Heavy metals (Zn, Pb, Cd and Cr) in fish, water and sediments sampled form Southern Caspian Sea, Iran

Abstract

Environmental pollution is a worldwide problem, heavy metals belonging to the most important pollutants. The progress of industries has led to increased emission of pollutants into ecosystems. Southern Caspian Sea coast is one of the most important aquasystems at the eastern south of Caspian Sea, which receives effluents discharges from heavily industrialized and highly populated settlements. Metals tend to accumulate in water and move up through the food chain. So, studies to ascertain the level of heavy metals in environment and determine potentially hazardous levels for human are necessary. In this investigation, concentration of four heavy metals (zinc [Zn], chromium (Cr), cadmium, [Cd] and lead [Pb]) in three species of most-consumed fishes, water and sediments have been determined. Samples were collected from 10 stations along the Southern coast of Caspian Sea, in spring 2008. Heavy metal concentrations were measured by graphite furnace atomic absorption spectrometry. Then, the data were analyzed by means of one-way analysis of variance (ANOVA) statistical analysis. The results showed that the highest concentration of heavy metals in water and fish and sediment samples were related to Pb and Zn. The minimal and maximal concentrations of these metals in fishes, water and sediments were 53.67-2360.67 and 50.36-2497.25 for Pb and Zn, respectively. However, the observed heavy metals concentrations in fish, water and sediments were below the recommended limits. The investigation showed elevating levels of heavy metals in environment. Thus, a serious notification to industrial and manmade pollution, which can lead to ecosystem and food chain contamination, is necessary.