiology but also potentially related to environmental exposures. Environmental epidemiology considers the effect of environmental factors on health. More exposure with increasing number of potential environmental hazards has changed the initial application of environmental epidemiology. As a consequence, nowadays it is strongly emphasized on some fields such as molecular epidemiology, but some others have discussed about the importance of its population dimension and the reintegration of epidemiology into public health.\ud \ud Environmental epidemiology research, as a very substantial scope of epidemiology, can consider risk assessments, development of standards and other risk management activities. In addition, it could estimate the co-benefits and co-harms of policies designed to reduce global environment changes, including policies implemented in other sectors (e.g. food and water) affecting human health. Environmental epidemiology has indeed several unique features that could make these debates very important. Furthermore, a large number of environmental exposures may require prioritization, with usually very low relative risks. However, environmental epidemiology has also a more restricted connotation, referring to those environmental factors that are outside of the immediate control of the individual.The most important difference of environmental epidemiology with general epidemiology is that the first one could focus more on the living/working environment of people rather than on their personal characteristics or lifestyles.\ud \ud During the recent centuries, environmental epidemiology has achieved remarkable positive health gains by efforts on reduction of the population’s exposure to contaminants in air, water, and soil. However, in the last decades, this concentration has been changed to follow the developments in epidemiology and molecular biology. In fact, with increasing focus on individual exposures and his/her own susceptibility as well as potential mechanisms, environmental epidemiologists may lose their traditional population perspective of disease causation and prevention.\ud \ud Generally, environmental epidemiology may concern on the potential health effects of environmental factors, mostly outside the immediate control of the person. In industrialized countries, environmental epidemiologists must mainly assess a large number of low-level inter-correlated exposures, often occurring in complex mixtures. In that respect, environmental epidemiology could be similar to nutritional epidemiology, except for the fact that environmental exposures may usually be involuntary and may not differ significantly among population of one area.6\ud \ud It is worth to note that many of the problems of environmental epidemiology may become especially severe during local field investigations in response to acute public health problems, such as a cluster of cancer in a neighborhood or around a point source. In this situation, the level of exposure is often low and may have happened in the distant past. Most of the time, there is no clear hypothesis; for example, the small number of residents may give sufficient power to detect only relative risks that are unrealistically high in the environmental setting, or the latency period may be insufficient.\ud \ud Environmental epidemiologists may not be ready to consider other health outcomes and issues of public concern, such as psychological effects, aesthetic values, social disruption, or effects on property values which may be the main concern of the public at this moment. Therefore, the large number of environmental exposures should be considered by environmental epidemiology, but it needs to be prioritized the issues to be studied, based on the local environmental problems by (environmental) epidemiologists

Determination of hydrogen peroxide index in the consumption edible oils in fast food shops

زمینه و هدف: پراکسید اولین ترکیبی است که بعد از اکسیداسیون چربی ها و روغن ها به وجود آمده و می تواند زمینه ساز بیماری های مختلفی از جمله تصلب شرائین، سرطان، پیری زودرس، التهاب آلرژیک، ایسکمی قلبی و مغزی، سندرم دیسترس تنفسی و اختلالات مختلف کبدی گردد. هدف کلی این تحقیق بررسی میزان پراکسید موجود در روغن های مصرفی در ساندویچی های شهر شهرکرد در سال 89-1388 می باشد. روش بررسی: این مطالعه توصیفی – تحلیلی بر روی 50 از واحدهای ساندویچی شهر شهرکرد (40 واحد)، انجام گرفت. از هر واحد 4 نمونه برداشت شد. در مجموع 160 نمونه از واحدهای ساندویچی مناطق مختلف شهر در میانه روز یعنی از حدود ساعت 11 تا 14 در ابتدا و آخر هر هفته به مدت سه ماه و بر اساس استاندارد کشوری شماره 493 جمع آوری گردید. برای انجام آزمایش پراکسید هیدروژن از رفرانس AOAC (Association of official analytical chemists) استفاده شد. حد استاندارد مجاز پراکسید برای روغن های جامد و مایع به ترتیب 2 و 5 میلی اکی والان در هر کیلوگرم می باشد. داده ها با استفاده از آزمون من- ویتنی و آزمون رتبه علامت دار ویلکاکسون مورد تجزیه و تحلیل قرار گرفتند. یافته ها: عدد پراکسید در کلیه نمونه های روغن سرخ شده جامد و مایع (خوراکی و غیر خوراکی) بالاتر از حد مجاز استاندارد بود. میزان پراکسید هیدروژن در نمونه های روغن های خوراکی و سرخ کردنی خام اول و آخر هفته به طور معنی داری بیشتر از نمونه های روغن های خوراکی و سرخ کردنی اول و آخر هفته بود (001/0P). نتیجه گیری: با توجه با نتایج بدست آمده از این مطالعه، تقریباً 100 روغن های سرخ شده از نوع جامد و مایع (خوراکی و سرخ کردنی) دارای عدد پراکسید بالاتر از حد مجاز استاندارد می باشند. بنابراین می توان نتیجه گیری کرد که نحوه استفاده از روغن ها در واحدهای ساندویچی نامطلوب بوده لذا پیشنهاد می گردد تمهیدات لازم در خصوص آموزش متصدیان این واحدها و نیز نظارت صحیح آنها توسط مراکز بهداشتی انجام بگیرد

Field studies to investigate the eutrophication problem in the Anzali wetland

Background: In the recent years, eutrophication has become a serious challenge for many of the water ecosystems. It has affected the environmental and economical aspects of the Anzali Wetland, which is known as one of the significant ecosystem. Due to the increase of the nutrient loadings from the industrial, agricultural and human activities, the wetland’s health is faced many serious problems. Therefore, in this study the wetland condition is evaluated through the field measurements and sampling from various regions of the wetland; then the data obtained were analyzed in order to review this conditions from the Eutrophicational point of view that is one of the most important conditional indexes of the lakes and wetlands. Methods: In this research, in addition to use the field measurements to determine the wetland quality status related to the nutrient loadings, the results from total nitrogen (TN) and total phosphorus (TP) measured parameters of 21 stations in the study area were transferred to the Geographical Information System (GIS) and then the Eutrophication condition of the wetland was determined in comparison to international standards. Findings: This study illustrated that since the wetland has received more nutrients loading comparing to the few past years, so most of the wetland regions have high levels of TN and TP. Also, performing more investigations using Nurnberg method based on TN and TP depicted that hypertrophic status is dominated in all over the wetland. Conclusion: although the procedure used in this research was very simple and with the least computational cost to determine the hypertrophic status of the Anzali Wetland, but the findings gained from the study is in compliance with the previous results achieved

Removal of copper ions Cu (II) from industrial wastewater

Background and aims: Nowadays heavy metals are the environmental priority pollutants and are becoming as the most serious environmental problems. In recent years removing those from diverse industrial effluents and metal cleaning have been studied. The aim of the present study was to investigate the different methods for cooper removal of cooper ions from industrial wastewater. Methods: This study was a review research. Data were collected from different database in various articles. The various methods for cooper removal from industrial effluents were compared to each other. Results: The present study showed the various methods for cooper removal from industrial wastewater including chemical precipitation, ion exchange, membrane filtration, flotation, electrochemical treatments, coagulation/flocculation and adsorption. High efficiency, cost-effectiveness and easy handling are important factors in the selection of the most suitable treatment systems for industrial effluents. Conclusion: Adsorption is recommended as an effective and economical method for maintaining of cooper ions from aqueous industrial wastes because of high efficiency, cost-effectiveness and simplicity

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) in petroleum contaminated soils

Polycyclic aromatic hydrocarbons are a class of potentially hazardous chemicals of environmental and health concern. PAHs are one of the most prevalent groups of contaminants found in soil. Biodegradation of complex hydrocarbon usually requires the cooperation of more than single specie. In this research biotreatment of PAH (phenanthrene) was studied in a solidphase reactor using indigenous bacteria isolated from two petroleum contaminated sites in Iran, (i.e., Tehran refinery site with clayey-sand soil composition and Bushehr oil zone with silty-sand soil composotion). Phenanthrene (C14H10) was made in three rates (100, 500, and 1000 mg/kg of soil) synthetically and was conducted with two bacterial mixed cultures for a period of 20 weeks. Highest removal (more than 85 ) of phenanthrene with rates of 100, 500 and 1000 mg/kg in clayey-sand soil with BMTRS (Bacterial Mix of Tehran Refinery Site) consortium was achieved within 3, 5 and 14 weeks, respectively as for silty-sand soil composition with BMBOZ (Bacterial Mix of Bushehr Oil Zone) consortium was achieved within 10, 17, and 19 weeks, respectively. Results for phenanthrene biotreatment in solid phase reactor revealed a significance relationship between concentration and type of microbial consortium with the removal efficiency of phenanthrene over the time (P value<0.001). Furthermore, there was a significant relationship between soil type with removal efficiency of phenanthrene over the time (P value=0.022). That means the bioremediation of the lower concentrations of phenanthrene needs shorter time compared with the higher concentrations. Microbial analysis using confirmative series tests and analytical profile index (API) kit tests showed the Pseudomonas fluorescence, Serratia liquefaciens, Bacillus and Micrococcus strains as dominant bacteria in the mixed cultures

A screen for Benzo(a)pyrene in fish samples from crude oil polluted environments

Several studies have shown that exposure to Benzo(a)pyrene increases the risk of cancer. In this study several fish samples from Niger the Delta region of Nigeria were screened for the presence of Benzo(a)pyrene. The study was carried out using Gas chromatograph coupled to a mass spectrometry detector. Benzo(a)pyrenes in the samples were identified through both retention time match with authentic standards and simultaneous maximization of several major ions from GC/MS data. Perylene-d12 was used as the internal standard for quantitation. Concentration of benzo(a)pyrene in the samples ranged from 1.47 to 10.53 μg/kg which is more than WHO recommended maximum allowable concentration. Therefore this study concludes that the population is at an elevated risk of cancer of occurrence. © 2008 Science Publications

Phenanthrene contaminated soil biotreatment using slurry phase bioreactor

Problem Statement: Polycyclic Aromatic Hydrocarbons (PAHs) are suspected toxins that accumulate in soils and sediments due to their insolubility in water and lack of volatility. Slurry-phase biological treatment is one of the innovative technologies that involve the controlled treatment of excavated soil in a bioreactor. Due to highly soil contamination from petroleum compounds in crude oil extraction and also oil refinery sites in Iran, this research was designed based on slurry phase biotreatment to find out a solution to decontamination of oil compounds polluted sites. Approach: Soil samples were collected from Tehran oil refinery site and Bushehr oil zones. Two compositions of soils (clay and silt) were selected for slurry biotreatment experiment. Soil samples were contaminated with three rates of phenanthrene (a 3 ring PAH), 100, 500 and 1000 mg kg ?1 and mixed with distilled water in solid concentration of 30 by weight after washing out with strong solvent (hexane) and putting in to the oven. Bacterial consortium was revived in culture medium which consisted of Mineral Salt Medium (MSM) based on phenanthrene concentrations and ratio of C/N/P in the range of 100/10/2. Prepared soil samples were mixed with distilled water, nutrient and bacterial consortium together in the 250 mL glass Erlenmeyer and putted in the shaker incubator with 200 rpm revolutions and 25°C for 7 weeks (45 days). Samples were analyzed for residual phenanthrene, bacterial population every week. For statistical analysis, general linear model with repeated measures (type III) analysis was applied. Results: The concentration of 100 mg L?l of phenanthrene in clayey and silty soils reached to non detectable limit after 5 and 6 weeks, respectively. While concentration of 500 mg L?l of phenanthrene both in clayey and silty soils reached to non detectable limit after 6 weeks. But concentration of 1000 mg L?l both in clayey and silty soil samples has not met this limitation after 7 weeks. Due to presence of Pseudomonas strains in clayey soil samples and their ability in breaking down of benzene rings, the removal efficiency of phenanthrene in our slurry bioreactor in clayey soil was a little more than silty soil samples over time. There was a significance relationship between initial concentrations of phenanthrene and type of soil with time of biotreatment (p<0.001). Conclusion: Therefore, this technology may be applied to remediation of small foot print oil contaminated sites, e.g., gas station, oil extraction and refinery sites in Iran, in the case of urgency. Thus this study concludes that the remediation of phenanthrene with concentration up to 1000 mg kg?1 in the oil contaminated sites can be removed to the acceptable limits using slurry based system. © 2009 Science Publications

Removal of lead ions from industrial wastewater: A review of Removal methods

Background and aims: The removing of (potential) toxic heavy metal ions from sewage, especially in industrial and mining waste effluents, has been widely studied in recent years. The aim of present study was to investigate the various methods for lead removal of lead ions from industrial wastewater. Methods: This study was a review research. Data were collected through different databases in various articles. The various methods for lead removal from industrial wastewater were compared to each other. Results: The present study showed the various methods for lead removal from industrial wastewater including chemical precipitation, electrochemical reduction, ion exchange, reverse osmosis, membrane separation, and adsorption. Technical applicability, plant simplicity and cost-effectiveness are the key factors that play major roles in the selection of the most suitable treatment system for inorganic effluents. Conclusions: Adsorption is proposed as an economical and effective method for the retention of lead ions from aqueous industrial wastes because it is simple, effective and economic in removal of heavy metals from aqueous solution