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ABSTRACT
Surface sediment is often used to monitor contamination and assess ecological risk. We used multiple indices to assess sediment condition and ecotoxicity caused by heavy metal(loid)s (HMs) in Zarivar International Wetland (Zarivar) of Iran. We sampled the wetland at 12 stations using a Grab sampler, during both rainy and dry seasons. Using an atomic absorption spectroscopy and a mercury analyzer, we measured As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg. HMs temporal and spatial changes and general features of sediment were analyzed. Except Fe and Mn, all metals appear to have anthropogenic sources. We calculated toxic units (TUs) and contamination factors (CF) for all HMs. ∑TU calculations showed As> Cd> Cr and Ni to have the highest contributions in succession. CF indicated Cd, As, Pb and Cr, to have the highest concentrations, respectively. As (38.54 ± 10 mg/kg −1) and Cd (5.75 ± 2.01 mg/kg −1) exceeded their probable effect levels in 100% and 90% of the stations, respectively. Zarivar is classified as “very highly polluted” in rainy season (755.34 ± 289.97) and “considerably polluted” in dry season (489.98 ± 232.62) based on risk index values we calculated.
Acknowledgments
Our sincere gratitude goes to the University of Kurdistan and Tarbiat Modares University for the use of their facilities. Department of Environment of Marivan City helped in sampling, we thank them. We are indebted to Dr. Seyed Mahmoud Ghasempouri and Dr. Samereh Falahatkar for their helpful and valuable review of this paper and their constructive comments to improve this research. We also thank Mr. Hoshyar Gavilian for technical assistance.
Disclosure statement
The authors declare that they have no competing interests.