جستجوی مقالات مرتبط با کلیدواژه « آلاینده » در نشریات گروه « پزشکی »

The presence of toxic mercury in fish has caused global concern, as one of the main ways of humans are exposed to it is through fish consumption. Therefore, the main goal on this research was to determine the concentration of mercury in fish and evaluate the health risk to consumers.

Samples of pike, common perch, European perch, common carp and goldfish were collected from Anzali wetland. Mercury concentration was measured using a graphite furnace atomic absorption spectrometer. Differences in mercury concentration among the species and the comparison of mercury concentration with the standards were analyzed using one-way analysis of variance and one sample t-test, respectively.

The average concentrations of mercury for pike, common perch, European perch, common carp and goldfish were 59.59, 67.55, 30.45, 9.84, and 10.44 µg/kg ww, respectively. The results showed significant differences in mercury concentrations among different species. The concentrations of mercury in all samples were below the permissible limits of international standards (300 and 500 µg/kg dw), and the HQ index values were less than 1. Therefore, the results indicated no potential risk to consumer health. Additionally, the consumption of European perch, common carp and goldfish is considered safe for sensitive people (children and pregnant women).

In general, there was no potential concern regarding mercury exposure from consuming the studied fish species.

There is a possibility of more accumulation of environmental pollutants due to lower levels of iron in the body of women. Different results have been reported on the association of lead with breast cancer, therefore, this systematic review study was performed with aim to determine the relationship between lead and breast cancer.

In this review study, to find the related articles, international databases (Web of Science, Embase, Scopus, Google Scholar and PubMed) and national (Irandoc, Magiran, SID and IranMedex) were searched with different keyword combinations related to "Lead" And "Breast Cancer" obtained from MESH in 2000 to 2022. Selection of articles was based on inclusion and exclusion criteria and articles' quality was assessed using the Newcastle Ottawa scale.

Out of 4057 articles reviewed, 13 articles had good quality. All studies were in English and were observational. According to most studies, serum lead levels were not associated with breast cancer, but lead levels in bone and breast tissue were also associated with exposure to lead as an environmental contaminant with breast cancer.

Different ways of exposure to lead have led to different results and it cannot be certainty said that exposure to lead causes breast cancer, while this relationship also depends on the method of measuring lead. In this regard, long-term studies with accurate measurement of environmental lead and body tissues, especially for women at higher risk are recommended.

River sediments are one of the most important environmental indicators to determine the level of pollution in ecosystems. The purpose of this study is to investigate the quality of Mahabad river sediments in West Azerbaijan province.

For this purpose, 15 samples of surface sediments (from 0-20 cm depth) of the river were collected. Physical and chemical properties of sediments including: texture, organic matter, Total neutralizing Value, electrical conductivity, pH, and total amount of heavy metals was measured. Correlation between physical and chemical properties of sediments with heavy metals was performed using Pearson correlation test in SPSS software.

Mean total concentrations of heavy metals including arsenic, nickel, zinc, cadmium, lead, cobalt, chromium and copper, were respectively 13.29, 63.40, 60.53, 0.47, 0.39, 18.40, 44.47 and 25.93 mg / kg. Arsenic, nickel and cadmium had higher levels of standard concentrations of heavy metals in sediments. According to the results of Pearson correlation coefficient, cation exchange capacity, organic matter, clay and silt have the most significant positive correlation with the distribution of heavy metals. On the other hand, except for copper, chromium and cobalt, all other elements show a significant positive correlation of 99%. The results showed that all the elements have the same origin.

According to the separation of upstream and downstream samples, it can be said that the concentration of elements in the upstream was due to natural factors, and downstream, heavy metal pollution has increased with increasing human activity.

Air pollution has been recognized as the most important environmental risk factor worldwide. Benzene which is one of the four pollutants attributed to BTEX (Benzene, Toluene, Ethylbenzene, and Xylene) has been proven to be a carcinogenic component. These pollutants can be easily absorbed and taken into the body via inhalation. With this background in mind, the present study aimed to investigate the concentration of benzene and its zoning in Tehran air using Geographic Information System (GIS)  within 2016-2017.

In the present study, 26 sampling stations were selected in different parts of the city and sampled in four seasons to determine benzene concentration, as well as other meteorological parameters, such as temperature, humidity, and wind velocity. Thereafter, the obtained data were analyzed in SPSS software (version 22) using the one-way analysis of variance and correlation. Subsequently, modeling of pollutant distribution was performed using ArcGIS software. 

The obtained results demonstrated that in terms of location, the maximum and minimum annual mean concentrations of benzene were calculated at 45.12±15 and 12.36±8 μg/m3, respectively, in the center and north of the city. Temporally, the maximum and minimum values were measured at 47±17 µg/m3 in autumn and 9.82±7 µg/m3 in spring, respectively. Statistical analysis revealed that emission of this pollutant showed a significant relationship with geographical direction and wind velocity (P<0.01).

The average annual concentration of benzene in different geographical areas of Tehran was higher than the standard values of clean air. Therefore, it is suggested that fundamental measures be implemented to control this chemical compound.

Considerable increase in carbon dioxide gas in the Earth's atmosphere has caused several problems such as increasing the temperature of the earth, droughts and sudden changes in the climate. The purpose of this study was to evaluate the capability of carbon dioxide as greenhouse gas absorption using activated nanobiocarbon from the Crataegus Sanguinea core. In this experimental study, the carbon dioxide gas penetration time in three subgroups with pressure (5,10,15 bars), flow (5,10,15 ml/min) and temperatures (20,30,60 °C) at concentrations of 0 to 1 gr / ml through a carbon dioxide gas capsule in a fixed bed column filled with 2 g of adsorbent synthesized by a carbon dioxide gas sensor. The synthesized nano-biocarbon adsorbent from the Crataegus Sanguinea Core was pyrolysed at a temperature of 300 ° C and activated at 600 °C. The research data were examined with pseudo -first-order and pseudo-second-order models. Significant increase in gas infiltration time was observed at 15 bars pressure (86.71±0.09 min, p<0.001), temperature of 20 ºC (67.68±0.13 min, p≤0.001) and flow of 5 ml/min (75.78±0.11 min, p≤0.001) was more than 5 bars (37.14±0.17 min) and 10 bars (60.33±0.27 min) and 30 °C (54.36±0.03 min) and 60 ºC (45.34±0.31 min) and 10 ml/min (53.8±0.13 min) and 15 ml/min (45.09±0.09 min) respectively. Both models fit well with a coefficient of R2>0.98 on empirical data from absorption. The results of the study showed that increasing pressure and decreasing temperature and flow increase the time of carbon dioxide penetration onto synthesized adsorbent.

Presence of pharmaceutical compounds in the environment is considered a serious threat for the human being and entrance of these compounds into aquatic water causes contamination of plants, soil, and animals and develops some problems for the public health. This necessitates provision of the facilities for wastewater treatment in the production sources of these compounds, so that they are not released to the environment indiscriminately. In this research, having reviewed previous studies, the effects of these compounds on the environment have been examined and their different methods of removal were studied.
This research is of descriptive-explanatory type and has been developed using library documents.
The results indicated that antibiotics are not removed completely in the treatment process and cause resistance of microorganisms in the environment. Although the concentration of these compounds in water is of nano gram or microgram scale, their storage in the body of livestock and poultry and plants can develop diseases for the human and animals. Further, nanotechnology with its novel and new solutions states that the materials with this size can result in less expensive, more sustainable, and more effective water treatment technologies. In this way, they can meet a part of the needs of developing countries.
In addition to the therapeutic advantages of antibiotics, their indiscriminate usage has caused them to be considered as environmental contaminants. Accordingly, consumption of antibiotics requires accurate and systematic control.

With regard to the presence of agricultural and recreational activities as well as Aqua culture (fish farming) industries around the Zarin-Gol River, the current study aimed to evaluate water quality of this river in terms of water quality indices.
Regarding to the agricultural and livestock activities around the river, seasonal patterns of water quality indices (NSF-WQI and IRWQISC) were estimated using physic-chemical and biological parameters from 9 water quality monitoring stations. Sampling was done biweekly throughout summer and autumn. Measured parameters included fecal coliforms, biochemical oxygen demand, nitrate, dissolved oxygen, conductivity, chemical oxygen demand, phosphorus, turbidity, total hardness, pH and total solids. Because of the nature of the project, there were not ethical issues in this study.
The results of this study show that the WQI values in the samples from all stations were 54 to 61, based on both indices. NSF WQI index was moderate (70-50) and IRWQISC was also considered as moderate (55-45) and relatively good (55.1-70).
Total solids, turbidity, nitrate, temperature, and fecal coliforms were the most affecting parameters. Furthermore, although the quality of river water was suitable for agriculture, it should be treated for drinking, based on the water quality index value.

About 60% of body weight contains water. This study aimed to evaluate the quality of drinking water in military units. This is a descriptive cross-sectional study on water specimen of military units. The specimen was sent to the quality for microbial and physio-chemical control lab related to Tehran University of Medical Sciences. The result was compared with the ISIRI number 1503 and 1014. Our findings indicated that total hardness, Mg, So4 and Po4 of some military units were over the standard. Only in one unit a solar desalination was used and all parameters were under the standards. It is needed to improve the quality of drinking water in some units.

Along with industrial development, various pollutants release into the environment. The most toxic pollutants are Dioxins and Furans that enter to the environment from natural and anthropogenic sources. This study conducted to estimate Dioxin and Furan emission from various sources and determine source strength of pollutants in different provinces of Iran and their zoning in GIS. In order to achieve study targets, emission sources of Dioxin and Furan were identified and necessary data was then gathered using UNEP prepared questionnaire from relevant organizations. Emission rates were estimated applying UNEP suggested emission factors. Collected data then processed using Excel and Arc GIS softwares. Total Dioxin and Furan emission was 1957 g for Iran in 2009. From this, 705.8, 0.5, 463.5, and 144.1 g were emitted to air, water, ground, and products, respectively and 643.2 g remain in residual ashes. This study shows that the emission rate of Dioxin and Furan is very high in Iran and that appropriate management strategies are required to control these dangerous pollutants.

Biofiltration is one of the most effective methods for pollutant removal from a gas stream. An accurate mathematical model to predict removal efficiency can be applied in design and optimization of such equipment and also in investigating biofiltration process.The objective of this study was to develop a mathematical model for predicting biofiltration process performance in hydrogen sulfide removal from a gas stream and also examining the influence of several main parameters such as biofilm diffusivity and biofilm thickness on the predicted results. In order to achieve the goals, the governing equations expressing mass conservation for a differential control volume in both gas and biofilm phases were solved. Hydrogen sulfide concentration distributions in gas and biofilm phases were determined by solving these equations. The presented model is capable of predicting the variation of biofilm thickness through time due to bacteria growth and biofilm surface abrasion. The results from the expanded mathematical model were well in agreement with empirical data. The results revealed that hydrogen sulfide removal efficiency increases by increments in packing specific surface area and biofilm diffusivity along with decreasing entering gas velocity. In addition, the results of the model showed that increasing biofilm thickness tends to raise the removal efficiency for biofilm thickness of less than 5 micrometer. This fact reveals that the reaction rate is the rate-controlling step for lower biofilm thickness and the biofilm-diffusion resistance does not affect mass transfer rate significantly. However, further increasing biofilm thickness (to more than 20 micrometers) causes hydrogen sulfide removal efficiency to decrease. It can be attributed to magnifying the influence of biofilm diffusion on mass transfer rate.

Backgrounds and Today the crisis rising from over consumption energy and materialand environmental pollution pose serious problems that challenges present resources of man.Sustainable development is probably an inevitable strategy for human being in such a way that theleast possible damage be inflicted to the environment.In this way, the role played by universities in reaching the objectives of sustainable development is crucial. In this paper, we examine the present state of consumption energy resources (Electricity and natural gas) in the central main campus of Tehran University and so we calculate the extent of environmental pollutants resulted of these energy consumptions. For surveying of our objectives the first step is a survey of the current state of campus by way of reexamination of Gas and Electricity bills and distribution of a questionnaire. Second is an estimate of the entering pollutants to the environment with online software in site of http://www.abraxasenergy.com/emissions.annual consumption of 16.5 million KWHS of electricity along with 4312392 m3 of naturalgas leads to 0.0218 million tones Co2, 778 kg VOCS, 374.6 tones NOX, 2.41 tones CO, 65.341 tones So2, 93 kg Mercury compounds and 868 kg particles. It is shown that there is no objective effort and green management in this part ofuniversity officials. This project suggests that the implementation of green management in the framework of programs such as green university can be crucial in reaching the objectives.

With increasing development of technology and use of different types of fuels, environmental pollutants are increasing more and more in volume. Air pollution is an important issue with regard to its role in affecting human population health and especially the children. Studies in other countries have shown that the exhaust particles resulting from gasoline and diesel motors contain large amounts of mutagens and carcinogens including Polycyclic Aromatic Hydrocarbons (PAHs). There are different methods for mutagenesis assessment of PAHs and other organic substances available in air pollutants among which the "AMES" method is the easiest, fastest, and the most cost-effective one. This method has been introduced by Dr. Bruce N. Ames in 1967. The Ames method uses different strains of Salmonella typhimurium bacteria, which are genetically manipulated so that they can not grow in media without histidin. These bacterial strains are cultivated in histidin-free media and the substance, whose mutagenicity is under investigation, is also added to the medium. If the substance is mutagen, the bacteria will transform to mutant strains and will be able to synthesize histidin and therefore will begin to grow. Investigations with the Ames method have shown that 83% of substances which are identified as mutagen with this method are carcinogen. We applied this method in the current study. Seventy six ambient air samples were collected on fiberglass filters using a "High Volume Sampler Set" during the spring, summer, and fall. The organic substances of the samples were extracted by dichloromethane and Soxhlet. The bacterial Strains (TA98 & TA100) were provided by the courtesy of Dr. Ames from the United States upon our contact with him and genotypes of the bacteria were confirmed using the pertinent assay methods. The extracted samples were assessed with the Ames method at three different concentrations of 0.8, 1.6, and 3.2 mg of dry material per 100 µl solvent. One-way analysis of variance and Post Hoc tests were used for statistical analysis. The results indicated the presence of mutagenic substances in Tehran's air pollutants. Findings from TA98 and TA100 strains demonstrated that the mutagenicity ratios of the organic substances had significant differences with the critical value of two, for concentrations of 1.6 and 3.2 mg/100 µl. The mutagenicity ratios calculated for samples collected in spring, summer, and autumn did not have any significant difference with each other at the three tested concentrations. Also the mean colony counts did not demonstrate any significant difference in the mentioned seasons and at the three concentrations, but the colony counts were lower than the colony counts of the negative control group at the three concentrations (P value = 0.001). Comparison of our results with those form studies in other countries shows that the mutagenesis rates of Tehran's air pollutants are more than the similar rates in other countries in some cases. This is alarming for the authorities in order to do more efforts for decreasing the air pollution, especially in Tehran.