1 Department of Environmental Engineering, Faculty of Environment, University of Tehran, P.O. Box 14155-6135, Tehran, Iran

2 Department of Environmental Science, Graduate School of the Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran


Estuaries are well known for their potential in removing metal from fresh water to provide micro-nutrients to aquatic life. In the present investigation, we have tried to bring out the metal removal potential of estuaries during accidental spills. For this purpose artificial river water containing high concentration of Mn, Cu, Zn, Ni and Pb were mixed with sea water at different salinity regimes. Water samples were taken from a station on the main branch of Tajan River that flows in to the Caspian Sea. For this purpose, solutions with a concentration of 5 mg/L of each studied metal (Mn,Cu, Zn, Pb) were prepared in Tajan River water. The salinity regimes include 3, 6, 8, 10 and 11 ppt. It was noted that metal concentration decreased by increasing salinity. Metals were flocculated at different rates: Cu (88%) > Ni (86%) > Pb (84%) > Mn (74%).Thus, as average about 80% of total elemental content flocculates. Hence, it was concluded that a large amount of micro nutrients is carried by the river and flocculated in the estuary where the river water mixes with the sea water which may play a vital role in supplying nutrients to the aquatic animals. Cluster analyses have shown that Mn and Ni are governed by EC, pH and salinity. 

Graphical Abstract

Role of estuarine natural processes in removal of trace metals under emergency situations


  • Flocculants as a major source of micro nutrients in marine environment
  • The governing factor for flocculation of Ni and Mn are pH, EC and salinity
  • pH, EC and salinity govern flocculation of Ni and Mn


Main Subjects

Ahmed, M.K.; Islam, S.; Rahman, S.; Haque, M.R.; Islam, M.M., (2010). Heavy metals in water, Sediment. Res., 4 (2): 321-332 (12 pages).
Akoto, O.; Ephraim, J.H.; Darko, G., (2008). Heavy metals pollution in surface soils in the vicinity of abundant railway servicing workshop in Kumasi, Ghana. Int. J. Environ. Res., 2 (4): 359-364 (6 pages).
Basavarajappa, H.T.; Karbassi, A.R.; Monavari, S.M., (2011). Heavy metal pollution in water and sediments in the kabini river, Karnataka, India. Environ. Monit Assess., 182 (1-4):1-13 (13 pages).
Boyle, E.A.; Edmond, J.M.; Sholkovitz, E.R, (1977). The mechanism of iron removal in estuaries. Geochim. Cosmochim. Acta., 4 (1): 1313-1324 (12 pages).
Gerringa, L.J.A.; de Baar, H.J.W.; Nolthing, R.F.; Paucot, H., (2001). The influence of salinity on the solubility of Zn and Cd sulfides in the Scheldt estuary. J. Sea. Res. 46: 201-211 (11 pages).
Kalani,N.; Riazi, B.; Karbassi, A.R.; Moattar, F., (2014). Heavy metal concentrations in liza saliens muscle and human health risk estimates from fish consumption in Gomishan international wetland, Iran. J. Aquat. Anim. Fish., 5(17): 65-79 (15 pages).
Karbassi, A.R.; Amir, M.J.; Zoghi, M.; Sadat, M.; Tajziehch, S., (2015b). The development of strategies for wetland restoration by comprehensive assessment of ar hydrological, land use and climate changes. Int. J. Environ. Res., 9(2): 621-634 (14 pages).
Karbassi, A.R.; Tajziehchi, S.; Afshar, S., (2015a). An investigation on heavy metals in soils around oil field area. Global J. Environ. Sci. Manage., 4(1): 275-282  (8 pages).
Karbassi, A.R.; Monavari, S.M.; Nabi Bidhendi, G.H.R.; Nouri, J.; Nematpour, K., (2008b). Metal pollution assessment of sediment and water in the Shur River. Environ. Monit. Assess. 14(7):107-116 (10 pages).
Karbassi, A.R.; Nouri, J.; Mehrdadi, N.; Ayaz, G.O., (2008a). Flocculation of heavy metals during mixing of freshwater with Caspian Seawater. Environ. Geol., 5(3): 1811-1816  (6 pages).
Karbassi, A.R.; Nouri,J.; Nabi Bidhendi, G.H.R.; Ayaz, G.O, (2008c). Behavior of Cu, Zn, Pb, Ni and Mn during mixing of freshwater with the Caspian Seawater. Desalination, 22(9): 118–124 (7 pages).
Lee, J.N.; Mohamed, C.A.R., (2009). Trace metal contents in the Porites Corals of Peninsular Malaysia. Int. J. Environ. Res., 3 (1): 85-94 (10 pages).
Mensi, G.S.; Moukha, S.; Creppy, E.E.; Maaroufi, K., (2008). Metals accumulation in marine bivalves and seawater from the lagoon of Boughrara in Tunisia- North Africa. Int. J. Environ. Res., 2 (3): 279-284 (10 pages).
Meybeck, M., (1988). How to establish and use world budgets of riverine materials. In: Lerman A, Meybeck M (Eds.) Physical and chemical weathering in geochemical cycles. Kluwer Academic Publishers, 247-272 (88 pages).
Nasehi, F.; Hassani, A.H.; Monavari, S.M.; Karbassi, A.R.; Khorasani, N., (2013). Evaluating the metallic pollution of riverine water and sediments: a case study of Aras River. Environ. Monit. Assess., 18(5):197-203 (7 pages).
Nouri, J.; Fatemi, M.R.; Danekar, A.; Fahimi, F.G.; Karimi, D. (2009). Determination of environmentally sensitive zones along Persian Gulf coastlines through geographic information system. J. Food, Agri. Environ 7 (2), 718-725 (8 pages).
Nouri, J.; Karbassi, AR.; Mirkia,S., (2008). Environmental management of coastal regions in the Caspian Sea. Int. J. Environ. Sci. Tech., 5(1): 43-52 (10 pages).
Pejman, A.; Karbassi, A.; Nabi Bidhendi, G.; Mehrdadi, N.; Baghvand, A., (2011). Classification of surface water quality and assessment of dominant ions origin in Haraz River basin, Iran. Fresen. Environ. Bull., 20(3): 683-689 (7 pages).
Shamkhali Chenar, S.; Karbassi, A.R.; Zaker, N.H.; Ghazban, F., (2013). Electro flocculation of metals during estuarine mixing  in Caspian Sea. J. Coast. Res., 29(4): 847-854 (8 pages).
Troup, B.N.; Bricker, O.P., (1975). Processes affecting the transport of materials from continents to Oceans. In: Church TM (Ed.) Marine chemistry in the coastal environment. American Chemical Society, 18: 133–151(19 pages).
Vaezi, A.R.; Karbassi, A.R.; Fakhraee, M.;Valikhani Samani, A.R.; Heidari, M., (2014). Assessment of sources and concentration of metal contaminants in marine sediments of musa estuary of Persian Gulf. J. Environ. Stud., 40(2): 345-360 (16 pages).
Viswanathan, M.; Chakrapani, G.J., (2010). Laboratory experiments on river estuary geonanomaterials. Curr. Sci., 99(2): 213-221 (12 pages).
Wollast, R.; Peters, J.J., (1978). Biogeochemical properties of an estuarine system: The river Scheldt. In: Goldberg, E.D. (Ed.). Biochem. Estuary Sediment, 279-293 (15 pages).

Letters to Editor

GJESM Journal welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in GJESM should be sent to the editorial office of GJESM within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.
[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.
[3] Letters can be no more than 300 words in length.
[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.
[5] Anonymous letters will not be considered.
[6] Letter writers must include their city and state of residence or work.
[7] Letters will be edited for clarity and length.