Geochemical normalization and assessment of heavy metals (Cu, Pb, Zn, and Ni) in sediments from the Huaihe River, Anhui, China

• Concentrations of heavy metals were determined in sediments from the Huaihe River (Anhui Province).
• The natural metal variability in sediments was normalized by the concentration of Al.
• Heavy metal pollution sources were analyzed using principle component analysis.
• The modified geo-accumulation index was utilized to assess heavy metal contamination.
• Possible control over Zn and Pb by coal fields was found.

Fifty-four surface sediment samples were collected in July 2013, from the Huaihe River (Anhui Province) in eastern China, which flows through Shouxian, Fengtai and Huaiyuan counties and Huainan city. The total Cu, Pb, Zn, Ni, Al and Fe concentrations were determined using an inductively coupled plasma-optical emission spectrometer (ICP-OES). Heavy metal geochemical normalization with Al was utilized to minimize the natural metal variability in the sediments before the metal enrichment was evaluated. Moreover, the predicted and maximum Cu, Pb, Zn and Ni natural concentrations were obtained using a linear regression model. A modified geo-accumulation index, where the regional background value was substituted with the predicted natural metal concentrations, was used to assess heavy metal contamination. Zn exhibited the most substantial contamination, followed by Pb, Cu, and Ni. Furthermore, the high Pb concentrations are likely attributed to exhaust discharged by automobile or ships, and coal combustion flue gas deposition, the latter of which may also be the source of Zn. Copper and Ni originate mainly from natural sources, with only a small anthropogenic contribution.