Seyed Mostafa Haghshenas - Department of Chemical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Ebrahim Akhondi - Department of Chemical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran,
Hossein Sakhaeinia - epartment of Chemical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran,

Estuaries are marine embayment which is significantly diluted by fresh water. They are often preferred sites for shipping corridors and harbor construction. Because ofshallow depths, slow currents and long residence times for water, estuaries are prone to accumulation of pollutants. Industrial and domestic wastewater flows are two mainpollution sources that affect aquatic life; nutrients and organic contents are two important kinds of pollutants including several elements and compounds. Seasonalchanges, distance to the pollution sources, and components of the pollution streams, are the main parameters affecting pollution level and accumulation.The concentration ratio of two elements, nitrogen and phosphorus, indicate biomass productivity and nutrient removal in water treatment. Moreover, the ratio ofbiological oxygen demand (BOD) and chemical oxygen demand (COD) in waste water, represent the ability of water or wastewater to be purified biologically. For gaining a better understanding of these values and the ranges of change in different seas in the world, some studies are mentioned in the following. Many researchersand organizations deal with analysis and monitoring of nutrients and organic matters standard levels. Japan International Cooperation Agency (2014) determinedacceptable levels of nitrogen, phosphorus, and chemical oxygen demand (COD) in this area using standards which was issued by Department of Environment of Iran forambient water in the Persian Gulf and Oman Sea [1, 5]. In addition, Payandeh et al. (2015) developed a 2D hydrodynamic model for nitrogen and phosphorus capacityof Musa estuary [6]. In that study, some scenarios defined for eutrophic zones where remarkable presence of nutrients with high consumption of oxygen occur in different partsof the study area. Furthermore, Z.Wan et al. (2011), and Hee Jeong Choi et al. (2014) used a criteria for the balance of mass productivity and nutrient removal as the ratio ofnitrogen (N) to phosphorus (P) [2, 4]. According to their results, the values between 5-30 of that ratio are acceptable for sea water. In addition, Curtis Deutsch et al. (2012)introduced a standard level for N to P ratio around 15 for the oceans. For biological purification ability of water, Khaled Zaher et al. (2015) used the ratio of BOD to COD.For values more than 0.6, water can purified biologically, for the values between 0.3 to 0.6 the treatment process rate is slow, and if the ratio is less than 0.3 biologicalpurification do not proceed due to having some toxic components and non-biodegradable substances or water acclimated microorganisms may be required in itsstabilization [3]. In this study, we try to make a comprehensive data set of nutrients and organic compounds concentrations in different parts of an estuary, in order to determine effective parameters and evaluate the level of effectiveness on pollution distribution using visual analysis of these effective parameters.