ABESSI, O.; SAEEDI, M.; DAVIDSON, M., and ZAKER, N.H., 2012. Flow classification of negatively bu... more ABESSI, O.; SAEEDI, M.; DAVIDSON, M., and ZAKER, N.H., 2012. Flow classification of negatively buoyant surface discharge in an ambient current. Journal of Coastal Research, 28(1A), 148-155. West Palm Beach (Florida), ISSN 0749-0208.
As the largest lake, the Caspian Sea is one of the most important lakes in the world from ecologi... more As the largest lake, the Caspian Sea is one of the most important lakes in the world from ecological, political and natural resources points of view. The Caspian Sea is increasingly being under environmental threats and pressures because of residential, industrial and agricultural areas, oil exploitation and production activities within and in the vicinity of long coastlines of this lake. Studying bottom sediments as the final sink of the fated pollutants have been of interest to evaluate the overall quality of the aquatic environments. Many studies on the water and sediment quality and ecology of the Caspian Sea have been carried out before. In the present study, heavy metals and petroleum hydrocarbon contents in surface sediment samples of a large area from east to central coasts of southern Caspian sea (from Miankaleh bay in Golestan province to Ramsar coasts in Mazandaran province, Iran) were studied. Twenty sediment samples from different depths in 7 zones along coastline were taken and analyzed for metals (Fe, Al, Ba, Ni, Cu, Zn, V, Cr, Sn and Pb), Total Petroleum Hydrocarbons (TPH) and Polycyclic Aromatic Hydrocarbons (PAHs). Samples were taken by a Van Veen grab sampler and preserved, prepared and analyzed for hydrocarbons according to U.S.EPA SW-846 using gas chromatography. Samples for metal analysis were prepared according to MOOPAM and measured by atomic absorption spectrometry. Hydrocarbons in marine environments may either be originated from biogenic or petrogenic sources. Results of the present study showed that the contents of TPH fall in the range of 10-64 µg/g of sediments with more enriched (40-64 µg/g) sediments of central part of Mazandaran province coasts. It should be pointed out that TPH contents of some other parts of the world that are recognized as polluted areas are as follows: 60-464 µg/g in Hong Kong, 35-2900 µg/g in New York Bay, 11-690 µg/g in Persian Gulf and 0.059- 34.09 µg/g in northern Caspian sea. Based on some published works, TPH content in sediments more than 500 µg/g is indicative of pollution while sediments containing less than 10 µg/g of TPH may be considered as unpolluted. According to this rule of thumb, sediments of the study area may be unpolluted in most of the region except for coasts of Mahmudabad to Tonkabon which may have low pollution of hydrocarbons (30<TPH<64 µg/g). PAHs content variations in sediments of the study area show that the concentrations fall in the range of 150-1600 µg/kg while more concentrated sediments are those in Sari to Chalus coasts and lower PAHs content sediments are those for eastern part of Miankaleh bay at south eastern Caspian. PAHs contents in sediments of the study area seems relatively high in comparison with Black Sea coastlines 7-638 µg/kg, coastal area of the Adriatic Sea 24-501 µg/kg, Victoria harbor in Hong Kong 350-450 µg/kg, Antarctica in adjacent of South Orkney Islands 8-280 µg/kg, Gironde estuary in France 19-252 µg/kg, Balearic Islands in Mediterranean Sea 30 µg/kg, Russian coast of Caspian Sea 6-345 µg/kg and Kazakhstan coast of Caspian Sea 7-294 µg/kg. Comparing the results of this study with those mentioned above and NOAA guidelines on sediment quality (4000 µg/kg PAHs) shows that sediments of the central coasts of southern Caspian Sea may be relatively low polluted to PAHs. This particularly can be observed for central parts in the vicinity of coastal cities. Major (Fe, Al and Ba) and trace metals (Ni, Cu, Zn, V, Cr, Sn and Pb) in fine (<63µm) sediments analyses showed that metals contents in samples fall in the following ranges in the study area: Fe; 22200-44000 mg/kg, Al; 43600-71000 mg/kg, Ba; 200-512 mg/kg, Ni; 35-67 mg/kg, Cu; 15-50 mg/kg, Zn; 56-104 mg/kg, V; 90-140 mg/kg, Cr; 60-92 mg/kg, Sn; 3-4 mg/kg and Pb; 22-25 mg/kg. In order to have a better assessment on the sediments metal pollution, it is necessary to have studied metals background concentration or the metals concentration of preindustrial era in sediments for the area. Since core sediments sampling and dating analyses is usually required to achieve these information and these experiments did not performed in the present studies, to have an approximate evaluation of the metal pollution of studied sediments, some public applied geochemical indices such as geochemical accumulation index (Igeo), Enrichment Factors (EF), Degree of Contamination (Cd) and modified degree of contamination index (mCd) have been used. Mean Fe content (36000 mg/kg) in the area of study sediments observed about 22% and 12% lower than that of mean world sediment (46000 mg/kg) and mean crust (41000 mg/kg), respectively. Mean Al content (59500 mg/kg) in the area of study sediments is about 17% and 27% lower than that of mean world sediment (72000 mg/kg) and mean crust (82000 mg/kg), respectively. Mean Zn content (85 mg/kg) in the area of study sediments is about 7% lower than that of mean world sediment (95 mg/kg) and 20% more than that of mean crust (75 mg/kg). Mean Cr content (81 mg/kg) in the area of study sediments is also lower than that of mean crust (100 mg/kg) and shale (90 mg/kg). Mean Cu content (35 mg/kg) in the area of study sediments is about 7% more than that of mean world sediment (33 mg/kg), 30% less than that of mean crust (50 mg/kg) and 22% less than that of shale (45 mg/kg). Mean Ni content (49 mg/kg) in the area of study sediments is about 5% more than that of mean world sediment (52 mg/kg), 38% less than that of mean crust (80 mg/kg) and 28% less than that of shale (68 mg/kg). Mean Pb content (19 mg/kg) in the area of study sediments is approximately equal to that of mean world sediment and shale (20 mg/kg) and 35% more than that of mean crust (14 mg/kg). As it is obvious, evaluation of the contamination of the studied sediments using just mean world sediment, mean crust and shale concentrations to compare seems impossible. So mentioned geochemical indices were applied to have a better assessment of contamination. Enrichment Factor analyses showed that most of metals in the sediments are relatively low enriched while amongst them Pb, Sn and Zn enrichment in sediments seemed to have a higher rate. Indices of geochemical accumulation (Igeo) for V, Cr, Cu and Ni were about zero showing no contamination using this index as assessment tool. Igeo for Pb and Sn in sediments of the central part of the study area is higher than that for other metals and areas showing low contamination of sediments with these metals. Modified degree of contamination index for studied metals in the study area also showed no major metals contamination of sediments. To have a better understanding of correlations of different studied contaminates behavior and origins within the study area; statistical analyses (correlation coefficients and cluster analysis) have been performed. Result of the cluster analysis is indicative of high correlations among Fe, Al, Cu and Ni contents in sediments. High correlations of V, Zn, Pb and Cr and to some extent Ba and Sn contents with hydrocarbon contents in sediments may be indicative of existence of some same sources of releasing these contaminants into the coastal environment of the studied area though it is hard to determine that these sources are lithougenous or anthropogenic. Regarding the nature of the geology and anthropogenic activities in coastal and inland boundaries of the studied area both kinds of sources may contribute discharging the contaminants into the sediments. Concluding the results, reveal that no extreme contamination of sediments were observed in the area having in mind that sediments of central part of the southern Caspian is being enriched by some metals and hydrocarbons which highlights the need for more detailed and extensive researches on the nature of contaminant sources and trend of pollution in sediments of the southern part of the Caspian Sea. Need for determining the background concentration of metals in sediments and historical changes of metal contents through core sediment sampling and analyses is also noticeable.
A new aggregative index called modified risk assessment code (mRAC) was developed based on heavy ... more A new aggregative index called modified risk assessment code (mRAC) was developed based on heavy metal toxicity and fractionation in aquatic sediment. Results of the application of mRAC to assess metal pollution in surface sediment samples of Anzali international wetland revealed that the new index led to more precise results than those of other prevalent aggregative indexes, such as modified degree of contamination (mC d ) and ecological risk index (RI). Based on assessment by mRAC, sediments of the study area were at high or very high potential adverse effect levels, compared to using mC d and RI where sediments were at a moderate or low potential adverse effect level. This is due to mRAC taking both metal toxicity and fractionation into account.
ABSTRACT A new bioavailability/bioaccessibility risk assessment index (BRAI) was used to assess h... more ABSTRACT A new bioavailability/bioaccessibility risk assessment index (BRAI) was used to assess heavy metals’ (Cu, Cr, Zn, Pb, Ni, Cd) bioavailability/bioaccessibility of the aquatic sediments of Anzali International Wetland. This wetland, registered under the Ramsar Convention, is located along the southwestern part of the Caspian Sea coast. Heavy metal concentrations in the surface sediments of Anzali wetland were determined. Four single extraction tests (with, respectively, CaCl2, ammonium acetate, EDTA and glycine as extractants) were conducted to assess both the metal bioavailability and the human bioaccessibility of 15 surface sediment samples from the study area. In the different single extraction tests, higher extraction of Cd and Pb was observed than for the other metals under study. The results of the tests revealed that 21.3, 36.4, 57.3, and 70 % of Cd were extracted by CaCl2, ammonium acetate, EDTA and glycine, respectively. When the new BRAI index was applied, the results showed high bioavailability/bioaccessibility of heavy metals in the surface sediments of the study area.
Response to the comments of Zhang et al. (2014) on "Heavy metals and polycyclic aromatic hydrocar... more Response to the comments of Zhang et al. (2014) on "Heavy metals and polycyclic aromatic hydrocarbons: Pollution and ecological risk assessment in street dust of Tehran" Dear Editor, In the comments published by Zhang et al. [1] on "Heavy metals and polycyclic aromatic hydrocarbons: Pollution and ecological risk assessment in street dust of Tehran", the authors commented on the application of ecological risk index (RI) initially introduced by Hakanson [2] to road-deposited sediments (RDS), and shared their understanding on two major points:
Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
In recent years the increases in the popularity of applying environmental criteria in national pl... more In recent years the increases in the popularity of applying environmental criteria in national planning and management has provided a wide range of scientific approaches to determine the best location of hazardous wastes to be land filled. In the present study, concern to the hydro-geological and socialeconomical considerations as well as national environmental legislations, an efficient method to determine suitable sites for land filling of hazardous wastes is presented. Site screening study based on GIS database in two scales, and priority processing are utilized. This approach demonstrates how the criteria such as geology, topography, land use, climate, surface and ground water chrematistics, accessibility, applicability and other related factors can be used into the over layer technique to determine some appropriate sites in a vast region. For priority processing between candidate sites also a new approach based on DRASTIC and MPCA methods and zonal feature of the study area is given. The introduced method was used to find a disposal site for hazardous wastes of Shahid Rajaee power plant in Qazvin province, located in west central part of Iran. Results showed that site named 1 in Abyeck zone next to Shahid Rajaee power plant has highest score between 17 primarily selected sites.
Solidified samples of fuel oil combustion bottom ash with two sets of Ordinary Port-land Cement (... more Solidified samples of fuel oil combustion bottom ash with two sets of Ordinary Port-land Cement (OPC) and Pozzolan added OPC were investigated with three sets of chemical leaching tests. Toxicity characteristic leaching test (TCLP) results classified waste material and its solidifica-tion products as hazardous. Although Ni and Cr have over-leached, but their close examination with Sequential Chemical Extraction (SCE) test revealed new insights as follows. Nickel fixation in cement matrix has shifted over 20% of leachable Ni from first 4 fractions of SCE test to residual fraction with less likelihood of leaching. Chromium fixation in matrix has made shifts on leachable fractions that are not generally in favor of a successful fixation in matrix. In the case of Cd leaching, the only obvious finding from SCE test is that solidification processes have made a slight shift between fractions in bound to Iron and Manganese oxide and fraction in bound to carbonates. Compared to TCLP results ...
In the present investigation sedimentation rate, contents of heavy metals (Zn, Co and Ni), enrich... more In the present investigation sedimentation rate, contents of heavy metals (Zn, Co and Ni), enrichment factors and speciation of Zn, Co and Ni of a sediment core from Gorgan Bay have been studied. Sedimentation rate in the study area has given an ample opportunity to track contents of Zn, Co and Ni with different sedimentary phases for the past 500 years (1500 t0 2002). Sedimentation rate of 1.4 mm/yr was obtained based on 210 Pb activity study of sediment core. A very low content of Al and Fe in the core compared to those of the mean crust was observed. Heavy metal contents increase towards the top of the sediment core. Chemical partitioning studies revealed that percentiles and amounts of Zn, Ni and Co in non-lithogenous phases increase slightly towards the top of the core sediment sample. There seems to be a slight increasing trend in pollution level of the sediments of the study area over the last 70 years. Further, despite many research reports, application of Enrichment Factors...
Many air dispersion models have been developed to calculate concentration of pollutants in differ... more Many air dispersion models have been developed to calculate concentration of pollutants in different distances from the emission source. These models have different precisions subject to some errors relating to discrete stability classes which would affect the lateral and vertical dispersion coefficient calculations. In order to reduce these errors in the present investigation, a fuzzy rule-based pollution dispersion model is developed. Structure of the proposed fuzzy model is based upon established mathematical equations in the literature. The fuzzy model, however, resolves the resultant problems of the mutation between piecewise stability classes, dispersion coefficients, as well as mathematical equations by considering fuzzy constraints instead of crisp ones. Efficiency of the proposed model is represented via a real numerical example and comparison of the results with other existing models.
Air pollution is one of the most important environmental problems in metropolitan cities like Teh... more Air pollution is one of the most important environmental problems in metropolitan cities like Tehran. Rain and snow, as natural events, may dissolve and absorb contaminants of the air and direct them onto the land or surface waters which become polluted. In the present study, precipitation samples were collected from an urbanized area of Tehran. They were analyzed for NO 3 -, PO4 3 -, SO 4 2-, pH, turbidity, Electrical Conductivity (EC), Cu, Fe, Zn, Pb, Ni, Cr, and Al. We demonstrate that snow samples were often more polluted and had lower pH than those from the rain, possibly as an effect of adsorption capability of snow flakes. Volume weighted average concentrations were calculated and compared with some other studies. Results revealed that Tehran's precipitations are much more polluted than those reported from other metropolitan cities. Cluster analysis revealed that studied parameters such as metals and acidity originated from the same sources, such as fuel combustion in res...
Oily wastewaters are the most important discharges of gas refineries from an environmental point-... more Oily wastewaters are the most important discharges of gas refineries from an environmental point-of-view. In the present study, treatment of gas refinery oily wastewater by electrocoagulation using aluminum electrodes was investigated. The effects of electrode distance, initial pH, sodium sulfate (Na2SO4) as a supporting electrolyte, polyaluminum chloride dosage as a coagulant aid, and current density on the efficiency of chemical oxygen demand (COD) removal were examined. The results revealed that the COD removal rate increases by applying more current density and polyaluminum chloride and, to a lesser extent, Na2SO4 dosage. The results also showed that 97% COD can be removed at optimum operational conditions. Specific electrical energy consumption could be reduced from 19.48 kWh (kg COD removal)(-1) to 11.057 kWh (kg COD removal)(-1) using Na2SO4 as a supporting electrolyte. Gas chromatographic analysis of raw and treated wastewater also revealed that most normal hydrocarbons (nea...
ABESSI, O.; SAEEDI, M.; DAVIDSON, M., and ZAKER, N.H., 2012. Flow classification of negatively bu... more ABESSI, O.; SAEEDI, M.; DAVIDSON, M., and ZAKER, N.H., 2012. Flow classification of negatively buoyant surface discharge in an ambient current. Journal of Coastal Research, 28(1A), 148-155. West Palm Beach (Florida), ISSN 0749-0208.
As the largest lake, the Caspian Sea is one of the most important lakes in the world from ecologi... more As the largest lake, the Caspian Sea is one of the most important lakes in the world from ecological, political and natural resources points of view. The Caspian Sea is increasingly being under environmental threats and pressures because of residential, industrial and agricultural areas, oil exploitation and production activities within and in the vicinity of long coastlines of this lake. Studying bottom sediments as the final sink of the fated pollutants have been of interest to evaluate the overall quality of the aquatic environments. Many studies on the water and sediment quality and ecology of the Caspian Sea have been carried out before. In the present study, heavy metals and petroleum hydrocarbon contents in surface sediment samples of a large area from east to central coasts of southern Caspian sea (from Miankaleh bay in Golestan province to Ramsar coasts in Mazandaran province, Iran) were studied. Twenty sediment samples from different depths in 7 zones along coastline were taken and analyzed for metals (Fe, Al, Ba, Ni, Cu, Zn, V, Cr, Sn and Pb), Total Petroleum Hydrocarbons (TPH) and Polycyclic Aromatic Hydrocarbons (PAHs). Samples were taken by a Van Veen grab sampler and preserved, prepared and analyzed for hydrocarbons according to U.S.EPA SW-846 using gas chromatography. Samples for metal analysis were prepared according to MOOPAM and measured by atomic absorption spectrometry. Hydrocarbons in marine environments may either be originated from biogenic or petrogenic sources. Results of the present study showed that the contents of TPH fall in the range of 10-64 µg/g of sediments with more enriched (40-64 µg/g) sediments of central part of Mazandaran province coasts. It should be pointed out that TPH contents of some other parts of the world that are recognized as polluted areas are as follows: 60-464 µg/g in Hong Kong, 35-2900 µg/g in New York Bay, 11-690 µg/g in Persian Gulf and 0.059- 34.09 µg/g in northern Caspian sea. Based on some published works, TPH content in sediments more than 500 µg/g is indicative of pollution while sediments containing less than 10 µg/g of TPH may be considered as unpolluted. According to this rule of thumb, sediments of the study area may be unpolluted in most of the region except for coasts of Mahmudabad to Tonkabon which may have low pollution of hydrocarbons (30<TPH<64 µg/g). PAHs content variations in sediments of the study area show that the concentrations fall in the range of 150-1600 µg/kg while more concentrated sediments are those in Sari to Chalus coasts and lower PAHs content sediments are those for eastern part of Miankaleh bay at south eastern Caspian. PAHs contents in sediments of the study area seems relatively high in comparison with Black Sea coastlines 7-638 µg/kg, coastal area of the Adriatic Sea 24-501 µg/kg, Victoria harbor in Hong Kong 350-450 µg/kg, Antarctica in adjacent of South Orkney Islands 8-280 µg/kg, Gironde estuary in France 19-252 µg/kg, Balearic Islands in Mediterranean Sea 30 µg/kg, Russian coast of Caspian Sea 6-345 µg/kg and Kazakhstan coast of Caspian Sea 7-294 µg/kg. Comparing the results of this study with those mentioned above and NOAA guidelines on sediment quality (4000 µg/kg PAHs) shows that sediments of the central coasts of southern Caspian Sea may be relatively low polluted to PAHs. This particularly can be observed for central parts in the vicinity of coastal cities. Major (Fe, Al and Ba) and trace metals (Ni, Cu, Zn, V, Cr, Sn and Pb) in fine (<63µm) sediments analyses showed that metals contents in samples fall in the following ranges in the study area: Fe; 22200-44000 mg/kg, Al; 43600-71000 mg/kg, Ba; 200-512 mg/kg, Ni; 35-67 mg/kg, Cu; 15-50 mg/kg, Zn; 56-104 mg/kg, V; 90-140 mg/kg, Cr; 60-92 mg/kg, Sn; 3-4 mg/kg and Pb; 22-25 mg/kg. In order to have a better assessment on the sediments metal pollution, it is necessary to have studied metals background concentration or the metals concentration of preindustrial era in sediments for the area. Since core sediments sampling and dating analyses is usually required to achieve these information and these experiments did not performed in the present studies, to have an approximate evaluation of the metal pollution of studied sediments, some public applied geochemical indices such as geochemical accumulation index (Igeo), Enrichment Factors (EF), Degree of Contamination (Cd) and modified degree of contamination index (mCd) have been used. Mean Fe content (36000 mg/kg) in the area of study sediments observed about 22% and 12% lower than that of mean world sediment (46000 mg/kg) and mean crust (41000 mg/kg), respectively. Mean Al content (59500 mg/kg) in the area of study sediments is about 17% and 27% lower than that of mean world sediment (72000 mg/kg) and mean crust (82000 mg/kg), respectively. Mean Zn content (85 mg/kg) in the area of study sediments is about 7% lower than that of mean world sediment (95 mg/kg) and 20% more than that of mean crust (75 mg/kg). Mean Cr content (81 mg/kg) in the area of study sediments is also lower than that of mean crust (100 mg/kg) and shale (90 mg/kg). Mean Cu content (35 mg/kg) in the area of study sediments is about 7% more than that of mean world sediment (33 mg/kg), 30% less than that of mean crust (50 mg/kg) and 22% less than that of shale (45 mg/kg). Mean Ni content (49 mg/kg) in the area of study sediments is about 5% more than that of mean world sediment (52 mg/kg), 38% less than that of mean crust (80 mg/kg) and 28% less than that of shale (68 mg/kg). Mean Pb content (19 mg/kg) in the area of study sediments is approximately equal to that of mean world sediment and shale (20 mg/kg) and 35% more than that of mean crust (14 mg/kg). As it is obvious, evaluation of the contamination of the studied sediments using just mean world sediment, mean crust and shale concentrations to compare seems impossible. So mentioned geochemical indices were applied to have a better assessment of contamination. Enrichment Factor analyses showed that most of metals in the sediments are relatively low enriched while amongst them Pb, Sn and Zn enrichment in sediments seemed to have a higher rate. Indices of geochemical accumulation (Igeo) for V, Cr, Cu and Ni were about zero showing no contamination using this index as assessment tool. Igeo for Pb and Sn in sediments of the central part of the study area is higher than that for other metals and areas showing low contamination of sediments with these metals. Modified degree of contamination index for studied metals in the study area also showed no major metals contamination of sediments. To have a better understanding of correlations of different studied contaminates behavior and origins within the study area; statistical analyses (correlation coefficients and cluster analysis) have been performed. Result of the cluster analysis is indicative of high correlations among Fe, Al, Cu and Ni contents in sediments. High correlations of V, Zn, Pb and Cr and to some extent Ba and Sn contents with hydrocarbon contents in sediments may be indicative of existence of some same sources of releasing these contaminants into the coastal environment of the studied area though it is hard to determine that these sources are lithougenous or anthropogenic. Regarding the nature of the geology and anthropogenic activities in coastal and inland boundaries of the studied area both kinds of sources may contribute discharging the contaminants into the sediments. Concluding the results, reveal that no extreme contamination of sediments were observed in the area having in mind that sediments of central part of the southern Caspian is being enriched by some metals and hydrocarbons which highlights the need for more detailed and extensive researches on the nature of contaminant sources and trend of pollution in sediments of the southern part of the Caspian Sea. Need for determining the background concentration of metals in sediments and historical changes of metal contents through core sediment sampling and analyses is also noticeable.
A new aggregative index called modified risk assessment code (mRAC) was developed based on heavy ... more A new aggregative index called modified risk assessment code (mRAC) was developed based on heavy metal toxicity and fractionation in aquatic sediment. Results of the application of mRAC to assess metal pollution in surface sediment samples of Anzali international wetland revealed that the new index led to more precise results than those of other prevalent aggregative indexes, such as modified degree of contamination (mC d ) and ecological risk index (RI). Based on assessment by mRAC, sediments of the study area were at high or very high potential adverse effect levels, compared to using mC d and RI where sediments were at a moderate or low potential adverse effect level. This is due to mRAC taking both metal toxicity and fractionation into account.
ABSTRACT A new bioavailability/bioaccessibility risk assessment index (BRAI) was used to assess h... more ABSTRACT A new bioavailability/bioaccessibility risk assessment index (BRAI) was used to assess heavy metals’ (Cu, Cr, Zn, Pb, Ni, Cd) bioavailability/bioaccessibility of the aquatic sediments of Anzali International Wetland. This wetland, registered under the Ramsar Convention, is located along the southwestern part of the Caspian Sea coast. Heavy metal concentrations in the surface sediments of Anzali wetland were determined. Four single extraction tests (with, respectively, CaCl2, ammonium acetate, EDTA and glycine as extractants) were conducted to assess both the metal bioavailability and the human bioaccessibility of 15 surface sediment samples from the study area. In the different single extraction tests, higher extraction of Cd and Pb was observed than for the other metals under study. The results of the tests revealed that 21.3, 36.4, 57.3, and 70 % of Cd were extracted by CaCl2, ammonium acetate, EDTA and glycine, respectively. When the new BRAI index was applied, the results showed high bioavailability/bioaccessibility of heavy metals in the surface sediments of the study area.
Response to the comments of Zhang et al. (2014) on "Heavy metals and polycyclic aromatic hydrocar... more Response to the comments of Zhang et al. (2014) on "Heavy metals and polycyclic aromatic hydrocarbons: Pollution and ecological risk assessment in street dust of Tehran" Dear Editor, In the comments published by Zhang et al. [1] on "Heavy metals and polycyclic aromatic hydrocarbons: Pollution and ecological risk assessment in street dust of Tehran", the authors commented on the application of ecological risk index (RI) initially introduced by Hakanson [2] to road-deposited sediments (RDS), and shared their understanding on two major points:
Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
In recent years the increases in the popularity of applying environmental criteria in national pl... more In recent years the increases in the popularity of applying environmental criteria in national planning and management has provided a wide range of scientific approaches to determine the best location of hazardous wastes to be land filled. In the present study, concern to the hydro-geological and socialeconomical considerations as well as national environmental legislations, an efficient method to determine suitable sites for land filling of hazardous wastes is presented. Site screening study based on GIS database in two scales, and priority processing are utilized. This approach demonstrates how the criteria such as geology, topography, land use, climate, surface and ground water chrematistics, accessibility, applicability and other related factors can be used into the over layer technique to determine some appropriate sites in a vast region. For priority processing between candidate sites also a new approach based on DRASTIC and MPCA methods and zonal feature of the study area is given. The introduced method was used to find a disposal site for hazardous wastes of Shahid Rajaee power plant in Qazvin province, located in west central part of Iran. Results showed that site named 1 in Abyeck zone next to Shahid Rajaee power plant has highest score between 17 primarily selected sites.
Solidified samples of fuel oil combustion bottom ash with two sets of Ordinary Port-land Cement (... more Solidified samples of fuel oil combustion bottom ash with two sets of Ordinary Port-land Cement (OPC) and Pozzolan added OPC were investigated with three sets of chemical leaching tests. Toxicity characteristic leaching test (TCLP) results classified waste material and its solidifica-tion products as hazardous. Although Ni and Cr have over-leached, but their close examination with Sequential Chemical Extraction (SCE) test revealed new insights as follows. Nickel fixation in cement matrix has shifted over 20% of leachable Ni from first 4 fractions of SCE test to residual fraction with less likelihood of leaching. Chromium fixation in matrix has made shifts on leachable fractions that are not generally in favor of a successful fixation in matrix. In the case of Cd leaching, the only obvious finding from SCE test is that solidification processes have made a slight shift between fractions in bound to Iron and Manganese oxide and fraction in bound to carbonates. Compared to TCLP results ...
In the present investigation sedimentation rate, contents of heavy metals (Zn, Co and Ni), enrich... more In the present investigation sedimentation rate, contents of heavy metals (Zn, Co and Ni), enrichment factors and speciation of Zn, Co and Ni of a sediment core from Gorgan Bay have been studied. Sedimentation rate in the study area has given an ample opportunity to track contents of Zn, Co and Ni with different sedimentary phases for the past 500 years (1500 t0 2002). Sedimentation rate of 1.4 mm/yr was obtained based on 210 Pb activity study of sediment core. A very low content of Al and Fe in the core compared to those of the mean crust was observed. Heavy metal contents increase towards the top of the sediment core. Chemical partitioning studies revealed that percentiles and amounts of Zn, Ni and Co in non-lithogenous phases increase slightly towards the top of the core sediment sample. There seems to be a slight increasing trend in pollution level of the sediments of the study area over the last 70 years. Further, despite many research reports, application of Enrichment Factors...
Many air dispersion models have been developed to calculate concentration of pollutants in differ... more Many air dispersion models have been developed to calculate concentration of pollutants in different distances from the emission source. These models have different precisions subject to some errors relating to discrete stability classes which would affect the lateral and vertical dispersion coefficient calculations. In order to reduce these errors in the present investigation, a fuzzy rule-based pollution dispersion model is developed. Structure of the proposed fuzzy model is based upon established mathematical equations in the literature. The fuzzy model, however, resolves the resultant problems of the mutation between piecewise stability classes, dispersion coefficients, as well as mathematical equations by considering fuzzy constraints instead of crisp ones. Efficiency of the proposed model is represented via a real numerical example and comparison of the results with other existing models.
Air pollution is one of the most important environmental problems in metropolitan cities like Teh... more Air pollution is one of the most important environmental problems in metropolitan cities like Tehran. Rain and snow, as natural events, may dissolve and absorb contaminants of the air and direct them onto the land or surface waters which become polluted. In the present study, precipitation samples were collected from an urbanized area of Tehran. They were analyzed for NO 3 -, PO4 3 -, SO 4 2-, pH, turbidity, Electrical Conductivity (EC), Cu, Fe, Zn, Pb, Ni, Cr, and Al. We demonstrate that snow samples were often more polluted and had lower pH than those from the rain, possibly as an effect of adsorption capability of snow flakes. Volume weighted average concentrations were calculated and compared with some other studies. Results revealed that Tehran's precipitations are much more polluted than those reported from other metropolitan cities. Cluster analysis revealed that studied parameters such as metals and acidity originated from the same sources, such as fuel combustion in res...
Oily wastewaters are the most important discharges of gas refineries from an environmental point-... more Oily wastewaters are the most important discharges of gas refineries from an environmental point-of-view. In the present study, treatment of gas refinery oily wastewater by electrocoagulation using aluminum electrodes was investigated. The effects of electrode distance, initial pH, sodium sulfate (Na2SO4) as a supporting electrolyte, polyaluminum chloride dosage as a coagulant aid, and current density on the efficiency of chemical oxygen demand (COD) removal were examined. The results revealed that the COD removal rate increases by applying more current density and polyaluminum chloride and, to a lesser extent, Na2SO4 dosage. The results also showed that 97% COD can be removed at optimum operational conditions. Specific electrical energy consumption could be reduced from 19.48 kWh (kg COD removal)(-1) to 11.057 kWh (kg COD removal)(-1) using Na2SO4 as a supporting electrolyte. Gas chromatographic analysis of raw and treated wastewater also revealed that most normal hydrocarbons (nea...
Uploads
Papers by Mohsen Saeedi
Concluding the results, reveal that no extreme contamination of sediments were observed in the area having in mind that sediments of central part of the southern Caspian is being enriched by some metals and hydrocarbons which highlights the need for more detailed and extensive researches on the nature of contaminant sources and trend of pollution in sediments of the southern part of the Caspian Sea. Need for determining the background concentration of metals in sediments and historical changes of metal contents through core sediment sampling and analyses is also noticeable.
Concluding the results, reveal that no extreme contamination of sediments were observed in the area having in mind that sediments of central part of the southern Caspian is being enriched by some metals and hydrocarbons which highlights the need for more detailed and extensive researches on the nature of contaminant sources and trend of pollution in sediments of the southern part of the Caspian Sea. Need for determining the background concentration of metals in sediments and historical changes of metal contents through core sediment sampling and analyses is also noticeable.