Spatial Distribution and Contamination Assessment of Surface Heavy Metals off the Western Guangdong Province and Northeastern Hainan Island.

Qian Ge,Fengyou Chu,Zuo George Xue

doi:10.3390/ijerph15091897

Qian Ge, Fengyou Chu + Show 1 more

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https://doi.org/10.3390/ijerph15091897

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Abstract

Surface sediments collected from the continental shelf off the western Guangdong Province and northeastern Hainan Island are analyzed for selected heavy metals contents including Cd, Cr, Cu, Pb, Zn, and As to determine spatial distribution, potential ecological risks, and sources. In addition, some of the controlling factors of heavy metals distribution are also discussed. The average heavy metals contents decrease in the order of Zn > Cr > Pb > Cu > As > Cd. The averaged pollution degree, as shown by the index of geo-accumulation (Igeo), decreases in the order of Zn > Cu > Pb > Cr > Cd > As. Due to the barrier of islands, the Igeo values of Zn, Pb, Cr, Cu, and Cd near the Hailing and Xiachuan Islands are larger than those in other areas. Meanwhile, the Igeo value of As near the coastal area off the estuary of Wanquan River is clearly larger than that in other areas. Based on the results of potential ecological risk index, Cd, Cu, and As should be paid more attention for the contamination risk in future. The results of Pearson correlation analysis and principal component analysis indicate that Zn, Cr, Pb, Cu, and Cd are mainly from the Pearl River and surrounding small rivers, whereas As originates from the Hainan Island. The grain size is one of the main controlling factors for heavy metals distribution, and the anthropogenic activity also plays an important role.

Highlights

Over the past century, because of the rapid industrialization, estuaries and coastal areas have become the main sinks of the anthropogenic pollutants, which mainly consist of industrial and domestic sewage discharges, smelting, mining, and e-wastes recycling
The chemical and biological processes may allow heavy metals to be desorbed from surface sediments upon which they are released into the water column [2]
Where Ci is the mean content of the heavy metal i in the surface sediments; Cni is the baseline content of i; Cif is the contamination factor of i; Cdg is the degree of contamination; Tni is the toxic-response factor for i; Eni is the potential ecological risk factor for i; RI is the potential ecological risk index (PERI); and k is the species of the heavy metals

Summary

Introduction

Because of the rapid industrialization, estuaries and coastal areas have become the main sinks of the anthropogenic pollutants, which mainly consist of industrial and domestic sewage discharges, smelting, mining, and e-wastes recycling. Toxic contaminants such as persistent organic pollutants and metals bring increasing pressure to the coastal and estuarine ecosystems over the past decades due to the enhanced human activities [1]. The research on heavy metals in surface sediments provides significant insights into the metal pollution in aquatic systems. Public Health 2018, 15, 1897; doi:10.3390/ijerph15091897 www.mdpi.com/journal/ijerph

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