Assessing the trace metal pollution in the sediments of Mahshahr Bay, Persian Gulf, via a novel pollution index.

Sediment samples were collected from the Petrochemical Special Economic Zone of Mahshahr Bay, Persian Gulf, and analyzed for possible trace metal contamination by means of a chemical partitioning method. The heavy metal contents in the sediments follow the order of Al > Sr > Mn > Zn > Ni > Ba > Cr > Cu > As > Co. The degree of sediment contamination was evaluated using pollution load index (PLI), modified degree of contamination (mC d), geo-accumulation index (I geo), and enrichment factor (EF). All these indices compare present concentrations of metals to their background levels in crust and shale. In a specific area with high geological background like Mahshahr Bay, such a comparison may lead to erroneous conclusions. Due to the remarkable contribution of lithogenous fraction, as the natural component, to the bulk concentration of trace metals in the sediments of such an area, assessment of chemical hazard to the surrounding aquatic environment should not be carried out through traditional approaches. In the present study, anthropogenic portion of the metals was determined through one-step chemical sequential extraction and lithogenous portion substituted for the mean crust and shale levels in the new pollution index (RIAquatic). PLI, mC d, and I geo revealed overall low values, but EF, pollution index (I POLL), and newly developed pollution index were relatively high for all samples.

Sorbed metals fractionation and risk assessment of release in river sediment and particulate matter.

Fractionation of metals in natural sediment and suspended particulate matter (SPM) of Tadjan River is investigated. Competitive sorption, sorption capacities of sediment and SPM as well as fractionation of metal-loaded sediment and SPM are also examined. A risk assessment code (RAC) is applied to estimate the risk of heavy metals release into the environment during the sorption process. Results revealed that sediments and SPM containing more than 25 % of clay minerals and higher amounts of calcite have great capacity of metal sorption, particularly for Cu, Ni, and Mn. Assessing the risk of metals release prior to and following sorption tests indicates that RAC of metals would significantly increase from the level of no or low risk in natural sediment and SPM to high or very high risk after sorption. The Langmuir model reveals that the highest affinity for Cu, Mn, and Ni in sediment is the organic fraction. The classic isotherm models of Freundlich and Langmuir can fit the data from chemical extraction studies of adsorbed metals, indicating that although sorption was apparently a physical and chemical process in the river, isotherm models can be used to simulate the sorption and accumulation in different geochemical phases within the particulate matter.

Evaluating the metallic pollution of riverine water and sediments: a case study of Aras River.

Metallic pollution caused by elements Zn, Cu, Fe, Pb, Ni, Cd, and Hg in water and sediments of Aras River within a specific area in Ardabil province of Iran is considered. Water and sediment samples were collected seasonally and once respectively from the five selected stations. Regarding WHO published permissible values, only Ni concentration in spring and summer water samples has exceeded the acceptable limit up to four times greater than the limit. The concentration of metals Ni, Pb, and Fe in river water shows a direct relationship with river water discharge and the amount of precipitation. Enhanced soil erosion, bed load dissolution, and runoffs may play a key role in remarkable augmentation of metallic ions concentration. Furthermore, excessive use of pesticides which contain a variety of metallic ions (mainly Cu) in spring and summer may also result in an increase in the metals' concentration. The potential risk of Ni exposure to the water environment of the study area is assigned to juice, dairy products, edible oil, and sugar cane factories as well as soybean crop lands which are located within the sub-basin of Aras River in the study area. Regarding the sediment samples, the bioavailable metal concentrations indicate an ascending order from the first station towards the last one. In comparison with earth crust, sedimental and igneous rocks the reported metallic concentration values, except for Cd, lie within the low-risk status. Regarding Cd, the reported values in some stations (S2, S4, and S5) are up to ten times greater than that of shale which may be considered as a remarkable risk potential. The industrial and municipal wastewater generated by Parsabad moqan industrial complex and residential areas, in addition to the discharges of animal husbandry centers, may be addressed as the key factors in the sharp increase of metallic pollution potential in stations 4 and 5.

Evolution of a new surface water quality index for Karoon catchment in Iran.

Water quality standards are developed worldwide by national and international agencies for pollution control decision-making. Use-based water quality classification criteria and Water Quality Indices (WQIs) also play an important role in the assessment of the suitability of water resources for various applications. The present study proposes a better overall index for water quality in Iran and its application in Karoon River by exploring the behavior and limitations of conventional methods for quality evaluation. For this purpose, six variables were employed. Water quality determinants of the new index include Dissolved Oxygen, Total Dissolved Solids, Turbidity, Nitrate, Fecal coliform and pH. Besides, the mathematical equations applied to transform the actual concentration values into quality indices have been formulated. This study compares a new index called the Iranian Water Quality Index with other pre-existing indices such as NSFWQI, Oregon, CPCB WQI, MDOE WQI, Kaurish and Younos WQI, and Ahmed Said WQI. Results revealed that the overall quality of the surface water falls under the 'good' class. A case study of Karoon River is made to illustrate the application of this new index system.

Heavy metal pollution in water and sediments in the Kabini River, Karnataka, India.

The River Kabini in Karnataka, India carries natural and anthropogenic pollutants, mainly heavy metal concentrations of Cr, Cu, Fe, Mn, Ni, Pb and Zn which are released from industrial effluents, agricultural return flows and domestic sewage. Kabini, which is a tributary of the Cauvery, drains through the industrial area at Nanjangud, Karnataka, India. Heavy metals were determined in waters and sediment (2 µm) of Kabini River. In the present investigation, chemical partitioning studies was carried out to know the association of base metals with various sedimentary phases. The concentrations of heavy metals are higher in loosely bonded fraction than the other studied fractions. Furthermore, the degree of sediment contamination was assessed by geochemical index. It should be pointed out that Cu and Cr show the highest pollution intensity. Cluster analysis was used to know about the inter correlation amongst the studied metals. It is evident that higher concentrations of metals are found in the vicinity of industrial effluents. The concentrations of Cr followed by Zn and Ni are rather higher than the maximum background values in the Kabini River sediment. This is especially true at the influx of paper mill effluents into the River.

Development of a model to assess environmental performance, concerning HSE-MS principles.

The main objective of the present study was to develop a valid and appropriate model to evaluate companies' efficiency and environmental performance, concerning health, safety, and environmental management system principles. The proposed model overcomes the shortcomings of the previous models developed in this area. This model has been designed on the basis of a mathematical method known as Data Envelopment Analysis (DEA). In order to differentiate high-performing companies from weak ones, one of DEA nonradial models named as enhanced Russell graph efficiency measure has been applied. Since some of the environmental performance indicators cannot be controlled by companies' managers, it was necessary to develop the model in a way that it could be applied when discretionary and/or nondiscretionary factors were involved. The model, then, has been modified on a real case that comprised 12 oil and gas general contractors. The results showed the relative efficiency, inefficiency sources, and the rank of contractors.

Metal pollution assessment of sediment and water in the Shur River.

Intensified industrialization and human activities have resulted in the release of various contaminants into the environment. Among them, heavy metals are often present as a result of mining, milling and industrial manufacturing. In the present investigation, bulk concentrations Pb, Cd, Zn, Cu, Fe, Ca and Al in Shur River (Iran) bed sediments and water around the Sarcheshmeh copper mine were measured from several sample locations. In addition, partitioning was assessed to determine the proportions of metals in different forms. The degree of sediment contamination was evaluated using an Enrichment Factor (EF) and geo-accumulation index (I (geo)) and a newly developed pollution index (I (POLL)). Elevated metals in sediment and water were found to be correlated with areas of the river that were proximal to direct and indirect mining activities. Cadmium and Zn showed the highest pollution index. Cluster analysis was performed in order to assess heavy metal interactions between water and sediment. Chemical partitioning studies revealed that organic metallic bonds were not significantly present in the sediment of the Shur River.

Potential for reducing air pollution from oil refineries.

Islamic Republic of Iran has to invest 95 billion US$ for her new oil refineries to the year 2045. At present, the emission factors for CO(2), NO( x ) and SO(2) are 3.5, 4.2 and 119 times higher than British refineries, respectively. In order to have a sustainable development in Iranian oil refineries, the government has to set emission factors of European Community as her goal. At present CO(2) per Gross Domestic Production (GDP) in the country is about 2.7 kg CO(2) as 1995's USD value that should be reduced to 1.25 kg CO(2)/GDP in the year 2015. Total capital investment for such reduction is estimated at 346 million USD which is equal to 23 USD/ton of CO(2). It is evident that mitigation of funds set by Clean Development Mechanism (3 to 7 USD/tons of CO(2)) is well below the actual capital investment needs. Present survey shows that energy efficiency promotion potential in all nine Iranian oil refineries is about 165,677 MWh/year through utilization of more efficient pumps and compressors. Better management of boilers in all nine refineries will lead to a saving of 273 million m(3) of natural gas per year.

Flocculation of dissolved Pb, Cu, Zn and Mn during estuarine mixing of river water with the Caspian Sea.

This is the first study of the flocculation of dissolved Pb, Cu, Zn and Mn during mixing of river water with the largest lake in the world (the Caspian Sea). Flocculation of dissolved metals was investigated on a series of mixtures with salinities ranging from 3.2 to 7.4 per thousand. The flocculation rates {Cu (74%) > Pb (61%) > Mn (58%) > Zn (34%)} are indicative of the non-conservative behavior of metals during estuarine mixing. Statistical analysis indicates that the flocculation of Pb and Mn is governed by salinity. The flocculation rates reveal that the overall metal pollution loads may decline by about 57% during estuarine mixing.