ABSTRACT:The nearshore marine environment of the Caspian sea is a major repository for toxic metals originating from various sources. Since the persistent toxic metals pose serious health risks this research concentrated on investigating the concentrations and spatial distribution of metals in the nearshore sediments along the Iranian coast of the Caspian sea. Fourteen sampling sites were selected along the coast and approximately 400 g of surficial sediments were obtained. Samples were sieved and three grain size fractions from each sample plus fourteen bulk samples were selected for the analysis of metals. Laboratory analysis of the samples utilized the Cold Acetic protocol, followed by Inductively coupled plasma optical emission spectroscopy. The statistical techniques were used to analyze all obtained data. Linear regression analysis demonstrated that grain size of the sediments was not a major factor controlling the concentrations and spatial distributions of heavy metals. Box and Whisker plots emphasized that metal concentrations were not homogeneously distributed. Discriminant analysis was also proved to be useful in identifying geographic areas where heavy metal concentrations occur along the coast.

Concentrations of heavy metals (Al, Cd, Cu, Pb, Ni, Zn) were analyzed from nearshore surficial sediments collected from the alongshore direction of the Iranian coast of the Caspian Sea. The granulometric composition of fourteen samples was determined. Three grain-size fractions (0.355, 0.212 and 0.075 mm) from each sample, plus fourteen bulk samples, were examined for the presence of heavy metals. Laboratory analysis utilized a cold acetic acid extraction procedure, followed by inductively coupled plasma optical emission spectroscopy. Box and Whisker plots demonstrated that metal concentrations were not homogeneously distributed, and there were large spatial variations in the median concentrations of heavy metals at each sample site. The statistical technique of discriminant analysis revealed that the six heavy metals had distinct and statistically significant concentrations at various locations along the coast. Elevated concentration levels reflected metal loadings from anthropogenic sources located in the vicinity of sampled sites.