ORIGINAL ARTICLE Metal pollution assessment and multivariate analysis in sediment of Anzali international wetland Ahmad Jamshidi-Zanjani • Mohsen Saeedi Received: 18 September 2012 / Accepted: 17 January 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract Anzali international wetland located in south- western Caspian Sea coast is one of the most important wetlands of Iran from environmental and ecological points of view. Metal concentrations (Cu, Zn, Cr, Fe, Mn, Pb, Ni, Cd, and Li) in 41 surface sediment samples from Anzali wetland were determined. Assessment of ecological risk of sediment samples as well as their degree of contamination revealed considerable ecological risk and moderate degree of contamination in eastern part of the study area. Multi- variate statistical analyses were used to identify metal content relationship and their origin. Higher enrichment factors of Cd, Pb, and Zn exhibited probable effects on human activities. Based on sediment quality guidelines (SQGs), moderate potential toxicity levels of sediment samples were identified. A new sediment quality index named sediment toxicity degree was developed based on the results of the multivariate statistical analysis to assess metal toxicity in surface sediments of aquatic systems. Results showed higher sensitivity of the new index (ST d ) to assess toxic effect of heavy metals on sediments and better capability to differentiate zones with different levels of risk within the study area than that of some other indices such as SQG-Q. Keywords Anzali wetland  Heavy metals  Ecological risk  Sediment quality guidelines  Index Introduction Aquatic ecosystems such as wetlands have been receiving significant amounts of anthropogenic contaminants such as heavy metals from industrial, agricultural, and urban dis- charge during past decades (Rivail Da Silva et al. 1996; Mucha et al. 2003; Caeiro et al. 2005). Most of heavy metals in aquatic systems are bound to sediments and suspended particulate matter (Calmano et al. 1993; Jain 2004; Rath et al. 2009; Saeedi et al. 2012). Regarding the role of sediment and suspended particulate matter (SPM) in transportation, retention and release of metals in aquatic environments, research into metal pollution of sediment and SPM has been going on (Salomons and Fo ¨rstner 1984; Dickinson et al. 1996; Sharma et al. 1999; Abrahim and Parker 2008; Dey and Jana 2010; Sarkar et al. 2011; Silva et al. 2011). Therefore, the proper assessment of metal pollution in aquatic sediments could be considered as a crucial issue to management of wetlands and other aquatic ecosystems. Environmental monitoring programs usually provide a large set of raw data that may be difficult to interpret due to inherent complex relationship between measured parameters (Shin and Lam 2001). Sediment quality indicators and indices are capable tools to integrate lots of raw data to comprehensible value and provide proper insight about monitoring results from the study area. Such useful information can help decision makers and local managers to determine proper decision to control or prevent pollution (Chapman 1990; Caeiro et al. 2005). Moreover, as for decision makers, special visuali- zation through Geographic Information System (GIS) facilitates decision making. In recent decades, many researchers developed different sediment quality indices to assess heavy metal pollution in aquatic ecosystems. Caeiro et al. (2005) classified such A. Jamshidi-Zanjani  M. Saeedi (&) Environmental Research Laboratory, Department of Water and Environmental Engineering, School of Civil Engineering, Iran University of Science and Technology, P.O. Box 16765-163, Narmak, Tehran, Iran e-mail: msaeedi@iust.ac.ir 123 Environ Earth Sci DOI 10.1007/s12665-013-2267-5