Investigation of Heavy Metal Pollution in The Sediments of Salehieh Wetland, Karaj

Abstract

With the entry of various effluents into aquatic ecosystems such as wetlands, pollutants containing heavy metals are deposited in the sediments. The aim of this study was to determine the level of heavy metal contamination of surface sediments in Salehieh Wetland, Karaj, Alborz Province. For this purpose, samples were taken from the sediments of six stations along with the wetland in May 2020. After preparation and chemical digestion of the samples, the concentration of heavy metals was determined by the flame atomic absorption instrument. Mean concentrations with standard deviation of lead, cadmium, nickel and chromium in wetland bed sediments were 14.11 ± 1.52, 1.14± 0.17, 19.87± 2.67 and 64.1± 7.03 µg/g, respectively and the accumulation pattern of heavy metals obtained was Cr> Ni> Pb> Cd. The highest concentration of metals was observed in station number 1. Comparison of metal concentrations with the values ​​of international standards showed that the mean concentrations of lead 14.11, cadmium 1.14 and chromium 64.1 µg/g were higher than LAL standards for lead (2), cadmium (0.04) and chromium (26 µg/g), respectively. The mean concentration of nickel was 19.87 µg/g, which is more than the HAL standard (15.9 µg/g). The amount of cadmium and chromium was higher than the ISQGS standards (0.7 and 43 µg/g for cadmium and chromium respectively). Therefore, increasing the concentration of these metals, especially cadmium and chromium, if not monitoring and controlling the discharge of effluent from the industrial town adjacent to the wetland, can lead to a threat to the health of ecosystems and the region.

Keywords

• effluent
• heavy metal
• surface sediments
• salehieh wetland