Assessment on Pollution by Heavy Metals and Arsenic Based on Surficial and Core Sediments in the Cam River Mouth, Haiphong Province, Vietnam

Abstract

The Cam River mouth (Haiphong Province) is one of the main river mouths of the Red River System, which is one of the most important water resources in Northern Vietnam. Over the past 50 years, the strong socio-economic development in the area has caused a considerable contamination with heavy metals (Co, Cr, Cu, Mn, Ni, Pb, and Zn) and arsenic. In this study, the vertical and horizontal distributions of heavy metals and arsenic in sediments from the Cam River mouth were investigated. In addition, the history, origin, and degree of contamination were assessed. Normalized (with respect to Al) heavy metal and arsenic concentrations in sediment cores and absolute dates obtained from the ¹³⁷Cs analysis were used to reconstruct the pollution history of the river mouth. As, Cu, Mn, Pb, and Zn concentrations increase rapidly by approximately two times or more from 1954 to 1975, and then remain nearly unchanged from 1975 until 2008, whereas Co, Cr, and Ni concentrations slightly increase from 1954 until 2008. In addition, background values for heavy metals and arsenic have also been determined with regard to the period before 1954. In the study area, Co, Cr, Cu, Ni, Mn, and Zn are evaluated as minorly enriched, whereas As and Pb are classified as moderately enriched. Generally, the anthropogenic activities in the Haiphong harbor and industrial zone locally contribute to the contamination by heavy metals and arsenic in the Cam River mouth.

Keywords:

• Heavy metals and arsenic
• sediment
• Al-normalization
• spatial distribution
• historical trend
• contamination

Acknowledgment

We would like to thank Prof. Noel Vandenberghe, Mr. Rieko Adriaens, and Ms. Ria Brepoels from the Division of Applied Geology & Mineralogy (Department Earth & Environmental Sciences, KU Leuven) for the grain-size and XRD mineralogical analyses. This research is supported by the Belgian Technical Cooperation (BTC) through a Ph.D. scholarship, and the International Foundation for Science, Stockholm, Sweden, and the Organization for the Prohibition of Chemical Weapons, The Hague, The Netherlands, through a grant to Ho Huu Hieu.