Baseline Assessment of nutrient and heavy metal contamination in the seawater and sediment of Yalujiang Estuary Hongjun Li a , Lin Lin b , Sheng Ye a , Hongbo Li a , Jingfeng Fan a, ⁎ a Marine Ecology Department, National Marine Environmental Monitoring Center, Dalian 116023, China b Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China abstract article info Article history: Received 9 November 2016 Received in revised form 21 January 2017 Accepted 27 January 2017 Available online xxxx Yalujiang River is a famous border river between China and North Korea. In this study, 22 sample sites (seawater and sediments) were investigated to determine the concentrations of nutrients (dissolved inorganic nitrogen and soluble reactive phosphorus) and trace elements (Hg, As, Pb, Cu, Cd, Cr, and Zn) during the flood season (August). Generally, the concentration of nutrients were higher in the entrance of the estuary than that in the downstream region and the trophic index ranged from moderate to high production, indicating a potential eutro- phication risk. With the exception of Cd, the mean concentrations of most metals attained the first level of sea- water quality. Sediment pollution assessment was undertaken using contamination factor (CF) and geoaccumulation index (I geo ). The CF values of the seven trace elements were in the following order: Cd N Hg N Pb N As N Cu N Zn N Cr. Both CF and I geo values indicated the elevated Cd and Hg concentrations in the region. Cluster analysis indicated that the sources of Cu, Cd, Cr, and Zn were mainly derived from copper mine and coastal industrial effluents, whereas Pb, Hg, and As were mainly from vehicle emissions and oil com- bustion. This study could provide a basis for the sustainable management of the marine ecosystem in this region. © 2017 Elsevier Ltd. All rights reserved. Keywords: Yalujiang Estuary Nutrient Heavy metal Seawater Sediment As the confluence area of land runoff and seawater, an estuary trans- ports terrestrial matter to the sea. With the rapid economic develop- ment of coastal, estuaries receive substantial amounts of anthropogenic inputs from both point and non-point upstream sources of pollution from industrialization and urbanization activities, and eco- logical problems have become severe as a result. Consequently, the es- tuarine ecosystem is one of the most heavily used and globally threatened natural systems (Lotze et al., 2006; Liu et al., 2016a, b). Estu- aries often act as nurseries to numerous forms of aquatic life; thus, estu- aries are important to aquaculture and fisheries. The intertidal areas of estuaries attract a variety of birds, and these zones are often globally im- portant sites for migratory species. Thus, assessing the contamination in estuaries and its biological influence is crucial. Heavy metal pollution in the marine environment has received glob- al attention because of the ubiquity, difficult degradation, and easy ac- cumulation of heavy metal pollutants. In estuarine and coastal regions, sediments have been regarded as both carriers and sinks of various con- taminants originating from industrial and agricultural processes (Gan et al., 2013; Yang et al., 2012), As a result, sediment contamination is rec- ognized as a major source of marine ecosystem health stress (Chapman and Wang, 2001). Sediments release more heavy metals into the seawa- ter when local environmental conditions (e.g., salinity, pH, and redox potential) change (Valdés et al., 2005; Hill et al., 2013). Consequently, the transfer of metals from sediment to water columns and the subse- quent bioaccumulation along the food chain are detrimental to the ma- rine environment and public health (Pan and Wang, 2012; Zhang et al., 2012). Yalujiang Estuary is located in the Northern Yellow Sea, Liaoning Province, China. This estuary is known for being the boundary river be- tween China and North Korea. Yalujiang River originates from Tianchi Lake in Changbaishan Mountain and flows a distance of approximately 790 km from northeast to southwest through Jilin Province and Liao- ning Province. This river supplies the most important sources of drink- ing water for the surrounding cities. With the rapid urbanization and industrialization in recent years, Yalujiang River suffers from industrial, agricultural, and domestic pollution, which results in potential ecologi- cal risks (Gao et al., 2008). Some industrial enterprises (e.g., automobile, papermaking, printing, and textile) are concentrated in the cities of Dandong and Donggang. Substantial amounts of industrial effluents have been taken to the sea by the river, particularly during the flood sea- son. The average water discharge is 3.02 × 10 8 m 3 /a, of which 70%–80% occurs during the flood season. However, only few pollution investiga- tions have been conducted in Yalujiang Estuary (Wu et al., 2003; Gao et al., 2008; Cheng et al., 2011); as a result, the understanding of the in- fluence of human activities on the marine ecosystem in this region is limited. In the current study, the spatial distribution of heavy metals during the flood season in Yalujiang Estuary is determined, and the Marine Pollution Bulletin xxx (2017) xxx–xxx ⁎ Corresponding author. E-mail address: jffan@nmemc.org.cn (J. Fan). MPB-08369; No of Pages 8 http://dx.doi.org/10.1016/j.marpolbul.2017.01.069 0025-326X/© 2017 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Please cite this article as: Li, H., et al., Assessment of nutrient and heavy metal contamination in the seawater and sediment of Yalujiang Estuary, Marine Pollution Bulletin (2017), http://dx.doi.org/10.1016/j.marpolbul.2017.01.069