Status and Trends of Sediment Metal Pollution in Bohai Sea, China

Curr Pollution Rep (2015) 1:191–202 DOI 10.1007/s40726-015-0021-1 SEDIMENT AND OTHER POLLUTIONS (R DATTA AND P ZHANG, SECTION EDITORS) Status and Trends of Sediment Metal Pollution in Bohai Sea, China Yunfang Li 1 & Lei Guo 2 & Huan Feng 3 Published online: 7 November 2015 # Springer International Publishing AG 2015 Abstract This paper summarizes the advancement in the Bohai Sea sediment metal pollution studies in China. It includes spatial metal distributions, anthropogenic sources, and pollutant transport as well as factors affecting concentrations and potential ecological risk due to metal contamination. The results indicate that the pollution in the Bohai Sea is serious in coastal areas and, if no protection procedures are implemented, the situation can become worse with the economic development in the Bohai Sea rim. It is found that the metal distributions are quite different due to different pollutant sources in the coastal areas as well as along-shore current transport. The study shows that metal pollution is the most serious in the northern Liaodong Bay, followed by Bohai Bay and Laizhou Bay. The pollution in these three bays is much more serious than that in the central basin of the Bohai Sea. Hg, Cd, and Pb are the predominant pollutants commonly found in the Bohai Sea although the degree of the pollution varies with different regions of the Bohai Sea. Finally, the paper points out the current environmental concerns with the Bohai Sea sediment metal pollution. This article is part of the Topical Collection on Sediment and Other Pollutions * Yunfang Li 1 School of Science, Qingdao Technological University, Qingdao, Shandong 266033, People’s Republic of China 2 Guangdong Research Institute of water resources and Hydropower, Guangzhou, Guangdong 510610, People’s Republic of China 3 Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA Keywords China . Bohai Sea . Sediment . Heavy metal . Pollution Introduction The Bohai Sea in China is a semi-enclosed inland sea, including three bays (i.e., Liaodong Bay in the north, Bohai Bay in the west, and Laizhou Bay in the south) and a central basin and is connected with the Yellow Sea via the Bohai strait in the east (Fig. 1). It covers an area of 1.60×104 km2 with a population of about 70 million living in its coastal area. The average water depth in the Bohai Sea is 12.5 m with a maximum depth of 32 m [1, 2]. Both water exchange capacity and selfpurification ability are poor in the Bohai Sea. With the rapid social and economic development around the Bohai Sea rim, discharge of heavy metal pollutants into the Bohai Sea is increasing, which has rapidly worsened the Bohai Sea environmental quality [3]. Yellow River, Haihe River, Liaohe River, and Luanhe River also discharge into the Bohai Sea, carrying different materials from different land-based sources. It is reported that rivers and streams around the Bohai Sea are the main source input of heavy metals [4]. Before the early 1990s, there were very few sediment studies in the Bohai Sea. Investigations were limited to some estuaries and harbors [5, 6–8] until August–October 1998 when the National Oceanic Administration of China organized the second campaign of sediment pollution investigation in all China seas. The survey parameters included heavy metals (such as Hg, Cd, Pb, and Cs), total nitrogen and phosphorus, organic matters, sulfide, and organic pollutants (such as DDTs, PCBs, PAHs, and phthalate). This investigation provided a reference for study of sediment pollutant distributions, sources, transport, chemical speciation, and sedimentation in the Bohai Sea [9, 10]. The results of the survey showed that 192 Curr Pollution Rep (2015) 1:191–202 Fig. 1 Map of the Bohai Sea, China the pollution in The Bohai Sea was very serious and became worse. In December 1998, the Bohai Blue Sea Plan [11] was officially launched with a focus on the comprehensive control of some key areas, estuaries, and pollutants. Since then, studies have been paying more attention to sediment pollution in the Bohai Sea. Many studies have indicated that the interaction among heavy metals, biological macro-molecules group, and genetic materials may cause deformity, mutation, and cancer [12–14]. Most of the heavy metals in water body are scavenged by suspended particles falling down to the sediments. However, metals adsorbed on the sediments can be released into the overlying water due to contaminated sediment resuspension under certain environmental conditions, e.g., current and wave activities. Furthermore, toxic metals can threaten the ecological system directly and indirectly due to biological accumulation and magnification [15]. Therefore, heavy metal pollution research is very critical in order to protect the ecological system. In the past two decades, environmental scientists have conducted numerous heavy metal pollution studies in the Bohai Sea, including characterization of heavy metal sources, transport, and distributions, as well as the controlling factors by tracking the pollution history in this area [16, 17]. Characterization of Sediment Metal Concentrations and Spatial Distributions The 210 Pb radioisotope dating technique is useful to study the history of metal (e.g., Cu, Pb, Zn, and Cd) concentrations and distributions in the Bohai Sea sediments [6, 18–20] because the concentrations and spatial distributions of heavy metals in the sediments are important indicators of the aquatic environment [21, 22]. The results of some heavy metal concentrations in the Bohai Sea sediments from the selected studies are summarized in Table 1. As shown in Table 1, the heavy metal 10 5 N/A 1983–1985 N/A 2003 2003 2004 2009 2008 2008 1997 2003 2008 Bohai Sea Dagu & Beitang Estuary Dagu Estuary Bohai Bay Yongding Estuary south of Bohai Bohai Dagu Estuary Bohai Bay Bohai Bay Bohai Bay 90 N/A N/A 11 21 12 21.00 21 25 25 15 2012 2011 Coast of Bohai Bay 15 119 11 15 42 35 33 18 35 25 14 4 6 Bohai Bay 2008 2009 Dongjiang Harbor 2008 2008 Bohai intertidal zone Haihe estuary 2008 NW Bohai Bay South Bohai Bay 2008 N/A Bohai Bay 2008 N/A Southern sea Huludao City North Bohai Bay 2009.10 Jinzhou Bay North Bohai Bay 2005.05 2006.09 Liangshanhe River Jinzhou Bay 2005.05 2005.05 Wulihe River Cishanhe River 2 2008.07 ShuangtaiziheEstuary 22 12 N/A 2000.05 1985 Liaohe River Estuary 128 56 2000.03 2009 Liaodong Bay River mouths Liaodong Bay 2007 Liaodong Bay Sample size Liaoning coastal region Sampling date N/A N/A N/A 20.24±1.00 N/A N/A N/A 6.66 7.24 N/A N/A N/A 12.70 N/A N/A N/A N/A N/A N/A 8.50±1.90 N/A 12 N/A 397 N/A N/A N/A N/A N/A 13 N/A 8.3 9.11±3.15 As N/A N/A 0.05±0.03 N/A N/A N/A 0.12 0.57 26.34 N/A N/A 0.12 0.40±0.30 N/A N/A N/A N/A N/A N/A 0.028±0.028 N/A 0.169 N/A N/A 1.59 33.07 8.6 (...truncated)