Study of Heavy Metal Concentrations in Water and Fish Samples from Dam Lake (Case Study: Hamadan Province, Kalan Malayer Dam)

Heavy metals are a major environmental problem and have become a global problem due to their high toxicity and their ability to accumulate in the body of living organisms. The aim of this study was to investigate the concentrations of heavy metals such as arsenic (As), cadmium (Cd), chromium (Gago-Ferrero et al.), copper (Cu), silver (Hg), manganese (Mn), nickel (Ni) and zinc (Zn) in samples of water and fish from the Malayer Dam in Hamadan Province, Iran. Samples of water and fish were collected in five steps (in May, June, September, October, February) from 19 locations in Kalan dam route of Malayer, in Hamedan, Iran. Water and fish species including Vimba vimba and Cyprinus carpio species were transferred to the laboratory. Fish samples were digested by 4 ml HNO3 and 1 ml HClO4. The amounts of heavy metals in water and fish were determined using ICP-AES and Duncan's test (0.05) was used for data analysis with SAS software. Results showed that the mean concentrations of the studied heavy metals were lower than the WHO, FAO, and USEPA guidelines for drinking water. The mean concentrations of Zn and Cr were significantly higher than other heavy metals in water samples. The results also showed that the highest concentrations of heavy metals (except Zn) were observed in spring than other seasons. The mean concentration of the heavy metals for Cyprinus carpio followed the sequence Cr≥ Zn>Ni>Cu>Cd>Hg>As>Mn in first sampling. There were significant correlations between all heavy metals’ accumulation in the Cyprinus carpio fish with heavy metals concentration in water samples. The results showed that the concentration of heavy metals in fish samples was correlated with the concentration of heavy metals in water samples and the accumulation of heavy metals in fish increased with increasing concentrations of heavy metals in water samples. The concentrations of heavy metals studied in fish are lower than those limits in the WHO and FAO guidelines and will not cause any harm in human consumption.