جستجوی مقالات مرتبط با کلیدواژه « atomic absorption » در نشریات گروه « محیط زیست »

Accumulation of heavy metals in aquatic ecosystems causes soft tissue destruction and weakens the immune system. On the other hand, consumption of contaminated fish causes several complications in humans. This study aims to measure the amounts of heavy metals lead, nickel, zinc, iron and copper in the edible tissue of gariz fish in islands (Qeshm, Hengam and Hormoz) of Hormozgan province. In the three mentioned regions, during the two seasons of summer and winter, a total of 180 samples were collected in 1398 (30 samples in each station and in each season separately). After bioassay, the concentration of heavy elements in the studied organ was measured using a flame atomic absorption device (Model 700Contr AA). The results showed that the highest mean concentrations of lead, nickel, zinc and copper were observed in Qeshm Island and iron metal in Hormoz Island and the lowest mean concentrations of metals were observed in Hengam Island. Metal concentrations in the analyzed samples were lower than international standards FAO, WHO, FDA, NHMRC and UKMAFF. Also, the level of potential risk and risk index for non-cancerous diseases in adults and children in the aquifer muscle tissue was less than 1. Therefore, it can be concluded that there are currently no problems for human health in terms of consumption of this fish.

Heavy elements, due to their indissoluble structure, pose a serious threat to the health of aquatic animals as well as humans at high level of concentrations in aquatic tissues. For this purpose, the present study aims to investigate concentration and order of elements accumulated in the muscle tissue of Caspian roach (Rutilus rutilus caspicus) in Siah Darvishan River as one of the fish species with high economic value and also the determination of its health for human consumption.

In this study, concentration level of eleven heavy elements (Pb, Hg, Cr, Cu, Zn, Cd, As, Fe, Mn, Ni and Se) in muscle tissue of 25 Caspian roach (Rutilus rutilus caspicus) caught by cast net from Siah Darvishan River (Guilan province, Iran) in summer 2016 were digested with closed-vessel method in CEM microwave digestion system afterwards measured and evaluated using by Varian® atomic absorption spectroscopy.

The least and most accumulated elements have been observed, as follows: Zinc 30.58-33.53, Iron 18.63-20.89, Copper 3.54-4.24, Manganese 1.55-1.86, Lead 0.81-0.83, Arsenic 0.74-0.79, Nickel 0.56-0.61, Selenium 0.46-0.51, Cadmium 0.26-0.32, Chromium 0.13-0.16 and Mercury 0.079-0.095 microgram per gram dry weight, respectively.

The results show that, mean concentrations of all elements in muscle tissue of Caspian roach, except the five heavy elements; Nickel (0.584±0.026), Arsenic (0.764±0.027), Cadmium (0.296±0.024), Manganese (1.665±0.166) and Lead (0.817±0.011), were below than the standard approved by the international organization (FAO/WHO).

Ducks due to their own curious behavior and diet which includes sludge, materials and objects left on the banks of rivers and swamps. They are prone to chronic forms of lead poisoning. Therefore, the aim of this study was to determine the effect of dipenicillamine and silymarin on lead residue in lead affected duck muscles. To study the effect of dipenicillamine and silymarin on lead residue in lead affected duck muscles, 120 one-day old ducks of Pekin breed into 4 groups of 30 pieces in three replications, including group 1: receiving the basic diet in the whole experimental period, group 2: recievingbasic diet+lead nitrate at a dose of 40 mg/kg (control),group 3: receiving basic diet+lead nitrate at a dose of 40 mg/kg+dipenicillamin at a dose of 20 mg/kg, group 4: receiver of basal diet+lead nitrate at a dose of 40 mg/kg +sage extract at a dose of 300 mg/kg was divided and raised for 60 days. After the end of breeding and slaughter period of ducks according to ethical protocols, sampling of chest and thigh muscles in each slaughtered piece was done. The lead concentration of each sample was measured by atomic absorption spectrophotometry by furnace method. According to the results, dipenicillamine and silymarin with their antioxidant properties, they were able to significantly (p < 0.05) reduce the amount of lead remaining in the thigh and chest muscles.

1. Environmental pollution to heavy metals is increasing every year and cause serious risks to human health, animals and plants. In terms of adverse effects on human health, particulate matter contains heavy metals are perhaps the most important air pollutants because of their non-biodegradable nature. They are released to the atmosphere via different processes and natural and man-made (anthropogenic) sources and enter body organs and tissues as a result of absorption through respiration of suspended particulate matter (SPM) which contains heavy metals and trace elements. Because of the risks posed by elements in Suspended Particulate Matter to human health and the ecosystem, it is important to develop effective control measure for air particulate emission. However, an important step in air pollution control program is the identification of pollutants, the contributing source and the relative contribution of each source. Elemental composition of SPM in ambient air of Rey city in Tehran has been investigated. Some of these pollutants, particularly the SPM and their elemental constituents are known to be hazardous to human health. It is therefore pertinent to investigate the activities of these industries. This has necessitated the present study to ascertain the degree of contamination of air in Rey City. Zone 20 of Tehran (Rey city) with an area of 176 square kilometer and population more than 370 thousand people is the most polluted area of Tehran due to the establishment of polluting industries such as cement factory, refinery, oil collection include pipelines, etc. The aim of this study is select the suitable sites in accordance with the US EPA standards to install air pollution monitoring station, investigate the change of metals concentrations as inorganic pollutants in ambient air and comparison with international standards and finally, their sources and anthropogenic contributions for the first time for this region.
2. There are different methods for sampling and determination of total suspended particulate matter in the atmosphere. This study has used the gravimetric techniques to sample and determine TSPM in Rey city according to the Standard Method, Compendium Method IO-3.1. In this method, the amount of particulate matter accumulated on the filter over a specified period of time is measured by weighing a pre-weighed filter after exposure. The flow rate of air sampled is measured over the test period. The result is expressed in terms of particulate mass collected (or loading) per unit volume of air sampled, usually as micrograms per cubic meter (μg/m3). The volume of air sampled is recorded by measurement of the device flow rate(s). Therefore, to achieve this purpose, 6 different stations were specified around this area according to the EPA standards included a residential, a traffic, two residential-industrial and two industrial stations.
High volume sampler, TCR TECORA model was used for the collection of the airborne particulate component of the atmosphere. The sample collection was carried out at 1394 in two seasons, summer and winter. Glass-fiber filter papers were dried and weighted before and after the sampling. So the daily concentrations of particulate matter with the size 3. The main purpose of this study is determination and monitoring some of heavy metals (such as Cr, Ni, Pb, Cd, Cu, Hg, Zn, Al and Fe) in ambient air in Rey city. So, 6 sampling stations were selected based on the effect of residential sources, mobile sources (vehicles) and stationary sources (industrial centers). Sampling of particulate matter in less than 10 micron diameter, were performed and the samples were analyzed to measure heavy metals according to the standard methods and EPA instructions. Analyzing the results of the measurements show that:  Annual concentration of chromium is higher than standard (0.01 μg/m3) at all sampling stations which shows the role of transportation (due to the corrosion of catalyst convertor and presence of asbestos in brake pad) and also industry, specially cement production in it’s emission to the ambient air. Chromium is naturally not an earth’s crust metal, so it increases at cold and rainy seasons and inversion.  Annual concentration of nickel is higher than standard (0.02 μg/m3), nearby different emission sources such as cement production, foundry and refinery which are the main emission sources of nickel in ambient air. Gradually, away from these sources and close to the residential zone, it will decrease.  Due to the production and distribution of lead-less gasoline since 1382, Lead pollution in ambient air which is most affected with traffic emissions, is lower than standard (0.5 μg/m3), but, it is higher than standard at stations locating near industrial zone, foundry, refinery and cement factory respectively.  Annual concentration of Cadmium is higher than standard (0.005 μg/m3) at all sampling stations. The most concentration is near industrial zone and then, cement factory which are the main emission sources. Analyzing the results shows that, the concentration of this metal increase in cold seasons due to the increasing of high temperature combustion processes.  All 6 stations show lower Mercury and Cupper emissions than standards (1 μg/m3). So, this area is in a satisfactory situation in terms of ambient emission of these parameters.  Regarding to the Zinc, Iron and Aluminum, no national or international standards is determined for ambient air emission, therefore, it is impossible to judge these metals emissions. However, the main sources of these metals in Rey city has been dust generated from calcareous soils (raw materials), cement clinker dust and metal smelting plants. These emissions are higher in summer than winter due to the less rain.
4. Airborne particulate matter (PM) emissions can be minimized by pollution prevention and emission control measures. Prevention, which is frequently more cost-effective than control, should be emphasized. Accordingly, some of the proposed measures to prevent or control their emissions include: 1. Management: Measures such as improved process design, operation, maintenance and other management practices, improving combustion efficiency, improving fuel injection zone configuration and combustion along with an adequate amount of excess air. 2. Choice of Cleaner Fuels: Such as natural gas, lighter distillate oil-based processes, low-ash fossil. 3. Fuel Cleaning: To reduce ash and sulfur content and/or co-firing of coal with higher and lower ash content, which can reduce ash content by up to 40%. 4. Choice of more efficient Technology and Processes: Advanced coal combustion technologies such as coal gasification and fluidized-bed combustion. 5. Select optimal particulate removal devices cyclones, wet scrubbers, electrostatic precipitators (ESPs) and bag-houses. ESPs are especially efficient in collecting fine particulates and can also capture trace emissions of some toxic metals with an efficiency of 99% and are the most cost effective according to the other equipments. Hence, continuity the monitoring and revision of filtration systems at pollutant zone are the main measures to eliminate the pollution. However, controlling emissions of many heavy metals, such as cadmium, lead, and mercury that are present as trace elements in fuels is a difficult and largely unsolved problem.