جستجوی مقالات مرتبط با کلیدواژه « آلودگی » در نشریات گروه « مهندسی دریا »

In this study, in order to investigate the concentration of heavy metals in Sefidrud river sediments and environmental effects, 15 sediment samples collected and concentrations of heavy metals (iron, arsenic, cobalt, chromium, nickel, lead, copper and zinc) by ICP- OES method were determined. Concentration of heavy metals in sediments for arsenic (0.25-26.24 ppm), cobalt (10.28-2.2ppm), chromium (50.2-126.2 ppm), nickel (26.50-50.25 ppm) copper (19.5- 49.3 ppm), lead (15-45 ppm) and zinc (60-74 ppm) were obtained. Based on the degree of pollution (Cd), Sefidrud sediments are classified in the moderate pollution range. Also, based on the modified degree of contamination index (mCd), all samples except 5 stations are classified in the range of low to medium degree of pollution and pollution load index (PLI) in most stations showed in the range of more than 1 (slightly polluted to polluted), but ecological risk (RI) were still in the low risk range. Evaluation of enrichment factor (EF) also showed chromium, lead and zinc are enriched.

The aim of this study was to determine the accumulation of heavy metals (nickel, mercury and cadmium) in muscle and skin tissue of Tanoalosa ilisha in Khuzestan province (Karun River, Arvand Rud River, Bahrakan). For this purpose, after determining the stations by GPS, sampling of the Tanoalosa ilisha fish was performed using a fishing trip. After catching fish randomly, fish were placed in contact with ice in standard conditions and quickly transferred to the laboratory. Subsequently, the samples were evaluated for measuring the factors of this study based on international standard methods. The results of this experiment showed that the highest concentrations of heavy metals evaluated in this research (nickel, cadmium and mercury) were at the Bahrakan station and the lowest concentration of metals were in the Arvand Rud station. Generally, the concentration of nickel metal found in the fish muscle in Karun was 1±162.11 ???and Arvandroud Rud station, 0.0±908.09, was higher than the FDA limit. However, nickel in the Tanoalosa ilisha fish skin was higher than the permissible level in all three stations, 1±901.219, 1±588.22. 1±222.15. Regarding cadmium levels in muscle tissue at the Bahrekan and Karun stations, 0.0±547.08, 0.0±421.05, were higher than the WHO and below the FDA recommendations, but at Arvand river the levels were lower than WHO and FDA limits. However, the cadmium content of the endangered fish of all three stations, 0.0±648.106, 0.0±494.07, 0.0±340.09 was higher than the WHO standard and was below the FDA standard. The accumulation of mercury metal in skin tissue and Tanoalosa ilisha fish muscle in all three stations was lower than the FDA and FAO limits. In addition, the amount of elemental accumulation in fish skin was more intense than in muscle tissue.

In this study nickel and vanadium heavy metals were investigated in sediments and gammarus in Gilan Province. Sampling was carried out from sediments and dominant Gammarus, from 5 stations in Gilan province, in the spring of 2016. Nickel and vanadium analysis was carried out using an ICP/MS instrument. The results were statistically analyzed using one-way ANOVA and Duncan's test. The results showed that the amount of vanadium in sediment and Gammarus was higher compared to nickel and more accumulation of both metals was observed in the western part of the province (Rudsar area) compared to the eastern part. There was no significant correlation between environmental parameters and the concentration of metals. Based on the regression equation, a weak positive correlation was found between the amount of nickel and vanadium in sediments and Gammarus, which was not significant. Comparing results with NOAA standard (2004), the amount of nickel and vanadium in the sediments of the coast of Gilan province were not higher than the permissible range.

In this research for the study of geochemical changes and heavy metals contaminations in Gorgan Bay deposits, 5 sedimentary cores (K1,K3,K5,N1) were collected by using a gravity corer from different part of Gorgan bay. After geochemical analysis, the trend of each element was drawn up. The concentration range of toxic elements: arsenic (2.89-10.18 ppm), lead (9.88-43.8 ppm), copper (6.01-45.2 ppm), zinc (22.8-106.18 ppm), nickel (8.78-105.4 ppm), cobalt (5.38-44.18) and chromium (15.3-140.9 ppm) were obtained. Generally, the highest concentration of elements was observed in the surface parts of the cores and the lowest concentration was perceived at depths more than 50 cm. Enrichment factor index (EF) for all elements exception core K7 was less than 1-1.5 indicated natural sources for elements. Based on the average value of Cd, mcd, RI, the sediment contamination degree was defined as low pollution (expect in surfaces considerable), low contamination and low ecological risk, respectively. The pollution load index (PLI) was between 1 and 2, representative low pollution. Finally, the comparison of the concentration of selected elements in this area with the American and Canadian sediment quality guidelines signified the ranges between low risk to dangerous and harmful.

Because of the ever-increasing importance of Green Ports’ subject, which involves different aspects like ports, environment, health and economic matters and also the shortage of researches and studies about this field, the subject of “Key Attributes of Upgrading Traditional Ports to Green Ports at the Case Study of Chabahar’s Port” was determined as the subject of this research by the researcher. This research is quantitative as 9 identified attributes by means of the internal or external previous studies and researches, consultations with the experts and specialists of ports and environment and, moreover fieldworks of the researcher with using the Fuzzy Delphi Method; were reduced to 7 important, influential and localized attributes of “Pollutions, the Marine Ecology, Garbage, Transportation, Economics, Technology and Management” to determine the prioritization and importance of each attribute at upgrading traditional ports to green ports with using Fuzzy Analytical Hierarchy Process. According to the results of Fuzzy Analytical Hierarchy Process the attributes of “Pollutions, Marine Ecology, Garbage, Environment and Managements” were identified as priorities consequently.

Considering the increase in number of offshore oil production projects and for better understanding of plume dynamics in accidental underwater oil blowouts, a series of laboratory experiments in a square cross section open top basin were carried out to investigate the effect of changes in seawater stratification and water column stability on plume dynamics and peeling height.  Accordingly the open top basin was filled with stratified salt water at different buoyancy frequencies and the results of experiments were numerically expanded to marine condition of shallow waters. Non-dimensionalized form of experimental and numerical results showed that decrease in basin buoyancy frequency increases the plume peeling height and reduces the plume width. Experimental results showed that the neutral buoyancy level was the applicable transition criterion from plume dynamic phase to advective and diffusive phase.

Over time, the quality of water resources is subject to physical, chemical and biological changes due to natural and human factors. Most of these changes are decreasing trend. Qualitative and quantitative monitoring plays an important role in the sustainable management of river ecosystems. The Lasem River is one of the most important sources of surface water in Amol and is one of the major nutritionists in the river Haraz. In this study, five stations were considered along the river route in terms of accessibility and proximity to agricultural land and rural areas. The samples were taken in the summer and autumn of 1394. Physical and chemical properties were determined in standard methods (T, pH, EC, TS, TDS, TSS, DO, BOD5, NO3, PO4 and FC). The results showed that total solids, biological oxygen demand, nitrate and phosphate ion and fecal coliform have an increasing trend in the river route. The quality of the waters of the Lasm River is significantly lower in the summer than in the autumn. The most polluted station is the fifth station (at the confluence of the Lasm River to Heraz). Comparison of measured quantities with standard values showed that dissolved oxygen at most stations at sampling times was lower than the standard river limits. It is likely that the input of agricultural waste and fish farms and sewage in rural areas could be due to its causes. Comparing other quantities measured with standard values, it can be stated that the river is in good condition

This study was conducted to determine water quality of Aras River (Western Azerbaijan), based on metals (Mo, Cu, As, Hg) at four stations (From Julfa to 25km after Nourdos border) during four seasons from 2015 to 2016. Thirty two samples of water and sediments were collected. All samples were analyzed using standard methods (digestion and extraction), using an atomic absorption specphotometer instrument. Results showed that Mo, Cu, As and Hg concentrations in waterand sediments ranged between 0.10-23.01, 3.0-40.0, 0.02-0.81, 23.7-104.6 µg/l, and 0.1-111.6, 17.5-482.5, 0.001-0.145, 46.8-303.6 µg/g.dw, respectively. As a conclusion, water quality of Aras River was classified as class III (moderately polluted) based on mean concentration of Cu. Mo concentration was found to be less than permissible level. Water quality of Aras River was classified as class IV and II based on mean values of Hg and As, respectively. Maximum levels of Mo and Cu in surface sediments were found at stations 3 and 4 during all seasons, which is because of effluents and sewage from Mo, gold and other metal mines from Armenia. Mean concentration of As at surface sediment was higher than recommended standard value, but concentration of Hg was lower than recommended value.

Anzali Lagoon is an internationally protected lagoon located in west-south of Caspian Sea which has special ecologic, economic, social importance with vast diversity of plants and animals. According to entrance of contaminants into this lagoon, concentration of several heavy metals in muscle of Esox lucius fish have been investigated in this study. First stage of sampling from three stations of lagoon, have been fulfilled at dry season of September and second stage have been implemented at rainy season of November 2010. In each season nine samples of fish have been collected and transported to laboratory in freezed condition. Evaluation and measurement of heavy metal concentration has been fulfilled by Graphite furnace atomic absorption equipment. Maximum mean concentration of Hg, Ni, Se, Zn, Al, and Fe have been detected in the summer and maximum mean concentration of Cu has been detected in the winter. Maximum mean value of Hg, Ni, Zn,Al in Abkenar, maximum mean value of Se in Siah Darvishan and maximum mean value of Cu, Fe in Komeh Aghajani have been detected, while concentraton of Mo, Cd, V and Pb are equal in the three above mentioned stations. Statistical analysis of this study has been fulfilled by SPSS, V14 software. Pearson correlation test, showed a positive strong correlation between temperature and the amount of Fe (r=0.83, P<0.05). Only significant difference in concentration of Fe has been obtained between summer and winter seasons (P=0.016, df=16, P<0.05). Significant difference in concentration was detected only for Hg between Abkenar and Komeh Aghajani stations (P=0.05).This study shown that, the concentration of Ni, Hg, and Cd in the muscle of Esox lucius are high and it is considered as a serious warning.

To determine the heavy metals Zinc, Lead, Chromium and Copper in soft tissues of Thais mutabilis (gastropod) in three transect of tidal coast of Bandar Abbas, sampling was done in winter of 1389 (2011). Each Transect had three stations; Upper, mid and lower tidal zone. Sampling was done randomly with 0.5 square meter quadrate. Each area was sampled 9 times. The samples were analyzed for determination of heavy metals (Zn, Pb, Cr, Cu). The results showed that in the gastropod, zinc (577/18 ±438.9 ppm) was at the highest concentration between the heavy metals and Lead (0/17±0/6 ppm) was at the lowest. Generally, the highest concentration of Zinc (9/438±18/577), Lead (8/0±67/0) and Chromium (8/0±23/1) in soft tissues of gastropod was in Golshahr jonobi station, and the highest concentration of copper (6/134±77/88) was in the Posht shahr station. Statistical analysis showed that there was a significant difference (P≤0/05) in the concentration of chromium metal in soft tissue of gastropod in Golshahr jonobi transect with Soro. However, there is no significant difference between the concentrations of lead, copper and zinc in samples of soft tissue of gastropod in each transect (P≥0/05). The concentration of lead and chromium in this aquatic environment is lower than admissible range (WHO, 1985). It shows that the input of pollution containing these metals to this environment is low. The concentration of heavy metals such as zinc and copper is higher than admissible range (WHO, 1985) in every 3 transect. The result of bioaccumulation of heavy metals (Zink, Lead, Copper, and Chromium) in soft tissues of Thais mutabilis (Gastropoda) exhibited the following order: Zn> Cu> Cr >Pb.

This study performed in Caspian Sea in order to estimate nutrients nitrate factors (pH, temperature and salinity) from April to October 2008. Sampling was done in southeast Caspian Sea in five transects in 45 stations on surface water, 5 and 10 meter depths based on national standard. The mean concentration of nitrate was 5.37, 8.87 and 0.47 mg/l in first transect, it was 5.81, 9.98 and 0.76 mg/l in second transect, and 5.31, 11.76 and 0.71 mg/l in third transect, 5.40, 11.38 and 0.69 mg/l in fourth transect and 14.28, 14.89 and 2.09 mg/l in fifth transect. The concentration of nitrate was increasing from Salman Shahr to Amirabad. There was significant differences in nitrate concentration in transects (P<0.05), but the other parameters were not significantly different among surface, 5 and 10 m waters (P>0.05).

Five heavy metals (Co, Cr, Cd, Ni, V) in whole body tissue of Solen rosemaculatus of Bandar-e Khamir in summer and winter 2010 were determined. Bandar-e Khamir is one of the major fishing ports in Hormozgan Province in Iran. A sample size of 5-7 cm was harvested from three stations in tidal zone of Bandar-e Khamir. Bivalves transferred to laboratory and biometry whole tissue of  bivalves were separated after preparation and digestion process. Using Atomic Absorption Spectrometer (graphite furnace) amount of heavy metals were measured. Results indicated that: In summer and winter MeanSD concentrations of Cobalt, Chromium, Cadmium and Nickel were (0.0750.026 and 0.0830.034), (0.1000.038 and 0.1420.042), (0.0260.017 and 0.0130.009), (0.9840.287 and 1.1040.344) micrograms per gram dry weight, respectively. Vanadium concentration were in trace amounts below detection limit of the AAS. Results of this study showed that concentration of heavy metals in all samples were less than the permissive international standards. There was a significant difference in the specific concentration of Cr between samples from either different sites or seasons (P<0.05). A significant difference was also observed in comparison of Cd concentrations between samples of different seasons (P<0.05).

Concentrations of PAH’s known as carcinogenic compositions were studied in the muscle of Pike fishes (Esox lucius) in Iranian international wetland of Anzali in year 2010. Fifteen samples were taken at three stations of Mahruzeh, Koumeh Aghajani and Siah darvishan in dry (early September) and wet (early December) seasons. Some environmental parameters like pH, dissolved oxygen and water temperature were also measured at the same time. Biometry and age determination were done for each sample prior to their preparation for measurement of PAH’s concentrations using HPLC method. Acenaphtene with the concentration of (31.9 ± 11.37 ppb) and Benzo[a]pyrene with (0.2 ± 0.1 ppb) were the highest and lowest recorded concentrations in each season respectively. In both seasons, significant negative correlations (P<0.05) were observed between Naphthalene and Acenaphtene with fish age (2 year and under 1 year) and also between Benzo[b]fluoranthene and Benzo[ghi]perylene with dissolved oxygen. In both seasons, significant correlation were observed between dissolved oxygen and pH with PAH’s while  between PAH’s and fish weight it was significant only in cold season (P<0.05).Considering the 52.63 ppb (dry weight) as the highest measured concentration of PAH’s in this study and 30 µg/kg (wet weight) as the maximum allowable contamination level for aquatic organisms it can be concluded that the PAH’s concentration in Pike’s muscle is almost within the allowable limit in Anzali Wetland.

In this paper, by using NASIR1 software the pollution distribution in Musa Estuary is simulated, which has lots of branches and a complicated topography. After introducing the governing equations and a short explanation about the model, the tidal currents in Musa Estuary are modeled and calibrated. In the next step, by inserting pollution source points into the modeling environment, the state of pollution diffusion is analyzed. Finally, by source point displacement, the distribution is compared with the previous condition.