Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction, Guangdong Ocean University, Zhanjiang 524088, China.
College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China.
Int J Environ Res Public Health. 2018 Mar 12;15(3):496. doi: 10.3390/ijerph15030496.
The Beibu Gulf (also named the Gulf of Tonkin), located in the northwest of the South China Sea, is representative of a bay suffering from turbulence and contamination associated with rapid industrialization and urbanization. In this study, we aim to provide the novel baseline levels of heavy metals for the research area. Concentrations of five heavy metals (i.e., Cu, Pb, Zn, Cd and Cr) were determined in surface sediments from 35 sites in the eastern Beibu Gulf. The heavy metal content varied from 6.72 to 25.95 mg/kg for Cu, 16.99 to 57.98 mg/kg for Pb, 73.15 to 112.25 mg/kg for Zn, 0.03 to 0.12 mg/kg for Cd, and 20.69 to 56.47 mg/kg for Cr, respectively. With respect to the Chinese sediment quality criteria, sediments in the eastern Beibu Gulf have not been significantly affected by coastal metal pollutions. The results deduced from the geoaccumulation index (I) showed that the study area has been slightly polluted by Pb, which might be caused by non-point sources. Relatively high concentrations of Cu, Pb and Cd were found around the coastal areas of Guangxi province, the Leizhou Peninsula and the northwest coast of Hainan Island, whereas the highest concentrations of Zn and Cr were found on the northwest coast of Hainan Island. Spatial distribution patterns of the heavy metals showed that bioavailable fractions of Pb were higher than in the residual fractions, while Cu and Cd concentrations in exchangeable and carbonate fractions were relatively higher than those in the bioavailable fractions. Hierarchical clustering analysis suggested that the sampling stations could be separated into three groups with different geographical distributions. Accompanying their similar spatial distribution in the study area, significant correlation coefficients among Cu, Cd and Pb were also found, indicating that these three metals might have had similar sources. Overall, the results indicated that the distribution of these heavy metals in the surface sediments collected from the Beibu Gulf was complex.
北部湾（又称东京湾）位于南海西北部，是一个因工业化和城市化快速发展而饱受动荡和污染的海湾。本研究旨在为该地区提供重金属的全新基准水平。在北部湾东部的 35 个采样点采集了表层沉积物，测定了其中 5 种重金属（Cu、Pb、Zn、Cd 和 Cr）的含量。重金属含量范围为 Cu 6.72-25.95mg/kg、Pb 16.99-57.98mg/kg、Zn 73.15-112.25mg/kg、Cd 0.03-0.12mg/kg 和 Cr 20.69-56.47mg/kg。就中国沉积物质量标准而言，北部湾东部的沉积物尚未受到明显的沿海金属污染。地积累指数（I）的结果表明，研究区受 Pb 的轻微污染，这可能是由非点源造成的。广西沿海地区、雷州半岛和海南岛西北部的表层沉积物中 Cu、Pb 和 Cd 的浓度相对较高，而海南岛西北部的 Zn 和 Cr 浓度最高。重金属的空间分布模式表明，Pb 的可利用部分高于残留部分，而可交换态和碳酸盐态的 Cu 和 Cd 浓度则高于可利用态。层次聚类分析表明，采样点可分为具有不同地理分布的三组。Cu、Cd 和 Pb 之间存在显著的相关性，表明这些三种金属可能具有相似的来源，这与它们在研究区域内相似的空间分布相一致。总的来说，这些结果表明，从北部湾采集的表层沉积物中重金属的分布较为复杂。
